[The application of a new type of sterile elastic exsanguination tourniquet in aspiration surgery for upper limb lymphedema]

Objective: To evaluate the effect of a new type of sterile elastic exsanguination tourniquet (SEET) in aspiration surgery for upper limb lymphedema. Methods: The clinical data of 159 patients who underwent aspiration surgery for upper limb lymphedema from January 2017 to June 2022 in the Beijing Shijitan Hospital, Capital Medical University were retrospectively analyzed. Among them, 54 patients were treated with SEET (SEET group), while 105 patients were not treated with SEET (No-SEET group). The propensity score matching method was used, and the surgical indicators and complications were compared between the two groups. The factors affecting intraoperative bleeding volume were analyzed through multiple linear regression analysis. Results: A total of 49 pairs of patients were successfully matched by the propensity score method. The age of patients in the SEET and No-SEET groups was (57.7±8.9) years and (56.8±9.1) years, respectively. Compared with the Non-SEET group, the SEET group had less bleeding volume [(311±164) ml vs (437±173) ml, P<0.001]. The results of multiple linear regression analysis showed that the factors affecting intraoperative bleeding volume included age (β=-0.142, P=0.041), using the SEET (β=-0.249, P=0.002), surgical time (β=0.195, P=0.010) and the amount of fat mixture sucked out (β=0.464, P<0.001). Conclusions: The clinical application of the SEET in aspiration surgery for upper limb lymphedema is safe, and can significantly reduce the bleeding volume and alleviate blood shortage.

[Lower extremity lymphedema as the initial symptom of malignant disease]

To investigate the diagnosis of malignancy with lower extremity lymphedema as the initial manifestation. We performed a retrospective study of 33 patients with malignant lymphedema treated at the Department of Lymphatic Surgery, Beijing Shijitan Hospital, Capital Medical University, from May 22, 2007 to December 31, 2018. A total of 33 cases of lower extremity lymphedema caused or aggravated by malignant tumors were found. The age range of 33 patients with malignant lymphedema was 21 to 84 years. Twenty-two patients were male, and 11 patients were female, with a mean age of (57.5±15.0) years. The time from the occurrence of lymphedema to the diagnosis of malignant tumors ranged from a month to 2 years. The proportion of patients with abnormal tumor markers was 88.9% (24/27), the prevalence of anemia among patients with malignant lymphedema was 42.4% (14/33), and the positive rates of ultrasonography, CT, MRI, and radionuclide imaging were 100.0% (17/17), 100.0% (25/25), 100.0% (4/4) and 60.0% (12/20), respectively. Twenty-seven cases with malignant tumors were confirmed by pathological diagnosis. To avoid delays in the diagnosis and therapy of malignant lymphedema, physicians should actively look for signs or symptoms of lymphedema during the follow-up period and promptly manage patients developing problems.

[Long-term efficacy and safety of simultaneous integrated boost radiotherapy in non-operative esophageal squamous cell carcinoma: a multicenter retrospective data analysis (3JECROG R-05)]

Objective: To analyze the survival benefits and treatment related toxic effects of simultaneous integrated boost intensity-modulated radiotherapy (SIB-RT) for non-operative esophageal squamous cell carcinoma patients. Methods: The data of 2 132 ESCC patients who were not suitable for surgery or rejected operation, and underwent radical radiotherapy from 2002 to 2016 in 10 hospitals of Jing-Jin-Ji Esophageal and Esophagogastric Cancer Radiotherapy Oncology Group (3JECROG) were analyzed. Among them, 518 (24.3%) cases underwent SIB (SIB group) and 1 614 (75.7%) cases did not receive SIB (No-SIB group). The two groups were matched with 1∶2 according to propensity score matching (PSM) method (caliper value=0.02). After PSM, 515 patients in SIB group and 977 patients in No-SIB group were enrolled. Prognosis and treatment related adverse effects of these two groups were compared and the independent prognostic factor were analyzed. Results: The median follow-up time was 61.7 months. Prior to PSM, the 1-, 3-, and 5-years overall survival (OS) rates of SIB group were 72.2%, 42.8%, 35.5%, while of No-SIB group were 74.3%, 41.4%, 31.9%, respectively (P=0.549). After PSM, the 1-, 3-, and 5-years OS rates of the two groups were 72.5%, 43.4%, 36.4% and 75.3%, 41.7%, 31.6%, respectively (P=0.690). The univariate survival analysis of samples after PSM showed that the lesion location, length, T stage, N stage, TNM stage, simultaneous chemoradiotherapy, gross tumor volume (GTV) and underwent SIB-RT or not were significantly associated with the prognosis of advanced esophageal carcinoma patients who underwent radical radiotherapy (P<0.05). Cox model multivariate regression analysis showed lesion location, TNM stage, GTV and simultaneous chemoradiotherapy were independent prognostic factors of advanced esophageal carcinoma patients who underwent radical radiotherapy (P<0.05). Stratified analysis showed that, in the patients whose GTV volume≤50 cm(3), the median survival time of SIB and No-SIB group was 34.7 and 30.3 months (P=0.155), respectively. In the patients whose GTV volume>50 cm(3), the median survival time of SIB and No-SIB group was 16.1 and 20.1 months (P=0.218). The incidence of radiation esophagitis and radiation pneumonitis above Grade 3 in SIB group were 4.3% and 2.5%, significantly lower than 13.1% and 11% of No-SIB group (P<0.001). Conclusions: The survival benefit of SIB-RT in patients with locally advanced esophageal carcinoma is not inferior to non-SIB-RT, but without more adverse reactions, and shortens the treatment time. SIB-RT can be used as one option of the radical radiotherapy for locally advanced esophageal cancer.

Hydrogen agronomy: research progress and prospects

Agriculture is the foundation of social development. Under the pressure of population growth, natural disasters, environmental pollution, climate change, and food safety, the interdisciplinary "new agriculture" is becoming an important trend of modern agriculture. In fact, new agriculture is not only the foundation of great health and new energy sources, but is also the cornerstone of national food security, energy security, and biosafety. Hydrogen agronomy focuses mainly on the mechanism of hydrogen gas (H₂) biology effects in agriculture, and provides a theoretical foundation for the practice of hydrogen agriculture, a component of the new agriculture. Previous research on the biological effects of H₂ focused chiefly on medicine. The mechanism of selective antioxidant is the main theoretical basis of hydrogen medicine. Subsequent experiments have demonstrated that H₂ can regulate the growth and development of plant crops, edible fungus, and livestock, and enhance the tolerance of these agriculturally important organisms against abiotic and biotic stresses. Even more importantly, H₂ can regulate the growth and development of crops by changing the soil microbial community composition and structure. Use of H₂ can also improve the nutritional value and postharvest quality of agricultural products. Researchers have also shown that the biological functions of molecular hydrogen are mediated by modulating reactive oxygen species (ROS), nitric oxide (NO), and carbon monoxide (CO) signaling cascades in plants and microbes. This review summarizes and clarifies the history of hydrogen agronomy and describes recent progress in the field. We also argue that emerging hydrogen agriculture will be an important direction in the new agriculture. Further, we discuss several scientific problems in hydrogen agronomy, and suggest that the future of hydrogen agronomy depends on contributions by multiple disciplines. Important future research directions of hydrogen agronomy include hydrogen agriculture in special environments, such as islands, reefs, aircraft, and outer space.

[Clinical features of primary isolated chylopericardium: a retrospective review study]

Objective: To examine the clinical characteristics and abnormal reflux branches of primary isolated chylopericardium. Methods: Totally 43 patients with primary isolated chylopericardium at Department of Lymphatic Surgery, Affiliated Beijing Shijitan Hospital,Capital Medical University from June 2007 to January 2018 were recruited in this study. There were 21 males and 22 females, aging (23.0±15.9) years (range: 2 to 57 years). The levels of triglyceride, total cholesterol, total protein and albumin in pericardial effusion and blood were compared by paired-t test, and the characteristics of lymphatic system in direct lymphangiography and postoperative CT were analyzed. Results: Pericardial effusion was mainly milky white and monocytes, and 95.3%(41/43) were positive for Rivalta test. The level of triglyceride in pericardial effusion was significantly higher than that of blood ((9.67±5.11) mmol/L vs. (1.28±0.89) mmol/L, t=10.557, P<0.01), and the levels of total cholesterol ((2.19±0.52) mmol/L vs. (4.12±1.06) mmol/L, t=-3.732, P<0.01), total protein ((61.25±16.17) g/L vs. (68.26±8.30) g/L, t=-2.958, P=0.005) and albumin ((36.63±7.06) g/L vs. (42.32±4.73) g/L, t=-5.747, P<0.01) were significantly lower than that of blood. In the direct lymphangiography, the imaging of iliac and retroperitoneal lymphatics showed dilated or tortuous in 90.7% (39/43), the thoracoabdominal segment of thoracic duct showed dilation in 46.5% (20/43), and cervical thoracic duct imaging showed dilation in 44.2% (19/43) and stenosis in 55.8% (24/43). The image of lipiodol flowing into the vein showed obstruction at the venous angle. There were 60.5%(26/43) of the patients with lipiodol reflux through the bronchomediastinal trunk (type Ⅰ), 11.6%(5/43) with lipiodol diffusion to the pericardium through the abnormal pathway from the thoracic segment of the thoracic duct (type Ⅱ), while no communication pathway between the thoracic duct and the pericardial cavity (type Ⅲ) found in 27.9%(12/43). CT images obtained after the direct lymphangiography showed 34.9%(15/43) had abnormal distribution of lipiodol in pericardium, mediastinal lymph nodes and lung hilar lymph nodes, 46.5%(20/43) in mediastinal lymph nodes and lung hilar lymph nodes, 14.0%(6/43) only mediastinal lymph nodes, 4.6%(2/43) had no lipiodol in the above areas. Conclusions: Pericardial effusion compared with same period blood, has higher triglyceride, lower total cholesterol, total protein and albumin. The obstruction of the cervical segment of the thoracic duct and the formation of abnormal reflux branches would be corelative to primary isolated chylopericardium.

[Efficacy analysis of the radiotherapy and chemotherapy in patients with stage Ⅳ esophageal squamous carcinoma: a multicenter retrospective study of Jing-Jin-Ji Esophageal and Esophagogastric Cancer Radiotherapy Oncology Group (3JECROG R-01F)]

Objective: To evaluate the survival and prognostic factors of radiotherapy in patient with Ⅳ stage esophageal squamous carcinoma treated with radiation or chemoradiation. Methods: The medical records of 608 patients with stage Ⅳ esophageal squamous cell carcinoma who met the inclusion criteria in 10 medical centers in China from 2002 to 2016 were retrospectively analyzed. The overall survival and prognostic factors of all patients at 1, 3 and 5 years were analyzed. Results: The 1-, 3-, 5- year overall survival (OS) rates was 66.7%, 29.5% and 24.3% in stage ⅣA patients, and 58.8%, 29.0% and 23.5% in stage ⅣB patients. There was no statistical difference between the two groups (P=0.255). Univariate analysis demonstrated that the length of lesion, treatment plan, planned tumor target volume (PGTV) dose, subsequent chemotherapy, and degrees of anemia, radiation esophagitis, radiation pneumonia were related to the prognoses of patients with Ⅳ stage esophageal carcinomas after radiotherapy and chemotherapy (P<0.05). Multivariate analysis demonstrated that PGTV dose (OR=0.693, P=0.004), radiation esophagitis (OR=0.867, P=0.038), and radiation pneumonia (OR=1.181, P=0.004) were independent prognostic factors for OS. Conclusions: For patients with stage Ⅳ esophageal squamous cell carcinoma, chemoradiotherapy followed by sequential chemotherapy is recommended, which can extend the total survival and improve the prognosis of the patients. PGTV dose more than 60 Gy has better efficacy.

[Prognostic analysis of definitive radiotherapy for early esophageal carcinoma(T1-2N0M0): a multi-center retrospective study of Jing-Jin-ji Esophageal and Esophagogastric Cancer Radiotherapy Oncology Group]

Objective: To evaluate the prognostic factors of T1-2N0M0 esophageal squamous cell carcinoma (ESCC) treated with definitive radiotherapy. Methods: The clinical data of 196 patients with T1-2N0M0 ESCC who were treated with definitive radiotherapy in 10 hospitals were retrospectively analyzed. All sites were members of Jing-Jin-Ji Esophageal and Esophagogastric Cancer Radiotherapy Oncology Group (3JECROG). Radiochemotherapy were applied to 78 patients, while the other 118 patients received radiotherapy only. 96 patients were treated with three-dimensional conformal radiotherapy (3DCRT) and 100 treated with intensity-modulated radiotherapy (IMRT). The median dose of plan target volume(PTV) and gross target volume(GTV) were both 60 Gy. The median follow-up time was 59.2 months. Log rank test and Cox regression analysis were used for univariat and multivariate analysis, respectively. Results: The percentage of normal lung receiving at least 20 Gy (V(20)) was (18.65±7.20)%, with average dose of (10.81±42.05) Gy. The percentage of normal heart receiving at least 30 Gy (V(30)) was (14.21±12.28)%. The maximum dose of exposure in spinal cord was (39.65±8.13) Gy. The incidence of radiation pneumonia and radiation esophagitis were 14.80%(29/196) and 65.82%(129/196), respectively. The adverse events were mostly grade 1-2, without grade 4 toxicity. Median overall survival (OS) and progression-free survival (PFS) were 70.1 months and 62.3 months, respectively. The 1-, 3- and 5-year OS rates of all patients were 75.1%、57.4% and 53.2%, respectively. The 1-, 3- and 5-year PFS rates were 75.1%、57.4% and 53.2%, respectively. Multivariate analysis demonstrated that patients'age (HR=1.023, P=0.038) and tumor diameter (HR=1.243, P=0.028)were the independent prognostic factors for OS, while tumor volume were the independent prognostic factor for PFS. Conclusions: Definitive radiotherapy is a promising therapeutic method in patients with T1-2N0M0 ESCC. Patients' age, tumor diameter and tumor volume may impact patients' prognosis.

[Liposuction combined with lymphatico-venous anastomosis for treatment of secondary lymphedema of the lower limbs: a report of 49 cases]

Objective: To study the clinical effects of liposuction combined with lymphatico-venous anastomosis for treatment of secondary lymphedema of the lower limbs. Methods: A retrospective analysis was performed for 49 patients who had undergone liposuction combined with lymphatico-venous anastomosis to treat secondary lymphedema of the lower limbs at Department of Lymph Surgery, Beijing Shijitan Hospital from November 2013 to February 2015.All patients were female aging from 31 to 70 years with median age of (52±10)years.All patients had history of pelvic surgery.There were 32 cases with cervical carcinoma, 11 cases with endometrial cancer, 1 case with ovarian cancer who accepted radical hysterectomy, 2 cases with benign tumor who accepted resection, 2 cases accepted inguinal lymph node dissection, 1 case with rectal cancer accepted radical resection.There were 30 cases with history of radiation therapy and 23 cases with history of erysipelas recurrent((2.1±3.9)/year). The limb swelling degree in preoperative and postoperative patients was explored using one-way analysis of variance with replicate measures and paired sample t-test. Meanwhile the incidence of lymphogenous infection was used as an evaluation of operation efficacy. Results: The mean lower limb circumference difference at 7 days, 6 months and 12 months was (0.17±1.36)cm, (1.25±1.62)cm and(1.58±1.56)cm, respectively, which was significantly decreased compared with preoperative((4.92±2.16)cm) (t=-5.712, -5.777, -5.765; all P<0.01). The mean lower limb volume difference at 7 days, 6 months and 12 months was (522±799)ml, (726±973)ml and (889±895)ml, respectively, which was significantly decreased compared with preoperative((2 729±1 335) ml)(t=-5.905, -6.093, -5.777; all P<0.01). The incidence of erysipelas was 0.0(0.0, 0.0)/6 months within 6 months after operation and 0.0(0.0, 0.0)/6 months within 6-12 months after operation, which was significantly lower than that before operation(0.0(0.0, 2.0)/year). The feeling of tightness and heaviness of the limb was significantly improved compared with preoperative. Conclusion: Liposuction combined with lymphatico-venous anastomosis is an effective method for the treatment of secondary lymphedema of the lower limbs.

[Clinical analysis of two cases with diffuse pulmonary lymphatic disease]

OBJECTIVE

To analyze the clinical characteristics and diagnosis of 2 cases with diffuse pulmonary lymphatic disease.

METHOD

Clinical manifestations of the children were retrospectively analyzed. Two patients were both from Beijing Children Hospital in 2013 and 2014.Diffuse pulmonary lymphatic disease was diagnosed by pathology of pleura in case 1 and by lymphoscintigraphy in case 2.

RESULT

The first patient was a male aged 10-year-5-month who presented with a history of pleural effusion for 2 years. Examination revealed chylothorax and pericardial effusion. After pleural decortications and ligation of thoracic duct was performed, he still had recurrent chylothorax. Pathology of pleura revealed lymphangioma. Physical examination showed diminished breath sound and heart sounds. A bronchoscope revealed too much white viscous secretions. Thorax ultrasound revealed lymphangioma in bilateral lower thoracic cavity and post inferior mediastinum. Chest computed tomography showed diffuse thickening of the interlobular septa and bronchovascular bundle in both lungs, many punctate calcification in the lower field. Abdomen ultrasound revealed a small quantity seroperitoneum. Lymphoscintigraphy revealed radioactivity enhancement in bilateral thoracic cavity. The second patient was a female aged 6 years and 9 months, who presented with a history of recurrent cough for 2 years and 9 months. Physical examination showed normal result. Pulmonary function showed mixed ventilation function disturbance. A bronchoscopy showed extensive viscous secretions. Mediastinum, heart and abdomen were normal on ultrasound. Chest computed tomography showed diffuse thickening of the interlobular septa and bronchovascular bundle in both lungs and bilateral pleural thickening. Lymphoscintigraphy revealed diffuse lymphangiectasis in both lungs. Both patients received a diagnosis of diffuse pulmonary lymphatic disease. Case 1 who had died was diagnosed with diffuse pulmonary lymphangiomatosis. Case 2 had no exacerbation after 9 months' treatment with prednisone.

CONCLUSION

Diffuse pulmonary lymphatic disease might present with cough and shortness of breath and result in diffuse interstitial disease with thickening of the interlobular septa, refractory chylothorax, multiple lymphangioma in mediastinum, pericardial effusion and seroperitoneum. It could be diagnosed by pleura or lung tissue pathology and lymphoscintigraphy.

Effects of astaxanthin and emodin on the growth, stress resistance and disease resistance of yellow catfish (Pelteobagrus fulvidraco)

Yellow catfish (Pelteobagrus fulvidraco) has become a commercially important fish species in China and eastern Asia. High-density aquaculture has led to congestion and excessive stress and contributed to bacterial infection outbreaks that have caused high mortality. We investigated the effects of dietary supplementation with astaxanthin and emodin alone and in combination on the growth and stress resistance of yellow catfish. After 60 days of feeding, each group of fish (control, astaxanthin, emodin, and astaxanthin plus emodin (combination) groups) was exposed to acute crowding stress for 24 h, and a subsample of fish from the four groups was challenged with the bacterial septicemia pathogen Proteus mirabilis after the end of the crowding stress experiment. Compared with the control, the astaxanthin and emodin groups showed increases in serum total protein (TP), hepatic superoxide dismutase (SOD) activity and hepatic heat shock proteins 70 (HSP70) mRNA levels at 12 and 24 h after the initiation of crowding stress. The combination group exhibited increases in alanine aminotransferase (ALT) activity, aspartate aminotransferase (AST) activity, serum TP, hepatic SOD activity and hepatic HSP70 mRNA levels within 24 h after the initiation of crowding stress. However, decreases relative to the control were observed in the serum cortisol and glucose contents in the three treatment groups at 12 and 24 h after the initiation of crowding stress, in ALT and AST activity in the astaxanthin and emodin group at 24 h after the initiation of crowding stress, and in the serum lysozyme activity, serum alkaline phosphatase (ALP) activity, and hepatic catalase (CAT) and malondialdehyde (MDA) activity in the combination group at 24 h after the initiation of crowding stress. Additionally, the cumulative mortality after P. mirabilis infection was lower in all three treatment groups (57.00%-70.33%) than in the control (77.67%). Dietary supplementation with astaxanthin and emodin decreased the specific growth rate (SGR) and weight gain (WG) of healthy yellow catfish, although significant differences in mortality were not observed. These results indicate that dietary supplementation with 80 mg/kg astaxanthin and 150 mg/kg emodin can improve the anti-oxidative capabilities, hepatic HSP70 levels, and resistance to acute crowding stress of yellow catfish. Finally, an appropriate strategy for enhance yellow catfish stress resistance and disease resistance is proposed.

Genetic variation in Whitmania pigra, Hirudo nipponica and Poecilobdella manillensis, three endemic and endangered species in China using SSR and TRAP markers

Leeches are not only important medicinal animals worldwide but also are endangered. We aimed to (i) explore the level of genetic diversity within/among populations of three leeches, (ii) assess genetic differentiation among these three leeches, and (iii) discuss an appropriate strategy for conserving leech germplasm. A total of 315 individuals of Whitmania pigra, Hirudo nipponica and Poecilobdella manillensis from 21 populations were collected in China and Vietnam. The genetic structure and genetic diversity among and within the 21 populations were evaluated using target region amplified polymorphism (TRAP) and simple sequence repeat (SSR) markers. Sixteen pairs of TRAP primers generated a total of 398 fragments, of which 396 (99.50%) were polymorphic; fourteen pairs of SSR primers generated a total of 60 fragments, of which 59 (98.33%) were polymorphic. Shannon's index (I) and Nei's gene diversity index (H) for the three leeches were high at the species level (I=0.4980 and H=0.3323 for TRAPs, I=0.4487 and H=0.2969 for SSRs in W. pigra; I=0.4147/0.3769, H=0.2788/0.2566 for H. nipponica; and I=0.4616/0.4717, H=0.3099/0.3203 for P. manillensis). However, low genetic diversity was determined at the population level; the average genetic diversity measures within populations were H=0.1767/0.1376, I=0.2589/0.2043 for W. pigra, H=0.2149/0.2021, I=0.3184/0.3000 for H. nipponica and H=0.2850/0.2724, I=0.4152/0.3967 for P. manillensis. We conclude that there was limited gene exchange within/among populations and species, as the gene flow number (Nm) was 0.5493/0.5807. However, for all three species, the genetic diversity was different at the population level. Gene differentiation (Gst) and Nm were 0.4682 /0.5364 and 0.5678/0.4321 for W. pigra, 0.2294/0.2127 and 1.6797/1.8512 for H. nipponica and 0.1214/0.1496 and 3.6202/2.8412 for P. manillensis. STRUCTURE analysis, Unweighted Pair-Group Method with Arithmetic means (UPGMA) cluster analysis and Principal Coordinates Analysis (PCOA) all yielded similar results. The isolation-by-distance pattern was not significant for any of the three species by the Mantel test. These data emphasize the need for management, conservation, and rehabilitation of this animal species. Finally, an appropriate strategy for conserving leech is proposed.

Novosphingobium chloroacetimidivorans sp. nov., a chloroacetamide herbicide–degrading bacterium isolated from activated sludge

Strain BUT-14T, a Gram-reaction-negative, non-spore-forming, ellipse-shaped bacterium, was isolated from activated sludge of a chloroacetamide-herbicides-manufacturing wastewater treatment facility. The strain was able to degrade more than 90 % of butachlor, acetochlor and alachlor (100 mg l−1) within 5 days of incubation. The taxonomic position was investigated using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain BUT-14T was a member of the genus Novosphingobium and showed the highest sequence similarities to Novosphingobium soli DSM 22821T (97.9 %), N. naphthalenivorans KACC 15258T (97.4 %), N. pentaromativorans JCM 12182T (97.4 %) and N. barchaimii DSM 25411T (97.1 %) and lower (<97 %) sequence similarities to all other species of the genus Novosphingobium . Chemotaxonomic analysis revealed that strain BUT-14T possessed Q-10 as the predominant ubiquinone, spermidine as the major polyamine and C18 : 1ω7c (46.9 %), C17 : 1ω6c (17.9 %), summed feature 3, C14 : 0 2-OH (4.4 %), C15 : 0 2-OH (3.1 %) and C16 : 0 (5.51 %) as the major fatty acids. The polar lipids included lipid, glycolipid, phosphatidylglycerol, phospholipid, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and phospatidyldimethylethanolamine. Strain BUT-14T showed low DNA–DNA relatedness with N. soli DSM 22821T (41.5±2.9 %), N. naphthalenivorans JCM 12182T (49.2±4.2 %), N. pentaromativorans KACC 12295T (53.2±1.9 %) and N. barchaimii DSM 25411 (51.2±4.5 %). The DNA G+C content was 66±0.3 mol%. The combination of phylogenetic analysis, phenotypic characteristics, chemotaxonomic data and DNA–DNA hybridization supports the suggestion that strain BUT-14T represents a novel species of the genus Novosphingobium , for which the name Novosphingobium chloroacetimidivorans sp. nov. is proposed. The type strain is BUT-14T ( = CCTCC AB 2013086T = KACC 17147T = JCM 19923T).

ZmHO-1, a maize haem oxygenase-1 gene, plays a role in determining lateral root development

Previous results revealed that haem oxygenase-1 (HO-1)/carbon monoxide (CO) system is involved in auxin-induced adventitious root formation. In this report, a cDNA for the gene ZmHO-1, encoding an HO-1 protein, was cloned from Zea mays seedlings. ZmHO-1 has a conserved HO signature sequence and shares highest homology with rice SE5 (OsHO-1) protein. We further discovered that N-1-naphthylacetic acid (NAA), haemin, and CO aqueous solution, led to the induction of ZmHO-1 expression as well as the thereafter promotion of lateral root development. These effects were specific for ZmHO-1 since the potent HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX) differentially blocked the above actions. The addition of haemin and CO were able to reverse the auxin depletion-triggered inhibition of lateral root formation as well as the decreased ZmHO-1 transcripts. Molecular evidence showed that the haemin- or CO-mediated the modulation of target genes responsible for lateral root formation, including ZmCDK and ZmCKI2, could be blocked by ZnPPIX. Overexpression of ZmHO-1 in transgenic Arabidopsis plants resulted in promotion of lateral root development as well as the modulation of cell cycle regulatory gene expressions. Overall, our results suggested that a maize HO-1 gene is required for the lateral root formation.

In vivo imaging of nitric oxide and reactive oxygen species using laser scanning confocal microscopy

Both nitric oxide (NO) and reactive oxygen species (ROS) are versatile molecules that mediate a variety of cellular responses in plants. In this chapter, methods for imaging NO and ROS using laser scanning confocal microscopy (LSCM) are presented. Arabidopsis roots, dyed with DAF-FM or H(2)DCF, are observed using the Leica TCS-SP2 LSCM. NO or ROS production are imaged and their kinetic changes monitored with the laser excitation and emission wavelengths at 488 nm and between 500 and 530 nm, respectively. In addition, Leica software is employed to visualize and calculate the fluorescence intensity data.

Molecular cloning and expression of a cucumber (Cucumis sativus L.) heme oxygenase-1 gene, CsHO1, which is involved in adventitious root formation

Our previous work showed that in cucumber (Cucumis sativus), auxin rapidly induces heme oxygenase (HO) activity and the product of HO action, carbon monoxide (CO), then triggers the signal transduction events leading to adventitious root formation. In this study, the cucumber HO-1 gene (named as CsHO1) was isolated and sequenced. It contains four exons and three introns and encodes a polypeptide of 291 amino acids. Further results show that CsHO1 shares a high homology with plant HO-1 proteins and codes a 33.3 kDa protein with a 65-amino transit peptide, predicting a mature protein of 26.1 kDa. The mature CsHO1 was expressed in Escherichia coli to produce a fusion protein, which exhibits HO activity. The CsHO1:GFP fusion protein was localized in the chloroplast. Related biochemical analyses of mature CsHO1, including Vmax, Km, Topt and pHopt, were also investigated. CsHO1 mRNA was found in germinating seeds, roots, stem, and especially in leaf tissues. Several well-known adventitious root inducers, including auxin, ABA, hemin, nitric oxide donor sodium nitroprusside (SNP), CaCl(2), and sodium hydrosulfide (NaHS), differentially up-regulate CsHO1 transcripts and corresponding protein levels. These results suggest that CsHO1 may be involved in cucumber adventitious rooting.

Molecular cloning, characterization, and expression of an alfalfa (Medicago sativa L.) heme oxygenase-1 gene, MsHO1, which is pro-oxidants-regulated

It has been documented that plant heme oxygenase-1 (HO-1; EC 1.14.99.3) is both development- and stress-regulated, thus it plays a vital role in light signalling and stress responses. In this study, an alfalfa (Medica sativa L.) HO-1 gene MsHO1 was isolated and sequenced. It contains four exons and three introns within genomic DNA sequence and encodes a polypeptide with 283 amino acids. MsHO1 had a conserved HO signature sequence and showed high similarity to other HOs in plants, especially HO-1 isoform. The MsHO1:GFP fusion protein was localized in the chloroplast. Further biochemical activity analysis of mature MsHO1, which was expressed in Escherichia coli, showed that the Vmax was 48.78 nmol biliverdin-IXα (BV) h⁻¹ nmol⁻¹ protein with an apparent Km value for hemin of 2.33 μM, and the optimum Tm and pH were 37 °C and 7.2, respectively. Results of semi-quantitative RT-PCR and western blot showed that the expressions of MsHO1 were higher in alfalfa stems and leaves than those in germinating seeds and roots. Importantly, MsHO1 gene expression and protein level were induced significantly by some pro-oxidant compounds, including hemin and nitric oxide (NO) donor sodium nitroprusside (SNP). In conclusion, MsHO1 may play an important role in oxidative responses.

Evidence of Arabidopsis salt acclimation induced by up-regulation of HY1 and the regulatory role of RbohD-derived reactive oxygen species synthesis

In Arabidopsis thaliana, a family of four genes (HY1, HO2, HO3 and HO4) encode haem oxygenase (HO), and play a major role in phytochrome chromophore biosynthesis. To characterize the contribution of the various haem oxygenase isoforms involved in salt acclimation, the effects of NaCl on seed germination and primary root growth in Arabidopsis wild-type and four HO mutants (hy1-100, ho2, ho3 and ho4) were compared. Among the four HO mutants, hy1-100 displayed maximal sensitivity to salinity and showed no acclimation response, whereas plants over-expressing HY1 (35S:HY1) exhibited tolerance characteristics. Mild salt stress stimulated biphasic increases in RbohD transcripts and production of reactive oxygen species (ROS) (peaks I and II) in wild-type. ROS peak I-mediated HY1 induction and subsequent salt acclimation were observed, but only ROS peak I was seen in the hy1-100 mutant. A subsequent test confirmed the causal relationship of salt acclimation with haemin-induced HY1 expression and RbohD-derived ROS peak II formation. In atrbohD mutants, haemin pre-treatment resulted in induction of HY1 expression, but no similar response was seen in hy1-100, and no ROS peak II or subsequent salt acclimatory responses were observed. Together, the above findings suggest that HY1 plays an important role in salt acclimation signalling, and requires participation of RbohD-derived ROS peak II.

Endogenous hydrogen peroxide plays a positive role in the upregulation of heme oxygenase and acclimation to oxidative stress in wheat seedling leaves

Pretreatment of lower H(2)O(2) doses (0.05, 0.5 and 5 mM) for 24 h was able to dose-dependently attenuate lipid peroxidation in wheat seedling leaves mediated by further oxidative damage elicited by higher dose of H(2)O(2) (150 mM) for 6 h, with 0.5 mM H(2)O(2) being the most effective concentrations. Further results illustrated that 0.5 mM H(2)O(2) pretreatment triggered the biphasic production of H(2)O(2) during a 24 h period. We also noticed that only peak I (0.25 h) rather than peak II (4 h) was approximately consistent with the enhancement of heme oxygenase (HO) activity, HO-1 gene expression. Meanwhile, enhanced superoxide dismutase (SOD) activity, Mn-SOD and Cu,Zn-SOD transcripts might be a potential source of peak I of endogenous H(2)O(2). Further results confirmed that 0.5 mM H(2)O(2) treatment for 0.5 h was able to upregulate HO gene expression, which was detected by enzyme activity determination, semi-quantitative reverse transcription-polymerase chain reaction and western blotting. Meanwhile, the application of N,N'-dimethylthiourea, a trap for endogenous H(2)O(2), not only blocked the upregulation of HO, but also reversed the corresponding oxidation attenuation. Together, the above results suggest that endogenous H(2)O(2) production (peak I) plays a positive role in the induction of HO by enhancing its mRNA level and protein expression, thus leading to the acclimation to oxidative stress.

The heme oxygenase/carbon monoxide system is involved in the auxin-induced cucumber adventitious rooting process

Indole acetic acid (IAA) is an important regulator of adventitious rooting via the activation of complex signaling cascades. In animals, carbon monoxide (CO), mainly generated by heme oxygenases (HOs), is a significant modulator of inflammatory reactions, affecting cell proliferation and the production of growth factors. In this report, we show that treatment with the auxin transport inhibitor naphthylphthalamic acid prevented auxin-mediated induction of adventitious rooting and also decreased the activity of HO and its by-product CO content. The application of IAA, HO-1 activator/CO donor hematin, or CO aqueous solution was able to alleviate the IAA depletion-induced inhibition of adventitious root formation. Meanwhile, IAA or hematin treatment rapidly activated HO activity or HO-1 protein expression, and CO content was also enhanced. The application of the HO-1-specific inhibitor zinc protoporphyrin IX (ZnPPIX) could inhibit the above IAA and hematin responses. CO aqueous solution treatment was able to ameliorate the ZnPPIX-induced inhibition of adventitious rooting. Molecular evidence further showed that ZnPPIX mimicked the effects of naphthylphthalamic acid on the inhibition of adventitious rooting, the down-regulation of one DnaJ-like gene (CSDNAJ-1), and two calcium-dependent protein kinase genes (CSCDPK1 and CSCDPK5). Application of CO aqueous solution not only dose-dependently blocked IAA depletion-induced inhibition of adventitious rooting but also enhanced endogenous CO content and up-regulated CSDNAJ-1 and CSCDPK1/5 transcripts. Together, we provided pharmacological, physiological, and molecular evidence that auxin rapidly activates HO activity and that the product of HO action, CO, then triggers the signal transduction events that lead to the auxin responses of adventitious root formation in cucumber (Cucumis sativus).

[Effects of exogenous nitric oxide donor on germination and activities of hydrolytic enzymes in wheat seed under osmotic stress]

Results in this paper showed that the effect of nitric oxide (NO) donor, sodium nitroprusside (SNP), which could promote the germination of wheat seeds under osmotic stress, was through enhancing imbibition using water content determination and imbibition analysis of wheat seed. SNP could also enhance amylase isozyme I activities, accelerate the liquefaction of endosperms, while have no effect on esterase. Moreover, SNP could strongly increase the sugars, such as the fructose, glucose and sucrose contents in wheat seeds during early germination (12 h) under normal conditions. When the seeds were treated with SNP with or without PTIO, an NO scavenger, and different exogenous sugars, i.e. fructose, glucose and sucrose, it was found that these sugars might activate amylase isozyme I activity mediated by the signal molecule NO to start the early stage of germination.

[The effect of exogenous glucose, fructose and NO donor sodium nitroprusside (SNP) on rice seed germination under salt stress]

The effects and the relationship between soaking rice seed of exogenous glucose, fructose and nitric oxide (NO) donor sodium nitroprusside (SNP) on the seed germination under salt stress were investigated. The results showed that employment of exogenous fructose, glucose and NO donor SNP could significantly promote the germination index and the early germination rate of rice seed under salt stress. Also, SNP pretreatment enhanced endogenous glucose and fructose contents. Effects of exogenous glucose and fructose combined with different concentrations of SNP on the rice seed germination and seedling growth under salt stress were surveyed. The results also showed that there existing positive effect of application of glucose plus SNP on the rice seed germination in comparison with existing a few negative effects of fructose plus SNP pretreatment. Additionally, the alleviation of inhibition of early rice seedling growth under salt stress by SNP could be modulated by glucose and fructose pretreatment, also the effect of glucose was stronger.

A rapid response of beta-amylase to nitric oxide but not gibberellin in wheat seeds during the early stage of germination

The effects of nitric oxide (NO) and gibberellic acid (GA(3)) on the responses of amylases in wheat (Triticum aestivum L.) seeds (caryopses) were investigated during the first 12 h of germination. GA(3) had no effects on the activities of alpha-amylase (EC 3.2.1.1) or beta-amylase (EC 3.2.1.2), either in intact seeds or embryoless halves within 12 h. In contrast, addition of sodium nitroprusside (SNP), an NO donor, was able to induce a rapid increase in beta-amylase activity without affecting alpha-amylase. Furthermore, the rapid response of beta-amylase to SNP in wheat seeds could be attributed to NO and was approximately dose-dependent. Some other aspects of SNP induction of amylase isozymes were also characterized. Further investigations showed that SNP might play an interesting role in the dissociation of free beta-amylase from small homopolymers or heteropolymers. Furthermore, SNP also directly induced the release of bound beta-amylase from glutenin and its crude enzyme preparation. However, the slight increase in protease also induced by SNP might not be responsible for this action. Interestingly, based on the fact that the rapid response of beta-amylase to NO also existed in seeds of other species, such as barley, soybean, rice and watermelon, it might be a universal event in early seed germination.

QTL detection for eating quality of cooked rice in a population of chromosome segment substitution lines

The genetic mechanism underlying six palatability properties of cooked rice and three physico-chemical traits was dissected in 66 BC(3)F(2) chromosome segment substitution lines (CSSLs), using a complete linkage map in three successive years. The CSSLs showed transgressive segregation for all traits studied. Significant correlation was detected among most palatability traits. A total of 25 QTLs for the nine traits were identified on nine chromosomes, and many QTLs affecting different quality traits were mapped in the same regions. Six QTLs--qLT-8 for luster, qTD-6 and qTD-8 for tenderness, qIVOE-6 and qIVOE-8 for integrated value of organoleptic evaluation, and qAC-8 for amylose content--were repeatedly detected across the 3 years. Phenotypic values were significantly different between the recurrent parent, cultivar Asominori, and the CSSLs harboring any of the six QTL alleles across the three environments, indicating that these six QTLs were non-environment-specific and could be used for marker-assisted selection in rice quality improvement.

[Effects of nitric oxide on root growth and its oxidative damage in wheat seedling under salt stress]

Effects of nitric oxide (NO), a substance newly found to have protective functions in plants, on root growth of wheat (Triticum aestivum L. Yangmai 158) seedlings under salt stress were studied. Sodium nitroprusside (SNP), an NO donor, markedly alleviated the inhibitory effect of salt on root elongation at salt concentrations around 150 mmol/L, but was ineffective when NaCl concentration was at 300 mmol/L or higher. It was most effective at 0.05-0.1 mmol/L, and had harmful effect at 0.30-5 mmol/L. Furthermore, when wheat seedling roots were treated with 150 mmol/L NaCl in combination with 0.05 mmol/L SNP and NO scavenger (hemoglobin, Hb), NO(-)(2)/NO(-)(3) and K(3)Fe(CN)(6) as controls, both of which were the two other major products besides NO when SNP dissolved in water, respectively, activities of superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) were enhanced to some extent. While, the generation of O(-.)(2) and the accumulation of MDA and H(2)O(2) were alleviated. DNA laddering was observed when wheat seedling roots exposed to 150 mmol/L NaCl for 6 d, also suggesting that salt stress might induce oxidative damage in root-tips. In combination with hemoglobin, NO(-)(2)/NO(-)(3) and K(3)Fe(CN)(6) as controls, the results showed that NO could block DNA ladders. Above results suggest that it is NO rather than any substances which is protecting root-tip cells of wheat seedlings from oxidative damage caused by salt stress.

[Exogenous nitric oxide alleviates osmotic stress-induced membrane lipid peroxidation in wheat seedling leaves]

When wheat (Triticum aestivum L. Yangmai 158) seedling (with three fully expanded leaves) roots were treated with 15% PEG-6000 in combination with different concentrations (0.1 and 0.5 mmol/L) of exogenous nitric oxide donor sodium nitroprusside (SNP) and NO(-)(3)/NO(-)(2) (control), the enhancement of lipoxygenase (LOX) activity in wheat seedling leaves under osmotic stress was delayed at the lower concentration of SNP treatment (0.1 mmol/L), while the generation rate of O(-.)(2), the enhancement of membrane permeability and the accumulation of MDA and H(2)O(2)were also alleviated. SNP 0.1 mmol/L significantly enhanced the activity of superoxide dismutase (SOD), and accelerated the accumulation of proline. In comparison with these changes, the effects of higher concentration of SNP (0.5 mmol/L) and corresponding control (NO(-)(3)/NO(-)(2)) were not so obvious. The above results indicate that lower concentrations of in vitro nitric oxide (NO) can protect wheat seedling leaves from membrane lipid peroxidation caused by osmotic stress.

[A novel method of extracting total RNA from rice embryo samples]

A novel and simple CTAB-LiCl-based extraction method for high-quality and total RNA of rice embryo samples is developed. This method can efficiently eliminate the interference of polysaccharide and lipids rich in rice (Oryza sativa L.) embryo obtained under room temperature without using liquid nitrogen. The results of ultraviolet spectrophotometer and agarose gel electrophoresis analysis show that the obtained RNA has no obvious degradation and a good purity sufficient for further RT-PCR and RNA gel blotting. Therefore, it is also especially useful for the RNA extraction of plant material plenty of polysaccharide and lipids.

Lymphogenous cyst-vein shunt in the management of chylothorax and chylorrhea

A 36 year-old woman developed marked lymphedema and chylous cysts of the lower abdominal wall, groin, labia, accompanied by chylorrhea. After cyst excision and transplantation of the greater omentum, a left chylothorax occurred. After thoracic duct ligation and left pleurodesis, pleural effusion recurred and worsened. Lymphangioscintigraphy and conventional lymphography suggested that undrained enlarged retroperitoneal lymphatics in the right iliac fossa had disrupted and lymph had leaked into the left chest from the right iliac fossa. Treatment by a lymphatic cyst-vein anastomosis redirected excess chylous lymph into the blood circulation and chylothorax initially remitted. Several years later with recurrence of chylorrhea, the anastomosis was found to be occluded. After a second operative connection between a lymphogenous cyst and the greater saphenous vein, chylorrhea subsided and chylothorax has remitted for more than 4 years.

Development of the perforating pathway: an ipsilaterally projecting pathway between the medial septum/diagonal band of Broca and the cingulate cortex that intersects the corpus callosum

The perforating pathway (PFP) intersects the corpus callosum perpendicularly at the midline in the dorsoventral axis. Therefore axons in either the PFP or the corpus callosum make different axonal guidance decisions in the same anatomical region of the developing cortical midline. The mechanisms underlying these axonal choices are not known. To begin to identify these guidance mechanisms, we characterized the development of these two pathways in detail. The development of the corpus callosum and its pioneering projections has been described elsewhere (Shu and Richards [2001] J. Neurosci. 21:2749--2758; Rash and Richards [2001] J. Comp. Neurol. 434:147--157). Here we examine the development, origins, and projections of axons that make up the PFP. The majority of axons within the PFP originate from neurons in the medial septum and diagonal band of Broca complex. These neurons project in a topographic manner to the cingulate cortex. In contrast to previous reports, we find that a much smaller projection originating from the cingulate cortex also contributes to this pathway. The pioneering projections of the PFP and the corpus callosum arrive at the corticoseptal boundary at around the same developmental stage. These findings show that ipsilaterally projecting PFP axons and contralaterally projecting callosal axons make distinct guidance decisions at the same developmental stage when they reach the corticoseptal boundary.

Release of amines from acidified stores following accumulation by Transport-P

1. Transport-P is an uptake process for amines in peptidergic neurones of the hypothalamus. It differs from other uptake processes by its anatomical location in post-synaptic neurones, its functional properties and by the structure of its ligands. Transport-P accumulates amines in intracellular vesicles, derives its energy from the electrochemical proton gradient and is linked to vacuolar-type ATPase (V-ATPase). Transport-P is blocked by antidepressants. We have now studied the release of amines following uptake by Transport-P in a cell line of hypothalamic peptidergic neurones. 2. Release of prazosin was not inhibited by the antidepressant desipramine; as Transport-P is blocked by desipramine, this indicated that amines are released by a mechanism which is independent of Transport-P. 3. Release of prazosin was sensitive to temperature and conformed to the Arrhenius equation. Release was minimal in the range 0-25 degrees C but accelerated exponentially at higher temperatures up to 33 degrees C. The activation energy for the release of prazosin is 83.1 kJ x mol(-1), corresponding to a temperature quotient (Q10) value of 3. 4. Release was accelerated by the organic base chloroquine, the ionophore monensin, bafilomycinA1 which inhibits V-ATPase and by increasing extracellular pH. Thus, retention of prazosin requires an intracellular proton gradient which is generated by V-ATPase. 5. Fluorescence microscopy demonstrated that release of BODIPY FL prazosin was temperature dependent and was accelerated by chloroquine and monensin. 6. Thus, following uptake by Transport-P, amines are accumulated in acidified intracellular stores. Their retention in peptidergic neurones requires intracellular acidity. The amines are released by a temperature-dependent process which is resistant to antidepressants.

alpha(1B) adrenergic receptors in gonadotrophin-releasing hormone neurones: relation to Transport-P

1. Peptidergic neurones accumulate amines via an unusual uptake process, designated Transport-P. [(3)H]-prazosin binds to alpha(1) adrenoceptors on these cells and is displaceable by unlabelled prazosin in concentrations up to 10(-7) M. However, at greater concentrations of prazosin, there is a paradoxical accumulation of [(3)H]-prazosin which we have attributed to Transport-P. Uptake of prazosin via Transport-P is detectable at 10(-10) M prazosin concentration, is linear up to 10(-7) M and at greater concentrations becomes non-linear. In contrast, in noradrenergic neurones, noradrenaline uptake is linear and saturates above 10(-7) M. In noradrenergic neurones and in non-neuronal cells, there is no uptake of prazosin in concentrations up to 10(-6) M, suggesting that Transport-P is a specialised function of peptidergic neurones. 2. Using a mouse peptidergic (gonadotrophin-releasing hormone, GnRH) neuronal cell line which possesses Transport-P, we have studied the interaction of alpha(1) adrenoceptors with Transport-P. Polymerase chain reactions and DNA sequencing of the products demonstrated that only the alpha(1B) sub-type of adrenoceptors is present in GnRH cells. 3. In COS cells transfected with alpha(1b) adrenoceptor cDNA and in DDT(1) MF-2 cells which express native alpha(1B) adrenoceptors, [(3)H]-prazosin was displaced by unlabelled prazosin in a normal equilibrium process, with no prazosin paradox in concentrations up to 10(-6) M. In DDT(1) MF-2 cells, [(3)H]-prazosin was displaced likewise by a series of alpha(1) adrenergic agonists, none of which increased the binding of [(3)H]-prazosin. Hence, the prazosin paradox is not due to some function of alpha(1) adrenoceptors, such as internalization of ligand-receptor complexes. 4. In neurones which possess Transport-P, transfection with alpha(1b) adrenoceptor cDNA resulted in over-expression of alpha(1B) adrenoceptors, but the prazosin paradox was unaltered. Thus, alpha(1) adrenoceptors and Transport-P mediate distinct functions in peptidergic neurones.

Castration rapidly decreases hypothalamic gamma-aminobutyric acidergic neuronal activity in both male and female rats

The postcastration LH response is greater and somewhat more rapid in male than female rats. We have previously demonstrated that hypothalamic gamma-aminobutyric acid (GABA)ergic neuronal activity decreases following gonadectomy in male rats. To investigate whether these same hypothalamic GABA neurons decrease their activity postcastration in female rats, and whether more rapid and or greater postcastration decreases occur in male rats, we determined the timing and magnitude of the postcastration decreases in GABA turnover which are associated with the sexually dimorphic postcastration LH response. Adult male and 4-day cycling female rats were castrated between 0800 and 1000 h (females ovariectomized on diestrus day 1). Serum LH levels increased significantly by 12 h postcastration in both males and females with the magnitude of the increases being 6.2-fold in males and 2.8-fold in females. GABA turnover was determined in 16 microdissected brain structures by the GABA transaminase inhibition method at 0 h (sham-operated controls), 6 h, 12 h and 1, 2, 4 and 6 days postcastration. In male rats, in the diagonal band of Broca at the level of the organum vasculosum of the lamina terminalis [DBB(ovlt)], the rate of GABA turnover decreased significantly already by 6 h postcastration compared with the 0 h controls, and remained suppressed through 6 days. This rapid down regulation of DBB(ovlt) GABAergic neurons also occurred in female rats, however, the duration of the decrease was not as prolonged as in male rats. Similar changes occurred in the tuberoinfundibular GABAergic (TIGA) neurons projecting to the median eminence in both males and females. Down regulation of these GABAergic neurons precedes or is coincident with increased postcastration LH secretion in both sexes, and the duration of the decreases is consistent with the less robust postcastration LH response in female rats. In addition, the rate of GABA turnover decreased after castration in the interstitial (bed) nucleus of the stria terminalis, ventral aspect (INSTv), the medial preoptic nucleus, dorsomedial aspect (MPNdm) and the ventromedial nucleus, ventrolateral aspect (VMNvl) in male rats, and in the INSTv and VMNvl of female rats, while there was no effect of castration in other hypothalamic regions or control structures. The result in the female VMNvl is consistent with reports that GABA facilitates lordosis behavior in this hypothalamic structure. These findings are consistent with the hypothesis that discrete hypothalamic populations of sex steroid-sensitive GABAergic neurons mediate the postcastration LH responses in both male and female rats, and may underlie other sexually dimorphic adult phenotypes such as sex behavior.

Sex differences in GABA turnover and glutamic acid decarboxylase (GAD(65) and GAD(67)) mRNA in the rat hypothalamus

GABAergic neurons are estimated to make up more than half of the neuronal population of the hypothalamus and they likely account for some of the structural and functional sexual dimorphisms observed in the mammalian brain. We previously reported sex differences in the rate of GABA turnover in discrete hypothalamic structures of adult rats. In the present study, we extended our search for sex differences in GABA turnover to additional structures, and further determined whether these differences were associated with differences in GAD(65) and or GAD(67) mRNA levels. Utilizing the GABA transaminase inhibition method, we determined GABA turnover in 14 microdissected brain regions. The rate of GABA turnover was about 2-fold greater in male than in diestrous day one (D(1)) female rats in the diagonal band of Broca at the level of the organum vasculosum of the lamina terminalis [DBB(ovlt)], anteroventral periventricular nucleus (AVPv), median eminence (ME), and dorsomedial portion of the ventromedial nucleus (VMNdm). A sex difference also was noted in the DBB(ovlt) for GAD(65) mRNA determined by microlysate RNase protection assay. Here, GAD(65) levels were almost 2-fold greater in male rats, which suggests that differences in the activity of this GAD enzyme isoform contributes to the difference in turnover in this area. Additionally, in the dorsomedial nucleus (DMN), the GAD(65) mRNA level was significantly higher in female rats, and in the medial amygdaloid nucleus (Am), GAD(67) mRNA was higher in male rats. These data reveal striking sexual dimorphisms in the rate of GABA turnover and in GAD mRNA levels in specific populations of hypothalamic GABAergic neurons. The functional relationships between these GABAergic neurons and sexually dimorphic phenotypes associated with these structures, such as gonadotropin secretion, reproductive behaviors, seizure threshold and others, warrant further investigation.