[Therapeutic strategy for totally thoracoscopic repeat mitral valve surgery under moderate hypothermia-induced ventricular fibrillation]

Objective: To examine the therapeutic strategy and its impacting factors by analyzing the perioperative outcomes of total thoracoscopic repeat mitral valve surgery under moderate hypothermia-induced ventricular fibrillation with cardiopulmonary bypass. Methods: This study is a retrospective case series. Totally 63 patients who underwent repeat mitral valve surgery by the same surgeon from January 2021 to December 2023 in Department of Cardiovascular Surgery, the First Medical Center of People's Liberation Army General Hospital were retrospectively enrolled. There were 28 males and 35 females with an age of (58.3±15.9) years (range: 13 to 84 years). Surgery was performed using a totally thoracoscopic approach under moderate hypothermia-induced ventricular fibrillation. Mitral valvuloplasty was completed in 32 cases and mitral valve replacement in 31 cases. Preoperative baseline data and perioperative outcomes of the patients were collected and Logistic regression was used to analyze independent influencing factors of premature ventricular contractions in the early postoperative period. Results: The intraoperative cardiopulmonary bypass time was (191.5±50.9) minutes (range: 95 to 286 minutes), and the hypothermic ventricular fibrillation time was (99.0±39.8) minutes (range: 34 to 203 minutes). The anal temperature before the start of cardiopulmonary bypass was (36.3±0.5) ℃ (range: 35.2 to 38.0 ℃), the lowest intraoperative anal temperature was (27.3±1.3) ℃(range: 23.7 to 30.1 ℃), and the anal temperature at the time of the cessation of cardiopulmonary bypass was (36.3±0.4) ℃ (range: 35.2 to 37.0 ℃), and excessive rewarming was observed in 33 cases. Six cases applied the artificial heart assist device. Seventeen cases developed premature ventricular contractions in the early postoperative period. Two cases developed neurologic complications. Five cases developed respiratory complications. One case developed urological systemic complications. Six cases were mechanically ventilated for more than 3 days, and the duration of ICU stay in 16 cases was more than 3 days and the postoperative discharge time of (M(IQR)) 8.0 (3.5) days (range: 3 to 26 days). Two cases died or were discharged voluntarily. Logistic regression results showed that persistent preoperative atrial fibrillation (OR=11.424, 95%CI: 1.477 to 144.564, P=0.033) and excessive rewarming (OR=15.249, 95%CI: 1.357 to 279.571, P=0.038) were independent risk factors for the appearance of premature ventricular contractions in the early postoperative period. Conclusions: The technique of total thoracoscopic surgery under induced moderate hypothermic ventricular fibrillation with cardiopulmonary bypass could be applied to repeated mitral valve surgeries with less trauma and faster recovery. Persistent preoperative atrial fibrillation and excessive rewarming are independent risk factors for the occurrence of premature ventricular contractions in the early postoperative period.

[Long-term outcome follow-up of Oxford unicompartmental knee arthroplasty for medial compartment osteoarthropathy:a single center's experience for 10 years]

Objective: To investigate the long-term outcomes of minimally invasive Oxford phase Ⅲ unicompartmental knee arthroplasty (UKA) for patients with medial compartment osteoarthropathy. Methods: The clinical data of 594 patients (701 knees) who underwent minimally invasive UKA with Oxford phase Ⅲ unicompartmental prosthesis at Department of Orthopedics,the Affiliated Hospital of Qingdao University from January 2007 to January 2016 were retrospectively analyzed.There were 155 males and 439 females,aged (62.6±10.9) years (range: 44 to 81 years),with a body mass index of (26.9±3.8) kg/m² (range: 21.1 to 36.2 kg/m²).There were 359 left knees and 342 right knees,676 knees with osteoarthritis and 25 knees with idiopathic osteonecrosis of the medial femoral condyle.There were 487 cases underwent UKA (66 cases underwent UKA on one side and total knee arthroplasty on the other) and 107 cases underwent bilateral UKA.Patients' prosthetic survival,complications,range of motion(ROM) of the knee,visual analogue score (VAS),Western Ontario and McMaster University (WOMAC) osteoarthritis index,and American knee society score (KSS) were collected to assess clinical outcomes.Paired sample t test was used to compare the data before and after operation. Results: All patients completed the surgery successfully.There was no intraoperative fractures,postoperative infections or symptomatic vascular embolic disease occurred.The postoperative complications,including mobile bearing dislocation,prosthesis loosening,tibial plateau collapse,the lateral compartment degeneration and postoperative pain were occurred in 18 cases (3.0%,18/594).Thirteen patients suffered complications were transferred to total knee arthroplasty,4 underwent partial revision,if this was used as the endpoint of the study,the surgical success rate was 97.1% (577/594) and the prosthetic revision rate was 2.9%.The ROM was improved from(105.9±11.8)°preoperatively to (114.0±13.3)° at the last follow-up (t=10.796,P<0.01);the KSS clinical score was increased from 54.3±3.6 to 90.1±6.0 (P<0.01) and the functional score was increased from 55.9±3.9 to 87.5±5.7(t=124.325,P<0.01;t=110.985,P<0.01).The WOMAC osteoarthritis index was decreased from 54.8±6.7 to 9.2±3.1 at the last follow-up(t=150.860,P<0.01) and the VAS was decreased from 6.1±1.1 to 1.5±1.0 at the last follow-up(t=74.941,P<0.01). Conclusions: Minimally invasive Oxford phase Ⅲ UKA for medial compartment knee osteoarthritis has a favorable prosthesis survival rate,low revision rate,and few complications at long-term follow-up.Patients have significant improvement in knee function with satisfactory clinical outcomes.

[Roles of adenosine monophosphate activated protein kinase in skeletal muscle atrophy in rats with severe scald]

Objective: To investigate the expression and phosphorylation level change of adenosine monophosphate activated protein kinase (AMPK) in skeletal muscle of severely scald rats and its roles in skeletal muscle atrophy in severely scalded rats. Methods: The experimental research method was applied. Totally 100 6-week-old male Wistar rats were divided into sham injury group and scald group according to the random number table, with 50 rats in each group. After weighing the body weight, rats in scald group were inflicted with full-thickness scald of 30% total body surface area on the back, and rats in sham injury group were simulated with scald. At 6 h and on 1, 3, 5, and 7 d post injury, 10 rats in each group were taken to measure their body weights and weights of extensor digitorum longus and soleus muscle. At 6 h and on 1, 3, 5, and 7 d post injury, the tibialis anterior muscles were collected, the mRNA expressions of muscle atrophy F-box protein (MAFbx) and muscle-specific RING finger protein 1 (MuRF1) were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction; the content of adenosine monophosphate (AMP), adenosine diphosphate, and adenosine triphosphate (ATP) were detected by high performance liquid chromatography, and AMP/ATP ratio and energy charge were calculated; the protein expressions of AMPK-α and phosphorylated AMPK-α (p-AMPK-α) were detected by Western blotting, and the p-AMPK-α/AMPK-α ratio was calculated, with sample number of 4 in each time point of each group. Data were statistically analyzed with analysis of variance for factorial design and least significant difference test. Results: The body weights of rats in 2 groups before injury and at each time point post injury were close (P>0.05). At 6 h post injury, the weight of extensor digitorum longus of rats in scald group was (0.107±0.007) g, which was significantly heavier than (0.086±0.0607) g of sham injury group (P<0.01). On 3 d post injury, the weight of extensor digitorum longus of rats in scald group was (0.083±0.016) g, which was significantly lighter than (0.102±0.005) g of sham injury group (P<0.01). The weight of soleus of rats in 2 groups were close at each time point post injury (P>0.05). Compared with those of sham injury group, the mRNA expression of MAFbx in tibialis anterior muscle of rats in scald group was significantly up-regulated at 6 h post injury (P<0.01), and the mRNA expressions of MuRF1 in tibial anterior muscle of rats in scald group were significantly up-regulated at 6 h and on 1 d post injury (P<0.01). At 6 h and on 7 d post injury, compared with those of false injury group, the AMP/ATP ratios of the tibial anterior muscle of rats in scald group were significantly increased (P<0.05 or P<0.01), and energy charges of the tibial anterior muscle of rats in scald group were significantly decreased (P<0.01). At each time point post injury, the protein expressions of AMPK-α of the tibial anterior muscle of rats in 2 groups were close (P>0.05). The p-AMPK-α/AMPK-α ratios of the tibial anterior muscle of rats in scald group at 6 h and on 7 d post injury were significantly higher than those in sham injury group (P<0.05 or P<0.01). Conclusions: The decrease in energy charge and increase in AMP/ATP ratio of skeletal muscle of rats after severe scald activate AMPK. The activation of AMPK in the early stage of injury is consistent with the up-regulation of MAFbx and MuRF1 expressions and down-regulation of skeletal muscle weight. The above-mentioned changes may be one of the molecular mechanisms of skeletal muscle atrophy in rats with severe scald.

[Imaging judgment of soft tissue and vascular injuries in limbs with high-voltage electric burn and its clinical significance]

The injury mechanism of high-voltage electric burn in limbs is complex and special. The soft tissue and vascular injuries caused by high-voltage electric burn are serious and concealed. It is difficult to judge the severity and extent of injury before surgery, which affects the diagnosis and treatment effects and remains a major problem in burn field. In recent decades, a series of clinical studies have been conducted by scholars at home and abroad, using various imaging methods for the judgment of soft tissue and vascular injuries, which have their own advantages and disadvantages. According to the principle of accuracy, precision, safety, and easy operation, magnetic resonance imaging and magnetic resonance angiography are required at the same time in general for the imaging judgment of soft tissue and vascular injuries in limbs with high-voltage electric burn. The B-mode ultrasonography shall be performed if a precise judgment of vascular injury is needed.

[Transbronchial lung cryobiopsy in diffuse lung disease: a pathological analysis of 173 cases]

Objective: To evaluate the value of transbronchial lung cryobiopsy (TBCB) in pathological diagnosis for diffuse lung disease. Methods: The clinicopathological data of 173 patients from the first affiliated hospital of Guangzhou medical university between Jaunary 2017 and June 2019 with transbronchial lung cryobiopsy of diffuse lung disease were retrospectively analyzed and summarized with review. Among 173 cases, TBCB and conventional transbronchial lung biopsy (TBLB) were performed in 54 patients. The size of biopsy samples and diagnostic yield were compared. Results: Among 173 cases, the diagnostic yield was 85.54% (148/173) , 160 (92.49%) cases provided definite diagnosis and valuable pathological results, according to age, sex, occupation, past history, contact history, smoking history, laboratory serology and imaging findings. Among 160 cases, there were 72 cases of known etiology (45.00%), 27 cases of idiopathic interstitial pneumonia (16.88%), 7 cases of granulomatous lesions (4.38%) and 54 cases of other types (33.75%). With TBCB and TBLB in 54 patients, the specimens sizes of TBCB and TBLB were (3.3±1.3) mm(2) and (1.0±0.3) mm(2) respectively (t'=12.67 P<0.01) . The diagnostic yields of TBCB and TBLB were 81.48% (44/54) and 42.59% (23/54) respectively (χ(2)=17.33, P<0.01) . The diagnostic yields of TBCB and TBLB for interstitial lung diseases were 48.15% (26/54) and 5.56% (3/54) respectively (χ(2)=24.94, P<0.01) . However, the diagnostic yields of TBCB and TBLB for the other diffuse lung disease except interstitial lung diseases were 33.33% (18/54) and 37.04% (20/54) respectively, with no significant difference (χ(2)=0.1624, P=0.687). Conclusion: Compared with TBLB, TBCB has obvious advantages and application value in the diagnosis of diffuse pulmonary diseases, especially interstitial pulmonary diseases.

[Clinical analysis of 30 cases of Castleman disease with different types of thoracic involvement]

目的

总结不同类型胸部受累Castleman病（CD）的临床、影像学、病理及诊治特征，以提高临床医师对CD的认识。

方法

回顾性分析广州医科大学附属第一医院自2009年6月至2019年5月收治入院的胸部受累CD患者30例，将其分为闭塞性细支气管炎（BO）组、不伴BO的单中心型Castleman病（UCD）组及不伴BO的多中心型Castleman病（MCD）组，分析其临床资料并总结其特征。

结果

30例患者中，5例（16.7%）纳入BO组，18例（60.0%）纳入不伴BO的UCD组，7例（23.3%）纳入不伴BO的MCD组。不伴BO的MCD组中位年龄明显大于BO组[（49.29±5.39）岁对（27.20±3.76）岁，P=0.005]和不伴BO的UCD组[（49.29±5.39）岁对（37.17±2.87）岁，P=0.034]。胸部症状在BO组（100%）和不伴BO的MCD组（71.4%）多见，而不伴BO的UCD组无胸部症状。贫血及IgG增高仅在不伴BO的MCD组出现（发生率均为57.1%），红细胞沉降率增快及低氧血症在BO组（发生率分别为40.0%和60.0%）及不伴BO的MCD组（发生率分别为57.1%和28.6%）均可出现。BO组患者的肺功能均表现为极重度混合性通气功能障碍。胸部CT所示肺实质受累率：BO组为100%；不伴BO的MCD组为57.1%，表现为双肺弥漫性病变；不伴BO的UCD组为11.1%，表现为孤立性肺结节。不伴BO的MCD组的淋巴结短径明显小于BO组[（1.83±0.51）cm对（4.73±1.63）cm，P=0.006]和不伴BO的UCD组[（1.83±0.51）cm对（3.62±0.26）cm，P=0.011]。BO组病理类型均为透明血管型（100%），不伴BO的UCD组88.9%为透明血管型，而不伴BO的MCD组以浆细胞型为主（57.1%）。BO组患者均出现口腔溃疡，在肿物切除术后予免疫调节剂治疗，溃疡症状缓解，但肺部症状仍进行性加重。不伴BO的UCD组主要治疗方式为胸腔镜下肿物切除，不伴BO的MCD组主要治疗方式为化疗、免疫调节剂、靶向治疗等。

结论

三组患者的年龄、临床症状、实验室检查、肺功能、影像学表现、病理类型、治疗及预后均有所不同，此分类能促进临床医师对本病的认识。

[Uni-port totally thoracoscopic surgery in tricuspid insufficiency patients after previous left-sided valve surgery]

Objective: To examine minimally invasive tricuspid valve operations applied in tricuspid valve insufficiency patients with previous left-sided valve surgery. Methods: Between September 2017 and June 2019, thirty-six consecutive patients received minimally invasive totally thoracoscopic tricuspid surgery through right thoracotomy at Department of Cardiovascular Surgery, Fisrt Medical Center, People's Liberation Army General Hospital. There were 13 males and 23 females, aging (56±11) years (range: 43 to 79 years). All the patients had isolated significant tricuspid regurgitation after previous left-sided cardiac surgeries. A right anterolateral thoracotomy incision about 4 cm was made from the fourth intercostal space as main operating port. The arterial cannula was placed in femoral artery. The venous cannula was placed in femoral vein using Seldingger technique. Tricuspid valve operation was performed on beating heart by assist of vena vacuum. Results: Tricuspid valve repair was performed in 7 patients. Tricuspid valve replacement with bioprosthesis was performed in 29 patients. The operation time was (2.9±0.3) hours (range:2.5 to 3.6 hours). There was no conversion to sternotomy during operation. There was no severe complications during operation period. There were no complications related to this cannulation technique. The time of cardiopulmonary bypass establishment was (22±5) minutes (range: 12 to 24 minutes) and pump time was (82±16) minutes (range: 62 to 93 minutes). The length of hospital stay was (9±3) days after operation (range: 5 to 13 days). There was no early death in hospital. All patients were followed up for 3 to 22 months. No patient died. Conclusions: One single port-based minimally invasive approach seems to be safe, feasible, and reproducible in case of redo tricuspid valve operations. Only cannulation of inferior vena cava significantly simplified the complexity of isolated redo tricuspid surgery.

[Analysis on treatment of eight extremely severe burn patients in August 2nd Kunshan factory aluminum dust explosion accident]

Objective: To summarize the measures and experience of treatment in mass extremely severe burn patients. Methods: The clinical data and treatment of 8 extremely severe burn patients in August 2 Kunshan factory aluminum dust explosion accident who were admitted in the 100th Hospital of PLA on August 2nd, 2014, were retrospectively analyzed. There were 4 males and 4 females, aging 22-45 (34±7) years, with total burn area of 55%-98% [(89±15)%] total body surface area (TBSA) and full-thickness burn area of 45%-97% [(80±21)%] TBSA. All the 8 patients were accompanied with severe shock, inhalation injury, and blast injury. According to the requirements of former PLA General Logistics Department and Nanjing Military Command, a treatment team was set up including a special medical unit and a special care unit, with Chai Jiake from the First Affiliated Hospital of PLA General Hospital as the team leader, Zheng Qingyi from the 175th Hospital of PLA (the Affiliated Dongnan Hospital of Xiamen University) as the deputy leader, the 100th Hospital of PLA as the treatment base, and burn care, respiratory, nephrology, nursing specialists from the First Affiliated Hospital of PLA General Hospital, and the burn care experts and nursing staff from the 180th Hospital of PLA, 118th Hospital of PLA, 98th Hospital of PLA, and 175th Hospital of PLA, and nurses from the 85th Hospital of PLA, 455th Hospital of PLA, 101th Hospital of PLA, 113th Hospital of PLA as team members. Treatment strategies were adopted as unified coordination by the superior, unified responsibility of team leader, division of labor and cooperation between team members, and multidisciplinary cooperation led by department of burns. With exception of one patient who received deep vein catheterization before admission, the other 7 patients were treated with deep vein catheterization 0.5 to 3.0 hours after admission to correct hypovolemic shock as soon as possible. Eight patients received tracheotomy, and 7 patients were treated with mechanical ventilation by ventilator in protective ventilation strategy with low tide volume and low volume pressure to assist breathing. Fiberoptic bronchoscopy was done one to three times for all the 8 patients to confirm airway injuries and healing status. Escharectomy and Meek dermatoplasty in the extremities of all the 8 patients were performed 3 to 6 days after injury for the first time. Escharectomy, microskin grafting, and covering of large pieces of allogeneic skin on the trunks of 4 patients were performed 11 to 16 days after injury for the second time. The broad-spectrum antibiotics were uniformly used at first time of anti-infective therapy, and then the antibiotics species were adjusted in time. The balance of internal environment was maintained and the visceral functions were protected. One special care unit was on responsibility of only one patient. Psychological intervention was performed on admission. The rehabilitative treatment was started at early stage and in company with the whole treatment. Results: Acute renal injury occurred in 5 patients within 36 hours after injury and their renal function was restored to normal 4 days after injury due to active adjustment of fluid resuscitation program. No pulmonary complications, such as severe pulmonary infection and ventilator-associated pneumonia, occurred in the survived patients. One of the 8 patients died, and the other 7 patients were cured successfully. The wounds were basically healed in 2 patients in 26 or 27 days by 2 or 3 times of operation, and in 5 patients by 4 or 5 times of operation. The basic wound healing time was 26-64 (48±15) days for all the 7 patients. Conclusions: Treatment strategies of unified coordination by the superior, unified responsibility of team leader, division of labor and cooperation between team members, and multidisciplinary cooperation led by department of burns are the bases to successful treatment. Correcting shock as soon as possible is the prerequisite and closing wound as soon as possible is the key to successful treatment. Comprehensive treatment measures, such as maintaining and regulating the function of viscera, improving the body immunity, and preventing and treating the complications, are the important components to successful treatment. It is emphasized that in the treatment of mass extremely severe burn patients, specialist burn treatment should always be in the dominant position, and other related disciplines may play a part in auxiliary function.

16α, 17α-epoxypregnenolone-20-oxime inhibits NO and IL-6 production in LPS-treated RAW264.7 cells

It has previously been reported that 16α, 17α-epoxypregnenolone-20-oxime (EPREGO) exerts an inhibitory effect on nitric oxide (NO) production and inducible NO synthase (iNOS) expression in microglia. The present study aimed to investigate the effects of EPREGO on the lipopolysaccharide (LPS)‑induced inflammatory response in RAW264.7 macrophage cells, and to determine the underlying molecular mechanisms using western blot analysis, enzyme‑linked immunosorbent assays and fluorescence‑activated cell sorting. The present study demonstrated that LPS‑induced production of NO and interleukin (IL)-6, and the protein expression levels of iNOS, were reduced by EPREGO in a dose‑ and time‑dependent manner, whereas, EPREGO did not affect tumor necrosis factor‑α production. In addition, EPREGO suppressed LPS‑induced cellular reactive oxygen species production and phagocytosis. Furthermore, EPREGO significantly inhibited the LPS‑induced activation of mitogen‑activated protein kinases and inhibitor of κB α degradation in LPS‑stimulated RAW264.7 cells, thus resulting in modulation of the production of NO and IL‑6. Taken together, these results suggest that EPREGO exhibits anti-inflammatory activity in macrophages, thus validating the hypothesis that EPREGO may be useful as a therapeutic agent for the treatment of macrophage-mediated inflammation.

Magnesium Transporter 5 plays an important role in Mg transport for male gametophyte development in Arabidopsis

During anther development the male gametophyte develops inside the locule and the tapetal cells provide all nutrients for its development. Magnesium Transporter 5 (MGT5) is a member of the MGT family and has dual functions of Mg export and import. Here, we show that male gametophyte mitosis and intine formation are defective in a mgt5 mutant. The transient expression of GFP-MGT5 revealed that MGT5 is localized in the plasma membrane. These findings suggest that in the male gametophyte MGT5 plays a role in importing Mg from the locule and that Mg is essential for male gametophyte development. The expression of MGT5 in the knockout ABORTED MICROSPORES (AMS) mutant (AMS being an essential regulator of tapetum) is tremendously reduced. Chromatin immunoprecipitation and mobility shift assay experiments demonstrated that AMS can directly bind the promoter of MGT5. An immunoelectron microscopy assay revealed that MGT5-His is localized to the plasma membrane of the tapetum. These findings suggest that AMS directly regulates MGT5 in the tapetum and thus induces export of Mg into the locule. The mgt5 plant exhibits severe male sterility while the expression of MGT5 under the tapetum-specific promoter A9 partly rescued mgt5 fertility. mgt5 fertility was restored under high-Mg conditions. These findings suggest that the mgt5 tapetum still has the ability to export Mg and that a sufficient supply of Mg from the tapetum can improve the importation of Mg in the mgt5 male gametophyte. Therefore, MGT5 plays an important role in Mg transport from the tapetum to the microspore.

Phase transformation and enhanced photocatalytic activity of S-doped Ag2O/TiO2 heterostructured nanobelts

Ag2O/TiO2 nanobelt heterostructures have been found to possess high ultraviolet photocatalytic activity, but a poor cycling performance. After a S-doping treatment, the obtained Ag2O/Ag2S2O7/TiO2 heterostructured nanobelts exhibited an enhanced and stable photocatalytic activity under both ultraviolet and visible light irradiation, which was exemplified by photo-degradation of organic pollutants and photocurrent response measurements. Meanwhile, the crystal structure and phase transformation of Ag2O, Ag2S2O7 and Ag2S were studied by XRD and XPS measurements.

SbHKT1;4, a member of the high-affinity potassium transporter gene family from Sorghum bicolor, functions to maintain optimal Na⁺ /K⁺ balance under Na⁺ stress

In halophytic plants, the high-affinity potassium transporter HKT gene family can selectively uptake K⁺ in the presence of toxic concentrations of Na⁺. This has so far not been well examined in glycophytic crops. Here, we report the characterization of SbHKT1;4, a member of the HKT gene family from Sorghum bicolor. Upon Na⁺ stress, SbHKT1;4 expression was more strongly upregulated in salt-tolerant sorghum accession, correlating with a better balanced Na⁺ /K⁺ ratio and enhanced plant growth. Heterogeneous expression analyses in mutants of Saccharomyces cerevisiae and Arabidopsis thaliana indicated that overexpressing SbHKT1;4 resulted in hypersensitivity to Na⁺ stress, and such hypersensitivity could be alleviated with the supply of elevated levels of K⁺, implicating that SbHKT1;4 may mediate K⁺ uptake in the presence of excessive Na⁺. Further electrophysiological evidence demonstrated that SbHKT1;4 could transport Na⁺ and K⁺ when expressed in Xenopus laevis oocytes. The relevance of the finding that SbHKT1;4 functions to maintain optimal Na⁺ /K⁺ balance under Na⁺ stress to the breeding of salt-tolerant glycophytic crops is discussed.

The Arabidopsis nitrate transporter NRT1.8 functions in nitrate removal from the xylem sap and mediates cadmium tolerance

Long-distance transport of nitrate requires xylem loading and unloading, a successive process that determines nitrate distribution and subsequent assimilation efficiency. Here, we report the functional characterization of NRT1.8, a member of the nitrate transporter (NRT1) family in Arabidopsis thaliana. NRT1.8 is upregulated by nitrate. Histochemical analysis using promoter-beta-glucuronidase fusions, as well as in situ hybridization, showed that NRT1.8 is expressed predominantly in xylem parenchyma cells within the vasculature. Transient expression of the NRT1.8:enhanced green fluorescent protein fusion in onion epidermal cells and Arabidopsis protoplasts indicated that NRT1.8 is plasma membrane localized. Electrophysiological and nitrate uptake analyses using Xenopus laevis oocytes showed that NRT1.8 mediates low-affinity nitrate uptake. Functional disruption of NRT1.8 significantly increased the nitrate concentration in xylem sap. These data together suggest that NRT1.8 functions to remove nitrate from xylem vessels. Interestingly, NRT1.8 was the only nitrate assimilatory pathway gene that was strongly upregulated by cadmium (Cd(2+)) stress in roots, and the nrt1.8-1 mutant showed a nitrate-dependent Cd(2+)-sensitive phenotype. Further analyses showed that Cd(2+) stress increases the proportion of nitrate allocated to wild-type roots compared with the nrt1.8-1 mutant. These data suggest that NRT1.8-regulated nitrate distribution plays an important role in Cd(2+) tolerance.

AtMGT7: An Arabidopsis gene encoding a low-affinity magnesium transporter

Magnesium (Mg(2+)) is one of the essential cations in all cells. Although the Mg(2+) transport mechanism has been well-documented in bacteria, less is known about Mg(2+) transporters in eukaryotes. The AtMGT gene family encoding putative magnesium transport proteins had been described previously. We report here that one of the Arabidopsis MGT family members, the AtMGT7 gene, encodes two mRNAs that have resulted from alternative splicing variants, designated AtMGT7a and AtMGT7b. Interestingly, the two mRNA variants were expressed with different patterns with AtMGT7a expressing in all organs, but AtMGT7b appearing only in root and flowers. The AtMGT7a variant functionally complemented a bacterial mutant lacking Mg(2+) transport capacity, whereas AtMGT7b did not. The (63)Ni(2+) tracer uptake analysis in the bacterial model showed that AtMGT7a mediated low-affinity transport of Mg(2+). Consistent with the complementation assay result, (63)Ni(2+) tracer uptake analysis revealed that AtMGT7b did not transport Mg(2+). This study therefore has identified from a higher plant the first low-affinity Mg(2+) transporter encoded by a gene with alternatively spliced transcripts that produce proteins with distinct functions.

A mitochondrial magnesium transporter functions in Arabidopsis pollen development

Magnesium is an abundant divalent cation in plant cells and plays a critical role in many physiological processes. We have previously described the identification of a 10-member Arabidopsis gene family encoding putative magnesium transport (MGT) proteins. Here, we report that a member of the MGT family, AtMGT5, functions as a dual-functional Mg-transporter that operates in a concentration-dependent manner, namely it serves as a Mg-importer at micromolar levels and facilitates the efflux in the millimolar range. The AtMGT5 protein is localized in the mitochondria, suggesting that AtMGT5 mediates Mg-trafficking between the cytosol and mitochondria. The AtMGT5 gene was exclusively expressed in anthers at early stages of flower development. Examination of two independent T-DNA insertional mutants of AtMGT5 gene demonstrated that AtMGT5 played an essential role for pollen development and male fertility. This study suggests a critical role for Mg(2+) transport between cytosol and mitochondria in male gametogenesis in plants.

[Impaired gastric acid secretion in patients poisoned by cauterizing liquids]

Intragatric pH-metry made in 80 patients with chemical gastric burn (CGB) in the acute and early postburn periods revealed that in 17% of the victims, gastric acid secretion remains normal, 51.2% of cases showed its increase (hyperacidity) whose maximum rates (100%) are detected in patients with extensive CGB of the third degree and whose minimum rates (20%) were found in those with fourth-grade CGB. Hypoacidicity was diagnosed in 31.2% of the patients. A significant (1.7-6-fold) enhancement of acid secretion was observed during stimulation, which suggests the compensated hyperfunction of intact gastric mucosal portions and supports the fact that the values of basal acidicity are leveled by bile reflux duodenogastritis. The latter was diagnosed by pH-metry data in 63.8% and by esophagogastroduodenoscopy (EGDS) in 87.5% of cases. The detection rate of reflux gastroesophagitis (RGE) was also higher by EGDS than that by pH-metry: 42.5 and 26.3% of cases, respectively. The lowest detection rate of RGE was noted in patients with fourth-degree CGB whereas the endoscopic signs of reflex esophagitis (RE) were most pronounced: erosive and ulcerative RE was diagnosed in 28% of cases.

A rice quantitative trait locus for salt tolerance encodes a sodium transporter

Many important agronomic traits in crop plants, including stress tolerance, are complex traits controlled by quantitative trait loci (QTLs). Isolation of these QTLs holds great promise to improve world agriculture but is a challenging task. We previously mapped a rice QTL, SKC1, that maintained K(+) homeostasis in the salt-tolerant variety under salt stress, consistent with the earlier finding that K(+) homeostasis is important in salt tolerance. To understand the molecular basis of this QTL, we isolated the SKC1 gene by map-based cloning and found that it encoded a member of HKT-type transporters. SKC1 is preferentially expressed in the parenchyma cells surrounding the xylem vessels. Voltage-clamp analysis showed that SKC1 protein functions as a Na(+)-selective transporter. Physiological analysis suggested that SKC1 is involved in regulating K(+)/Na(+) homeostasis under salt stress, providing a potential tool for improving salt tolerance in crops.

Convectively driven polymerase chain reaction thermal cycler

We have fabricated a low-cost disposable polymerase chain reaction thermal chamber that uses buoyancy forces to move the sample solution between the different temperatures necessary for amplification. Three-dimensional, unsteady finite element modeling and a simpler 1-D steady-state model are used together with digital particle image velocimetry data to characterize the flow within the device. Biological samples have been amplified using this novel thermal chamber. Time for amplification is less than 30 min. More importantly, an analysis of the energy consumption shows significant improvements over current technology.

[Isolation, expression analysis of a chilling induced cDNA from rice root with differential display: an evidence role for caffeine-sensitive calcium signal]

Chilling-sensitive rice varieties acquire chilling tolerance when their roots are exposed to water stress for short time. Caffeine-sensitive calcium signal was involved in this procedure. By using total RNA differential display, a chilling induced cDNA(ICT: induction of chilling treatment) was isolated from roots of chilling-sensitive rice variety. It was determined that it is a novel cDNA by homology searching. The transcript level of ict mRNA is up-regulated under chilling stress, it is decreased to low level when the samples were transferred to standard culture conditions. Pre-treated with mannitol for two hours is beneficial to inducing ICT level of expression. This chilling induction was inhibited by caffeine, suggesting that it may play a putative role in signal transduction of caffeine-sensitive calcium.

[Repair and reconstruction of massively damaged wounds]

OBJECTIVE

To report repair and reconstruction of massively damaged wound under unusual condition.

METHODS

One hundred and forty-seven patients with deep tissue defects were admitted from January 1993 to December 2000, among them, 96 cases suffered from electrical injury, 18 cases with hot press injury, 18 cases with deep burns as a result of CO poisoning or epileptic seizure, 6 cases caused by chemical producing necrosis and wound infection, 3 cases with radiation injuries, 2 cases with chemical burn, 2 cases with explosive injury, 2 cases with frostbite. One hundred and seventy five wounds in 147 patients were repaired by transfer of local flap, forearm conversal island skin flap, pectoralis major myocutaneous flap, delto-pectoral skin flap, latissimus dorsi skin flap, gastroecnemius myocutaneous flap, anterior and posterior tibial artery island skin flap, and so on. The wound defect ranged from 1 cm x 1 cm to 20 cm x 28 cm, and the flaps were 1.5 cm x 2.0 cm to 22 cm x 30 cm. The necrotic tendon was replaced with acellular allogenic tendon simultaneously in 7 cases.

RESULTS

One hundred and sixty-nine flaps were survival with first intention, while necrosis of the tip of flap occurred in 6 cases. The transplantation of acellular allogenic tendon in all cases were survival. The function and configuration in 28 cases were satisfactory after 4 months to 8 years follow-up.

CONCLUSION

Various types of flaps are choosen according to the position, defect range and degree of wound, which is an ideal method to restore the function and to improve patients' living condition.

[Primary hepatosarcoma: reports of 8 cases]

Eight cases of the primary hepatosarcoma were reported in this paper. These cases were verified by resection and pathological examination. The abdominal pain and mass were of the main clinical features. The image studies showed the occupied lesions of the liver. The preoperative differential diagnosis is of difficulty. All these cases were misdiagnosed: 6 cases (75%) as cystic lesions and 2 cases (25%) as cancer of the liver, The sarcoma of the liver is usually huge and central necrotized which formed liquid-cavity. Therefore the differential diagnosis of huge mixed cystic lesions of the liver should be stressed. During operation, the frozen section pathological examination should be performed as a routine in case misdiagnosis and mistreatment happen. Early surgical resection is suggested in order to raise the survival rate.

[The diagnostic accuracy of gastric urease activity for Helicobacter pylori]

The diagnostic accuracy of gastric urease activity for Helicobacter pylori (HP) infection were studied in 98 patients with peptic ulcer, gastritis and chronic renal failure. Gastric aspirates were analyzed for urea nitrogen and ammonia. Urease activity was calculated as the ratio of gastric ammonia to sum of gastric urea nitrogen and ammonia. Gold standard assessments to HP infection were rapid urease test, histology and/or culture. The results showed that the values of urease activity in patients with HP infection higher than that in patients without HP infection. This were further assessed by eradication of HP. Sixteen patients with HP infection were treated with DeNol 330 mg/day for 4 weeks. HP was eradicated in 8/16 patients. In those cases urease activity reduced (P < 0.05). If taken 0.31 as the cut-off index of urease activity to diagnosis HP infection, the sensitivity, specificity and accuracy were 95%, 84%, 93% respectively and were not affected by blood urea nitrogen.

Thermal response of rat fibroblasts stably transfected with the human 70-kDa heat shock protein-encoding gene

The major heat shock protein hsp70 is synthesized by cells of a wide variety of organisms in response to heat shock or other environmental stresses and is assumed to play an important role in protecting cells from thermal stress. We have tested this hypothesis directly by transfecting a constitutively expressed recombinant human hsp70-encoding gene into rat fibroblasts and examining the relationship between the levels of human hsp70 expressed and thermal resistance of the stably transfected rat cells. Successful transfection and expression of the gene for human hsp70 were characterized by RNA hybridization analysis, two-dimensional gel electrophoresis, and immunoblot analysis. When individual cloned cell lines were exposed to 45 degrees C and their thermal survivals were determined by colony-formation assay, we found that the expression of human hsp70 conferred heat resistance to the rat cells. These results reinforce the hypothesis that hsp70 has a protective function against thermal stress.

Enhancement of nitrocaphane cytotoxicity by hyperthermia in vitro

HEp-2 cells were treated with hyperthermia (39-44 degrees C) and nitrocaphane (NC) at various time intervals. A 1 h exposure to 39 degrees C and 41 degrees C was non-lethal to cells, but it did potentiate the cell killing of NC (1.0 micrograms/ml). It was further shown that the sequence between heat and the drug can affect cell survival. Cell killing effect was decreased when heat was given before or after administration of drug. In contrast the simultaneous administration of these two modalities was synergistic. Maximal thermotolerance of HEp-2 cells was developed using an 8-h interval at 37 degrees C between the cell exposures to two equal thermal doses (44 degrees C, 30 min). HEp-2 cells became thermotolerant when preheated for 30 min at 44 degrees C followed by a 10-h interval at 37 degrees C. The thermotolerant cells showed resistance to subsequent heat at 44 degrees C (D0 = 2.26 h, control D0 = 0.38 h), to subsequent NC treatment, and to heat combined with NC. However, in the thermotolerant cells, cytotoxicity of NC was still enhanced by hyperthermia.

[Cytotoxic effect of hyperthermia and nitrocaphane on malignant HEp-2 cells]

Cytotoxic effect of hyperthermia combined with Nitrocaphane (NC) on HEp-2 cells was detected by colony formation assay. The results showed: 1. There was significant synergetic effect on survival fraction of HEp-2 cells when the heat was at 43 degrees C and 44 degrees C and NC at 0.5-4.0 micrograms/ml; 2. There was almost no effect on the cell survival when the heat was at 39 degrees C and 41 degrees C for 1 hr without NC; however, the cytotoxicity of NC (1.0 micrograms/ml) was enhanced when temperature was at 39 degrees C and 41 degrees C; 3. The sequence between heat and NC could influence the synergism. When the heat at 43 degrees C, 60 min and NC at 1.0 micrograms/ml were used simultaneously, the cytotoxicity was the strongest (SF = 0.025). When the heat was given 1-4 hr before or after the drug, the cytotoxicity was decreased. These results suggest that, over the range of 39-44 degrees C, the synergetic effects of hyperthermia and NC on malignant HEp-2 cells provide certain cell biologic basis for clinical application of local or systemic hyperthermia combined with NC.