Compositional and functional aberrance of the gut microbiota in treatment-naïve patients with primary Sjögren's syndrome

OBJECTIVES

To investigate the compositional and functional characteristics of the gut microbiota in primary Sjögren's syndrome (pSS) and compare them with those in systemic lupus erythematosus (SLE).

METHODS

Stool samples from 78 treatment-naïve pSS patients and 78 matched healthy controls were detected by shotgun metagenomic sequencing and compared with those from 49 treatment-naïve SLE patients. The virulence loads and mimotopes of the gut microbiota were also assessed by sequence alignment.

RESULTS

The gut microbiota of treatment-naïve pSS patients had lower richness and evenness and showed a different community distribution than that of healthy controls. The microbial species enriched in the pSS-associated gut microbiota included Lactobacillus salivarius, Bacteroides fragilis, Ruminococcus gnavus, Clostridium bartlettii, Clostridium bolteae, Veillonella parvula, and Streptococcus parasanguinis. Lactobacillus salivarius was the most discriminating species in the pSS patients, especially in those with interstitial lung disease (ILD). Among the differentiating microbial pathways, the superpathway of l-phenylalanine biosynthesis was also further enriched in pSS complicated with ILD. There were more virulence genes carried by the gut microbiota in pSS patients, most of which encoded peritrichous flagella, fimbriae, or curli fimbriae, three types of bacterial surface organelles involved in bacterial colonization and invasion. Five microbial peptides with the potential to mimic pSS-related autoepitopes were also enriched in the pSS gut. SLE and pSS shared significant gut microbial traits, including community distribution, altered microbial taxonomy and pathways, and enriched virulence genes. However, Ruminococcus torques was depleted in pSS patients but enriched in SLE patients compared to healthy controls.

CONCLUSIONS

The gut microbiota in treatment-naïve pSS patients was disturbed and shared significant similarity with that in SLE patients.

A-to-I RNA Editing in Klebsiella pneumoniae Regulates Quorum Sensing and Affects Cell Growth and Virulence

Millions of adenosine (A) to inosine (I) RNA editing events are reported and well-studied in eukaryotes; however, many features and functions remain unclear in prokaryotes. By combining PacBio Sequel, Illumina whole-genome sequencing, and RNA Sequencing data of two Klebsiella pneumoniae strains with different virulence, a total of 13 RNA editing events are identified. The RNA editing event of badR is focused, which shows a significant difference in editing levels in the two K. pneumoniae strains and is predicted to be a transcription factor. A hard-coded Cys is mutated on DNA to simulate the effect of complete editing of badR. Transcriptome analysis identifies the cellular quorum sensing (QS) pathway as the most dramatic change, demonstrating the dynamic regulation of RNA editing on badR related to coordinated collective behavior. Indeed, a significant difference in autoinducer 2 activity and cell growth is detected when the cells reach the stationary phase. Additionally, the mutant strain shows significantly lower virulence than the WT strain in the Galleria mellonella infection model. Furthermore, RNA editing regulation of badR is highly conserved across K. pneumoniae strains. Overall, this work provides new insights into posttranscriptional regulation in bacteria.

Antifungal susceptibility profiles and drug resistance mechanisms of clinical Candida duobushaemulonii isolates from China

Candida duobushaemulonii, type II Candida haemulonii complex, is closely related to Candida auris and capable of causing invasive and non-invasive infections in humans. Eleven strains of C. duobushaemulonii were collected from China Hospital Invasive Fungal Surveillance Net (CHIF-NET) and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF), VITEK 2 Yeast Identification Card (YST), and internal transcribed spacer (ITS) sequencing. Whole genome sequencing of C. duobushaemulonii was done to determine their genotypes. Furthermore, C. duobushaemulonii strains were tested by Sensititre YeastOne™ and Clinical and Laboratory Institute (CLSI) broth microdilution panel for antifungal susceptibility. Three C. duobushaemulonii could not be identified by VITEK 2. All 11 isolates had high minimum inhibitory concentrations (MICs) to amphotericin B more than 2 μg/ml. One isolate showed a high MIC value of ≥64 μg/ml to 5-flucytosine. All isolates were wild type (WT) for triazoles and echinocandins. FUR1 variation may result in C. duobushaemulonii with high MIC to 5-flucytosine. Candida duobushaemulonii mainly infects patients with weakened immunity, and the amphotericin B resistance of these isolates might represent a challenge to clinical treatment.

Compositional and functional aberrance of the gut microbiota in treatment naïve patients with primary Sjögren's syndrome

OBJECTIVES

To investigate the compositional and functional characteristics of the gut microbiota in primary Sjögren's syndrome (pSS) and compare them with those in systemic lupus erythematosus (SLE).

METHODS

Stool samples from 78 treatment naïve pSS patients and 78 matched healthy controls were detected by shotgun metagenomic sequencing and compared with those from 49 treatment naïve SLE patients. The virulence loads and mimotopes of the gut microbiota were also assessed by sequence alignment.

RESULTS

The gut microbiota of treatment naïve pSS patients had lower richness and evenness and showed a different community distribution than that of healthy controls. The microbial species enriched in the pSS-associated gut microbiota included Lactobacillus salivarius, Bacteroides fragilis, Ruminococcus gnavus, Clostridium bartlettii, Clostridium bolteae, Veillonella parvula, and Streptococcus parasanguinis. Lactobacillus salivarius was the most discriminating species in the pSS patients, especially in those with interstitial lung disease (ILD). Among the differentiating microbial pathways, the superpathway of l-phenylalanine biosynthesis was also further enriched in pSS complicated with ILD. There were more virulence genes carried by the gut microbiota in pSS patients, most of which encoded peritrichous flagella, fimbriae, or curli fimbriae, three types of bacterial surface organelles involved in bacterial colonization and invasion. Five microbial peptides with the potential to mimic pSS-related autoepitopes were also enriched in the pSS gut. SLE and pSS shared significant gut microbial traits, including the community distribution, altered microbial taxonomy and pathways, and enriched virulence genes. However, Ruminococcus torques was depleted in pSS patients but enriched in SLE patients compared to that in healthy controls.

CONCLUSIONS

The gut microbiota in treatment naïve pSS patients was disturbed and shared significant similarity with that in SLE patients.

First two fungemia cases caused by Candida haemulonii var. vulnera in China with emerged antifungal resistance

Candida haemulonii var. vulnera is a rare variant of C. haemulonii, which has been previously reported to cause human infections. Owing to the close kinship between C. haemulonii sensu stricto and C. haemulonii var. vulnera, accurate identification of C. haemulonii var. vulnera relied on DNA sequencing assay targeting, for example, rDNA internal transcribed spacer (ITS) region. In this work, two strains of C. haemulonii var. vulnera were collected from the China Hospital Invasive Fungal Surveillance Net (CHIF-NET). The identification capacity of three matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and VITEK 2 YST ID biochemical methods were evaluated against ITS sequencing. In addition, antifungal susceptibility testing was performed using Sensititre YeastOne. Moreover, we comprehensively screened drug-resistant related genes by whole-genome sequencing. The two strains were not correctly identified to species variant level using MALDI-TOF MS and YST ID cards. Both strains were resistant to amphotericin B (minimum inhibitory concentration [MIC] > 2 μg/ml). Moreover, strain F4564 and F4584 exhibited high MIC to fluconazole (>256 μg/ml) and 5-flucytosine (>64 μg/ml), respectively, which were supposed to result from key amino acid substitutions Y132F and G307A in Erg11p and V58fs and G60K substitutions in Fur1p. The rare species C. haemulonii var. vulnera has emerged in China, and such drug-resistant fungal species that can cause invasive diseases require further close attention.

Correlation of Moraxella catarrhalis macrolide susceptibility with the ability to adhere and invade human respiratory epithelial cells

Recently, the prevalence of macrolide-resistant Moraxella catarrhalis has been reported, especially among Chinese children. The fitness cost of resistance is reported to render the resistant bacteria less virulent. To investigate the correlation between macrolide susceptibility of M. catarrhalis and pathogenicity, the whole genome of 70 M. catarrhalis isolates belonging to four clonal complexes with different macrolide susceptibilities was sequenced. The gene products were annotated with the Gene Ontology terms. Based on 46 extracted essential virulence genes, 19 representative isolates were selected to infect type II alveolar cells (A549 cells). The ability of these isolates to adhere and invade human epithelial cells and to produce cytokines was comparatively analysed. Furthermore, mice were infected with a pair of M. catarrhalis isolates with different pathogenic behaviours and macrolide susceptibilities to examine pulmonary clearance, histological findings, and the production of cytokines. The percentages of annotations for binding, metabolic process, cellular process, and cell were non-significantly different between the macrolide-resistant and macrolide-susceptible groups. The presence of uspA2, uspA2H, pilO, lbpB, lex1, modM, mboIA, and mboIB significantly differed among the four clonal complexes and macrolide susceptibility groups. Furthermore, compared with those in macrolide-susceptible isolates, the adhesion ability was stronger (P = 0.0019) and the invasion ability was weaker (P < 0.0001) in the macrolide-resistant isolates. Mouse experiments revealed that pulmonary macrophages elicit immune responses against M. catarrhalis infection by significantly upregulating the Csf2, Il4, Il13, Il1b, Il6, Tnf, and Il18. Therefore, M. catarrhalis populations exhibited diverse pathogenicity in vitro and in vivo.

[Progress of researches on Fasciola and fascioliasis in Yunnan Province]

Fascioliasis is a zoonotic parasitic disease that seriously endangers human health and hinders socioeconomic development. Fasciola mainly infects ruminants, such as cattle and sheep. However, there has recently been a rise in the number of human cases with fascioliasis with the improvements of diagnostic techniques. During the past decades, sporadic cases of fascioliasis were predominantly identified; however, there were outbreaks of fascioliasis in Yunnan Province, which has been paid much attention. The review summarizes the advances in the distribution of Fasciola species and the progress of researches on fascioliasis in Yunnan Province.

Clinical-radiological characteristics and intestinal microbiota in patients with pancreatic immune-related adverse events

BACKGROUND

The pancreatic immune-related adverse event (irAE) is a rare but increasingly occurrence disease with limited knowledge, which was associated with the use of immune checkpoint inhibitors (ICIs).

METHODS

In this case series study of pancreatic irAE patients, clinical and radiological manifestations are summarized. Baseline and post-treatment fecal microbiota of immune-related acute pancreatitis (irAP) patients were analyzed by the 16 s rDNA amplicon sequencing method.

RESULTS

A total of six patients were enrolled into the study, and the onset of pancreatic irAEs occurred a median of 105 days after a median of 4.5 cycles with immune checkpoint inhibitors (ICIs). All patients had an effective response to ICIs. Abdominal pain was the main clinical manifestation. Serum amylase (sAMY) and lipase (sLIP) had dynamic changes parallel to clinical severity. Contrast-enhanced computed tomography (CT) did not accurately reveal the level of inflammation. However, magnetic resonance imaging (MRI) was a sensitive imaging method which showed decreased and increased signal intensity of pancreatic parenchyma in T1-weighted fat-saturated and diffusion-weighted imaging, respectively. Glucocorticoids were the main treatment with a rapid initial effect followed by a slow improvement. After reinitiation of ICI therapy, pancreatic irAEs either deteriorated, remained stable or the patient developed severe pancreatic β-cell destruction without irAP recurrence. The baseline microbiota of irAP had low Bacteroidetes/Firmicutes ratio at phylum level, low relative abundance of Alistipes, Bacteroides and high Lachnospiraceae at genus level, compared to levels of pancreatic β-cell destruction and post-treatment of irAP.

CONCLUSIONS

Pancreatic irAE patients had corresponding abdominal pain and increase in sAMY/sLIP. MRI was found to be an ideal imaging modality. Treatment with glucocorticoids were the main approach. The microbiota showed relative changes at baseline and during treatment.

Species distribution and antifungal susceptibilities of clinical isolates of Penicillium and Talaromyces species in China

Morphologically identified Penicillium (n = 103) and Talaromyces marneffei (n = 8) isolates were collected from various clinical sources between 2016 and 2017 at a medical centre in Beijing, China. Identification to species level was confirmed by sequencing of the internal transcribed spacer (ITS) region, β-tubulin gene (benA) and RNA polymerase II second largest subunit (RPB2) gene. Of the 111 isolates, 56 (50.5%) were identified as Penicillium spp. and 55 (49.5%) as Talaromyces spp. Eleven species of Penicillium were detected, of which Penicillium oxalicum was the commonest, accounting for 51.8% (29/56), followed by Penicillium rubens (10.7%; 6/56) and Penicillium citrinum (10.7%; 6/56). Among the 55 Talaromyces isolates, nine species were identified, with Talaromyces funiculosus (36.4%; 20/55), Talaromyces stollii (27.3%; 15/55) and Talaromyces marneffei (14.5%; 8/55) being the most common. Of note, 89.3% (50/56) of the Penicillium isolates and 98.2% (54/55) of the Talaromyces isolates exhibited growth at 37°C. The isolates were mainly recovered from patients with pulmonary disorders (56.8%; 63/111), autoimmune disease (12.6%; 14/111) and AIDS (5.4%; 6/111). The azoles and amphotericin B exhibited potent activity against T. marneffei, while various levels of activity were observed against Penicillium and other Talaromyces species The echinocandins had the lowest MECs (MEC_90, ≤0.12 mg/L) against most Penicillium and Talaromyces species, with the exception of T. marneffei whose MEC₉₀ (4 mg/L) was five or more dilutions higher than that of the other species tested. These data on the species distribution and antifungal susceptibility expand the current clinical knowledge of Penicillium and Talaromyces species.

An Autoimmunogenic and Proinflammatory Profile Defined by the Gut Microbiota of Patients With Untreated Systemic Lupus Erythematosus

OBJECTIVE

Changes in gut microbiota have been linked to systemic lupus erythematosus (SLE), but knowledge is limited. Our study aimed to provide an in-depth understanding of the contribution of gut microbiota to the immunopathogenesis of SLE.

METHODS

Fecal metagenomes from 117 patients with untreated SLE and 52 SLE patients posttreatment were aligned with 115 matched healthy controls and analyzed by whole-genome profiling. For comparison, we assessed the fecal metagenome of MRL/lpr mice. The oral microbiota origin of the gut species that existed in SLE patients was documented by single-nucleotide polymorphism-based strain-level analyses. Functional validation assays were performed to demonstrate the molecular mimicry of newly found microbial peptides.

RESULTS

Gut microbiota from individuals with SLE displayed significant differences in microbial composition and function compared to healthy controls. Certain species, including the Clostridium species ATCC BAA-442 as well as Atopobium rimae, Shuttleworthia satelles, Actinomyces massiliensis, Bacteroides fragilis, and Clostridium leptum, were enriched in SLE gut microbiota and reduced after treatment. Enhanced lipopolysaccharide biosynthesis aligned with reduced branched chain amino acid biosynthesis was observed in the gut of SLE patients. The findings in mice were consistent with our findings in human subjects. Interestingly, some species with an oral microbiota origin were enriched in the gut of SLE patients. Functional validation assays demonstrated the proinflammatory capacities of some microbial peptides derived from SLE-enriched species.

CONCLUSION

This study provides detailed information on the microbiota of untreated patients with SLE, including their functional signatures, similarities with murine counterparts, oral origin, and the definition of autoantigen-mimicking peptides. Our data demonstrate that microbiome-altering approaches may offer valuable adjuvant therapies in SLE.

[Investigation on Demodex infections among university students in Kunming City]

OBJECTIVE

To investigate the prevalence of Demodex infection among students in Kunming Medical University, and identify the factors affecting Demodex infections, so as to provide the evidence for the development of the strategy for the prevention of Demodex infections.

METHODS

A total of 1 463 students from Grade 2014 who studied Medical Parasitology in Kunming Medical University were included in the survey. Demodex was examined in students'facial skin using the cellophane tape method, and the species was identified using microscopy. The students'gender, ethnicity, place of origin and skin type were captured using a questionnaire survey.

RESULTS

The overall prevalence of Demodex infections was 19.07% (279/1 463) on the facial skin among the university students, and a higher prevalence was seen in girls (21.16%, 183/865) than in boys (16.05%, 96/598) (χ² =5.965,P <0.05).TheprevalenceofDemodex infectionswas18.33%(66/360)amongminorethnicstudents,andnoethnicity-specific prevalence was seen (P > 0.05). Demodex folliculorum was the predominant species, with a prevalence of 50.54% (141/279), and mild infections were predominant among all infections (96.77%, 270/279), without severe infections seen. Multivariate nonconditional logistic regression analysis revealed that gender and roommates with Demodex infections were risk factors of Demodex infections, and the infection was not associated with ethnicity, place of origin or skin type. There were only 2.53% (37/1 463) of the subjects understanding the knowledge pertaining to the prevention and control of Demodex infection.

CONCLUSIONS

A relatively low prevalence of Demodex infection is detected in the facial skin of students from Kunming Medical University, and Demodex infection is associated with gender and roommates with Demodex infections. Health education pertaining to the prevention of Demodex infections is suggested to be intensified among university students.

Genome sequence compression based on optimized context weighting

Context weighting is an important technology for genome compression. In this study, we discuss the relationship between the weighting of context models and the weighting of the description lengths corresponding to their respective context models. It indicates that weighting of context models is equivalent to the weighting of their description lengths. With these discussions, we present the weights optimization algorithm based on the minimum description length, and suggest implementing the least-square algorithm for the optimization of the weights. The proposed optimization algorithm is used in the compression of bacterial genome sequences. The experiment results indicate that by using the proposed weights optimization method, our context weighting-based genome compression algorithm can achieve better performance than context weighting-based algorithms reported in the literature.

Effect of thyroxine on SNARE complex and synaptotagmin-1 expression in the prefrontal cortex of rats with adult-onset hypothyroidism

Thyroid hormone insufficiency in adulthood causes a wide range of brain impairments, including altered synaptic proteins in the prefrontal cortex (PFC). The present study investigated whether adult-onset hypothyroidism altered the expression of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes and synaptotagmin-1 (syt-1) in the PFC of rats. Sprague-Dawley rats were randomly divided into 4 groups: control, hypothyroid, and hypothyroid treated with T(4) [5 or 20 μg/100 g body weight (BW)]. Adult-onset hypothyroidism was induced in rats with the antithyroid drug 6-n-propyl-2-thiouracil (ip injection). PFC levels of synaptosomal-associated protein of 25 kDa (SNAP-25), syntaxin-1, vesicle-associated membrane protein 2 (VAMP-2) and syt-1 were determined by immunohistochemistry and western blot analyses. The results showed that syntaxin-1 and syt-1 were expressed at significantly lower levels in hypothyroid rats, VAMP-2 levels were not altered, and SNAP-25 levels were much higher compared to controls. A 2-week treatment with 5 μg T(4)/100 g BW partially normalized levels of SNARE complex and syt-1, and 20 μg T(4)/100 g BW restored these proteins closer to normal levels. Our findings indicate that dysregulation of SNARE complex and syt-1 in PFC of adult-onset hypothyroidism can be restored by T(4) treatment.

Optimization of a bacterial consortium for nitrobenzene degradation

Three bacterial strains, Arthrobacter sp. NB1, Serratia sp. NB2 and Stenotrophomonas sp. NB3, were isolated from contaminated sludge by using nitrobenzene as a sole source of carbon and nitrogen. It was observed that all three strains could degrade nitrobenzene at 400 mg/L initial concentration and mixed-cultivation of these strains could enhance the degradation of nitrobenzene compared with mono-cultivation. Mixture design was used for adjusting the proportions of each strain and the optimal ratio of inoculation size was NB1:NB2:NB3 = 4:4:5, where the nitrobenzene degradation percentage was two times higher than for by the single strain. The results of Plackett-Burman design indicated that Mg(2+), Ca(2+), Fe(2+), Zn(2+) and Mn(2+) had a positive effect on the degradation of nitrobenzene, while Cu(2+) and Co(2+) had a negative effect on it.

Effect of thyroxine on synaptotagmin 1 and SNAP-25 expression in dorsal hippocampus of adult-onset hypothyroid rats

Adult-onset hypothyroidism causes cognitive dysfunctions of learning and memory, in which many synaptic proteins in hippocampus are involved. In our work, we studied the effect of adult-onset hypothyroidism on the expression of synaptotagmin 1 (syt 1) and SNAP-25 in dorsal hippocampus as well as its recovery by levothyroxine (L-T(4)) replacement therapy. Rats were divided into 4 groups: control, hypothyroidism, and hypothyroid rats treated with 5 μg T(4)/100 g body weight (BW) and 20 μg L-T(4)/100 g BW, respectively. Protein levels of syt 1 and SNAP-25 in dorsal hippocampus were determined by Western blot and immunohistochemistry. The immunoblot analysis indicated that syt 1 was expressed at a significantly lower level in hypothyroid rats, while the level of SNAP-25 was much higher compared to controls. Furthermore, using immunostaining, we found that on the one hand, expression of syt 1 was significantly down-regulated in the examined layers of CA1 and CA3 subregions but not dentate gyrus (DG); however, on the other hand, expression of SNAP-25 was up-regulated in the layers of CA1, CA3, and DG. Two-week treatment with 20 μg LT(4)/ 100 g BW fully restored the levels of syt 1 and SNAP-25 to the normal level, which was more effective than 5 μg LT(4)/ 100 g BW that partially restored the levels of both proteins. These results suggest that adult-onset hypothyroidism caused down-regulation of syt 1 and up-regulation of SNAP- 25 level in dorsal hippocampus, which could be restored by L-T(4) treatment, and the recovery degree is related to the LT(4) dosage.

The decolorisation capacity and mechanism of Shewanella oneidensis MR-1 for methyl orange and acid yellow 199 under microaerophilic conditions

Shewanella oneidensis MR-1 was found to reach 99.36% and 78.25% decolorisation for Methyl Orange and Acid Yellow 199 in solutions, respectively. The suitable pH range for decolorisation of Methyl Orange and Acid Yellow 199 by S. oneidensis MR-1 was 4.0-7.0 and 6.0-8.0, respectively, The azo dyes' removal by S. oneidensis MR-1 was slightly enhanced by addition of Mg(2+), but inhibited by Pb(2+), Cd(2+), Cu(2+), Fe(3+) and Fe(2+). The enzyme activities of NADH-DCIP reductase and azoreductase were 2.67 and 3.0 times higher, and 1.92 and 2.48 times higher, respectively, in the Methyl Orange treatment and in the Acid Yellow 199 treatment as compared to the control treatment. These findings indicated that the azo dyes' decolorisation by S. oneidensis MR-1 was via reduction mechanism.

Candida albicans THI13 disruption affects production of monocytic cytokines

INTRODUCTION

The Candida albicansTHI13 gene was identified by its homology to the Candida tropicalis CtNMT1 gene, which is involved in pyrimidine precursor biosynthesis.

METHODS

Disruption of THI13 revealed that this gene played a minor role in thiamin biosynthesis in C. albicans. Purified human monocytes were incubated with C. albicans at the optimal Candida: monocyte ratio of 0.5 and cytokines in the supernatants were measured by enzyme-linked immunosorbent assay.

RESULTS AND DISCUSSION

This experiment showed that the wild-type strain significantly induced interleukin-10 (IL-10) production but had little effect on IL-12 production, and that THI13 mutants had no significant effect on IL-10 production, though the IL-12 level was increased in the supernatants. These results suggest that THI13 is involved in the host effective immune response by regulating IL-10 and IL-12 production.

[Genetic diversity of Rh haplotypes among Chinese populations]

In the statistic study of Rh blood group system, whole Chinese data were re-calculated for haplotype frequency and linkage ratio, according to Counting Method. All Chinese majority populations and minority populations were divided into different groups, and variety genetic calculations on their gene diversity and gene differentiation were also calculated. The results shown obvious genetic differences between and among Southern and Northern Chinese populations. UPGMA phylogenetic dendrograms was plotted and the tree demonstrated that the genetic relationship among 68 Chinese populations are well corresponded with their geographical and linguistic distribution.

Routine assessment of viability in split-thickness skin

Effective quality control of allograft skin that is cryopreserved for transplantation requires a simple, reproducible technique for the assessment of cell viability. Tetrazolium reduction assays and an oxygen consumption technique have been the two methods of choice to determine the metabolic function of allograft skin after it has been thawed. In this study, we investigated the use of a novel tetrazolium salt, WST-1 (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzen e disulfonate), that is cleaved to a water-soluble formazan product. Porcine split-thickness skin in minimal essential medium without cryoprotectant was subjected to a graded freezing protocol to generate progressive amounts of cryoinjury. Recovery as determined with WST-1 was compared with measurements made with the use of the oxygen consumption technique. The similarity of the resulting recovery curves indicates that WST-1 is a simple, effective, and convenient technique for the assessment of metabolic function in porcine split-thickness skin. The WST-1 assay is applicable for the routine assessment of tissue viability in cryopreserved allograft skin.

Clinical use of homograft stored by vitrification

Using 20% DMSO and 6% propylene glycol in Kreb' Ringer phosphate solution as cryopotective agent for homograft vitrification storage, the viability of stored homograft (79.2%) was higher than that of slow cooling storage (59.7%). About 540000 cm2 of vitrified homograft were used to cover the wounds after excision of burn eschar in 135 patients with major burns. The take-rate was over 94%. The cryopreservation of skin by vitrification can improve the viability and quality of skin and save time and cost.

[Effects of different cooling rate on the viability of cryopreservation of skin]

The three methods of stored skin by vitrification and slow cooling and vitrification+slow cooling were studied in order to improve the viability of stored skin. The results showed that the viability (oxygen consumptions and succinate dehydrogenase) of skin cryopreserved by vitrification was superior than by slow cooling and vitrification+slow cooling. The viability of homograft stored by vitrification was 61% compared with that for other two groups of 51.7% and 49.2% (P < 0.05). So the skin stored by this vitrification may be suitable for clinical use.

Semi-differential voltammetry with carbon fiber electrodes for in vivo determination of monoamine metabolites and ascorbic acid in rat corpus striatum

Carbon fiber electrodes combined with semi-differential voltammetry were used to determine endogenous monoamine metabolites and ascorbic acid (AA). These electrodes treated by a new electrochemical procedure (30 microA for 30 s, then -2 V for 10 s) showed a significant improvement on the sensitivity and selectivity. In the rat corpus striatum, these electrodes allowed a distinct separation and continuous detection of AA, 3, 4-dihydroxyphenylacetic acid (DOPAC), and 5-hydroxyindoleacetic acid (5-HIAA) simultaneously. The normal striatal levels of AA, DOPAC, and 5-HIAA were found to be 168.2 +/- 19.5, 21.4 +/- 3.9, and 3.3 +/- 0.5 mumol.L-1. Our method is credible for detecting the changes of monoamine metabolite contents induced by pharmacologic manipulations.

[Improvement in the method of determination of succinic dehydrogenase in skin]

The authors improved Hershey's measurement of succinic dehydrogenase in the shin. Liquid paraffin was used to replace nitrogen gas sealing. The values of succinic dehydrogenase of guinea pig skin which was kept at 4 degrees C for 2, 4, 6, 8, 10 days were measured by two methods. There were no significant differences between the values measured by two methods (P greater than 0.05). Our method is simpler, more convenient and have good correlation with Hershey's method (r = 0.929).

[Dynamic changes in serum levels of T3 and T4 in burn patients and its clinical significance]

From May 1985 to May 1987, dynamic changes in T3 and T4 in serum of 34 burn patients were measured by radio-immunodiffusion method. Among them, 10 patients died. The normal levels of T3 and T4 in serum of 30 healthy person are presented. The levels of T3 and T4 in every burn groups were lower significantly than in normal healthy person group (P less than 0.01). After 3 days of burn injury, the levels of T3 and T4 in serum were low on 3 days postburn and were lowest on 30 days postburn. T3 in serum was markedly higher before sepsis than after sepsis (P less than 0.01) and T4 in serum was lower before sepsis than after sepsis. But no significant difference was found (P greater than 0.05). It also showed that the levels of T3, T4 were higher in groups of non-sepsis and survival than in those of sepsis and death. The results suggest that determination of T3 and T4 in serum are valuable to diagnose and predict the prognosis of sepsis in burn injuries.

The use of blood in burn shock. Clinical and experimental study

We have given whole blood as one of the main constituents of burn shock resuscitation for the past 28 years. To appraise the value of using whole blood, we have summarized the clinical experience of 2630 burn patients. Overall mortality was 4.18%. The lethal area of the burn were 50% of the population is expected to die was 82.8% total body surface area and 57.4% third-degree burns. The incidence of renal failure, pulmonary edema, and gastrointestinal bleeding was 0.9%, 0.4%, and 0.6% respectively. To confirm the advantage of transfusion of whole blood, we have carried out a series of experimental studies. Two groups of 25 dogs with 25% total body surface area full-thickness burns were treated with two resuscitation regimens. Group I was treated with whole blood, and group II with no blood, during the shock phase. After 48 hours, the infusions were stopped. Measurements were made before the burn and 2, 24, 48, 72, and 144 hours after the burn injury. The animals were then killed for histologic studies. From our data, we concluded that whole blood used in burn shock did not increase hemoconcentration or viscosity; it improved anemia, oncotic pressure, hypoproteinemia, acid-base balance, oxygenation, hemodynamics, and myocardial contractility, promoted cardionatrin secretion, reduced edema of tissue, and protected viscera from degenerative changes and bacterial colonization.

Changes in plasma fibronectin levels in burn patients

Plasma fibronectin was determined in 180 healthy individuals. No significant difference was found between males and females: therefore the values were pooled. The mean value was 286.94 +/- 51.35 micrograms/ml. In 24 patients with burns covering 30-95 per cent of the total body surface area (TBSA), plasma fibronectin was determined sequentially. There was a significant lowering in plasma fibronectin (FN) values in all cases on post-burn day 1 (112.56-185.85 micrograms/ml) and post-burn day 2 (44.03-298.0 micrograms/ml). The concentrations returned to within the normal range in 19 survivors within 3-6 days. In five non-survivors, plasma FN levels fell progressively until death. In another nine patients with burns ranging from 3 per cent to 25 per cent TBSA, plasma FN level was found to be normal on post-burn day 1. The likely causes of the reduced concentrations of plasma fibronectin in patients with burn injuries are briefly discussed. It seems that the level of plasma fibronectin may be used as a prognostic index in burn patients.