[Application of high-density polyethylene implants in adult cleft lip and palate nasal deformity and dysfunction]

Objective: Through the use of high-density polyethylene implants in adults with cleft lip and palate nasal deformities and abnormal functions, to evaluate the clinical effect of postoperative patients on improving nasal shape and symptoms. Methods: A retrospective study of 12 patients with nasal deformities after cleft lip and palate surgery in the Shanghai Ninth People's Hospital Affiliated to Shanghai JiaoTong University School of Medicine from January 2018 to January 2022 was completed, including 7 males and 5 females, with the age ranging from 18 to 29 years. All the patients underwent nasal deformity correction, and nasal septum correction was performed if necessary. High-density polyethylene implants (MEDPOR/Su-Por) were used intraoperatively. Follow-up for at least 6 months was performed to measure the relevant appearance indicators and subjective Visual Analog Scale (VAS) scores, and to compare the clinical effects before and after surgery. SPSS 22.0 software was used for statistical analysis. Results: Before and after surgery, the average VAS score of nasal obstruction decreased by (4.83±0.94) points; the average VAS score of appearance satisfaction increased by (3.92±1.08) points; the height of nasal columella was increased by (1.79±0.78)mm; the height of nasal tip was increased by (2.79±1.50)mm; the height of ipsilateral nostril was increased by (1.83±0.62)mm; the width of the ipsilateral nasal floor was reduced by (0.42±0.47)mm. All of above were statistically significant (all P<0.05). Conclusion: High-density polyethylene implants can effectively improve the shape and function of the nose in operations related to cleft lip and palate nasal deformity and abnormal functions, and are an ideal synthetic material.

[Study on static parameters of internal nasal valve in 3-dimensional model of nasal cavity space]

Objective: To identify the internal nasal valve (INV) and to evaluate its key parameters in the established 3D models of nasal cavity space via Mimics from CT images, in order to provide evidence for quantitative diagnosis of nasal valve compromise. Methods: A total of 32 Han adults without nasal diseases who underwent maxillofacial CT test in Shanghai Ninth People's Hospital from January 2015 to December 2018 were retrospectively recruited, including 16 males and 16 females, with the age ranged from 20 to 80 years (50% age<50 years old). Maxillofacial CT images were used to create 3D model of nasal cavity space. The INV was identified and the following parameters were measured: the angle between the INV and the nasal bone (θ_INV-B), unilateral cross-sectional area of the INV (A_INV-R, A_INV-L), total cross-sectional area of the INV (A_INV), unilateral height of the INV (H_INV-R, H_INV-L), unilateral nasal valve angle (α_INV-R, α_INV-L), and the sum of nasal valve angle (α_INV). The A_INV in our study was compared with the results of the previously adopted planes (Plane_C, perpendicular to the hard palate and Plane_B, plane perpendicular to the nasal bone). The parameters above were compared among genders, age and race groups. SPSS 26 and GraphPad Prism 9 software were used for statistical analysis and mapping of data. Results: The A_INV in our study was (214.87±52.94) mm², which was significantly less than that of Plane_C (254.97±47.80) mm² and Plane_B (226.07±57.36) mm². The measured parameters were as follows: θ_INV-B was (82.07±7.06)°; A_INV-R was (112.66±31.39) mm²; A_INV-L was (102.21±27.14) mm²; A_INV was (214.87±52.94) mm²; H_INV-R was (24.87±4.62) mm; H_INV-L was (24.35±4.86) mm; α_INV-R was (20.48±2.99)°; α_INV-L was (19.65±3.82)°; α_INV was (40.13±6.24)°. The A_INV-R was larger than A_INV-L (t=2.33, P<0.05); The H_INV, A_INV-R, A_INV-L and A_INV of males were more than those of females (t value was 5.77, 3.21, 2.91 and 3.52, respectively, all P<0.01). The A_INV of the young group (<50 years) was larger than that of the old group (t=2.83, P<0.01); The θ_INV-B was different between the Han people and the Caucasian (t=2.92,P<0.01). The α_INV of the Han people was larger than that of Caucasians (Z=-6.92, P<0.01), but the H_INV was smaller (Z=-3.89, P<0.01). Conclusion: The A_INV carried out in 3D models of nasal cavity space is significantly smaller than that obtained by the previous methods of CT evaluation. INV static parameters differ among genders, age and race groups.

[Arthroscopic-assisted fracture reduction combined with robot-navigated nail placement to treat talar neck fractures]

This study aims to explore the clinical efficacy of arthroscopic-assisted reduction combined with robot-navigated nail placement in the treatment of talar neck fractures. The clinical data of 13 patients with talar neck fracture in Xuzhou Benevolent Hospital from January 2018 to January 2021 were analyzed in the retrospective study. Among them, there were 9 males and 4 females, aged (36±12) years; there were 8 cases suffered on the right and 5 cases on the left. All patients were reset under arthroscopy and cannulated screws were placed in combination with three-dimensional navigation and positioning of orthopedic robot. The wounds and complications were observed in the postoperative follow-up. The activities of bilateral ankle dorsiflexion and plantar flexion were measured in the last follow-up. The visual analogue scale score (VAS) of pain in the affected feet before operation were compared with that at the last follow-up. The ankle and hind foot work energy scale of American Foot and Ankle Association (AOFAS) was used to assess the ankle function. The results showed that the wounds of 13 patients healed in one stage. The operation time was (95±45) min and the blood lose was (45±10) ml. All the patients were followed-up for (15.0±3.5) months. Two cases developed subtalar arthritis without talus necrosis and fracture nonunion. At the last follow-up, there was no significant difference in the dorsal extension and plantar flexion of the ankle between the affected side and the healthy side (25.8°±1.9° vs 26.2°±2.3°, 44.2°±2.7° vs 44.7°±2.8°, both P>0.05). The VAS score of pain in the affected foot at the last follow-up was 0.53±0.18, it was significantly lower than that before operation (0.87±0.29) (P<0.001). The mean AOFAS ankle and hind foot energy scale of the ankle function was 93.5 at the last follow-up. It's showed that treatment of talus neck fracture with arthroscopy assisted and robot guided nail placement is satisfactory and is worthy of clinical promotion.

[Evaluation of the effects auricular reconstruction with Medpor combined with hearing rehabilitation]

Objective: To investigate the clinical effects of single-stage auricular reconstruction and hearing rehabilitation in children with microtia and external auditory canal atresia. Methods: Sixty eight cases of microtia with external auditory canal atresia (53 males and 15 females, age from 7 to 12 years, with a median age of 8.8 years), who received operations in Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine from July 2017 to December 2019 were collected.A total of 28 cases received auricle reconstruction with high-density polyethylene (Medpor) framework and hearing reconstructions, among which 20 patients received the traditional external auditory canal and middle ear repair (EACR), and eight patients were implanted bone conduction device bone bridge(BB) simultaneously.In the control group, 40 patients only received Medpor frame implantation for auricle plasty. Postoperative changes in auricle morphology and auditory function and postoperative complications were evaluated. Results: After three to thirty months follow-ups, the auricles shape recovered well in all three groups. The average scores of 14 fine structures in the auricles were 9.43(EACR) and 10.67(BB) points. The average score of auricle symmetry were 6.83(EACR) and 6.00(BB) points. There was no significant difference compared to the auricle reconstruction group (8.23/6.20 points). P>0.05. After surgery, the average hearing improvement in the BB group was 43.33 dB HL and the average speech recognition threshold declined 42.28 dB HL. In the EACR group, the average hearing improvement was 4.13 dB HL and the average speech recognition threshold declined 11.36 dB HL. No vertigo, tinnitus, cerebrospinal fluid leakage and other complications occurred in all the patients. In the EACR group, sensorial hearing loss, auricle stent fracture, ear canal restenosis and ear canal atresia occurred in one patient respectively. In the auricle group, one auricle stent exposure and one facial branch nerve injury occurred. Nearly ten patients had difficulty in hair growth at scalp incisions. Conclusions: The operation of single-stage auricular reconstruction and hearing rehabilitation for microtia is feasible. The methods of hearing reconstruction should be determined by evaluating the development of the inner and middle ear of the patients. For those with poor mastoid development, bone bridge implantation is recommended to achieve a stable and significant hearing effect.

Forensic Analysis of 43 Medical Disputes Caused by Death after Cardiac Surgery

Abstract

Objective To explore the causes and characteristics of medical disputes caused by death after cardiac surgery and to analyze the pathological changes after cardiac surgery and the key points of forensic anatomy, thus to provide pathological evidence for clinical diagnosis and treatment of cardiac surgery and judicial appraisal as well as reference for the prevention of medical disputes in such cases. Methods Forensic pathological cases of medical disputes caused by death after cardiac surgery which were accepted by the Center for Medicolegal Expertise of Sun Yat-Sen University from 2013 to 2018 were analyzed retrospectively from aspects such as causes of death, pathological diagnosis, surgery condition, medical misconduct, and so on. Results The causes of death after cardiac surgery of 43 patients were abnormal operation, low cardiac output syndrome, postoperative infection, postoperative thrombosis, and other diseases. Among the 43 cases, there were 18 cases without medical fault while 25 cases had medical fault. Conclusion The medical disputes caused by death after cardiac surgery are closely related to the operative technique and postoperative complications. The causes of medical faults include defects in diagnosis and treatment technique, as well as unfulfillment of duty of care.

[Effects of Different Land Use Typess on the Molecular Ecological Network of Soil Bacteria]

The bacterial community composition in four land-use types was determined and the visualized bacterial network was constructed by 16S rDNA Illumina MiSeq high-throughput sequencing technology and a molecular ecological network method. The results show that Proteobacteria, Acidobacteria, Bacteroidetes, Chloroflexi, Actinobacteria, Planctomycetes, Verrucomicrobia, Cyanobacteria, Gemmatimonadetes, Firmicutes, Nitrospirae, and Chlorobi are the main bacteria in this area. The number of nodes of urban green land, paddy field, and dry field bacteria networks is higher, and that of natural forest land is lower. The number of connections and average connectivity of dry fields are the highest; following are those of urban green land and paddy field, and those of natural forest land are the lowest. The four bacterial networks are dominated by positive correlation, and the ratio of competition relationship is TL > LD > HT > ST. The average network path and modularity of the soil bacteria networks of paddy field and dry land are small, while the average connectivity and clustering coefficient are higher. Some flora of Acidobacteria, Firmicutes, and Proteobacteria play an important role in the soil bacterial network in this area. The classification of operational taxonomic units is different among the key nodes of different bacterial molecular ecological networks, and there is almost no overlap. The relative abundance of bacteria of some key nodes in the four bacterial networks is low (<1%), and these are not the main bacteria in this area. The soil microflora in dry land are mainly affected by TP (P<0.05), the soil microflora in paddy field were mainly affected by clay, silt, and water content (P<0.05), and that in natural forest land and urban green land were mainly affected by C/N (P<0.05). The above results show that different land-use patterns lead to changes in soil physical and chemical properties and the interaction between soil bacteria species. The bacterial network of dry land soil is larger and the relationship between species is more complex. The bacteria in different land-use types are mainly cooperative, and the competition is weak. Compared with other land-use types, there is stronger competition between the bacteria in natural forest soil. The soil bacteria in paddy field and dry land are the most sensitive to the external environment, respond more quickly, and the community structure is easier to change. The response of soil bacteria in natural forest land and urban green land is slower, and the disturbance of environmental factors does not affect the whole bacterial ecological network in a short time, and thus the community structure is more stable. Some bacteria have the phenomenon of species role transformation between networks. The abundance and community distribution of microorganisms cannot indicate the strength of their connectivity between network nodes; low-abundance bacteria in soil play an important role in the construction of bacterial networks.

[Effect of N2O produced by indigenous denitrifiers in oil reservoir on the physical properties of crude oil]

The success of microbial enhanced oil recovery (MEOR) relies on complex microbial processes. Nevertheless, the contribution and mechanism of in-situ denitrification to microbial oil recovery remain unclear. In this study, eight denitrifying bacterial strains, designated T1, D1, D44, D46, D15, S1, S2 and S6, were isolated from the produced water of Xinjiang Oilfield, China, by a double layered plate method. The16S rDNA gene sequences of these denitrifying strains shared 100% similarity with Pseudomonas stutzeri (T1, D1, and D44), Pseudomonas putida (D46 and D15), and Pseudomonas aeruginosa (S1, S2, S6), respectively. The N₂O production effects of these strains on the physical properties of crude oil were evaluated with batch experiment. Results showed that the highest total gas yield was observed with sucrose as carbon source, and the maximal concentration of N₂O occurred with glycerol as carbon source. The denitrification process by these bacterial strains led to volume expansion and viscosity reduction of crude oil. Crude oil expansion rate was positively correlated with the concentration of N₂O, with a correlation coefficient of 0.983, but not correlated with the volume of total gas production. Strain S1, S2, and S6 produced 530-730 mg·L^-1 of surfactant using glycerol as ole carbon source, which could reduce surface tension and emulsify crude oil. However, these surfactant-producing strains produced less N₂O, exhibited weaker effects on oil swelling and viscosity reduction, compared to the none-surfactant-producing denitrifying strains. Our results suggested that more attention should be paid to the ability of N₂O production by denitrifying bacteria when exploiting microbial resources towards enhancing oil recovery.

[Effects of medial upper arm bilobed free flaps in the repair of two skin and soft tissue defects of hand]

Objective: To summarize the effects of medial upper arm bilobed free flaps in the repair of two skin and soft tissue defects of hand. Methods: From May 2014 to May 2016, 7 patients of two skin and soft tissue defects of hand with exposures of phalanges and tendons were treated in Xuzhou Renci Hospital, including 5 males and 2 females, aged from 19 to 41 years. Each defect area ranged from 3.0 cm×1.5 cm to 6.0 cm×3.0 cm. The medial upper arm bilobed free flaps were used to repair the defects, and the area of each lobe of the flaps ranged from 4.0 cm×2.0 cm to 8.0 cm×3.5 cm. The donor sites were sutured directly. The survival of the flaps was recorded. During follow-up, the recovery of donor and recipient sites was observed, the two-point discrimination distance of the flaps was measured, and the hand function was assessed by the trial criteria of the upper limb functional assessment of the Hand Surgery Society of the Chinese Medical Association. Results: All flaps survived smoothly, and the wounds and donor site incisions were healed. All patients were followed up, and the follow-up time lasted for 6 to 15 months. The color and texture of the flaps were similar to the surrounding normal skin, and the shape of the flaps was good. There was no obvious scar in the donor site, and the elbow joint function was normal. One patient developed ulnar numbness one month after operation and relieved after 3 months of treatment with neurotrophic drugs and local physiotherapy, etc. Six months after operation, the two-point discrimination distance of the flaps was 5.5-8.0 mm, and the hand function evaluation was excellent in 3 cases, good in 3 cases, and middle in 1 case. Conclusions: The medial upper arm bilobed free flap has both good texture and good appearance, and the scar of donor site is concealed. It is a good method to repair two skin and soft tissue defects of hand.

[A Thermotolerant and Halotolerant Sulfate-reducing Bacterium in Produced Water from an Offshore High-temperature Oilfield in Bohai Bay, China: Isolation, Phenotypic Characterization, and Inhibition]

The growth and activity of sulfate-reducing prokaryotes (SRP) in oilfield environments could produce large amounts of H₂S, leading to multifaceted problems, including oilfield souring and microbially-influenced corrosion, yet knowledge about the diversity and physiology of SRP therein was quite limited. To further understand the phenotypic characteristics of SRP residing in an offshore high-temperature oilfield at Bohai Bay, China, and to explore the potential methods for control of SRP-mediated problems, we isolated, using Hungate techniques, a thermotolerant, halotolerant SRP strain, designated BQ₁, from the produced water of a high-temperature. We also presented the phenotypic features of BQ₁, and investigated the efficacy of five biocides, or metabolic inhibitors, in suppressing the sulfidogenic activity of BQ₁. Cells of BQ₁ were motile, short rod-shaped, 1.2-2.5 μm in length and 0.5-0.8 μm in width. Although BQ₁ shared 99% 16S rRNA gene sequence similarity with Desulfovibrio vulgaris Hildenborough, distinct phenotypic traits between them were observed. Isolated BQ₁ could grow at 14-70℃(optimum at 30℃) and pH 6.0-9.0 (optimum pH 7.0), and in the presence of 0%-10% NaCl. Isolated BQ₁ utilized a wide range of carbon substrates, including sodium formate, sodium lactate, and acetate. Sulfate, sulfite, thiosulfate, and sulfur were utilized as electron acceptors, but not nitrate or nitrite. Sodium hypochlorite (600 mg·L^-1), Benzyltrimethylammonium chloride (300 mg·L^-1), or nitrate (800 mg·L^-1) failed to inhibit H₂S production by BQ₁. By contrast, glutaraldehyde (50 mg·L^-1), bronopol (30 mg·L^-1), chlorine dioxide (50 mg·L^-1), and nitrite (70 mg·L^-1) inhibited H₂S production by BQ₁ for at least 30 d, indicating that these compounds may be suitable for the mitigation of microbial souring in this specific, high-temperature, offshore oilfield at Bohai Bay, China.

Bioaugmentation of oil reservoir indigenous Pseudomonas aeruginosa to enhance oil recovery through in-situ biosurfactant production without air injection

Considering the anoxic conditions within oil reservoirs, a new microbial enhanced oil recovery (MEOR) technology through in-situ biosurfactant production without air injection was proposed. High-throughput sequencing data revealed that Pseudomonas was one of dominant genera in Daqing oil reservoirs. Pseudomonas aeruginosa DQ3 which can anaerobically produce biosurfactant at 42 °C was isolated. Strain DQ3 was bioaugmented in an anaerobic bioreactor to approximately simulate MEOR process. During bioaugmentation process, although a new bacterial community was gradually formed, Pseudomonas was still one of dominant genera. Culture-based data showed that hydrocarbon-degrading bacteria and biosurfactant-producing bacteria were activated, while sulfate reducing bacteria were controlled. Biosurfactant was produced at simulated reservoir conditions, decreasing surface tension to 33.8 mN/m and emulsifying crude oil with EI₂₄ = 58%. Core flooding tests revealed that extra 5.22% of oil was displaced by in-situ biosurfactant production. Bioaugmenting indigenous biosurfactant producer P. aeruginosa without air injection is promising for in-situ MEOR applications.

Simultaneous inhibition of sulfate-reducing bacteria, removal of H2S and production of rhamnolipid by recombinant Pseudomonas stutzeri Rhl: Applications for microbial enhanced oil recovery

Sulfate-reducing bacteria (SRB) are widely existed in oil production system, and its H2S product inhibits rhamnolipid producing bacteria. In-situ production of rhamnolipid is promising for microbial enhanced oil recovery. Inhibition of SRB, removal of H2S and production of rhamnolipid by recombinant Pseudomonas stutzeri Rhl were investigated. Strain Rhl can simultaneously remove S(2-) (>92%) and produce rhamnolipid (>136mg/l) under S(2-) stress below 33.3mg/l. Rhl reduced the SRB numbers from 10(9) to 10(5)cells/ml, and the production of H2S was delayed and decreased to below 2mg/l. Rhl also produced rhamnolipid and removed S(2-) under laboratory simulated oil reservoir conditions. High-throughput sequencing data demonstrated that addition of strain Rhl significantly changed the original microbial communities of oilfield production water and decreased the species and abundance of SRB. Bioaugmentation of strain Rhl in oilfield is promising for simultaneous control of SRB, removal of S(2-) and enhance oil recovery.

[NO3-/NO2- inhibits sulfate-reducing activity of the enrichment culture of sulfate-reducing prokaryotes from an off-shore oil reservoir at Bohai Bay, China]

Long-term injection of sulfate-rich water into oil reservoirs stimulates the proliferation of sulfate-reducing prokaryotes (SRP) therein and results in production of a great amount of H2S, leading to souring in oil reservoirs and related environmental problems. In this study, we first, using modified API RP 38 medium, enriched SRP present in production water from a producing well at Bohai Bay, China, and then examined the inhibitory effects of nitrate or nitrite on sulfate reduction activity of the SRP. Results showed that the enriched SRP culture exhibited a high sulfate reduction activity as indicated by a sulfate-reducing rate of 10.4 mmol SO4(2-) x d(-1) x g(-1) dry cell. In presence of 0.4, 0.8, 1.8, and 4.2 mmol x L(-1) nitrate, sulfate reduction was inhibited for 5, 9, 20, and over 35 days, respectively. With the addition of 0.6, 0.9, 1.4, 2.6 and 4.6 mmol x L(-1) of nitrite, the inhibitory period lasted 3, 12, 22, and over 39 days, respectively. The SRP enrichment culture could dissimilatorily reduce nitrate to ammonium. When sulfate, nitrate and nitrite coexisted, nitrate or nitrite was preferentially used over sulfate as electron acceptor by the enriched SRP. This competitive use of electron acceptor and the strong inhibitory effect of nitrite possibly accounted for the suppression of nitrate and nitrite on the sulfate-reducing activity of the enriched SRP cultures from offshore oil reservoir at Bohai Bay.

Outcomes of laryngectomy in elderly patients with laryngeal carcinoma

Laryngeal carcinoma is a common tumor of the head and neck region. This study aimed to examine the outcomes of laryngectomy in elderly patients with laryngeal carcinoma. One-hundred twenty-two patients (male, 117; female, 5) aged 60 years or older (range, 60-94 years) who underwent laryngectomy between 1996 and 2010 were included. All patients were diagnosed with squamous cell carcinoma of the larynx, and 95 patients (77.9%) had additional concurrent diseases. Tumors were staged according to the TNM categories of the American Joint Committee on Cancer 2002 criteria; there were 16 stage-I, 24 stage-II, 52 stage-III, and 30 stage-IV cases. With regard to treatment modalities, 10 patients underwent transoral laser laryngectomy, 25 underwent partial laryngectomy, and 87 underwent total laryngectomy. When necessary, neck dissection was performed according to the Dalian criteria set in 2004 (a Chinese standard). Of the 122 cases, there were 114 cases of grade I (93.4%), 5 cases of grade II, and 3 cases of grade III (pharyngeal fistula in 2 cases recovered after 2 weeks of care) wound healing. No significant differences were observed in the occurrence or severity of comorbidities. The 1-, 3-, and 5-year actuarial survival rates were 97.5% (119/122), 84.4% (92/109), and 68.4% (67/98), respectively. Age alone should not be used to determine treatment options for elderly patients with squamous cell carcinoma. Presuming that careful pre-treatment evaluations are performed, laryngectomy is a key method for elderly patients with laryngeal carcinoma.

[Inhibition of the activity of sulfate-reducing bacteria in produced water from oil reservoir by nitrate]

Growth and metabolic activity of sulfate-reducing bacteria (SRB) can result in souring of oil reservoirs, leading to various problems in aspects of environmental pollution and corrosion. Nitrate addition and management of nitrate-reducing bacteria (NRB) offer potential solutions to controlling souring in oil reservoirs. In this paper, a facultive chemolithotrophic NRB, designated as DNB-8, was isolated from the produced fluid of a water-flooded oil reservoir at Daqing oilfield. Then the efficacies and mechanisms of various concentrations of nitrate in combination with DNB-8 in the inhibition of the activity of SRB enriched culture were compared. Results showed that 1.0 mmol x L(-1) of nitrate or 0.45 mmol x L(-1) of nitrite inhibited the sulfate-reducing activity of SRB enrichments; the competitive reduction of nitrate by DNB-8 and the nitrite produced were responsible for the suppression. Besides, the SRB enrichment cultures showed a metabolic pathway of dissimilatory nitrate reduction to ammonium (DNRA) via nitrite. The SRB cultures could possibly alleviate the nitrite inhibition by DNRA when they were subjected to high-strength nitrate.

[CaCl2-heat shock preparation of competent cells of three Pseudomonas strains and related transformation conditions]

Pseudomonas, due to its diversity in habitat and metabolic type, makes it have broad prospects applying in bioremediation, bioconversion, and biocontrol, while the introduction of exogenous gene is the key link to genetically modified Pseudomonas. The preparation and transformation of competent cells are the important methodological basis of the introduction of exogenous gene. In this paper, three Pseudomonas strains (P. putida TS11, P. stutzeri DNB, and P. mendocina JJ12) isolated from a petroleum-contaminated soil were taken as the recipient strains, and a three-factor and four-level orthogonal experiment was conducted to investigate the effects of CaCl2 concentration, heat shock duration, and recovery duration on the preparation and transformation efficiency of the strains competent cells. The results showed that CaCl2 concentration was the most important factor affecting the transformation efficiency (P<0.05), and the transformation efficiency was improved markedly when the Pseudomonas cells were repeatedly washed with sterile distilled water before the preparation of competent cells. When the P. putida TS11 cells were treated with 100 mmol L-1 of CaC12, heat-shocked for 3 minutes at 42 degrees, and incubated for 1.5 hours at 30 degrees C, the P. stutzeri DNB cells were treated with 50 mmol . L-1 of CaCl2, heat-shocked for 6 minutes, and incubated for 1.5 hours, and the P. mendocina JJ12 cells were treated with 75 mmol . L-1 of CaCl2, heat-shocked for 4. 5 minutes, and incubated for 0. 5 hours, the transformation efficiency of exogenous plasmids in the three strains all achieved 10(5) cells . microg-1 DNA.

[Temporal variations of soil microbial biomass and enzyme activities during the secondary succession of primary broadleaved-Pinus koraiensis forests in Changbai Mountains of Northeast]

By the method of space-for-time Substitution, and taking the matured (>200 years old) and over-matured (>200 years old) primary broadleaved-Pinus koraiensis forests and, their secondary forests at different succession stages (20-, 30-, 50-, 80-, and 100 years old Betula platphylla forests) in Changbai Mountains of Northeast China as test objects, this paper studied the temporal variations of soil organic carbon, soil microbial biomass, and soil enzyme activities during the secondary succession of primary broadleaved-Pinus koraiensis forests in the Mountains. Under the 20- and 80 years old B. platphylla forests, the soil organic carbon content in humus layer was the highest (154.8 and 154.3 g.kg-1, respectively); while under the matured and over-matured primary broad-leaved-Pinus koraiensis forests, this organic carbon content was relatively low, being 141. 8 and 133. 4 g.kg , respectively. The soil microbial biomass carbon and microbial quotient and the activities of soil cellulase, peroxidase, acid phosphatase, and cellobiase under the 50- and 80 years old B. platphylla forests were the highest, but the activity of soil polyphenol oxidase was the lowest, which revealed that under middle-aged and matured B. platphylla forests, soil organic carbon had a faster turnover rate, and was probably in a stronger accumulation phase. Statistical analysis showed that the soil microbial biomass carbon had significant positive correlations with the soil organic carbon, total nitrogen, and available phosphorus (r = 0.943, 0. 963, and 0.953, respectively;

[Effects of elevated CO2 on forest soil CH4 consumption in Changbai Mountains]

Elevated atmospheric CO2 concentration may affect the oxidation rate of methane (CH4 ) in forest soil. In this study, the effects of a 6-year exposure to elevated CO2 concentration (500 micromol x mol(-1)) on the soil microbial process of CH4 oxidation under Quercus mongolica seedlings were investigated with open top chamber (OTC), and specific 16S rRNA and pmoA gene fragment primers were adopted to analyze the diversity and abundance of soil methanotrophs. Comparing with that under ambient CO2 and open-air, the soil methane consumption under elevated atmospheric CO2 during growth season was reduced by 4% and 22%, respectively. The specific 16S rRNA PCR-DGGE analysis showed that under elevated CO2, the community structure of methane-oxidizing bacteria (MOB) changed, and the diversity index decreased. Elevated CO2 concentration had no distinct effects on the abundance of Type I MOB, but decreased the amount of Type II MOB significantly. The pmoA gene copy number under elevated CO2 concentration decreased by 15% and 46%, respectively, as compared with that under ambient CO2 and open-air. Our results suggested that elevated atmospheric CO2 decreased the abundance and activity of soil methanotrophs, and the main cause could be the increase of soil moisture content.

Effect of genetic variation in the organic cation transporter 1, OCT1, on metformin pharmacokinetics

The goal of this study was to determine the effects of genetic variation in the organic cation transporter 1, OCT1, on the pharmacokinetics of the antidiabetic drug, metformin. Twenty healthy volunteers with known OCT1 genotype agreed to participate in the study. Each subject received two oral doses of metformin followed by collection of blood and urine samples. OCT1 genotypes had a significant (P<0.05) effect on metformin pharmacokinetics, with a higher area under the plasma concentration-time curve (AUC), higher maximal plasma concentration (Cmax), and lower oral volume of distribution (V/F) in the individuals carrying a reduced function OCT1 allele (R61C, G401S, 420del, or G465R). The effect of OCT1 on metformin pharmacokinetics in mice was less than in humans possibly reflecting species differences in hepatic expression level of the transporter. Our studies suggest that OCT1 genotype is a determinant of metformin pharmacokinetics.

Cloning of guinea pig tissue factor cDNA: comparison of primary structure among six mammalian species

Tissue factor (TF) is a transmembrane glycoprotein that serves as an essential cofactor for plasma coagulation factor VII. TF procoagulant activity exhibits varying species specificity. In particular, guinea pig (GP) TF is unable to activate clotting in heterologous plasma systems, but the molecular basis for this phenomenon is not yet understood. The full-length GP TF cDNA was cloned and sequenced. The open reading frame encoded a predicted precursor protein of 289 amino acids (aa) which was expressed in a reticulocyte lysate system as a protein of apparent molecular weight of 34 kD. The identity of the predicted aa sequence of mature GP TF with rabbit, human, bovine, rat and mouse TF was 66.4, 64.4, 60.6, 53.2 and 52.2%, respectively. With a focus on sites of potential functional significance, we compared sequences within the known binding regions. The eleven residues at the interface region between the TF1 and TF2 modules, which bind to the EGF domain of VIIa, were perfectly conserved among the six species, with the exception of an isoleucine replacing a lysine in the guinea pig sequence. However, only four of the eleven binding residues in the TF1 module, known to interact with the catalytic domain of factor VII, and three of the five residues in the TF2 module, involved in binding the factor VII Gla domain, were conserved among species. We hypothesize that divergence at these regions contributes to the specificity and non-reciprocity of TF procoagulant activity between species.

Post-transcriptional regulation of endothelial cell plasminogen activator inhibitor-1 expression during R. rickettsii infection

Intracellular infection of endothelial cells with Rickettsia rickettsii results in increased steady-state levels of plasminogen activator inhibitor-1 (PAI-1) mRNA. Control mechanisms governing such increased expression in response to this novel stimulus have not been defined. In this study, we compared the stability of PAI-1 mRNA in infected and uninfected endothelial cells (EC) and explored the requirement for de novo host cell protein synthesis in the infection-induced increase of steady-state levels. The half-life of PAI-1 mRNA, which is constitutively expressed in cultured EC, increased from 18 h in uninfected EC to greater than 30 h in EC infected for 24 h, a time point at which increases in steady-state PAI-1 mRNA levels are noted. There was no change in stability of gamma-actin due to infection. Nuclear run-on studies revealed no apparent increase in transcription rate at 4, 18 and 24 h. R. rickettsii -induced increase in PAI-1 mRNA was blocked by the eukaryotic protein synthesis inhibitor, cycloheximide, which suggests that this response requires de novo host cell protein synthesis. These results provide evidence that post-transcriptional control mechanisms are operative in the regulation of PAI-1 during R. rickettsii infection.

Transcriptional regulation of endothelial cell tissue factor expression during Rickettsia rickettsii infection: involvement of the transcription factor NF-kappaB

The vascular endothelial cell (EC) is a primary target of infection with Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever. Changes in gene transcription elicited by intracellular infection, including EC expression of the coagulation pathway initiator known as tissue factor (TF), may contribute to the vascular pathology observed during disease. Nuclear run-on analysis of uninfected and infected, cultured human endothelial cells revealed that the rate of TF mRNA transcription is enhanced more than twofold at 3 h following infection, thus coinciding with increased steady-state levels of TF mRNA. TF mRNA remained relatively unstable during infection, with a half-life of 1.6 h. The eukaryotic protein synthesis inhibitor cycloheximide did not block R. rickettsii-induced increase in TF mRNA levels and actually resulted in its superinduction, thus revealing that de novo synthesis of host cell protein was not prerequisite to this transcriptional response. Involvement of the transcription factor NF-kappaB in R. rickettsii-induced TF expression was demonstrated by using two unrelated inhibitors of NF-kappaB activation. The antioxidant pyrrolidinedithiocarbamate and the proteasome inhibitor N-tosyl-L-phenylalanine chloromethyl ketone blocked expression of TF mRNA and activity during infection. This study demonstrates that R. rickettsii infection results in transcriptional activation of the TF gene and that this response involves activation of the transcription factor NF-kappaB.

Increased expression of plasminogen activator inhibitor-1 in R. rickettsii-infected endothelial cells

Changes in PAI-1 expression in human umbilical vein endothelial cells (HUVEC) were studied following in vitro infection with Rickettsia rickettsii. A 1.8-fold increase in secreted PAI-1 activity occurred in infected versus control cultures (p = 0.03) at 24 h but not at earlier timepoints. A similar increase (1.4-fold) in secreted PAI-1 antigen (p < 0.005) was measured by ELISA. To determine whether this increase was due to increased synthesis of PAI-1, HUVEC were metabolically labeled with 35S-methionine concurrent with R. rickettsii infection. Such infection resulted in a 1.9-fold increase in labeled PAI-1 in the medium at 24 h (p = 0.036). Increase steady-state levels of PAI-1 mRNA were detected as early as 18 h by Northern blot analysis, peaking (5.5-fold) at approximately 24 h. These results indicate that PAI-1 production is increased in RR-infected endothelial cells, an effect that may contribute to the vascular occlusions noted in Rocky Mountain spotted fever.

Rickettsia rickettsii infection of cultured human endothelial cells induces tissue factor expression

Microvascular thrombi underlie many of the clinical manifestations of Rocky Mountain spotted fever (RMSF), a disease characterized by Rickettsia rickettsii infection of vascular endothelial cells. Studies were designed to determine whether R rickettsii-infection of cultured human umbilical vein endothelial cells results in tissue factor (TF) induction, a process that could directly activate coagulation in infected vessels. Whereas uninfected endothelial cell cultures showed essentially undetectable TF mRNA and activity, both TF mRNA and activity were present after R rickettsii infection. TF mRNA levels were transient, peaking at 4 hours after the initiation of infection, whereas the peak of TF activity occurred at 8 hours. Induction of the TF response requires the intracellular presence of R rickettsii organisms, because uninfected rickettsia were ineffective and the response was blocked by inhibiting rickettsial entry using cytochalasin B. TF induction was not mediated by endothelial cell release of soluble factor, because no response was induced using culture medium conditioned by R rickettsii-infected cells. Furthermore, preadsorption of suspensions of R rickettsii with polymyxin B to remove contaminating lipopolysaccharide did not eliminate the TF response. Induction of TF in vital endothelial cells during R rickettsii infection could be the trigger for vascular thrombus formation of RMSF.

Rickettsia rickettsii infection of cultured endothelial cells induces release of large von Willebrand factor multimers from Weibel-Palade bodies

The clinical manifestations of Rocky Mountain spotted fever (RMSF) result from Rickettsia rickettsii (R rickettsii) infection of endothelial cells and are mediated by pathologic changes localized to the vessel, including in situ thrombosis and tissue ischemia. This study uses in vitro infection of cultured human umbilical vein endothelial cells with R rickettsii to test the hypothesis that such infection induces von Willebrand factor (vWF) release from Weibel-Palade bodies, a process that could contribute to thrombotic changes. At 24 hours postinfection, there was an increase in metabolically prelabeled large multimers of vWF in the culture medium, with a concomitant decrease of these forms in the cell lysate samples. This release reaction was specific for the large multimer pool of vWF, localized to Weibel-Palade bodies, because no change in the distribution of dimeric forms between cells and culture medium was detected. Double-label immunofluorescence staining showed an inverse correlation between the number of R rickettsii and the number of Weibel-Palade bodies in infected cells. Cell lysis was minimal at 24 hours postinfection, as no detectable intracellular precursor forms (molecular weight 260,000) of vWF were released into the culture medium, there was no decrease in cell viability as measured by trypan blue exclusion, and no increase in 51Cr-release into the culture medium was observed when compared with uninfected controls. Release was likely a direct effect of the intracellular presence of the organism, rather than due to a noxious soluble factor such as endotoxin, because culture medium conditioned by infected endothelial cells was ineffective at inducing release in uninfected endothelial cell cultures. In summary, in vitro infection of endothelial cells by R rickettsii induces release of Weibel-Palade body contents, a process that may contribute to the pathogenesis of RMSF.