水稻植株对稻田CH4排放日变化的影响

2005年采用静态箱法,在水稻分蘖期天气晴朗的条件下,全天观测了有、无水稻植株两种情况下稻田CH4的排放.结果表明:无论水稻种植与否,稻田CH4排放通量的昼夜变化均表现为单峰模式,极大值出现在下午14点;稻田CH4排放的昼夜变化与5cm处土温存在显著正相关关系(p＜0.05);有水稻植株处理稻田CH4日平均排放通量显著高于无水稻植株处理(p＜0.05);有水稻植株处理的稻田CH4排放通量最佳观测时间在上午8～10点,无水稻植株处理的最佳观测时间则在傍晚18点左右.     

水分管理对水稻生长期CH4排放的影响

通过温室盆栽试验研究相同施肥条件下,不同水分管理(持续淹水,分蘖肥后提前烤田、正常烤田和推迟烤田)对水稻生长期CH4排放的影响。结果表明,对烤田处理而言,CH4的排放峰值出现在烤田期间,在此期间CH4排放量占季节排放量的38.75%～52.21%。烤田初期出现排放高峰,然后急剧下降,烤田结束前接近于零;水稻生长后期干湿交替阶段只有少量CH4排放。提前烤田、正常烤田和推迟烤田3个处理水稻生长期CH4平均排放通量依次为0.86、0.96、1.45mg/(m2·h),烤田开始越晚,CH4排放越多。土壤Eh是影响不同烤田处理水稻生长期CH4排放的主要因素。持续淹水处理水稻移栽30天后的CH4排放通量与土壤温度呈显著性相关(r=0.682**,p<0.01)。持续淹水处理CH4排放通量是烤田处理的12～20倍。     

The effect of 7.2% hypertonic saline solution on m-mode echocardiographic indices in normovolemic dogs

This study investigated whether a small volume of 7.2% hypertonic saline solution (HSS) could affect M-mode echocardiographic indices in dogs. HSS induced significant increase in heart rate, stroke volume and cardiac index, when the fluid infusion was completed (P<0.05). In the HSS group, the left ventricular end-diastolic volume index, as an index of preload, significantly increased (P<0.05), whereas left ventricular end-systolic volume index were not altered. HSS induced slight increases in ejection fraction at end of infusion despite significantly differences were not observed. In conclusion, HSS did not induce a demonstrable effect on M-mode echocardiographic indices of systolic function-enhance cardiac contractility, but it caused preload augmentation that may contribute to an abrupt and transient increase in cardiac output just after HSS infusion.     

Primary hemangiosarcoma of the humerus in a Maltese dog

A 14-year-old intact male Maltese dog was presented with a history of pain and swelling of the left upper forelimb and lameness for 3 weeks. Hematological and radiographical examinations showed regenerative anemia and osteolysis of the humerus. Fine needle aspiration biopsy detected epithelioid- and fibroblast-like anaplastic cells with blood components. A hemorrhagic and osteolytic malignant tumor was suspected, and the affected forelimb was amputated. Histopathologically, the dog was diagnosed with primary hemangiosarcoma of the humerus. Thereafter, metastatic lesions appeared in the skin, and the dog was euthanized 1 month after the operation.     

Relationship between trace elements status in mane hair and atrial fibrillation in horse

To investigate the relationships between trace elements concentrations in hair and atrial fibrillation (AF) in horses, concentrations of nineteen trace elements were detected in hair using the particle induced X-ray emission (PIXE) method. The horses were assigned to either control (n=22, no abnormalities) or AF groups (n=5) based on electrocardiograph findings. The mean concentrations of Ca and Zn in the hair of the AF group were significantly higher than those in the control group. The Zn/Cu ratio of the hair in the AF group (29.8 +/- 5.5) was significantly higher than that in the control group (23.4 +/- 2.2, P<0.05). The results of the present study suggest that there is a relationship between elevated concentrations of Ca and Zn in hair and AF.     

Effect of nitrite accumulation on nitrous oxide emission and total nitrogen loss during swine manure composting

The present study investigated the nitrogen balance in swine manure composting to evaluate the effect of nitrite (     ) accumulation, which induces nitrogenous emissions, such as N₂O, during compost maturation. During active composting, most N losses result from NH₃ emission, which was 9.5% of the initial total nitrogen (TN_initial), after which,     began to accumulate as only ammonia-oxidizing bacteria proliferated. After active composting, the addition of mature swine compost (MSC), including nitrite-oxidizing bacteria (NOB), could prevent     accumulation and reduce N₂O emission by 70% compared with the control in which     accumulated as a result of delayed growth of indigenous NOB. Total N₂O emissions in the control and in the treatment of MSC addition (MA) were 9.3% and 3.0% of TN_initial, respectively, whereas N losses as the sum total of NH₃ and N₂O over the whole period were 19.0% (control) and 12.8% (MA) of TN_initial, respectively. However, the difference in total N losses was markedly greater than that measured as NH₃ and N₂O, which were 27.8% (control) and 13.3% (MA) of TN_initial, respectively. These results demonstrated that the magnitude of nitrogen losses induced by     accumulation is too large to ignore in the composting of swine manure.     

The genetic mechanisms of warfarin resistance in Rattus rattus found in the wild in Japan

Warfarin is commonly used worldwide as a rodenticide. It inhibits blood coagulation by inhibiting vitamin K 2,3-epoxide reductase (VKOR) activity leading to hemorrhage. However, it has been reported that repeated or long-term treatment with warfarin results in resistance emerging in wild rodents. Such resistance may explain why it is difficult to control rodents in many regions in Japan. In this report, we studied mutations in the VKOR gene (including the VKOR complex subunit 1 (VKORC1)), while also analyzing VKOR and clotting factor activity in black rats (Rattus rattus) in order to understand better the mechanism of warfarin resistance in this species.We sequenced the VKORC1 gene from 275 rats living in the wild in Japan. We found several types of novel base substitutions, some of which conferred warfarin resistance.There was no difference in coagulation times between warfarin-sensitive and resistant rats measured under physiological conditions. However, after warfarin administration, no effect was noted in warfarin-resistant rats, although a prolonged coagulation time was noted in warfarin-sensitive rats.We also determined the kinetic differences in hepatic microsomal VKOR-dependent activity between warfarin-resistant and sensitive rats. Warfarin-resistant rats showed 2-3-fold lower V_max/K_m values than did sensitive rats. In addition, we report that resistant rats found in the Tokyo area had a VKOR activity which was poorly inhibited by warfarin.Finally, we conclude that reduced VKOR activity and warfarin resistance in the Japanese black rat might be due to mutations in the VKORC1 gene. However, further study is needed to clarify how such rats can maintain adequate vitamin K-dependent clotting factor levels, while simultaneously exhibiting low VKOR activity and warfarin resistance.     

GeneScan analysis to detect clonality of T-cell receptor γ gene rearrangement in feline lymphoid neoplasms

Lymphoid neoplasms are usually diagnosed on the basis of cytological and histopathological findings. However, in some cases, discrimination of lymphoid neoplasms from reactive lymphoid proliferation is difficult. Polymerase chain reaction (PCR) amplification of the complementarity-determining region (CDR) 3 of the T-cell receptor (TCR) γ gene can be used to assess clonality of T-cell populations as a supportive diagnostic tool for T-cell neoplasms. Because the length variation in the TCRγ CDR3 is relatively small, false positive results may occur in non-neoplastic T-cell populations in the absence of high-resolution analytical methods for PCR products. In the present study, a PCR assay system was developed to detect clonal TCRγ gene rearrangement in feline lymphoid cells using GeneScan analysis. Thirty T-cell neoplasms, 27 B-cell neoplasms, and 34 non-neoplastic tissues were subjected to the newly developed TCRγ gene rearrangement analysis. Clonal TCRγ gene rearrangement was detected in 26 of 30 (87%) T-cell neoplasms, 2 of 27 (7%) B-cell neoplasms, and 1 of 34 (3%) non-neoplastic tissues. To compare GeneScan analysis with conventional PAGE and heteroduplex analysis, 20 clonal and 20 polyclonal samples were subjected to both analyses. Most of the results were concordant between the 2 analyses; however, several clonal peaks (bands) appeared as a single band when analyzed via conventional PAGE with heteroduplex analysis in 4 of the 20 (20%) clonal samples as a result of the difference in resolution. The PCR assay system to detect clonal TCRγ gene rearrangement in feline lymphoid cells, using GeneScan analysis, would be a useful molecular diagnostic tool for feline T-cell neoplasms, with high fidelity.     

Characterization of triple-phase computed tomography in dogs with pancreatic insulinoma

Little information is available regarding triple-phase computed tomography (CT) of canine pancreatic insulinoma. A few case reports with small numbers of cases have indicated that hyper-attenuation in the arterial phase was a common finding on multi-phasic CT in dogs with insulinoma. Our purpose was to clarify the characteristic findings of dogs with insulinoma on triple-phase CT. Nine dogs with insulinoma that underwent triple-phase CT were included in the present study. Attenuation patterns in the arterial phase indicated hypo-attenuation in 4 cases and hyper-attenuation in 2 cases. In the remaining 3 cases, 1 case showed hypo-attenuation and 1 case showed hyper-attenuation in the pancreatic phase, and 1 case presented hyper-attenuation in the later phase. Altogether, 5 cases showed hypo and 4 cases showed hyper-attenuation in at least one phase. The enhancement pattern was homogenous in 7 cases and heterogeneous in 2 cases. Tumor margins were well-defined in 5 cases and ill-defined in 4 cases. Capsule formation was present in 5 cases and absent in 4 cases. In conclusion, it is important to note that hypo-attenuation was as common as hyper-attenuation in dogs with insulinoma in triple-phase CT in at least one phase. Additionally, mass lesions were most conspicuous not only in the arterial phase but in the pancreatic and later phases in some cases. Therefore, it is important to perform triple-phase CT and notice about variable findings for the detection of canine pancreatic insulinoma.