Climate change linked to functional homogenization of a subtropical estuarine system.

Climate change causes marine species to shift and expand their distributions, often leading to changes in species diversity. While increased biodiversity is often assumed to confer positive benefits on ecosystem functioning, many examples have shown that the relationship is specific to the ecosystem and function studied and is often driven by functional composition and diversity. In the northwestern Gulf of Mexico, tropical species expansion was shown to have increased estuarine fish and invertebrate diversity; however, it is not yet known how those increases have affected functional diversity. To address this knowledge gap, two metrics of functional diversity, functional richness (FRic) and functional dispersion (FDis), were estimated in each year for a 38-year study period, for each of the eight major bays along the Texas coast. Then, the community-weighted mean (CWM) trait values for each of the functional traits are calculated to assess how functional composition has changed through time. Finally, principal component analysis (PCA) was used to identify species contributing most to changing functional diversity. We found significant increases in log-functional richness in both spring and fall, and significant decreases in functional dispersion in spring, suggesting that although new functional types are entering the bays, assemblages are becoming more dominated by similar functional types. Community-weighted trait means showed significant increases in the relative abundance of traits associated with large, long-lived, higher trophic level species, suggesting an increase in periodic and equilibrium life-history strategists within the bays. PCA identified mainly native sciaenid species as contributing most to functional diversity trends although several tropical species also show increasing trends through time. We conclude that the climate-driven species expansion in the northwestern Gulf of Mexico led to a decrease in functional dispersion due to increasing relative abundance of species with similar life-history characteristics, and thus the communities have become more functionally homogeneous.

Predictive factors of non-treatment and non-persistence to osteoporosis medication after fragility hip fractures at 3 years after discharge: a multicentre, prospective cohort study in the northern Kyushu district of Japan.

We examined osteoporosis medication use and factors affecting persistence in 497 patients with fragility hip fractures. Only 25.5% of patients received continuous medication for 3 years, and 44.1% of patients received no treatment. Low Barthel index at discharge was a risk factor for both non-treatment and non-persistence to osteoporosis medication. PURPOSE: Fragility hip fractures (FHF) caused by osteoporosis decrease the quality of life and worsen life expectancy. Use of osteoporosis medication may be an efficient method in the prevention of secondary FHF. However, previous studies have reported low rates of osteoporosis medication and persistence after FHF. This study aimed to evaluate osteoporosis medication use and factors affecting persistence in patients with FHF in the northern Kyushu area of Japan. METHODS: A total of 497 FHF patients aged ≥ 60 years with a 3-year follow-up were included. We prospectively collected data from questionnaires sent every 6 months regarding compliance with osteoporosis medication. We compared baseline characteristics among three groups: no treatment (NT), no persistence (NP), and persistence (P), and conducted multivariable regression models to determine covariates associated with non-treatment (NT vs. NP/P) and non-persistence (NP vs. P). RESULTS: There were 219 (44.1%), 151 (30.4%), and 127 (25.5%) patients in the NT, NP, and P groups, respectively. Factors associated with non-treatment were male sex, chronic kidney disease, no previous osteoporosis treatment, and low Barthel index (BI) at discharge. The only factor associated with non-persistence was a low BI at discharge. Factors associated with a low BI at discharge were male sex, older age, trochanteric fracture, and surgical delay. CONCLUSION: Low BI at discharge is a risk factor for both non-treatment and non-persistence to osteoporosis medication. Therefore, appropriate interventions to improve BI may result in persistence to osteoporosis medication.

The adverse effects of the phenylpyrazole, fipronil, on juvenile white shrimp Litopenaeus setiferus.

Chemical pesticides are commonly used world-wide, and they can flow into estuaries and affect non-targeted organisms. We evaluated the effects of six concentrations of the phenylpyrazole, fipronil (0.0, 0.005, 0.01, 0.1, 1.0, and 3.0 µg/L), which are environmentally relevant, on white shrimp Litopenaeus setiferus (initially averaging 0.80 ± 0.08 g/shrimp). Compared with the control, survivorship of shrimp over 45 days declined significantly at the higher concentration treatments. Growth was affected at all concentrations, and the percent weight gain decreased significantly. Inter-molt intervals were longer in all treatments. Changes in swimming and feeding behavior of shrimp were observed under all treatments, and change in body color was observed at higher concentration treatments. Lipid content in shrimp decreased significantly while ash content increased with fipronil concentration. Fipronil adversely affected white shrimp under the concentrations observed in the environment and monitoring of fipronil use is needed in coastal areas.

Assessment of a small-scale fishery: Lane Snapper (Lutjanus synagris) using a length metric method.

Small-scale fisheries are hard to assess because of the limited availability of data. Therefore, a method requiring easy-to-obtain catch-data is important for the assessment and management of small-scale fisheries. The objective of this study was to assess the effect of fishing gear selectivity on a length-based metric method proposed by Froese by estimating three indicators using catch-data from Lane Snapper (Lutjanus synagris) collected in Honduras. These indicators are (1) the percentage of mature individuals in the catch, (2) the percentage of fish within the range of estimated optimal lengths to be captured, and (3) the percentage of fish larger than the optimal length. These indicators determine the level of overfishing. The indicators were estimated separately for catch-data corresponding to gill nets, and each indicator was estimated with and without selectivity correction. Selectivity and mesh sizes of the fishing gear had a major impact on the estimation of indicators 1 and 2. As for indicator 3, it consistently showed a high level of exploitation. The three estimated indicators suggested that the Lane Snapper fishery in Honduras is experiencing overfishing. Overall, the method appears to be promising for the assessment of small-scale fisheries, but it should be used cautiously.

Changes in taxonomic and functional diversity of fish communities after catastrophic habitat alteration caused by construction of Three Gorges Dam.

Habitat alterations that result from anthropogenic disturbance impact both the abiotic and biotic conditions of ecosystems, causing changes in biodiversity in many parts of the world. Recently, the use of functional diversity has been suggested as an approach to better evaluate the effects of such disturbance on particular communities. Here, we investigated the temporal changes in species and functional diversities of fish communities in the downstream area of the Three Gorges Dam (TGD) before, during, and after impoundment. We found two regime shifts in the fish community in 2004 and 2013 following impoundment. Although taxonomic diversity declined sharply at the first regime shift, it increased at the second shift. On the other hand, functional diversity declined throughout the same period, indicating the loss of functional diversity despite increased species diversity. Our analysis also showed that the fish communities shifted from under-dispersion to over-dispersion due to both a decrease in the relative abundance of migratory fish and an increase in the number of fish adapted to the new hydrologic conditions. Our results indicated that the impacts of dams on downstream fish communities may change over time. Interactions between species may become more important when the environment is stable.

Surgery-related predictable risk factors influencing postoperative clinical outcomes for thoracic myelopathy caused by ossification of the posterior longitudinal ligament: a multicenter retrospective study.

OBJECTIVE: Compression of the spinal cord by thoracic ossification of the posterior longitudinal ligament (T-OPLL) often causes severe thoracic myelopathy. Although surgery is the most effective treatment for T-OPLL, problems associated with surgical intervention require resolution because surgical outcomes are not always favorable, and a small number of patients experience deterioration of their neurological status after surgery. The aim of the present study was to examine the surgery-related risk factors contributing to poor clinical outcomes for myelopathy caused by T-OPLL. METHODS: Data were extracted from the records of 55 patients with thoracic myelopathy due to T-OPLL at institutions in the Fukuoka Spine Group. The mean follow-up period was 5.3 years. Surgical outcomes were assessed using the Japanese Orthopaedic Association (JOA) scale. To investigate the definitive factors associated with surgical outcomes, univariate and multivariate regression analyses were performed with several patient-related and surgery-related factors, including preoperative comorbidities, radiological findings, JOA score, surgical methods, surgical outcomes, and complications. RESULTS: Neurological status improved in 33 patients (60.0%) and deteriorated in 10 patients (18.2%) after surgery. The use of instrumentation was significantly associated with an improved outcome. In the comparison of surgical approaches, posterior decompression and fusion resulted in a significantly higher neurological recovery rate than did anterior decompression via a posterior approach and fusion or decompression alone. It was also found that postoperative neurological status was significantly poorer when there were fewer instrumented spinal levels than decompression levels. CSF leakage was a predictable risk factor for deterioration following surgery. CONCLUSIONS: It is important to identify preventable risk factors for poor surgical outcomes for T-OPLL. The findings of the present study suggest that intraoperative CSF leakage and a lower number of instrumented spinal fusion levels than decompression levels were exacerbating factors for the neurological improvement in T-OPLL surgery.

Climate-related factors cause changes in the diversity of fish and invertebrates in subtropical coast of the Gulf of Mexico.

Climate change impacts physical and chemical properties of the oceans, and these changes affect the ecology of marine organisms. One important ecological consequence of climate change is the distribution shift of marine species toward higher latitudes. Here, the prevalence of nearly 150 species of fish and invertebrates were investigated to find changes in their distributions over 35 years along a subtropical coast within the Gulf of Mexico. Our results show that 90 species increased their occupancy probability, while 33 decreased (remaining species neither increase or decrease), and the ranges of many species expanded. Using rarefaction analysis, which allows for the estimation of species diversity, we show that species diversity has increased across the coast of Texas. Climate-mediated environmental variables are related to the changes in the occupancy probability, suggesting the expansion of tropical species into the region is increasing diversity.

Effects of insecticides, fipronil and imidacloprid, on the growth, survival, and behavior of brown shrimp Farfantepenaeus aztecus.

Increased use of pesticide is causing detrimental effects on non-target species worldwide. In this study, we examined the lethal and sub-lethal effects of fipronil and imidacloprid, two commonly used insecticides, on juvenile brown shrimp (Farfantepenaeus aztecus), one of the most commercially and ecologically important species in the United States. The effects of six concentrations of fipronil (0.0, 0.005, 0.01, 0.1, 1.0, and 3.0 µg/L) and six concentrations of imidacloprid (0.0, 0.5, 1.0, 15.0, 34.5, 320.0 µg/L) were tested in a laboratory. We examined five different endpoints: growth, moulting interval, survivorship, behavioral change, and body color change. Growth of shrimp was reduced significantly under higher concentrations of both insecticides. Under fipronil exposure, shrimp in control showed the shortest inter-moult interval (7.57 ± 2.17 day) compared with other treatments; similarly, in the imidacloprid experiment, moulting increased from 8.43 ± 2.52 day in control to 11.95 ± 4.9 day in 0.5 µg/L treatment. Higher concentrations of fipronil (1.0 and 3.0 µg/L) showed a 0.0% survival rate compared with 100% survival in the control and 0.005 µg/L treatment. Under imidacloprid, survivorship decreased from 100% in the control to 33.33% in the 320.0 µg/L treatment. The 96-h LC50 of fipronil was 0.12 µg/L, which makes brown shrimp one of the most sensitive invertebrates to the pesticide. Changes in behavior and body color were observed under both insecticides after different durations of exposures depending on concentrations. We conclude that, at the corresponding EPA benchmark concentrations, fipronil had more lethal effects than imidacloprid, and imidacloprid had more sub-lethal effects than fipronil. Both effects are of serious concern, and we suggest monitoring is necessary in estuaries.

Predictive factors of mortality of patients with fragility hip fractures at 1 year after discharge: A multicenter, retrospective study in the northern Kyushu district of Japan.

PURPOSE: Fragility hip fractures (FHFs) are associated with a high risk of mortality, but the relative contribution of various factors remains controversial. This study aimed to evaluate predictive factors of mortality at 1 year after discharge in Japan. METHODS: A total of 497 patients aged 60 years or older who sustained FHFs during follow-up were included in this study. Expected variables were finally assessed using multivariable Cox proportional hazards models. RESULTS: The 1-year mortality rate was 9.1% (95% confidence interval: 6.8-12.0%, n = 45). Log-rank test revealed that previous fractures (p = 0.003), Barthel index (BI) at discharge (p = 0.011), and place-to-discharge (p = 0.004) were significantly associated with mortality for male patients. Meanwhile, body mass index (BMI; p = 0.023), total Charlson comorbidity index (TCCI; p = 0.005), smoking (p = 0.007), length of hospital stay (LOS; p = 0.009), and BI (p = 0.004) were the counterparts for females. By multivariate analyses, previous vertebral fractures (hazard ratio (HR) 3.33; p = 0.044), and BI <30 (HR 5.42, p = 0.013) were the predictive variables of mortality for male patients. BMI <18.5 kg/m2 (HR 2.70, p = 0.023), TCCI ≥5 (HR 2.61, p = 0.032), smoking history (HR 3.59, p = 0.018), LOS <14 days (HR 13.9; p = 0.007), and BI <30 (HR 2.76; p = 0.049) were the counterparts for females. CONCLUSIONS: Previous vertebral fractures and BI <30 were the predictive variables of mortality for male patients, and BMI <18.5 kg/m2, TCCI ≥5, smoking history, LOS <14 days, and BI <30 were those for females. Decreased BI is one of the independent and preventable risk factors. A comprehensive therapeutic approach should be considered to prevent deterioration of activities of daily living and a higher risk of mortality.

Minimum viable population size and population growth rate of freshwater fishes and their relationships with life history traits.

The minimum viable population (MVP) size has been compared for a wide range of organisms in conservation biology, but a limited number of studies investigated it for freshwater fishes, which exhibit diverse life history strategies. In this study, the MVP size and population growth rate of 36 fish species in the Yangtze River were estimated and compared with their life-history traits. The results indicated that the MVP size ranged from 42 to 320 individuals, and instantaneous per-capita population growth rate ranged from 0.009 to 0.188 per year. MVP size and population growth rate were significantly associated with three life history traits: the age at maturity, generation time, and fecundity. Long-lived species with delayed maturation, long generation time, and high fecundity had a greater MVP size and a lower population growth rate than short-lived species. Therefore, our results emphasize a need for prioritizing our conservation effort more on long-lived species.

Regime shift in fish assemblage structure in the Yangtze River following construction of the Three Gorges Dam.

Dams have well-documented ecological impacts on downstream river segments; however, long-term impacts of river impoundment have rarely been investigated in upstream reaches. Using data from long-term standardized surveys, we analyzed temporal changes in fish assemblages in the Yangtze River upstream of the Three Gorges Dam (TGD) before, during and after its construction. Our analysis indicated fish assemblage regime shifts in the two closer reaches in 2008, in accordance with the filling to 172.5 m in 2008; and in the other reach, farthest from the TGD, in 2011, indicating timing of the effects being related to distance. These shifts were evident in relative abundance of native fish species rather than non-native species and have altered community structures and functional groups. Relative abundance of the lotic guilds declined in the two closer reaches, but increased in the farthest. Invertivores declined, but piscivores and opportunistic life-history strategists increased in all reaches. We conclude that construction of TGD had led to significant changes in species distributions influenced by species functional traits. Our findings emphasize the need for long-term monitoring of fish assemblages before and after dam construction in order to understand ecological responses to hydrological changes for effective resource management in regulated rivers.

Micellar Effects on the Hydrolysis Reaction of an Anionic Surfactant in Aqueous Solution.

The hydrolysis mechanisms of 2-sulfoalkanoic acid methyl ester salts (methyl ester sulfonate, MES) were studied. Under acidic, neutral, and alkaline conditions, the hydrolysis rates of MES were strongly affected by the state of aggregation and the hydrolysis rate changed at the critical micelle concentration (CMC). Under acidic conditions, the hydrolysis rates of MES were enhanced by micellar formation and correlated quantitatively with the amount of protons bound on the micellar surfaces being measured by the electric conductivity along with fluorescence and hydrogen-ion electrode measurements. MES having longer acyl chain lengths showed higher hydrolysis rates above the CMC because of the many bound protons and the higher degree of counterion binding to the micelle, ß. The rates were affected by the type of counterion and followed the order of sodium > potassium > calcium salts of MES. In alkaline conditions, the rates of MES hydrolysis were suppressed to lower values by micelle formation and MES with longer acyl chain lengths showed lower rates above the CMC. Additionally, the hydrolysis rates of MES under neutral conditions were suppressed to a very low value by micelle formation. These mechanisms of inhibitory effect of hydrolysis by the aggregation should be dominated by the electrical repulsive interactions between hydroxyl anions and anionic micellar surfaces, as well as by interference with the penetration of the hydroxyl anion to the ester group in the micelles for alkaline hydrolysis and by interference from water molecules for neutral hydrolysis.

A coupled recreational anglers' decision and fish population dynamics model.

The effective management of fish populations requires understanding of both the biology of the species being managed and the behavior of the humans who harvest those species. For many marine fisheries, recreational harvests represent a significant portion of the total fishing mortality. For such fisheries, therefore, a model that captures the dynamics of angler choices and the fish population would be a valuable tool for fisheries management. In this study, we provide such a model, focusing on red drum and spotted seatrout, which are the two of the main recreational fishing targets in the Gulf of Mexico. The biological models are in the form of vector autoregressive models. The anglers' decision model takes the discrete choice approach, in which anglers first decide whether to go fishing and then determine the location to fish based on the distance and expected catch of two species of fish if they decide to go fishing. The coupled model predicts that, under the level of fluctuation in the abundance of the two species experienced in the past 35 years, the number of trips that might be taken by anglers fluctuates moderately. This fluctuation is magnified as the cost of travel decreases because the anglers can travel long distance to seek better fishing conditions. On the other hand, as the cost of travel increases, their preference to fish in nearby areas increases regardless of the expected catch in other locations and variation in the trips taken declines. The model demonstrates the importance of incorporating anglers' decision processes in understanding the changes in a fishing effort level. Although the model in this study still has a room for further improvement, it can be used for more effective management of fish and potentially other populations.

Lethal and sub-lethal effects of the insecticide fipronil on juvenile brown shrimp Farfantepenaeus aztecus.

Chemical pesticides are widely used around the world, but at the same time, they may cause direct or indirect risks to many non-target organisms. Recent increased use of insecticides in coastal areas, for example to control invasive tawny crazy ants, raises concern that insecticides may affect ecologically and/or commercially important species found in estuaries. Here, we investigated the lethal and sub-lethal effects of fipronil on juvenile brown shrimp Farfantepenaeus aztecus over 29 days at five different nominal concentrations (0.1, 1.0, 3.0, 6.4, and 10.0 µg/L) in a laboratory experiment. Exposure to all of the fipronil treatments resulted in all individuals dying before the end of the experiment; whereas, no individual died in the control (0.0 µg/L). The 96-hour LC50 was determined to be 1.3 µg/L. Shrimp also experienced weight loss under all of the fipronil treatments. Inter-moult interval was increased from 12.2 ± 1.64 day in the control group to 15.5 ± 0.53 day in the 1.0 µg/L treatment. Lipid content of shrimp increased significantly in a concentration-dependent manner. Finally, behavioral and body color changes were also observed under the fipronil treatments. We conclude F. aztecus is very sensitive to fipronil and monitoring is needed in coastal areas.

Risk factors for surgical site infection after major hepatobiliary and pancreatic surgery.

Major hepatobiliary and pancreatic (HP) surgeries are complex procedures associated with a high incidence of surgical site infection (SSI) and are commonly performed in patients with cancer in Japan. This study was performed to investigate the risk factors for SSI, including incisional and organ/space SSI, in HP surgery. The following procedures were included in the study: hepatectomy with and without biliary tract resection, pancreatectomy [pancreaticoduodenectomy (PD), others], and open cholecystectomy. In total, 735 patients were analyzed. The incidence of SSI was 17.8% (incisional, 5.2%; organ/space, 15.5%; both 2.9%). The highest incidence of SSI was observed in patients who underwent hepatectomy with biliary tract resection (39.1%), followed by pancreatectomy (PD, 28.8%; others, 29.8%). Almost all SSIs after these three procedures were classified as organ/space (39.1%, 25.0%, and 27.7%, respectively), and these procedures were risk factors for not only total SSI but also organ/space SSI in the multivariate analysis. An American Society of Anesthesiologists physical status of ≥3 was a risk factor for incisional SSI. Preoperative biliary drainage, prolonged surgery, concomitant surgery, and massive intraoperative bleeding were associated with SSI. In conclusion, the main type of SSI was organ/space SSI after HP surgery, and different risk factors were identified between organ/space and incisional SSI. Procedure-related factors and preoperative biliary drainage were independent risk factors for SSI. To prevent SSI, the indication for preoperative biliary drainage should be carefully evaluated in patients undergoing HP surgery.

Selection of trilateral continuums of life history strategies under food web interactions.

The study of life history strategies has a long history in ecology and evolution, but determining the underlying mechanisms driving the evolution of life history variation and its consequences for population regulation remains a major challenge. In this study, a food web model with constant environmental conditions was used to demonstrate how multi-species consumer-resource interactions (food-web interactions) can create variation in the duration of the adult stage, age of maturation, and fecundity among species. The model included three key ecological processes: size-dependent species interactions, energetics, and transition among developmental stages. Resultant patterns of life history variation were consistent with previous empirical observations of the life history strategies of aquatic organisms referred to as periodic, equilibrium, and opportunistic strategies (trilateral continuums of life history strategies). Results from the simulation model suggest that these three life history strategies can emerge from food web interactions even when abiotic environmental conditions are held constant.

Characteristics of patients with fragility hip fractures in the northern Kyushu district in Japan: a multicenter prospective registry based on an electronic data capture system.

Osteoporosis has become a worldwide public health problem, in part due to the fact that it increases the risk of fragility hip fractures (FHFs). The epidemiological assessment of FHFs is critical for their prevention; however, datasets for FHFs in Japan remain scarce. This was a multicenter, prospective, observational study in the northern district of Kyushu Island. Inclusion criteria were age > 60 years with a diagnosis of FHF and acquisition of clinical data by an electronic data capture system. Of 1294 registered patients, 1146 enrolled in the study. Nearly one third of patients (31.8%) had a history of previous fragility fractures. The percentage of patients receiving osteoporosis treatment on admission was 21.5%. Almost all patients underwent surgical treatment (99.1%), though fewer than 30% had surgery within 48 h after hospitalization. Bone mineral density (BMD) was evaluated during hospitalization in only 50.4% of patients. The rate of osteoporosis treatment increased from 21.5% on admission to 39.3% during hospitalization. The main reasons that prescribers did not administer osteoporosis treatment during hospitalization were forgetfulness (28.4%) and clinical judgment (13.6%). Age and female ratio were significantly higher in patients with previous FHFs than in those without. There was a significant difference in the rate of osteoporosis treatment or L-spine BMD values in patients with or without previous FHFs on admission. In conclusion, this study confirmed that the evaluation and treatment of osteoporosis and FHFs is still suboptimal in Japan, even in urban districts.

Constructing stage-structured matrix population models from life tables: comparison of methods.

A matrix population model is a convenient tool for summarizing per capita survival and reproduction rates (collectively vital rates) of a population and can be used for calculating an asymptotic finite population growth rate (λ) and generation time. These two pieces of information can be used for determining the status of a threatened species. The use of stage-structured population models has increased in recent years, and the vital rates in such models are often estimated using a life table analysis. However, potential bias introduced when converting age-structured vital rates estimated from a life table into parameters for a stage-structured population model has not been assessed comprehensively. The objective of this study was to investigate the performance of methods for such conversions using simulated life histories of organisms. The underlying models incorporate various types of life history and true population growth rates of varying levels. The performance was measured by comparing differences in λ and the generation time calculated using the Euler-Lotka equation, age-structured population matrices, and several stage-structured population matrices that were obtained by applying different conversion methods. The results show that the discretization of age introduces only small bias in λ or generation time. Similarly, assuming a fixed age of maturation at the mean age of maturation does not introduce much bias. However, aggregating age-specific survival rates into a stage-specific survival rate and estimating a stage-transition rate can introduce substantial bias depending on the organism's life history type and the true values of λ. In order to aggregate survival rates, the use of the weighted arithmetic mean was the most robust method for estimating λ. Here, the weights are given by survivorship curve after discounting with λ. To estimate a stage-transition rate, matching the proportion of individuals transitioning, with λ used for discounting the rate, was the best approach. However, stage-structured models performed poorly in estimating generation time, regardless of the methods used for constructing the models. Based on the results, we recommend using an age-structured matrix population model or the Euler-Lotka equation for calculating λ and generation time when life table data are available. Then, these age-structured vital rates can be converted into a stage-structured model for further analyses.

Improved tolerance to transplanting injury and chilling stress in rice seedlings treated with orysastrobin.

In addition to their fungicidal activity, strobilurin-type fungicides are reported to show enhancing effects on crop growth and yield. Previous studies suggested that the fungicide has a mitigating effect on abiotic stresses. However, there are few reports about growth enhancement through abiotic stress alleviation by strobilurin-type fungicides, but the mechanism of action of the growth enhancement is still not clear. The present study revealed that orysastrobin enhanced rice seedling growth after root cutting injury and chilling stress. We also found that orysastrobin decreased the transpiration rate and increased ascorbate peroxidase and glutathione reductase activities. This stress alleviation was eliminated by the application of naproxen, a putative abscisic acid biosynthesis inhibitor. These results suggested that orysastrobin improved tolerance against transplanting injury and chilling stress in rice seedlings by inducing water-retaining activity through the suppression of transpiration, and also by inducing reactive oxygen scavenging activity thus inhibiting reactive oxygen species accumulation.

C2 spondylotic radiculopathy: the nerve root impingement mechanism investigated by para-sagittal CT/MRI, dynamic rotational CT, intraoperative microscopic findings, and treated by microscopic posterior foraminotomy.

PURPOSE: C2 radiculopathy is known to cause occipito-cervical pain, but their pathology is unclear because of its rarity and unique anatomy. In this paper, we investigated the mechanism of C2 radiculopathy that underwent microscopic cervical foraminotomies (MCF). METHODS: Three cases with C2 radiculopathy treated by MCF were investigated retrospectively. The mean follow-up period was 24 months. Pre-operative symptoms, imaging studies including para-sagittal CT and MRI, rotational dynamic CT, and intraoperative findings were investigated. RESULTS: There were 1 male and 2 females. The age of patients were ranged from 50 to 79 years. All cases had intractable occipito-cervical pain elicited by the cervical rotation. C2 nerve root block was temporally effective. There was unilateral spondylosis in symptomatic side without obvious atlatoaxial instability. Para-sagittal MRI and CT showed severe foraminal stenosis at C1-C2 due to the bony spur derived from the lateral atlanto-axial joints. In one case, dynamic rotational CT showed that the symptomatic foramen became narrower on rotational position. MCF was performed in all cases, and the C2 nerve root was impinged between the inferior edge of the C1 posterior arch and bony spur from the C1-C2 joint. After surgery, occipito-cervical pain disappeared. CONCLUSION: This study demonstrated that mechanical impingement of the C2 nerve root is one of the causes of occipito-cervical pain and it was successfully treated by microscopic resection of the inferior edge of the C1 posterior arch. Para-sagittal CT and MRI, rotational dynamic CT, and nerve root block were effective for diagnosis.