[Effects of regional citrate anticoagulation in continuous veno-venous hemofiltration of severe burn patients].

Objective: To investigate the effects of regional citrate anticoagulation in continuous veno-venous hemofiltration (CVVH) of severe burn patients. Methods: A retrospective non-randomized controlled study was conducted. From January 2017 to August 2020, sixty-eight severe burn patients who met the inclusion criteria were treated with CVVH in Affiliated Hospital of Nankai University. According to the different methods of blood anticoagulation in CVVH treatment, patients were divided into citrate group (n=40) and heparin group (n=28). In the citrate group, 32 males and 8 females were (40±18) years old with total burn area of (62±14)% total body surface area (TBSA); in the heparin group, 22 males and 6 females were (38±16) years old with total burn area of (57±20)%TBSA. Creatinine level, C-reactive protein (CRP) value, and urea nitrogen level in serum of patients were recorded at 0 (immediately), 48, and 96 h after CVVH treatment in 2 groups, urea clearance index was calculated based on urea nitrogen level at 0, 48, and 96 h after CVVH treatment in 2 groups, platelet count (PLT), prothrombin time (PT), and activated partial thromboplastin time (APTT) in total coagulation of patients were recorded. The frequency of forced hemofiltration termination caused by adverse reactions such as severe hypocalcemia, aggravated wound bleeding, and new bleeding on non-wound surface of patients was recorded within 96 h of CVVH treatment. The duration of daily CVVH use from the beginning to the end was recorded. Data were statistically analyzed with chi-square test, analysis of variance for repeated measurement, independent samples t test, and Bonferroni correction. Results: There were no significant differences in urea nitrogen level, creatinine level, and CRP value in serum of patients between 2 groups at 0 h after treatment (P>0.05). At 48 and 96 h after treatment, urea nitrogen level, creatinine level, and CRP value in serum of patients in citrate group were significantly lower than those in heparin group (t=3.366, -2.315, 2.942, -2.657, 2.011, -2.441, P<0.05), and urea clearance index of patients in citrate group was significantly higher than that in heparin group (t=1.017, 2.233, P<0.05). There were no statistically significant differences in PLT, PT, and APTT of patients between 2 groups at 0 h after treatment (P>0.05). At 48 and 96 h, PLT of patients in citrate group was significantly higher than that in heparin group (t=-3.417, -4.143, P<0.05 or P<0.01), PT of patients in citrate group was significantly shorter than that in heparin group (t=2.760, -3.655, P<0.01), APTT of patients in citrate group was significantly shorter than that in heparin group (t=3.719, 5.146, P<0.05 or P<0.01). Within 96 h of treatment, there was 1 case of hypocalcemia and 1 case of aggravated wound bleeding resulting in forced hemofiltration termination in citrate group, but there was no new bleeding on non-wound surface; in heparin group, there was no hypocalcemia, but 7 cases of aggravated wound bleeding and 2 cases of new bleeding on non-wound surface (both at the tracheotomy site) resulting in forced hemofiltration termination. The use time of blood purification filter of patients in citrate group was (11.7±4.8) h, obviously longer than (6.6±2.5) h in heparin group (t=3.310, P<0.01). Conclusions: The use of regional citrate anticoagulation in CVVH treatment of severe burn patients has the advantages including little effect on coagulation function and high safety, can effectively prolong the use time of filter and improve the therapeutic effect, but this conclusion still needs to be further verified in clinical application.

[Influence of directed restrictive fluid management strategy on patients with serious burns complicated by severe inhalation injury].

Objective: To explore the influence of directed restrictive fluid management strategy (RFMS) on patients with serious burns complicated by severe inhalation injury. Methods: Sixteen patients with serious burns complicated by severe inhalation injury hospitalized in our department from December 2014 to December 2017, meeting the inclusion criteria and treated with RFMS, were enrolled in directed treatment group. Thirty-four patients with serious burns complicated by severe inhalation injury hospitalized in our department from December 2012 to December 2017, meeting the inclusion criteria and without RFMS, were enrolled in routine treatment group. Medical records of patients in 2 groups were retrospectively analyzed. Within post injury day 2, mean arterial pressure (MAP), central venous pressure (CVP), extravascular lung water index (ELWI), global end-diastolic volume index, and pulmonary vascular permeability index of patients in directed treatment group were monitored by pulse contour cardiac output monitoring technology, while MAP and CVP of patients in routine treatment group were monitored by routine method. On post injury day 3 to 7, patients in 2 groups were treated with routine fluid supplement therapy of our Department to maintain hemodynamic stability, and patients in directed treatment group were treated according to RFMS directed with goal of ELWI≤7 mL·kg(-1)·m(-2). On post injury day 3 to 7, total fluid intake, total fluid output, and total fluid difference between fluid intake and output within 24 h, value of blood lactic acid, and oxygenation index of patients in 2 groups were recorded. Occurrence of acute respiratory distress syndrome (ARDS) on post injury day 3 to 7 and 8 to 28, mechanical ventilation time within post injury day 28, and occurrence of death of patients in 2 groups were counted. Data were processed with chi-square test, t test, and analysis of variance for repeated measurement. Results: The total fluid intakes within 24 h of patients in directed treatment group were close to those in routine treatment group on post injury day 3, 4, 5, 6, 7 (t=-0.835, -1.618, -2.463, -1.244, -2.552, P>0.05). The total fluid outputs and total fluid differences between fluid intake and output within 24 h of patients in 2 groups on post injury day 3 were close (t=0.931, -2.274, P>0.05). The total fluid outputs within 24 h of patients in directed treatment group were significantly higher than those in routine treatment group on post injury day 4, 5, 6, 7 (t=2.645, 2.352, 1.847, 1.152, P<0.05). The total fluid differences between fluid intake and output within 24 h of patients in directed treatment group were (2 928±768), (2 028±1 001), (2 186±815), and (2 071±963) mL, significantly lower than (4 455±960), (3 434±819), (3 233±1 022), and (3 453±829) mL in routine treatment group (t=-4.331, -3.882, -3.211, -4.024, P<0.05). The values of blood lactic acid of patients in directed treatment group and routine treatment group on post injury day 3, 4, 5, 6, 7 were close (t=0.847, 1.221, 0.994, 1.873, 1.948, P>0.05). The oxygenation indexes of patients in directed treatment group on post injury day 3 and 4 were (298±78) and (324±85) mmHg (1 mmHg=0.133 kPa ), which were close to (270±110) and (291±90) mmHg in routine treatment group (t=-1.574, 2.011, P>0.05). The oxygenation indexes of patients in directed treatment group on post injury day 5, 6, 7 were (372±88), (369±65), and (377±39) mmHg, significantly higher than (302±103), (313±89), and (336±78) mmHg in routine treatment group (t=3.657, 3.223, 2.441, P<0.05). On post injury day 3, 4, 5, 6, 7, patients with ARDS in directed treatment group were less than those in routine treatment group, but with no significantly statistical difference between the 2 groups (χ(2)=0.105, P>0.05). On post injury day 8 to 28, patients with ARDS in directed treatment group were significantly less than those in routine treatment group (χ(2)=0.827, P<0.05). The mechanical ventilation time within post injury day 28 of patients in directed treatment group was apparently shorter than that in routine treatment group (t=-2.895, P<0.05). Death of patients in directed treatment group within post injury day 28 was less than that in routine treatment group, but with no significantly statistical difference between the 2 groups (χ(2)=0.002, P>0.05). Conclusions: Under the circumstance of hemodynamics stability, RFMS directed with goal of ELWI≤7 mL·kg(-1)·m(-2) on post injury day 3 to 7 is an useful strategy, which can reduce occurrence rate of ADRS and shorten mechanical ventilation time of patients with serious burns complicated by severe inhalation injury at late stage of burns.

Note: An atomic self-sustaining magnetic gradiometer with a 1/τ uncertainty property based on Larmor precession.

We demonstrate an atomic magnetic gradiometer based on self-sustaining Larmor precession. By coherent optical pumping, we measure the phase of the Larmor precession directly and observe that the gradiometer shows a 1/τ improvement in magnetic field gradient uncertainty over time τ. Since the measurement gives frequency signals, the gradiometer can be easily implemented by mixing and filtering the different frequency signals from two adjacent magnetometers. A gradient sensitivity of 186 fT/Hz/cm-1) is realized, which is close to the shot-noise limit. In a noisy environment, the gradiometer can still maintain its 1/τ behavior by suppressing 90% of the common-mode noise. This method should be widely applicable to the measurement of magnetic field gradients owing to its simplicity and outstanding performance.

A stabilized laser continuously tunable over a range of 1.5 GHz.

We demonstrate a method to stabilize laser frequency which can be continuously tuned over a range of 1.5 GHz. It is based on saturated absorption spectroscopy (SAS) generated by an external-cavity diode laser (ECDL) which is modulated by an electro-optic amplitude modulator (EO-AM). The spectra consist of not only the original peaks corresponding to resonant and crossover lines of 133Cs D2 line, but also signals introduced by sidebands from an EO-AM. Thus, the laser frequency can be locked to any point within the range of the spectra. Furthermore, the tuning range of the laser can be doubled compared to the coverage of common SAS by fixing the frequency of the pumping laser. The best stability of the locked laser induced by the EO-AM is 1.27 × 10-11 over an integrating time of 125 s. This method may be applied for more precise and flexible manipulation of atoms and molecules.

[Evaluating the accuracy of three-dimensional reconstruction of the intercuspal position for dentition casts aided by a mechanical appliance].

OBJECTIVE: To develop a aided mechanical appliance for rapid reconstruction of three-dimensional(3D)relationship of dentition model after scanning and evaluation of its accuracy. METHODS: The appliance was designed by forward engineering software and fabricated by a high precision computer numerical control(CNC)system. It contained upper and lower body, magnetic pedestal and three pillars. Nine 3 mm diameter hemispheres were distributed equally on the axial surface of each pedestal. Faro Edge 1.8m was used to directly obtain center of each hemisphere(contact method), defined as known center. A pair of die-stone standard dentition model were fixed in intercuspal position and then fixed on the magnetic pedestals with low expansion ratio plaster. Activity 880 dental scanner was used to scan casts after the plaster was completely set. In Geomagic 2012, the centers of each hemisphere were fitted and defined as scanning centers. Scanning centers were aligned to known centers by reference point system to finish the 3D reconstruction of the intercuspal occlusion for the dentition casts. An observation coordinate system was interactively established. The straight-line distances in the X(coronal), Y(saggital), and Z(vertical)between the remaining 6 pairs of center points derived from contact method and fitting method were measured respectively and analyzed using a paired t-test. RESULTS: The differences of the straight-line distances of the remaining 6 pairs of center points between the two methods were X:(-0.05±0.10)mm, Y:(0.02±0.06)mm, and Z:(0.01 ± 0.05)mm. The results of paired t-test showed no significant differences(P>0.05). CONCLUSIONS: The mechanical appliance can help to reconstruct 3D jaw relation by scanning single upper and lower dentition model with usual commercial available dental cast scanning system.

Optimal pollinator attraction strategies in Trollius ranunculoides Hemsl. (Ranunculaceae) at different altitudes: increased floral display or promotion of nectar output?

For alpine plant species, patterns of resource allocation to functional floral traits for pollinator attraction can be highly significant in adaptation to low pollinator abundance and consequent pollen limitation. Increased pollination can be achieved either through a larger floral display or production of more pollen rewards. In this study, variation in resource allocation to different components for pollinator attraction was studied along an altitudinal gradient in Trollius ranunculoides, an obligate self-incompatible out-crosser of the Qinghai-Tibet Plateau. We compared resource allocation to conspicuous yellow sepals (which mainly provide visual attraction) and degenerate petals (which provide the major nectar reward) between populations at four altitudes. Furthermore, we investigated the contribution of sepals and petals to pollinator attraction and female reproductive success in an experiment with sepal or petal removal at sites at different altitudes. At the level of single flowers, resource allocation increased to sepals but decreased to petals with increasing altitude. Consistent with these results, sepals contributed much more to visitation rate and seed set than petals, as confirmed in the sepal or petal removal experiment. Sepals and petals contributed to female reproductive success by ensuring visitation rate rather than visitation duration. To alleviate increasing pollen limitation with increasing altitude, resource allocation patterns of T. ranunculoides altered to favour development of sepals rather than petals. This strategy may improve pollination and reproductive success through visual attraction (sepal) rather than nectar reward (petal) over a gradient of decreasing pollinator abundance.

Size-dependent sex allocation in Aconitum gymnandrum (Ranunculaceae): physiological basis and effects of maternal family and environment.

Theory predicts size-dependent sex allocation (SDS): flowers on plants with a high-resource status should have larger investment in females than plants with a low-resource status. Through a pot experiment with Aconitum gymnandrum (Ranunculaceae) in the field, we examined the relationship between sex allocation of individual flowers and plant size for different maternal families under different environmental conditions. We also determined the physiological base of variations in plant size. Our results support the prediction of SDS, and show that female-biased allocation with plant size is consistent under different environmental conditions. Negative correlations within families showed a plastic response of sex allocation to plant size. Negative genetic correlations between sex allocation and plant size at the family level indicate a genetic cause of the SDS pattern, although genetic correlation was influenced by environmental factors. Hence, the size-dependency of sex allocation in this species had both plastic and genetic causes. Furthermore, genotypes that grew large also had higher assimilation ability, thus showing a physiological basis for SDS.

Cloning of pig parotid secretory protein gene upstream promoter and the establishment of a transgenic mouse model expressing bacterial phytase for agricultural phosphorus pollution control.

This study examined the feasibility of using the promoter of the pig parotid secretory protein (PSP) gene for expression of the phytase transgene in mouse models. The pig parotid secretory protein gene is specifically expressed at high levels in the salivary glands. The 10-kb upstream promoter region of the gene necessary for tissue-specific expression has been identified. We have constructed phytase transgenes composed of the appA phytase gene from Escherichia coli driven by the upstream promoter region of the pig PSP gene with a 3' tail of either bovine growth hormone or the pig PSP gene polyadenylation signal. Transgenic mouse models with the construct showed that the upstream region of the pig PSP gene is sufficient for directing the expression of phytase transgenes in the saliva. Expression of salivary phytase reduced fecal phytate by 8.5 and 12.5% in 2 transgenic mouse lines, respectively. These results suggest that the expression of phytase in salivary glands of monogastric animals offers a promising biological approach to relieve the requirement for dietary phosphate supplements and to reduce phosphorus pollution from animal agriculture.

Cloning and sequencing of quail and pigeon prion genes.

Quail and pigeon PrP genes were cloned and sequenced. Like mammalian PrP genes, quail and pigeon genes are encoded by a single exon of a single copy gene in the genome. All of the structural features of mammalian PrP genes were found in the quail and pigeon PrP gene. Compared with the nucleotide sequences of mammalian PrP, they display generally 30% similarity. When compared with chicken PrP's DNA sequence, they show a higher homology (90%), and an even higher homology (99%) when compared to each other. A phylogenetic tree was constructed to trace the evolution of the prion gene in animals.

[Research on constructing phylogenetics trees of ruminants basing on the database of milk protein gene sequences].

Primers designed according to the sequences of four milk protein genes of cow Bos taurus (alpha-lactoalbumin, beta-lactoglobin, beta- and kappa-casein) were used to amplify the full length gene of alpha-lactalbumin in yak Bos grunniens (2999 bp), water buffalo Bubalus arnee bubalis (278 bp), partial sequence of this gene in red deer cervus elaphs xanthopygus (1582 bp), 5' and 3' flanking region of beta-lactoglobin gene (2167 bp and 1096 bp in length respectively), 5'-flanking region and exon VIII to exon IX of beta-casein gene (987 bp and 1096 bp in length respectively), exonIV of kappa-casein gene (780 bp). All the amplified DNA fragments were cloned and the Nt sequences were determined. Phylogenetic tree containing 20 species (or subspecies) of ruminantia suborder was constructed according to the partial sequence of kappa-casein gene exon IV (363 bp in length), which shows good monophyly of the Bovidae. And trees constructed according to other milk protein genes indicate that all the milk protein genes have good features for drawing phylogenetics tree at least among species belonging to different subfamilies.