[Determination of 14 volatile organic compounds in urine by headspace gas chromatography-mass spectrometry]

Objective: To establish a automatic headspace gas chromatography-mass spectrometry (HS/GC-MS) method for the determination of 14 volatile organic compounds in urine. Methods: In September 2022, 10 ml urine sample was taken into a 20 ml headspace bottle, balanced for 30 min at 65 ℃, and then detected by HS/GC-MS and quantified by external standard method. Results: The 14 volatile organic compounds showed good linearity at 0.2-8.0 μg/L and 0.1-4.0 μg/L, with correlation coefficients ranging from 0.9956-0.9999. The recoveries were 79.8%-113.1% with relative standard deviations 0.05%-0.27% when three different concentration levels were added. Detection limit was 0.03-0.05 μg/L. Conclusion: The method is simple and convenient, and the recovery and precision meet the requirements. It can be used for the determination of common volatile organic compounds in urine.

Identification and Dosimetric Analysis of Axillary Substructures Associated with Breast Cancer Related Lymphedema

PURPOSE/OBJECTIVE(S)

It has been hypothesized that substructures in the axillary region may be involved in the development of upper limb lymphedema in breast cancer patients. We aimed to compare dosimetric parameters of different substructures to identify risk regions and dose indicators related to the development of lymphedema.

MATERIALS/METHODS

A total of 486 patients with breast cancer treated with axillary node dissection (ALND) and regional node irradiation (RNI) between 2017 and 2020 were analyzed. Ten axillary substructures were retrospectively contoured, and dose-volume histogram (DVH) parameters (maximum dose [Dmax], Dmean, Dmin, V5 Gy, V10 Gy, V15 Gy, V20 Gy, V25 Gy, V30 Gy, V35 Gy, V40 Gy, V45 Gy and V50 Gy) were evaluated. EQD2 using α/β = 3 was applied for hypofractionation.

RESULTS

The cumulative incidence of lymphedema was 32.5% during the median follow-up of 25 month (IQR 15-35). Higher BMI (≥21.77 kg/m2, hazard ratio [HR]1.6, 95% CI 1.1-2.3, p = 0.019) and higher number of dissected lymph nodes (≥13, HR 1.8, 95% CI 1.1-3.0, p = 0.026) were baseline risk factors associated with breast cancer related lymphedema (BCRL). A cohort of 196 patients was obtained by 1:1 propensity score matching based on the above two factors (154 treated with 50 Gy/25 fractions [Fx] and 42 with 40.05 Gy/15Fx). The optimal metric was axillary-lateral thoracic vessel juncture (ALTJ) Dmean ≥36.84 Gy (HR 3.7, 95% CI 1.6-8.6, p = 0.002). Other significant risk factors are Medial of Axillary Nodes level I(ALN-I-M) Dmin <9.19 Gy (HR 2.3, 95% CI 1.4-3.7, p = 0.001) and Posterior of Axillary Nodes level II(ALN-II-P) Dmax <52.75 Gy (HR 2.0, 95% CI 1.2-3.5, p = 0.015). A nomogram incorporated the above three parameters was created to predict the risk of lymphedema with reasonable accuracy confirmed by both self-training (area under curve [AUC], 0.76; 95% CI, 0.67-0.84) and internal validation (AUC 0.66; 95% CI, 0.50-0.80).

CONCLUSION

A mean dose of 36.84 Gy of ALTJ may be a suggested dose limit for patients indicated RNI after ALND, especially when patients with higher BMI and higher dissected nodes. Ideally, avoidance of ALTJ may be realized without compromising dose coverage to high-risk nodal region. Confirmation of this finding in future prospective studies is needed.

[Influence of work engagement and self-efficacy of nurses on clinical practice ability in burn intensive care unit]

Objective: To analyze the influence of work engagement and self-efficacy of nurses on clinical practice ability in burn intensive care unit (BICU), and to explore its potential pathways of action. Methods: A cross-sectional survey was conducted. From May to October 2020, a total of 30 hospitals with BICU in China were selected by stratified sampling method. Among BICU nurses who met the inclusion criteria, their clinical practice ability, work engagement, and self-efficacy were evaluated by self-evaluation scale of oriented problem-solving behavior in nursing practice (OPSN), Utrecht work engagement scale (UWES), and general self-efficacy scale (GSES), respectively. The total scale scores of each index and the average item scores were recorded. The self-designed general data questionnaire was used to investigate the nurses' gender, age, marital status, education background, working years, professional title, and the economic region of the hospital that they belonged to. The total scale scores of the above-mentioned three evaluation indexes were compared after the classification of nurses according to general data, and the data were statistically analyzed with independent sample t test or one-way analysis of variance. Pearson correlation analysis was used to analyze the correlation between the total scale scores of the three evaluation indexes. Based on the total scale scores of the above-mentioned three evaluation indexes, a structural equation model was established, the mediation analysis of the relationship among the three evaluation indexes and the pathway analysis of the structural model were conducted, and the Bootstrap method was used to verify the pathways of action. Results: A total of 401 questionnaires were distributed, and 337 valid questionnaires were returned, with a valid return rate of 84.04%. The total scale scores of clinical practice ability, work engagement, and self-efficacy of 337 nurses were 98.2±11.7, 67.7±18.6, and 26.6±5.6, respectively, and the average item scores were 3.9±0.5, 4.5±1.2, and 2.7±0.6, respectively. Among the 337 nurses, the majority were female, aged 40 or below, married, and had a bachelor's degree with work experience of ≤10 years; both nurses with professional nurse title and nurses from the Southeast region accounted for about 50%. There were statistically significant differences in the total scale score of clinical practice ability among nurses with different ages, education backgrounds, working years, and professional titles (with F values of 3.26, 4.36, 3.12, and 2.80, respectively, P<0.05). There was statistically significant difference in the total scale score of work engagement among nurses with different working years (F=4.50, P<0.05). There were statistically significant differences in the total scale score of self-efficacy among nurses with different ages, working years, and professional titles (with F values of 4.91, 4.50, and 2.91, respectively, P<0.05). The total scale score of nurses' work engagement was significantly positively correlated with the total scale score of clinical practice ability and the total scale score of self-efficacy (with r values of 0.30 and 0.51, respectively, P<0.05). The total scale score of nurses' self-efficacy was significantly positively correlated with the total scale score of clinical practice ability (r=0.37, P<0.05). The model had good adaptability, and the intermediary model was established. Nurses' work engagement had a significantly positive effect on both self-efficacy and clinical practice ability (with β values of 0.54 and 0.16, respectively, P<0.05), and nurses' self-efficacy had a significantly positive effect on clinical practice ability (β=0.29, P<0.05). Work engagement had a direct effect on self-efficacy and clinical practice ability, and self-efficacy had a direct effect on clinical practice ability and played a mediating role between work engagement and clinical practice ability. Bootstrap validation showed that self-efficacy played a significantly mediating role in the influence of work engagement on clinical practice ability (with effect size of 0.16, with 95% confidence interval of 0.08-0.24, P<0.05), accounting for half of the total effect of work engagement on clinical practice ability (with effect size of 0.32). Conclusions: BICU nurses have an above-average level of clinical practice ability, a medium level of self-efficacy, and a high level of work engagement. Work engagement and self-efficacy are positively correlated with clinical practice ability. Work engagement can directly affect clinical practice ability or indirectly affect clinical practice ability through the mediating role of self-efficacy.

[Sinusitis, otitis media and diffuse bronchiectasis in both lungs]

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive or X-linked biallelic mutations inherited disease, characterized by motile cilia dysfunction. Typical manifestations include bronchiectasis, secretory otitis media, sinusitis, situs inversus, and infertility. PCD often needs to be differentiated from cystic fibrosis (CF) because of similar clinical manifestations. In this paper, a juvenile female who presented with recurrent cough and expectoration with fever since early childhood, had a history of secretory otitis media and sinusitis, and had been considered for the diagnosis of CF. After the discovery of compound heterozygous mutations in PCD related pathogenic genes by gene sequencing, combined with the clinical manifestations and imaging characteristics, PCD was finally diagnosed.

[Feasibility, safety and long-term efficacy of laparoscopic total gastrectomy combined with distal pancreaticosplenectomy for T4b gastric cancer]

Objective: To explore the feasibility, safety and long-term efficacy of laparoscopic total gastrectomy combined with distal pancreaticosplenectomy for the treatment of T4b gastric cancer. Methods: A retrospective cohort study was performed. Clinical data of consecutive patients with T4b gastric cancer invading pancreatic tail undergoing laparoscopic or open total gastrectomy combined with distal pancreaticosplenectomy from January 2010 to December 2014 were analyzed retrospectively. Enrollment criteria: (1) primary gastric cancer confirmed by pathology as T4b adenocarcinoma; (2) chest+abdominal+pelvic enhanced CT indicated cancer invading pancreatic tail without distant metastasis, and R0 resection was evaluated as feasible before operation; (3) physical status was ECOG score 0 to 2, and was tolerant to operation. Patients with peritoneal implant metastasis and tumor invasion of other organs during operation, or changes in surgical methods for other reasons were excluded. All the operations were performed by the same surgical team, which had the experiences of more than 100 cases of laparoscopic and 100 cases of open radical gastrectomy with D2 lymph node dissection. The choice of surgical procedure was discussed by the surgeon and the patient, and decided according to the patient's intension. Patients were divided into the laparoscopic group and open group according to the surgical method. Intraoperative and perioperative findings were compared between the two groups. The 3-year disease-free survival rate were analyzed with Kaplan-Meier survival curve and compared by using log-rank test. Results: A total of 37 consecutive patients were enrolled, including 21 in the laparoscopic group and 16 in the open group, and no one receiving laparoscopic procedure was converted to open surgery. The baseline data of two groups were comparable (all P>0.05). Compared with the open group, the laparoscopic group had significantly longer operation time [(264.0±35.1) minutes vs. (226.6±49.9) minutes, t=2.685, P=0.011], significantly less intraoperative blood loss [(65.7±37.4) ml vs. (182.2±94.6) ml, t=-4.658, P<0.001], significantly shorter time to postoperative flatus [(2.8±0.7) days vs. (4.1±0.7) days, t=-5.776, P<0.001] and significantly shorter postoperative hospital stay [(13.3±2.8) days vs. (16.6±4.3) days, t=-2.822, P=0.008]. Morbidity of postoperative complications, including anastomotic leakage, pancreatic fistula, abdominal abscess, intraperitoneal hemorrhage and duodenal stump leakage, in two groups was similar [19.0% (4/21) vs. 4/16, P=0.705]. There were no cases of anastomotic bleeding or stenosis. The 30-day postoperative mortality was 0 in the laparoscopic group and 1/16 in the open group, respectively (P=0.432). The 3-year disease-free survival rates were 38.1% and 37.5% in the laparoscopic and open group, respectively (P=0.751). Conclusion: Laparoscopic total gastrectomy combined with distal pancreaticosplenectomy performed by experienced surgeons for T4b gastric cancer is safe and effective.

[The clinical characteristics of 17 cases of primary ciliary dyskinesia]

Objective: To review the clinical data of cases of primary ciliary dyskinesia (PCD), and to explore the clinical characteristics for the understanding of PCD. Methods: We retrospectively summarized 17 patients with PCD diagnosed in Peking Union Medical College Hospital from Jan 2009 to Dec 2014. There were 7 male and 10 female patients, with the age from 6 to 57 years at the time of diagnosis. The mean onset age of the disease was 11.7±2.1 years, and the mean age at diagnosis was 29.5±3.5 years. We analyzed their clinical symtoms, radiologic images, pulmonary function test and the electron microscopic findings for the clinical characteristics of PCD. Results: The most common onset symptoms were cough (15/17) or sputum (13/17) among our 17 patients with PCD. Only 5 patients had situs inversus in our group. Sixteen patients had bronchiectasis on chest CT scan. Nasal sinusitis was confirmed by nasal CT scan in 15 patients. The most common pathogens from sputum cultures included Pseudomonas aeruginosa, Haemophilus influenzea, Aspergillus fumigates and Candida (3/14 respectively). None of the patients had evidence of mycobacterial infection. Twelve patients underwent spirometry and obstructive pattern was the most common disorder (8/12). Diffusion impairment (5/10) and restrictive pattern dysfunction (3/10) were also present in our patients. Two patients had normal pulmonary function test results. Thirteen patients underwent bronchial mucosal ciliary electron microscopy and the most abnormalities were outer or inner dynein arms deficiency (8/13), and other abnormalities included microtubule arrangement disorder (3/13), reduction of the number of microtubules (3/13) and reduction of the number of dynein arms (2/13). Four of our patients had multiple dysfunctions on their ciliaries. Conclusions: PCD should be considered in bronchiectasis patients with disease onset at childhood even without situs inverse, especially those accompanied with nasal sinusitis or otitis media. Chest or paranasal sinus CT scan, and male sperm examination were helpful for the diagnosis. Mucosal ciliary electron microscopy was an efficient diagnostic method for PCD.

[Effects of allogeneic bone marrow mesenchymal stem cells on polarization of peritoneal macrophages in rats with sepsis]

Objective: To explore the effects of allogeneic bone marrow mesenchymal stem cells (BMSCs) on polarization of peritoneal macrophages isolated from rats with sepsis induced by endotoxin/lipopolysaccharide (LPS). Methods: (1) BMSCs were isolated, cultured and purified from 5 SD rats with whole bone marrow adherent method. The third passage of cells were collected for morphologic observation, detection of expressions of stem cell surface markers CD29, CD44, CD45, and CD90 with flow cytometer, and identification of osteogenic and adipogenic differentiation. (2) Another 45 SD rats were divided into sham injury group (SI, n=5), LPS control group (LC, n=20), and BMSCs-treated group (BT, n=20) according to the random number table. Rats in groups LC and BT were injected with LPS (5 mg/kg) via tail vein to induce sepsis; rats in group SI were injected with the same amount of normal saline to simulate the damage. At post injury hour (PIH) 1, rats in group BT were given 1 mL BMSCs (2×10(6)/mL) via tail vein injection; rats in another two groups were injected with equal volume of phosphate buffer saline. Five rats in group SI at PIH 24 and in groups LC and BT at PIH 6, 12, 24, and 48 were sacrificed to harvest lung tissue for pathological observation with HE staining. In addition, rats in group SI at PIH 24 and in groups LC and BT at PIH 24 and 48 were simultaneously performed with intraperitoneal injection of low-glucose DMEM. Then peritoneal fluid was harvested to culture peritoneal macrophages. Flow cytometer was used to assess the positive expression of cell makers of macrophages including CD68 (making gate), CD11c, and CD206 in group SI at PIH 24 and in groups LC and BT at PIH 24 and 48. Data were processed with one-way analysis of variance and LSD test. Results: (1) The third passage of cells showed uniform fiber-like shape similar to fibroblasts. These cells showed positive expressions of CD29, CD44, CD90 and weak positive expression of CD45. They were able to differentiate into osteoblasts and adipocytes. These cells were identified as BMSCs. (2) At PIH 24, the structure of pulmonary alveoli of rats in group SI was clear and complete with no congestion or inflammatory cell infiltration. At PIH 6, the structure of pulmonary alveoli of rats in groups LC and BT was clear with a small amount of inflammatory cell infiltration, slight congestion and pulmonary interstitial thickening. At PIH 12, the inflammatory responses in lung tissue of rats in group LC were more severe than those in group BT with a large amount of inflammatory cell infiltration, serious congestion, and obvious pulmonary interstitial thickening. The pathological results of rats in group BT at PIH 12 was consistent with the results at PIH 6. At PIH 24, the pathological results of rats in groups LC and BT were similar to the results at PIH 12. At PIH 48, the structure of pulmonary alveoli tissue of rats in group LC was still severely disrupted, with a large number of inflammatory cell infiltration and congestion in lung tissue, but pulmonary interstitial thickening was slightly alleviated than before. The condition of rats in group BT nearly recovered to that in group SI. (3) At PIH 24, the positive expression rate of CD11c in peritoneal macrophages of rats in group LC [(83±10)%] was close to that in group BT [(87±7)%, P>0.05], and they were both significantly higher than the rate in group SI [(55±12)%, with P values below 0.01]. The positive expression rate of CD11c in peritoneal macrophages of rats in group LC [(59±11)%] at PIH 48 was close to that in group SI at PIH 24 (P>0.05), and they were both significantly higher than the rate in group BT [(20±11)%] at PIH 48 (with P values below 0.01). At PIH 24, the positive expression percentages of CD206 in peritoneal macrophages of rats were similar among the three groups (with P values above 0.05). The positive expression percentage of CD206 in peritoneal macrophages of rats in group SI at PIH 24 was close to that in group BT at PIH 48 (P>0.05), and they were both significantly lower than the percentage in group LC at PIH 48 (with P values below 0.01). Conclusions: BMSCs can reduce the pathological inflammatory responses in the lung of rats with sepsis and inhibit peritoneal macrophages from polarizing into M1 phenotype, whereas they can not promote macrophages to polarize into M2 phenotype.

[Experimental research of protective and therapeutic effects of zinc and vitamin E on mouse liver radiational damage]

OBJECTIVE

To study the effects of zinc and vitamin E on lipid peroxide (LPO) contents and glutathione peroxidase (GSH-Px) activities in liver homogenates of radiational damage mice.

METHODS

Two hundred and forty mice were divided randomly into five groups: normal control group (Group A), 60Co gamma-ray irradiator group (Group B), 60Co + zinc (Zn) group (Group C), 60Co + vitamin E(VE) group (Group D), and 60Co + Zn + VE group (Group E). After irradiated with 60Co gamma-ray 7.5 Gy, the mice were protectively treated with Zn and VE at different times. LPO contents and GSH-Px activities in liver homogenates of the mice were determined.

RESULTS

The level of liver LPO was significantly higher (P < 0.01), but the level of liver GSH-Px was significantly lower (P < 0.01) in Group B than those in Group A; the content of liver GSH-Px was markedly higher in Group C and Group D than that in Group B (P < 0.01), while the content of liver LPO was markedly lower in Group D than that in Group B (P < 0.05); the concentration of liver GSH-Px was markedly higher in Group E than that in Group D (P < 0.01).

CONCLUSIONS

VE may play an important role in lowering liver LPO contents and raising liver GSH-Px activities in radiational damage mice. vitamin E can cooperate with zinc in raising liver GSH-Px activities, stopping liver cells from lipids peroxidation and keeping integrity of liver cell membrane.

Evidence for the existence of an unfolding intermediate state for aminoacylase during denaturation in guanidine solutions

The equilibrium unfolding of pig kidney aminoacylase in guanidinium chloride (GdmCl) solutions was studied by following the fluorescence and circular dichroism (CD). At low concentrations of GdmCl, less than 1.0 M, the fluorescence intensity decreased with a slight red shift of the emission maximum (from 335 to 340 nm). An unfolding intermediate was observed in low concentrations of denaturant (between 1.2 and 1.6 M GdmCl). This intermediate was characterized by a decreased fluorescence emission intensity, a red-shifted emission maximum, and increased binding of the fluorescence probe 1-anilino-8-naphthalenesulfonate. No significant changes of the secondary structure were indicated by CD measurement. This conformation state is similar to a molten globule state which may exist in the pathway of protein folding. Further changes in the fluorescence properties occurred at higher concentrations of GdmCl, more than 1.6 M, with a decrease in emission intensity and a significant red shift of the emission maximum from 340 to 354 nm. In this stage, the secondary structure was completely broken. A study of apo-enzyme (Zn2+-free enzyme) produced similar results. However, comparison of the changes of the fluorescence emission spectra of native (Holo-) enzyme with Zn2+-free (Apo-) enzyme at low GdmCl concentrations showed that the structure of the Holo-enzyme was more stable than that of the Apo-enzyme.

Inactivation of creatine kinase is due to the conformational changes of the active sites during thermal denaturation

The conformational changes of the active site of creatine kinase (ATP: creatine N-phosphotransferase EC 2.7.3.2.) during thermal denaturation was followed by changes in fluorescence at the active site of the enzyme labeled by o-phthalaldehyde. Conformational changes of the active site occurred at the same time as inactivation of the enzyme. The active site changes occurred before the denaturation of the enzyme molecule as a whole was detected. The above results showed that the thermal inactivation of the creatine kinase was due to the conformational changes of its active sites.

Kinetics of irreversible inhibition of yeast alcohol dehydrogenase during modification by 4,4'-dithiodipyridine

The course of inactivation of yeast alcohol dehydrogenase (YADH) using 4,4'-dithiodipyridine (DSDP) has been studied in this paper. The results show that the reaction mechanism between DSDP and YADH is a competitive, complexing inhibition. The microscopic constants for the inactivation of the free enzyme and the enzyme-substrate complex were determined. The presence of the substrate NAD+ offers strong protection for this enzyme against inactivation by DSDP. The above results suggest that two Cys residues are essential for activity and are situated at the active site. These essential Cys residues should be Cys-46 and Cys-174 which are ligands to the catalytic zinc ion. Another Cys residue, which can be modified by DSDP, is non-essential for activity of the enzyme.

Ascertaining the number of essential thiol groups for the folding of creatine kinase

Although the unfolding and refolding of proteins have been extensively studied in the literature, relatively few attempts have been made to see how many residues of the total residues of a certain amino acid in an enzyme can be modified without seriously affecting its folding. Based on a statistical analysis of the quantitative relationship between the extent of modification of protein functional groups and the decrease in their biological activity, a method proposed by Tsou (Sci. Sin. 1962, 11, 1535-1558) is widely used to determine the number of residues essential for the catalytic activity of modified proteins. In the present paper, Tsou's method is applied to determine the number of cystein residues essential for the folding of creatine kinase. The thiol groups of the cysteine residues in fully unfolded creatine kinase were modified by 2-chloromercuri-4-nitrophenol (MNP). The relationship between the number of MNP-groups introduced and the recovery of activity after refolding was determined. Quantitative treatment of the data by Tsou's plot shows that among the cystein residue modified in each subunit of creatine kinase, only three are essential for its folding.

Optical properties of sputter-deposited cerium oxyfluoride thin films

CeO(x)F(y) films were made by reactive rf magnetron sputtering of Ce in Ar + O(2) + CF(4). Stoichiometries between CeO(2) and CeO(1.0)F(1.3) were obtained when the CF(4) content lay between 0% and 9%. For wavelengths λ of > 0.4 µm, the films were almost nonabsorbing, and the refractive index at λ = 0.55 µm went from 2.32 for CeO(2) to 1.62 at 9% CF4(4). At λ < 0.4 µm and <4% CF(4), the optical properties were consistent with an indirect band gap at 3.1-3.2 eV. CeO(2) films could serve as intercalation hosts for Li(+) ions.

Reflectance diagram-aided technique for optical coating design and monitoring

An amplitude reflectance diagram is a useful tool for visualizing the relationships between the performance of an optical coating and the optical parameters. This paper gives a brief description of the construction and characterization of the reflectance diagrams for different indices. Then, applications of reflectance diagramaided techniques to the design of both phase dispersion-induced narrow reflection and transmission filters, as well as to the optical monitoring of the symmetric multilayers of types (A2BA) and (AB2CBA), are illustrated. Some experimental results of phase dispersion-induced narrowband filters are reported.

Immunoprecipitation of the in vitro translation product of rabbit muscle protein phosphatase C-I mRNA

Rabbit muscle polyA+ mRNA was translated in vitro using a rabbit reticulocyte lysate system in the presence of [35S]methionine. A mouse monoclonal antibody to the catalytic subunit of rabbit muscle phosphorylase phosphatase ("phosphatase C-I") was used to immunoprecipitate the products which were then analyzed by SDS-PAGE and autoradiography. These studies showed that the major product of the phosphatase mRNA is a single ca. 36 kDa polypeptide. These findings are significant in view of suggestions that the catalytic subunit is derived from a larger precursor, and in view of the molecular cloning of two cDNAs for the phosphatase, which encode polypeptides of 35.4 kDa and 37.5 kDa, respectively.

The immunohistochemical localization of pregnancy-specific beta 1-glycoprotein in postimplantation rat trophoblast

Pregnancy-specific beta 1-glycoprotein (SP1) was identified by peroxidase-antiperoxidase (PAP) immunohistochemistry in the placenta of inbred strains of rat between 10 and 21 days of gestation. SP1 was located predominantly in basal zone trophoblast and in intravascular trophoblast of decidual vessels, but it was absent from labyrinthine trophoblast. No perivascular cells were identified by SP1 staining, but occasional clusters of interstitial trophoblast stained for SP1. The results suggest that basal and labyrinthine trophoblast are functionally different.