[Study on the mechanism of cross-linked hyaluronic acid-dexamethasone hydrogelin post-traumatic osteoarthritis]

Objective: To explore the mechanism of cross-linked hyaluronic acid-dexamethasone hydrogel (cHA-Dex) in inhibiting chondrocyte apoptosis and alleviating early post-traumatic osteoarthritis (PTOA). Methods: To generate PTOA model, anterior cruciate ligament transection (ACLT)was performed on SD rats (n=70), and the sham surgery group (n=70) was set as control. The changes in inflammatory indicators such as interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), matrix metalloproteinase-3 (MMP-3), and matrix metalloproteinase-13 (MMP-13) in the joint lavage fluid were measured at different time points (1-14 days, 5 rats at each time point) after surgery. The cHA-Dex (0.5 mg/ml) hydrogel (experimental group, n=70) and ordinary low-molecular-weight hyaluronic acid (HA) hydrogel premixed with Dex, that was, HA-Dex (0.5 mg/ml) hydrogel (control group, n=70) were injected into the joint cavity of PTOA rats, and the release amount and cumulative release amount of Dex in the joint fluid of rats at each time point(1-14 days, 5 rats at each time point) were detected to reveal the release mechanism of cHA-Dex hydrogel. The cartilage of knee joint of patients with osteoarthritis (OA) who underwent knee arthroplasty in the Second Hospital of Shanxi Medical University from January 2020 to December 2022 was taken for in vitro tissue block culture (Outbridge score=1 or 2,n=18). After the cartilage tissue block was treated with cHA-Dex hydrogel premixed with 0.1, 0.2, and 0.5 mg/ml Dex, the mRNA expression levels of IL-1β, IL-6, TNF-α, MMP-3, and MMP-13 in the articular cartilage tissue block were detected. OA chondrocytes were isolated from cartilage samples using enzymatic hydrolysis and cultured in vitro (n=18). Chondrocytes were divided into 4 groups: saline, cHA hydrogel, Dex (0.5 mg/ml), and cHA-Dex (0.5 mg/ml) hydrogel group. The effects of different interventions on chondrocyte proliferation and apoptosis were tested. Results: The Osteoarthritis Research Society International (OARSI) score of safranine O-solid green staining in PTOA group was 3.34±0.35, and it was 1.17±0.21 in Sham group(P=0.010). The Meachim score of knee joint osteophytes in PTOA rats was significantly higher than that in the Sham group (2.66±0.41 vs 0.22±0.17, P=0.010), indicating PTOA model in rat was established successfully. The cHA-Dex hydrogel, which corresponded to the peak changes of inflammatory factors in the joints of PTOA rats in the early stage, was also released in the early stage and sustained-released in the late stage. After the OA articular cartilage tissue block was treated with cHA-Dex hydrogel premixed with 0.1, 0.2, and 0.5 mg/ml Dex, the mRNA expression levels of IL-1 β, IL-6, TNF-α, MMP-3, and MMP-13 in the tissue block were reduced significantly (all P<0.05) and in a dose-dependent manner. Compared with Dex (0.5 mg/ml) alone group, the apoptosis rate of cHA-Dex (0.5 mg/ml) hydrogel group was significantly reduced (0.60±0.07 vs 6.63±0.98, P=0.010).Compared with the normal saline or the cHA hydrogel alone group, the cHA-Dex (0.5 mg/ml) hydrogel group had significant cell proliferation, and the difference at each time point were all significant statistically (all P<0.05). Conclusion: For the early inflammation of PTOA, cHA-Dex hydrogel can not only inhibit cartilage inflammation, but also reverse the increased apoptosis and decreased proliferation rate of chondrocytes caused by Dex, and finally alleviate the progress of PTOA by releasing Dex.

[Study on the distribution pattern of allergen sIgE in patients with respiratory allergic diseases in a hospital in Shanxi Province]

To explore the allergen sensitization status of patients with respiratory allergic diseases in Shanxi Province, and to provide a basis for the diagnosis, treatment and prevention of allergic diseases. It is a cross-sectional study, a total of 1 680 patients with allergic rhinitis and/or asthma diagnosed at the Department of Allergic Reaction of Shanxi Bethune Hospital from July 2021 to June 2023 who underwent allergen sIgE testing and/or skin prick test were retrospectively enrolled.There were 772 males and 908 females.The age range was 3 to 88 years. The median age was 35 years.There were 108 cases in the child group (≤12 years old), 102 cases in the adolescent group (13-17 years old), 819 cases in the youth group (18-40 years old), 498 cases in the middle-aged group (41-65 years old), and 153 cases in the elderly group (>65 years old). There were 333 cases in the allergic rhinitis group, 827 cases in the allergic asthma group, and 520 cases in the allergic rhinitis with asthma group. There were 1 254 urban patients and 426 rural patients.There were 253 cases in the northern Shanxi region, 1 195 cases in the central Shanxi region, and 232 cases in the southern Shanxi region. Statistical analyses were performed using the χ 2 test or Fisher's exact probability method to compare the differences in allergen sIgE positivity rates by sex, age, disease, living environment, and geography. The results showed that 1 027 patients (61.1%) were positive for at least one allergen sIgE, with Artemisia having the highest rate of positivity (603/1 680, 35.9%), followed by ragweed (302/1 680, 18.0%) and dust mite combinations (245/1 680, 14.6%). The number of individuals with single-allergen sIgE positivity was 357 (357/1 027, 34.8%), with the highest number of single-allergen sIgE positive results associated with Artemisia (114/357, 31.9%). The number of multiple-allergen sIgE positive results was 670 cases (670/1 027, 65.2%), with the highest number of patients having 2 allergen sIgE positive results (243/670, 36.3%). The overall positivity rate for allergen sIgE was significantly higher among males than among females (65.7% vs. 57.3%, χ2=12.405, P<0.001). Overall positivity for inhalant allergen sIgE was higher in the child and adolescent groups (88.0% vs. 88.2% vs. 59.8% vs. 40.2% vs. 19.0%, χ2=223.372, P<0.001), and food allergen sIgE positivity was highest in the child group (54.6% vs. 36.3% vs. 26.0% vs. 18.9% vs. 21.6%,χ2=66.383,P<0.001). The sIgE positivity rate of inhalant allergens was significantly higher in the allergic rhinitis group and the allergic rhinitis with asthma group than in the allergic asthma group, except for cockroaches and molds (P<0.05). The overall positive rate of allergen sIgE was significantly higher among urban patients than among rural patients (66.2% vs. 46.2%, χ2=53.230, P<0.001). The difference in the overall positive rate of allergen sIgE among patients from different regions was not statistically significant (56.1% vs. 62.0% vs. 62.1%, χ2=3.140, P=0.208). The sIgE positivity of dust mite combinations was significantly higher in the central Shanxi region and the southern Shanxi region than in the northern Shanxi region (15.5% vs. 18.1% vs. 7.1%,χ2=14.411, P=0.001). In conclusion, artemisia was the most important sensitizer for respiratory allergic diseases in Shanxi Province. The types of allergens and positivity rates were different for different sexes, ages, diseases, living environments, and regions. Therefore, patients with allergic diseases should be tested for allergens to help with the diagnosis, treatment and prevention of allergic diseases.

Development of a bispecific nanobody conjugate broadly neutralizes diverse SARS-CoV-2 variants and structural basis for its broad neutralization

The continuous emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with increased transmissibility and profound immune-escape capacity makes it an urgent need to develop broad-spectrum therapeutics. Nanobodies have recently attracted extensive attentions due to their excellent biochemical and binding properties. Here, we report two high-affinity nanobodies (Nb-015 and Nb-021) that target non-overlapping epitopes in SARS-CoV-2 S-RBD. Both nanobodies could efficiently neutralize diverse viruses of SARS-CoV-2. The neutralizing mechanisms for the two nanobodies are further delineated by high-resolution nanobody/S-RBD complex structures. In addition, an Fc-based tetravalent nanobody format is constructed by combining Nb-015 and Nb-021. The resultant nanobody conjugate, designated as Nb-X2-Fc, exhibits significantly enhanced breadth and potency against all-tested SARS-CoV-2 variants, including Omicron sub-lineages. These data demonstrate that Nb-X2-Fc could serve as an effective drug candidate for the treatment of SARS-CoV-2 infection, deserving further in-vivo evaluations in the future.

Structural and functional basis of low-affinity SAM/SAH-binding in the conserved MTase of the multi-segmented Alongshan virus distantly related to canonical unsegmented flaviviruses

Alongshan virus (ALSV), a newly discovered member of unclassified Flaviviridae family, is able to infect humans. ALSV has a multi-segmented genome organization and is evolutionarily distant from canonical mono-segmented flaviviruses. The virus-encoded methyltransferase (MTase) plays an important role in viral replication. Here we show that ALSV MTase readily binds S-adenosyl-L-methionine (SAM) and S-adenosyl-L-homocysteine (SAH) but exhibits significantly lower affinities than canonical flaviviral MTases. Structures of ALSV MTase in the free and SAM/SAH-bound forms reveal that the viral enzyme possesses a unique loop-element lining side-wall of the SAM/SAH-binding pocket. While the equivalent loop in flaviviral MTases half-covers SAM/SAH, contributing multiple hydrogen-bond interactions; the pocket-lining loop of ALSV MTase is of short-length and high-flexibility, devoid of any physical contacts with SAM/SAH. Subsequent mutagenesis data further corroborate such structural difference affecting SAM/SAH-binding. Finally, we also report the structure of ALSV MTase bound with sinefungin, an SAM-analogue MTase inhibitor. These data have delineated the basis for the low-affinity interaction between ALSV MTase and SAM/SAH and should inform on antiviral drug design.

Measurement of changes in uterine and fibroid volume during treatment of heavy menstrual bleeding (HMB)

STUDY QUESTION

Does application of an unbiased method for analysis of magnetic resonance (MR) images reveal any effect on uterine or fibroid volume from treatment of heavy menstrual bleeding (HMB) with three 12-week courses of the selective progesterone receptor modulator ulipristal acetate (SPRM-UPA)?

SUMMARY ANSWER

Application of an unbiased method for analysis of MR images showed that treatment of HMB with SPRM-UPA was not associated with a significant reduction in the volume of the uterus or in the volume of uterine fibroids.

WHAT IS KNOWN ALREADY

SPRM-UPA shows therapeutic efficacy for treating HMB. However, the mechanism of action (MoA) is not well understood and there have been mixed reports, using potentially biased methodology, regarding whether SPRM-UPA has an effect on the volume of the uterus and fibroids.

STUDY DESIGN SIZE DURATION

In a prospective clinical study (with no comparator), 19 women with HMB were treated over a period of 12 months with SPRM-UPA and uterine and fibroid size were assessed with high resolution structural MRI and stereology.

PARTICIPANTS/MATERIALS SETTING METHODS

A cohort of 19 women aged 38-52 years (8 with and 11 without fibroids) were treated with three 12-week courses of 5 mg SPRM-UPA given daily, with four weeks off medication in-between treatment courses. Unbiased estimates of the volume of uterus and total volume of fibroids were obtained at baseline, and after 6 and 12 months of treatment, by using the Cavalieri method of modern design-based stereology in combination with magnetic resonance imaging (MRI).

MAIN RESULTS AND THE ROLE OF CHANCE

Bland-Altman plots showed good intra-rater repeatability and good inter-rater reproducibility for measurement of the volume of both fibroids and the uterus. For the total patient cohort, two-way ANOVA did not show a significant reduction in the volume of the uterus after two or three treatment courses of SPRM-UPA (P = 0.51), which was also the case when the groups of women with and without fibroids were considered separately (P = 0.63). One-way ANOVA did not show a significant reduction in total fibroid volume in the eight patients with fibroids (P = 0.17).

LIMITATIONS REASONS FOR CAUTION

The study has been performed in a relatively small cohort of women and simulations that have subsequently been performed using the acquired data have shown that for three time points and a group size of up to 50, with alpha (Type I Error) and beta (Type II Error) set to 95% significance and 80% power, respectively, at least 35 patients would need to be recruited in order for the null hypothesis (that there is no significant reduction in total fibroid volume) to be potentially rejected.

WIDER IMPLICATIONS OF THE FINDINGS

The imaging protocol that we have developed represents a generic paradigm for measuring the volume of the uterus and uterine fibroids that can be readily incorporated in future studies of medical treatments of HMB. In the present study, SPRM-UPA failed to produce a significant reduction in the volume of the uterus or the total volume of fibroids (which were present in approximately half of the patients) after either two or three 12-week courses of treatment. This finding represents a new insight in respect of the management of HMB using treatment strategies that target hormone-dependence.

STUDY FUNDING/COMPETING INTERESTS

The UPA Versus Conventional Management of HMB (UCON) trial was funded by the EME Programme (Medical Research Council (MRC) and National Institutes of Health Research (NIHR)) (12/206/52). The views expressed in this publication are those of the authors and not necessarily those of the Medical Research Council, National Institute for Health Research, or Department of Health and Social Care.Medical Research Council (MRC) Centre grants to the Centre for Reproductive Health (CRH) (G1002033 and MR/N022556/1) are also gratefully acknowledged. H.C. has clinical research support for laboratory consumables and staff from Bayer AG and provides consultancy advice (All paid to Institution) for Bayer AG, PregLem SA, Gedeon Richter, Vifor Pharma UK Ltd, AbbVie Inc., and Myovant Sciences GmbH. H.C. has received royalties from UpToDate for an article on abnormal uterine bleeding. L.W. has received grant funding from Roche Diagnostics (Paid to Institution). All other authors have no conflicts to declare.

TRIAL REGISTRATION NUMBER

The study reported here is an embedded mechanism of action study (no comparator) within the UCON clinical trial (registration ISRCTN: 20426843).

[Application of CRISPR/Cas systems in the nucleic acid detection of pathogens: a review]

Rapid, sensitive and specific detection tools are critical for the prevention and control of infectious diseases. The in vitro nucleic acid amplification assays, including polymerase chain reaction and isothermal amplification technology, have been widely used for the detection of pathogens. Recently, nucleic acid detection-based on clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated proteins (Cas) have been developed, which are rapid, highly sensitive, highly specific, and portable. This review describes the classification and principle of CRISPR/Cas systems and their applications in pathogen detection, and discusses the prospects of CRISPR/Cas systems.

An engineered 5-helix bundle derived from SARS-CoV-2 S2 pre-binds sarbecoviral spike at both serological- and endosomal-pH to inhibit virus entry

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and related sarbecoviruses enter host cells by receptor-recognition and membrane-fusion. An indispensable step in fusion is the formation of 6-helix bundle by viral spike heptad repeats 1 and 2 (HR1 and HR2). Here, we report the construction of 5-helix bundle (5HB) proteins for virus infection inhibition. The optimal construct inhibits SARS-CoV-2 pseudovirus entry with sub-micromolar IC50. Unlike HR2-based peptides that cannot bind spike in the pre-fusion conformation, 5HB features with the capability of binding to pre-fusion spike. Furthermore, 5HB binds viral HR2 at both serological- and endosomal-pH, highlighting its entry-inhibition capacity when SARS-CoV-2 enters via either cell membrane fusion or endosomal route. Finally, we show that 5HB could neutralize S-mediated entry of the predominant SARS-CoV-2 variants and a wide spectrum of sarbecoviruses. These data provide proof-of-concept evidence that 5HB might be developed for the prevention and treatment of SARS-CoV-2 and other emerging sarbecovirus infections.

Hydrogen sulphide signalling in plant response to abiotic stress

Throughout their whole life cycle, higher plants are often exposed to diverse environmental stresses, such as drought, salinity, heavy metals and extreme temperatures. In response to such stress, plant cells initiate signalling transduction, resulting in downstream responses, such as specific gene transcription and protein expression. Accumulating evidence has revealed that hydrogen sulphide (H₂ S) serves as a signalling molecule in plant acclimation to stressful conditions. More important, H₂ S interacts with other signalling molecules and phytohormones, contributing to transcriptional regulation and post-translational modification. Overall, the H₂ S-mediated signalling pathway and its interaction with other signals remains elusive. Here, we describe the role of the H₂ S signalling network in regulating physiological and molecular processes under various abiotic stresses.

Resolvin D2 promotes host defense in a 2 - hit model of sepsis with secondary lung infection

In the development of sepsis, there is early, massive inflammation which can lead to multiple organ failure. Later there is an immunosuppressed phase where the host is susceptible to secondary infections or is unable to clear existing infection. Specialized Pro-resolving Mediators (SPMs) are endogenously produced lipids which resolve infection by decreasing bacteria load and reducing systemic inflammatory response. There has been little work studying if SPMs given late, can promote host defense. We examined if an SPM, Resolvin D2 (RvD2) could promote host defense in a 2-hit mouse model of cecal ligation and puncture (CLP) sepsis and secondary Pseudomonas aeruginosa lung infection. RvD2 given 48 h after mild CLP (1st hit), increased gene expression of Toll-like receptor-2 (TLR-2) and alveolar macrophage/monocyte phagocytic ability compared to CLP mice given saline vehicle. In this model, RvD2 did not affect plasma IL-6 or IL-10. These effects induced by RvD2, lowered lung bacterial load and decreased mortality after the secondary infection of Pseudomonas aeruginosa (2nd hit). Splenic T-cell numbers were also increased in RvD2 treated mice compared to saline vehicle treated animals. The results suggest that RvD2 promoted mechanisms of host defense in a 2-hit model sepsis and secondary lung infection.

Single-nucleus RNA-seq2 reveals functional crosstalk between liver zonation and ploidy

Single-cell RNA-seq reveals the role of pathogenic cell populations in development and progression of chronic diseases. In order to expand our knowledge on cellular heterogeneity, we have developed a single-nucleus RNA-seq2 method tailored for the comprehensive analysis of the nuclear transcriptome from frozen tissues, allowing the dissection of all cell types present in the liver, regardless of cell size or cellular fragility. We use this approach to characterize the transcriptional profile of individual hepatocytes with different levels of ploidy, and have discovered that ploidy states are associated with different metabolic potential, and gene expression in tetraploid mononucleated hepatocytes is conditioned by their position within the hepatic lobule. Our work reveals a remarkable crosstalk between gene dosage and spatial distribution of hepatocytes.

Lipoxin A4 promotes reduction and antibiotic efficacy against Pseudomonas aeruginosa biofilm

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic bacterium commonly found in wound infections and airways of cystic fibrosis patients. P. aeruginosa readily forms biofilms which can reduce the efficacy of antibiotics used to eradicate the pathogen. We have previously shown that a Specialized Pro-resolving Mediator (SPM), Lipoxin A4 (LxA₄) is a quorum sensing inhibitor which can reduce P. aeruginosa virulence. In this study, we examined the direct actions of LxA₄ and RvD₂ on P. aeruginosa biofilm formation and virulence gene expression. The influence of LxA₄ on antibiotic efficacy and the combined effects on biofilm formation were also investigated. LxA₄ and RvD₂ reduced P. aeruginosa biofilm formation and virulence gene expression. LxA₄ increased ciprofloxacin inhibition on biofilm formation but did not affect ciprofloxacin's action on non-adherent bacteria. On the other hand, LxA₄ increased bacterial killing action of imipenem but did not affect imipenem's action on biofilm. We also found that LxA₄ can increase ciprofloxacin's bacterial killing ability in established biofilm. Together these results suggest that LxA₄ has direct effects on P. aeruginosa biofilm formation and can increase antibiotic efficacy directly.

[Analysis of drug - resistant gene polymorphisms in Plasmodium falciparum imported from Equatorial Guinea to Shandong Province in 2015 and 2016]

OBJECTIVE

To investigate the drug-resistant gene polymorphisms in Plasmodium falciparum imported from Equatorial Guinea to Shandong Province.

METHODS

From 2015 to 2016, blood samples were collected from imported P. falciparum malaria patients returning from Equatorial Guinea to Shandong Province, and genome DNA of the malaria parasite was extracted. The drug-resistant Pfcrt, Pfmdr1, Pfdhfr, Pfdhps, and K13 genes of P. falciparum were amplified using a PCR assay, followed by DNA sequencing, and the sequences were aligned.

RESULTS

The target fragments of all 5 drug-resistant genes of P. falciparum were successfully amplified and sequenced. There were 72.8%, 18.6%, and 8.6% of P. falciparum parasites carrying the wild-, mutant-, and mixed-type Pfcrt gene, respectively, and all mutant haplotypes were CVIET (the underline indicates the mutation site). There were 20.0%, 61.4% and 18.6% of P. falciparum parasites carrying the wild-, mutant-, and mixed-type Pfmdr1 gene, respectively, and the mutant haplotypes mainly included YF and NF (the underlines indicate the mutation sites). There were 1.4%, 98.6%, and 0 of P. falciparum parasites carrying the wild-, mutant-, and mixed-type Pfdhfr gene, respectively, and AIRNI was the predominant mutant haplotype (the underline indicates the mutation site). There were 1.4%, 94.3%, and 4.3% of P. falciparum parasites carrying the wild-, mutant-, and mixed-type Pfdhps gene, respectively, and SGKAA was the predominant mutant haplotype (the underline indicates the mutation site). The complete drug-resistant IRNGE genotype consisted of 8.6% of the Pfdhfr and Pfdhps genes, and the K13 gene A578S mutation occurred in 1.4% of the parasite samples.

CONCLUSIONS

There are mutations in the Pfcrt, Pfmdr1, Pfdhfr, Pfdhps, and K13 genes of P. falciparum imported from Equatorial Guinea to Shandong Province, with a low frequency in the Pfcrt gene mutation and a high frequency in the Pfmdr1, Pfdhfr, and Pfdhps gene mutations, and the K13 gene A578S mutation is detected in the parasite samples.

[Epidemiological investigation of 169 inpatients with high-voltage electrical burns on the wrist]

Objective: To analyze the epidemiological characteristics of inpatients with high-voltage electrical burns on the wrist in Beijing Jishuitan Hospital (hereinafter referred to as the author's unit), so as to provide reference for the prevention and treatment of high-voltage electrical burns on the wrist. Methods: The medical records of inpatients suffered from high-voltage electrical burns on the wrist in the author's unit from January 2008 to December 2019 were collected. The patients' gender, age, population category, injury situation, injury season, total burn area, electrical burn type on the wrist of the affected limbs, the time from injury to first flap/myocutaneous flap transplantation, vascular reconstruction and flap/myocutaneous flap transplantation of the affected limbs, the total amputation rate of the affected limbs and the amputation rate of the affected limbs with type Ⅲelectrical burns on the wrist, the number of operation, postoperative infection rate of flap/myocutaneous flap, length of hospital stay, hospitalization expense, and treatment outcome were retrospectively analyzed. Comparison of the aforementioned statistical items between patients admitted from January 2008 to December 2013 (hereinafter referred to as the pre-stage) and January 2014 to December 2019 (hereinafter referred to as the post-stage) except gender, the total amputation rate of the affected limbs, treatment outcome were performed. Data were statistically analyzed with chi-square test, Fisher's exact probability test, and Wilcoxon rank-sum test. Results: During the 12 years, a total of 169 patients with high-voltage electrical burns on the wrist were admitted to the author's unit, including 162 males and 7 females, aged (35±13) years, and 75.15% (127/169) of patients were 21-50 years old. The top three groups in population category from high to low were workers, migrant workers, and primary and secondary school students, accounting for 48.52% (82/169), 28.99% (49/169), and 9.47% (16/169), respectively. At work of non-electric power accounted for 47.93% (81/169) and ranked the first in the proportion of injury situation. The injury occurred mostly in summer and autumn, accounting for 39.05% (66/169) and 28.99% (49/169), respectively. About 65.09% (110/169) of the patients were with total burn area less than 10% total body surface area. There were totally 216 affected limbs with high-voltage electrical burns on the wrist, of which the numbers of wrist with type Ⅲ and type Ⅳ injury were 25 (11.57%) and 21 (9.72%), respectively. The time from injury to first flap/myocutaneous flap transplantation was 6.00 (3.75, 8.00) d. There were 45 affected limbs operated with vascular reconstruction, 75 affected limbs transplanted with pedicled axial flap, and 86 affected limbs transplanted with free flap/myocutaneous flap. The total amputation rate of affected limbs was 12.96% (28/216), and the amputation rate of the affected limbs with type Ⅲ electrical burns on the wrist was 28% (7/25). The number of operation was 4 (3, 5) times, the postoperative infection rate of flap/myocutaneous flap was 7.18% (13/181), the hospitalization time was 39.00 (25.00, 50.00) d, and the hospitalization cost was 123 553.00 (50 656.50, 216 003.00) yuan. Compared with those of the pre-stage, the time from injury to first flap/myocutaneous flap transplantation was significantly shortened (Z=-4.038, P<0.01), the ratio of free flap/myocutaneous flap transplantation on affected limbs was significantly increased (χ(2)=13.478, P<0.01), the ratio of pedicled axial flap transplantation on affected limbs was significantly decreased (χ(2)=10.242, P<0.01), the number of operation was significantly reduced (Z=-5.903, P<0.01), the postoperative infection rate of flap/myocutaneous flap was significantly decreased (χ(2)=4.492, P<0.05), the length of hospital stay was significantly shortened (Z=-2.723, P<0.01), and the hospitalization expense was significantly decreased among patients hospitalized in the post-stage (Z=-2.121, P<0.05). The other items were close between patients hospitalized in the pre-stage and those in the post-stage. Conclusions: Men were more likely than women to suffer from high-voltage electrical burns on the wrist in the author's unit. Young workers and migrant workers may be the key groups for the prevention of high-voltage electrical burns on the wrist. It is very important to strengthen the management of high voltage safety education for non-electric power staff, warn and protect the surrounding area of high voltage environment, and prohibit non staff for entering the high voltage environment, especially in summer and autumn. In the last 6 years, the patients with high-voltage electrical burns on the wrist may benefit from the active vascular reconstruction at early stage and free flap/myocutaneous flap repair in the author's unit.

Application Prospects of Virtual Autopsy in Forensic Pathological Investigations on COVID-19

Abstract

Autopsy of patients who died of infectious diseases is of significance for public health management. Few forensic autopsies have been performed since the outbreak of the corona virus disease 2019 （COVID-19） due to some limitations, thus forensic pathological examination failed to contribute to the prevention and treatment of infectious diseases. Virtual autopsy has unique advantages in the forensic examination of patients who died of infectious diseases. Accumulated virtual autopsy image data are of great value to the study of the pathological mechanism and diagnosis of COVID-19. This article reviews the relationship between imaging changes and pathology of the COVID-19 as well as the application of virtual autopsy in autopsy of patients who died of infectious diseases, in order to provide reference for performing virtual autopsy in the outbreak of COVID-19.

[The impact of male circumcision on the natural history of genital HPV infection: a prospective cohort study]

Objective: To analyze the correlation between circumcision and incidence and clearance of male genital HPV infection. Methods: From May to July 2014, 18-55 year old men who had sexual behavior history were recruited from the general population in Liuzhou, Guangxi to set up a cohort. Totally, 113 circumcised and 560 uncircumcised men were enrolled and interviewed using a questionnaire (including information on demographic characteristics and sexual behaviors), then they were followed-up with 6-month interval for 2 times. On each visit, specimens of male external genitalia were collected and genotyped for HPV DNA. The differences of incidence and clearance of genital HPV infections between circumcised and uncircumcised men were analyzed by Log-rank test. Cox regression was used to analyze the relationship between circumcision and incidence and clearance of HPV infection. Results: The median age (P(25), P(75)) of circumcised and uncircumcised men were 28 (24, 35) and 32 (24, 31), respectively. The incidences of any HPV infections were 9.1 (95%CI: 2.4-15.7) and 8.4 (95% CI: 5.6-11.2) per 1 000 person-months (χ(2)=0.10, P=0.758), respectively. The clearance of circumcised men [136.3 (95%CI: 70.0-202.7) per 1 000 person-months] was higher than that in uncircumcised men [89.6 (95%CI: 65.9-113.3) per 1 000 person-months] (χ(2)=8.19, P=0.004). In multivariate COX regression analysis, compared with uncircumcised men, circumcised men had higher possibility to clear any HPV infections (HR: 2.41, 95%CI: 1.30-4.46). Compared with men having one sexual partner, people having more than 4 sexual partners had lower possibility to clear any HPV infections (HR: 0.49, 95%CI: 0.25-0.96). Compared with 18-25 years old men, men aged 26-35 years old had higher possibility to clear high-risk HPV infections (HR: 2.14, 95%CI: 1.08-4.23). Conclusion: Circumcised and uncircumcised men had similar incidence of genital HPV infection, whereas, men conducted circumcision and having fewer sexual partners could increase the clearance of genital HPV infections.

Quasi-periodic concave microlens array for liquid refractive index sensing fabricated by femtosecond laser assisted with chemical etching

In this study, a high-efficiency single-pulsed femtosecond laser assisted with chemical wet etching method has been proposed to obtain large-area concave microlens array (MLA). The quasi-periodic MLA consisting of about two million microlenses with tunable diameter and sag height by adjusting laser scanning speed and etching time is uniformly manufactured on fused silica and sapphire within 30 minutes. Moreover, the fabricated MLA behaves excellent optical focusing and imaging performance, which could be used to sense the change of the liquid refractive index (RI). In addition, it is demonstrated that small period and high RI of MLA could acquire high sensitivity and broad dynamic measurement range, respectively. Furthermore, the theoretical diffraction efficiency is calculated by the finite domain time difference (FDTD) method, which is in good agreement with the experimental results.

[Research Progress of Sudden Cardiac Death in Forensic Medicine]

Sudden death （SD） is a special kind of death owing to disease, which severely threatening the lives of community population. As the most common type of SD, sudden cardiac death （SCD） has always been a crucial content of identification and research in forensic pathology. This article reviews the research progress from the aspects of epidemiology, morphology, molecular pathology and virtual anatomy of SCD in forensic medicine, so as to provide a reference for the morphological identification, determination of cause of death, and integrated control of this kind of SD.

High-flow Nasal Cannula Versus Noninvasive Ventilation for Treatment of Acute Hypoxemic Respiratory Failure in Renal Transplant Recipients

OBJECTIVE

This study aimed to evaluate the outcomes of high-flow nasal cannula (HFNC) oxygen therapy compared with noninvasive ventilation (NIV) for the treatment of acute hypoxemic respiratory failure in renal transplant recipients.

METHODS

Data were retrospectively collected from a tertiary intensive care unit (ICU) from July 1, 2011, to September 31, 2015. All renal recipients who had acute respiratory failure at that period of time were classified into the HFNC or NIV group depending on the initial form of respiratory support.

RESULTS

A total of 38 patients were enrolled in this study. Twenty patients received HFNC and the other 18 received NIV as the initial respiratory support. The ICU mortality in the HFNC group was 5% (1 patient), compared with 22.2% (4 patients) in the NIV group (P = .083). The median length of the ICU stay was 12 days in the HFNC group, compared with 14 days in the NIV group (P = .297). The number of ventilator-free days at day 28 was significantly higher in the HFNC group than in the NIV group (26 ± 3 vs 21 ± 3; P < .001). The incidences of both pneumothorax (0% vs 22.2%; P = .042) and skin breakdown (0% vs 22.2%; P = .042) were significantly lower in the HFNC group.

CONCLUSIONS

In renal transplant recipients with acute hypoxemic respiratory failure secondary to severe pneumonia, HFNC achieved outcomes similar to NIV. In addition, HFNC was associated with an increased number of ventilator-free days at day 28 and fewer complications.

MiR-214 regulates oral cancer KB cell apoptosis through targeting RASSF5

Ras association domain family member 5 (RASSF5), a member of the Ras association domain family, induces cell apoptosis by phosphorylating FOXO3a, which triggers target gene BIM (pro-apoptotic factor) activation. MiR-214 is overexpressed in oral cancer tissue, indicating its possible involvement in oral cancer pathogenesis. Bioinformatics analysis has revealed a complimentary sequence between miR-214 and the 3'-UTR of RASSF5 mRNA. However, whether miR-124 regulates RASSF5 in oral cancer remains poorly understood. We aimed to investigate the role of miR-214 in RASSF5 expression regulation in oral cancer. Tumor and paracarcinoma tissues were obtained from 48 oral cancer patients to examine miR-214 and RASSF5 expression. The relationship between miR-214 and RASSF5 was investigated by dual luciferase reporter gene assay. Oral cancer KB cells were cultured in vitro and divided into inhibitor NC, miR-214 inhibitor, Scramble-pMD18, RASSF5-pMD18, and miR-214 inhibitor + RASSF5-pMD18 groups. Caspase 3 activity, cell apoptosis, and total protein expression were measured by spectrophotometry, flow cytometry, and western blot, respectively. MiR-214 expression was significantly increased, while that of RASSF5 decreased in oral cancer tumor tissues compared to paracarcinoma tissues. Luciferase assay showed that miR-214 suppressed RASSF5 expression by targeting its 3'-UTR. Down-regulation of miR-214 and/or enhancement of RASSF5 expression markedly increased FOXO3a phosphorylation, BIM expression, caspase 3 activity, and apoptosis. In conclusion, miR-214 expression was elevated and RASSF5 was down-regulated in oral cancer. Moreover, miR-214 regulated KB cell apoptosis through targeted inhibition of RASSF5 expression, FOXO3a phosphorylation, and BIM expression, suggesting its possible application as a novel therapeutic oral cancer target.

MoO2-CoO coupled with a macroporous carbon hybrid electrocatalyst for highly efficient oxygen evolution

Cost-effective electrocatalysts for oxygen evolution reactions are attractive for energy conversion and storage processes. A high-performance oxygen evolution reaction (OER) electrocatalyst composed of 3D ordered microporous carbon and a MoO2 skeleton modified by cobalt oxide nanoparticles (MoO2-CoO-Carbon) is produced through a template method. This unique 3DOM structure finely combines the larger surface area of the 3D carbon skeleton and MoO2 as well as stablizes anchoring sites for CoO nanocrystals on the skeleton. The synergistic effect between the catalytic activity between MoO2 and CoO as well as the enhanced electron transport arising from the carbon skeleton contributed to superior electrocatalytic OER properties of MoO2-CoO-Carbon. The M200-C-Carbon hybrid with an overpotential as low as 0.24 V is among the best reported Mo-based OER catalysts. Moreover, the turnover frequency at an overpotential of 0.35 V is 6 times as high as that of commercial RuO2.

Co-Extrusion Layer Multiplication of Rheologically Mismatched Polymers: A Novel Processing Route

Co-extruded films with up to 65 layers of two rheologically mismatched polymer systems – polystyrene/poly(methylmethacrylate) (PS/PMMA) and hard/soft thermoplastic polyurethanes (TPUs) – were successfully produced using a combination of a 9-layer feedblock, low-pressure drop multiplier dies, and external lubricants. Formation of viscoelastic instabilities was studied using a custom visualization and by finite element method (FEM) simulations of a standard multiplier. The results showed that the flow inside the standard multiplier die is highly non-uniform, with severe gradients in shear and normal stresses and viscous encapsulation occurring mainly in the initial multiplication stages where there is enough material available in the low-viscosity layers to proceed with the encapsulation. To mitigate layer degradation the standard 2- or 3-layer feedblock was replaced with a 9-layer one, thereby decreasing the thickness of each layer at the end of the feedblock. Also, subsequent layering was performed using a low flow resistance die. This new multiplier die yields a more uniform flow profile and imparts a more homogeneous thermo-mechanical history on the melt which results in an improved layer stability. Simulations showed that in the standard die the second normal-stress difference (N2) responsible for elastic instabilities at the edges of the die are very high. These can be reduced by inducing slip at the wall resulting in be much improved layer uniformity and stability. This was accomplished experimentally via the use of external lubricants, and the resulting layered structure was indeed much better than was possible to achieve with the conventional multiplier dies.

Effects of Lipoxin A4 on antimicrobial actions of neutrophils in sepsis

In sepsis, hyperactivation of neutrophils can lead to tissue injury. Later, neutrophil dysregulation with reduced levels of migration, decreased apoptosis and inadequate phagocytosis may impair the host׳s ability to clear infection. Lipoxin A4 (LXA4) is a pro-resolution lipid mediator which reduces neutrophil migration and inflammatory mediator expression. As neutrophil migration and activation are important in bacterial clearance, the role of LXA4 in regulating neutrophil function for bacterial clearance is unclear. Using the cecal ligation and puncture (CLP) rat model of sepsis, LXA4 given after 1h reduced blood bacterial load at 24h. LXA4 treatment decreased neutrophil migration to the peritoneum but augmented blood neutrophil phagocytic ability and promoted apoptosis without affecting free radical production. In contrast, LXA4 increased peritoneal neutrophil phagocytic ability without affecting apoptosis or free radical production suggesting that in vivo effects of LXA4 were compartment specific. To investigate if LXA4 acted directly on neutrophils, blood and peritoneal leukocytes were taken from CLP rats 1h after surgery and incubated ex vivo with and without LXA4. LXA4 (1nM) increased phagocytosis in blood neutrophils without affecting apoptosis or free radical production. Ex vivo LXA4 had no effect on peritoneal neutrophils which suggests that LXA4 enhanced peritoneal neutrophil phagocytic ability in vivo by an indirect mechanism. The results suggest that LXA4 reduced neutrophil migration, but increased neutrophil bacteria clearing function without excessive free radical production. This phenotype was associated with reduced blood bacteria load.

Thermal degradation of hexachlorobenzene in the presence of calcium oxide at 340-400 °C

Hexachlorobenzene (HCB) in the milligram range was co-heated with calcium oxide (CaO) powder in sealed glass ampoules at 340-400 °C. The heated samples were characterized and analyzed by Raman spectroscopy, elemental analysis, gas chromatography/mass spectrometry, ion chromatography, and thermal/optical carbon analysis. The degradation products of HCB were studied at different temperatures and heated times. The amorphous carbon was firstly quantitatively evaluated and was thought to be important fate of the C element of HCB. The yield of amorphous carbon in products increased with heating time, for samples treated for 8h at 340, 380 °C and 400 °C, the value were 17.5%, 34.8% and 50.2%, respectively. After identification of the dechlorination products, the HCB degradation on CaO at 340-400 °C was supposed to through dechlorination/polymerization pathway, which is induced by electron transfer, generate chloride ions and form high-molecular weight intermediates with significant levels of both hydrogen and chlorine, and finally form amorphous carbon. Higher temperature was beneficial for the dechlorination/polymerization efficiency. The results are helpful for clarifying the reaction mechanism for thermal degradation of chlorinated aromatics in alkaline matrices.

Lipoxin A(4) promotes more complete inflammation resolution in sepsis compared to stable lipoxin A(4) analog

In sepsis, excessive inflammation may lead to organ injury or a paradoxical immunosuppressed state where the host is unable to clear preexisting infection. Resolution of inflammation is the process which restores tissue homeostasis and ensures that a chronic cycle of infection/inflammation does not occur. Lipoxin A4 (LXA4) is one of a family of lipid mediators with novel inflammation resolution activity. We compared the actions of LXA4 to the stable 15-epi-16-(para-fluorophenoxy)-lipoxin A4 methyl ester (LXA4 analog) in the cecal ligation and puncture (CLP) model of sepsis. Both LXA4 compounds (at 7 μg/kg; i.v.) reduced plasma TNFα and IL-6 concentrations compared to rats given vehicle saline. Neither treatment altered plasma IL-10 compared to CLP given saline, but LXA4 analog, increased plasma IL-10 concentrations compared to rats given LXA4. LXA4 reduced blood bacterial load but the LXA4 analog did not. LXA4 increased 8 day survival and the LXA4 analog did not have a significant effect. To examine possible mechanisms for the differences, we investigated peritoneal leukocyte gene expression of iNOS and macrophage phagocytic ability. Only LXA4 increased the percentage of phagocytic peritoneal macrophages. LXA4 reduced neutrophil gene expression of iNOS compared to CLP rats given vehicle, while the LXA4 analog did not. Our results suggest that at doses which reduced systemic inflammation, only LXA4 inhibited bacterial spread and increased survival. This difference may be due to the shorter-lived compound being able to increase macrophage phagocytosis and reduce neutrophil iNOS expression.

Association between polymorphisms in IL17F and male asthma in a Chinese population

BACKGROUND AND OBJECTIVES

Interleukin (IL) 17F is a marker of type 17 helper T cells and has a proinflammatory role in asthma.The aim of the present study was to assess the possible association between asthma and polymorphisms in the IL17F gene in a Chinese population.

METHODS

A total of 318 asthmatic patients and 352 nonasthmatic controls were recruited. Two single-nucleotide polymorphisms in IL17F (rs763780 and rs13209590) were detected using GenomeLab SNPstream. Logistic regression methods were used to analyze data.

RESULTS

A significantly lower frequency of the C allele in rs763780 was observed in the control group (P = .0148). The rs763780 TC heterozygote was associated with an increased risk of asthma, and a similar trend was observed assuming a codominant genotype effect (adjusted OR, 1.58; 95% CI, 1.06-2.36; P = .0148; adjusted OR, 1.64; 95% CI, 1.10-2.45; P = .0217). Furthermore, a novel finding of the present study was that this association was exclusive to males (adjusted OR, 1.79; 95% CI, 1.06-3.05; P = .0308) and patients with higher immunoglobulin E levels (> or = 1.85 IU/mL) (adjusted OR, 1.88; 95% CI, 1.10-3.22; P = .0213). We also found that the haplotype with minor alleles for rs763780 was associated with an increased risk of asthma (adjusted OR, 1.62; 95% CI, 1.11-2.35; P = .0115).

CONCLUSION

Our findings indicated that polymorphisms might play a role in susceptibility to asthma.

The ratios of individual chemicals in a mixture determine the degree of joint effect: the climax hypothesis

A new hypothesis, the Climax Hypothesis, is proposed to describe how the ratios of individual chemicals influence the joint effects of chemical mixtures. This hypothesis is derived from a generalized approach using "isobolograms". With this hypothesis, one can predict that for a given mixture, a curvilinear correlation exists between the joint effects and the ratios of individual chemicals and that this curve has a climax at the equitoxic ratio. This prediction is supported by the observed toxicity to Vibrio fischeri of 18 mixtures (12 binary mixtures, 4 ternary mixtures, and 2 quaternary mixtures). With this prediction, the Climax Hypothesis has some promising applications such as controlling the discharge of effluents in environmental science, maximizing detoxifying effects in medicine, and optimizing combined pesticides in agriculture.

Heterogenous and compartment-specific activation of nonlymphocytic, mononuclear cells in intraabdominal sepsis

Although sepsis is associated with increased production of cellular pro- and anti-inflammatory mediators by monocyte/macrophages, the compartmentalization and nature of such activation has not been clearly defined. The authors examined the activation of nonlymphocytic mononuclear cells in different compartments in the cecal ligation and puncture (CLP) model of septic peritonitis. Control and CLP rat mononuclear cells from the peritoneal cavity, bronchoalveolar, as well as the lung vascular compartment were isolated 24 and 48 hours post surgery and release of nitric oxide (NO), interleukin (IL)-12, and monocyte chemoattractant protein-1 (MCP-1) was measured from culture media. Peritoneal macrophages (PMs) from CLP rats increased release of all three mediators compared to controls. Cells from the lung vascular compartment after CLP increased release of NO, but MCP-1 release was unchanged. Levels of IL-12 were not detectable. Similarly, bronchoalveolar macrophages (BMs) of CLP rats had increased release of NO, whereas IL-12 was not detectable. Release of MCP-1 increased 48 hours after CLP. Almost all PMs and BMs possessed innate phagocytic ability that was not altered during sepsis. The percentage of cells in the lung vascular compartment that had phagocytic ability, increased 48 hours post CLP, versus controls. The authors also evaluated lung injury at 24 hours after surgery by measurement of bronchoalveolar lavage protein and LDH activity. There was an increase in both these parameters 24 hours after CLP as compared to controls. Thus, there was heterogenous and compartment-specific activation of mononuclear cells in sepsis. There was nonspecific inflammatory activation in the primary site of injury. In a remote organ (lung), the authors show for the first time that there was selective activation of NO without increased release of the proinflammatory cytokine, IL-12. Phagocytic activity was maintained in the bronchoalveolar compartment whereas in the lung vascular compartment, the percentage of phagocytic cells increased.

Chemical-chemical interaction between cyanogenic toxicants and aldehydes: a mechanism-based QSAR approach to assess toxicological joint effects

A QSAR approach was proposed to assess toxicological joint effects based on the mechanism of chemical-chemical interactions between cyanogenic toxicants and aldehydes. It has been observed that the chemical-chemical interaction between cyanogenic toxicants and aldehydes resulted in the formation of carbanion intermediates, and therefore this interaction led to different toxicological joint effects between cyanogenic toxicants and aldehydes. Analysis of this chemical-chemical interaction showed that the formation of carbanion intermediate highly depended on the charge of the carbon atom in the -CHO of aldehydes and this of the carbon atom (C*) in the carbochain of cyanogenic toxicant. By using the Hammett Constant (sigma(p)) to measure the charge of carbon atom in the -CHO of aldehydes, a mechanism-based QSAR approach (M = 0.316 - 4.386sigma(p) with r2 = 0.933, SE = 0.082, F = 55.389, p = 0.002, M = sum of toxic units) was proposed to assess the toxicological joint effects between alpha-hydroxy-isobutyronitrile and individual aliphatic aldehydes. Another one (M = 0.978 - 0.720sigma(p) with r2 = 0.852, SE = 0.152, F = 40.148, p = 0.0001) was also proposed to assess the toxicological joint effects between alpha-hydroxy-isobutyronitrile and individual aromatic aldehydes. Lastly, by using the charge of carbon atom (C*) in the carbochain of cyanogenic toxicant, a mechanism-based QSAR model (M = -0.161 - 7.721C* with r2 = 0.847, SE = 0.227, F = 27.657, p = 0.003) was derived to assess toxicological joint effects between p-nitrobenzaldehyde and cyanogenic toxicants.

Development of a fragment constant method for estimating the mixture toxicity

Based on Group Contribution Theory, a fragment constant model to estimate mixture toxicity is proposed in this paper. The toxicity (EC50M) of 58 mixtures is determined using Photobacterium phosphoreum. Analysis of these EC50M and the mole fraction of the individual chemical fragments (Br, Cl, NO2, OH, NH2) helps work out the fragment toxicity contribution (deltaTi) to EC50M. Thus, a linear regression equation is established between the toxicity contribution deltaTi and the fragment constants of Hansch f(i), and this equation is so significant that it helps provide an approach for calculating EC50M.

Role of IFN-gamma in bacterial containment in a model of intra-abdominal sepsis

Interferon-gamma (IFN-gamma) is a specific activator of macrophage function and plays a critical role in the host immune defense to bacterial infection. In this study we examined the role of IFN-gamma in the regulation of bacterial load in the cecal ligation and puncture (CLP) model of intra-abdominal sepsis in the rat. In initial studies, levels of IL-12, MCP-1, and IFN-gamma were measured in the peritoneal lavage fluid 24 and 48 h after CLP. IL-12 and MCP-1 levels were both significantly increased at 24 h after CLP compared to sham controls and this difference was maintained at 48 h after CLP. Interestingly, IFN-gamma levels were not significantly increased 24 h after CLP, but were increased at 48 h after CLP. These results clearly suggest that although an inflammatory response had occurred 24 h post-surgery, with increases in the proinflammatory cytokine IL-12 and the potent chemotactic agent MCP-1, levels of IFN-gamma in CLP rats were similar to sham controls. To further investigate the role of IFN-gamma on the development of sepsis we examined the effect(s) of administering anti-IFN-gamma antibody on bacterial load after CLP. We show that use of anti-IFN-gamma antibody can significantly decrease bacterial load in the peritoneum. The mechanism of the effect(s) of anti-IFN-gamma is probably by increasing intestinal adhesions to seal the cecum and reduce bacterial movement into the peritoneum.

[Aneurysmal model induced by elastase]

OBJECTIVE

To induce the aneurysms by corrosion of aneurysmal wall with elastase, imitating clinical intracranial aneurysms patho-morhologically.

METHODS

The elastase-corroded arterial segments were transplanted onto lateral walls of carotid arteries. Follow-up and pathological examination of the aneurysms were made at two weeks and one month after construction.

RESULTS

The aneurysms formed by the transplantation of elastase-corroded arterial segments were found persistent or enlarge a little within one month. The aneurysms were purplish red and easy to rupture when exposed. The walls were deprived of elastic layer, and constructed by thin connective tissue.

CONCLUSIONS

The aneurysms made by transplanting elastase-corroded arterial segments are simple to built, while morphological and pathological characteristics are demonstrated good clinical mimicry, we believe our aneurysm model may well substitute the most popularly used aneurysms made of venous pouches.

Colon epithelial cell death in 2,4,6-trinitrobenzenesulfonic acid-induced colitis is associated with increased inducible nitric-oxide synthase expression and peroxynitrite production

Peroxynitrite, derived from the reaction of nitric oxide (NO(.)) with superoxide (O(2)), is a potent nitrating and oxidizing agent that can induce apoptosis in a variety of different cell types. In the present study, we investigated the possible role of peroxynitrite as a mediator of colon epithelial cell death in rat colitis. Rat colon inflammation was induced by intracolonic administration of 2,4,6-trinitrobenzenesulfonic acid (TNBS) and rats were sacrificed 24 h after TNBS administration. Expression of inducible nitric-oxide synthase (iNOS) was detected by reverse transcription-polymerase chain reaction and immunohistochemistry. The enzymatic activities of Ca(2+)-independent iNOS and Ca(2+)-dependent constitutive nitric-oxide synthase were determined biochemically. Evidence of peroxynitrite-mediated cell injury was detected by immunostaining of nitrotyrosine. Apoptosis was examined by in situ terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and DNA gel electrophoresis. To evaluate the specific contribution of peroxynitrite to the observed cell injury, a selective iNOS inhibitor, L-N(G)-[1-iminoethyl]lysine (L-NIL), was administered after TNBS induction. Morphological examination and analysis of TUNEL/cytokeratin double immunofluorescence revealed significant apoptosis in mucosal epithelial cells. Nitrotyrosine was colocalized with TUNEL, strongly demonstrating the association of peroxynitrite with the apoptotic death of colon epithelial cells. The administration of L-NIL reduced iNOS activity in 24-h lesions by 92% and also significantly attenuated both nitrotyrosine staining and apoptotic cell counts in the colon epithelium. These results strongly suggest that local elevated level of peroxynitrite produced from increased iNOS expression and activity is a major contributor to colon epithelial apoptosis during colon inflammation.

Pattern of cytokine and adhesion molecule mRNA in hapten-induced relapsing colon inflammation in the rat

We examined the mRNA expression of cytokines, chemokines, integrins, and selectins in colon lesions of rat colitis with a semi-quantitative RT-PCR assay. Rat colitis was induced by trinitrobenzene sulfonic acid (TNBS) in 50% ethanol. Within 24 h, an acute inflammation occurred with hyperemia, edema, necrosis and an intense infiltration of granulocytes in the mucosa. The lesion proceeded into a T-lymphocyte/monocyte-driven chronic inflammation for two weeks and healed in 6 weeks. An acute inflammation recurred at the same site when the recovered animals were systemically injected with TNBS. We isolated RNA from colon tissue at 24 h, 1, 2, 4, 6 weeks after TNBS treatment and from the relapsed animals. The mRNA for cytokines IL-1beta, IL-6, IL-10 and the chemokines CINC, MIP-1alpha, MCP-1 were significantly (P < 0.05) elevated and persisted for 2 weeks, decreased in 6 weeks and increased again during relapse. IFN-gamma mRNA stayed at control levels initially, but increased dramatically in the second weeks of chronic inflammation as well as in relapse. The mRNA levels of adhesion molecules, ICAM-1, VCAM-1, the mucosal homing integrin beta7 as well as P- and E-selectin were greatly enhanced between 1 and 3 weeks. The data showed that the chronically inflamed tissue expresses a time-dependent changing pattern of TH1 cytokines and adhesion molecules that maintain the infiltration and activation of inflammatory cells and tissue injury.

Re-evaluation of cellulose acetate polymer: angiographic findings and histological studies

BACKGROUND

Cellulose acetate polymer (CAP) is a new liquid embolic material that has been used experimentally in intravascular treatment of intracranial aneurysms. But this compound is still controversial in some aspects such as safety, efficiency, and histological changes. In this study, we re-evaluated the material with regard to intravascular treatment of aneurysms.

METHODS

The carotid arteries of rats and experimental aneurysms in canines were embolized with CAP. The effects of CAP were evaluated according to angiographic and histological results.

RESULTS

A strong chemo-corrosive effect was observed. This led to severe damage to vessels and rupture of two thrombosed canine aneurysm models. There were significant technical difficulties including out-flow of CAP and a high rate of occlusion of the parent arteries.

CONCLUSIONS

We conclude that currently CAP is not an ideal embolic material for intracranial aneurysms. Further tests and improvements are needed before it can be widely used clinically.