[Clinical characteristics of children with severe SARS-CoV-2 infection in Yunnan]

Objective: To investigate the clinical characteristics of 130 children with severe SARS-CoV-2 infection in Yunnan province after the relaxation of non-pharmaceutical interventions, and analyze the risk factors for mortality. Methods: This study is a retrospective case summary that analyzed the demographic data, underlying diseases, clinical diagnoses, disease outcomes, and laboratory results of 130 children with severe COVID-19 infections admitted to nine top-tier hospitals in Yunnan Province from December 2022 to March 2023. According to the prognosis, the patients were divided into survival group and death group. The clinical and laboratory data between the two groups were compared, and the risk factors of death were evaluated. The χ2 test and Mann-Whitney U test were employed to compare between groups, while Spearman correlation test and multiple Logistic regression were used to analyze the risk factors for death. The predictive value of independent risk factors was evaluated by receiver operating characteristic curve. Results: The 130 severe patients included 80 males and 50 females with an onset age of 28.0 (4.5, 79.5) months. There were 97 cases in the survival group and 33 cases in the death group with no significant differences in gender and age between the two groups (P>0.05). Twenty-five cases (19.2%) out of the 130 patients had underlying diseases, and the number with underlying diseases was significantly higher in death group than in survival group (36.4% (12/33) vs. 13.4%(13/97), χ2=8.36, P=0.004). The vaccination rate in the survival group was significantly higher than that in the death group (86.1% (31/36) vs. 7/17, χ2=9.38, P=0.002). A total of 42 cases (32.3%) of the 130 patients were detected to be infected with other pathogens, but there was no significant difference in the incidence of co-infection between the death group and the survival group (39.3%(13/33) vs. 29.9% (29/97), χ2=1.02, P>0.05). Among the 130 cases, severe respiratory cases were the most common 66 cases (50.8%), followed by neurological severe illnesses 34 cases (26.2%) and circulatory severe 13 cases (10%). Compared to the survival group, patients in the death group had a significantly higher levels of neutrophil, ferritin, procalcitonin, alanine aminotransferase, lactate dehydrogenase, creatine kinase isoenzyme, B-type natriuretic peptide, interleukin-6 and 10 (6.7 (4.0, 14.0) vs. 3.0 (1.6, 7.0)×109/L, 479 (298, 594) vs. 268 (124, 424) μg/L, 4.8 (1.7, 10.6) vs. 2.0 (1.1, 3.1) μg/L, 66 (20, 258) vs. 23 (15, 49) U/L, 464 (311, 815) vs. 304 (252, 388) g/L, 71(52, 110) vs. 24(15, 48) U/L, 484 (160, 804) vs. 154 (26, 440) ng/L, 43 (23, 102) vs. 19 (13, 27) ng/L, 216 (114, 318) vs. 86 (45, 128) ng/L, Z=-4.21, -3.67, -3.76, -3.31, -3.75, -5.74, -3.55, -4.65, -5.86, all P<0.05). The correlated indexes were performed by multivariate Logistic regression and the results showed that vaccination was a protective factor from death in severe cases (OR=0.01, 95%CI 0-0.97, P=0.049) while pediatric sequential organ failure assessment (PSOFA) (OR=3.31, 95%CI 1.47-7.47, P=0.004), neutrophil-to-lymphocyte ratio (NLR) (OR=1.56, 95%CI 1.05-2.32, P=0.029) and D dimer (OR=1.49, 95%CI 1.00-1.02, P=0.033) were independent risk factors for death (all P<0.05). The area under the curve of the three independent risk factors for predicting death were 0.86 (95%CI 0.79-0.94), 0.89 (95%CI 0.84-0.95) and 0.87 (95%CI 0.80-0.94), all P<0.001, and the cut-off values were 4.50, 3.66 and 4.69 mg/L, respectively. Conclusions: Severe SARS-CoV-2 infection can occur in children of all ages, primarily affecting the respiratory system, but can also infect the nervous system, circulatory system or other systems. Children who died had more severe inflammation, tissue damage and coagulation disorders. The elevations of PSOFA, NLR and D dimer were independent risk factors for death in severe children.

Identification of Ca(2+)-binding residues of a protein from its primary sequence

Calcium is one of the most abundant minerals in the human body, playing a critical role in many cellular activities by interacting with different calcium ion (Ca(2+))-binding proteins. Therefore, the correct identification of Ca(2+)-binding residues is essential for protein functional research. In this study, a new method was developed to predict Ca2+-binding residues from the primary sequence without using three-dimensional information. Through statistical analysis, four kinds of feature parameters were extracted from amino acid sequences: the increment of diversity values of amino acid composition, the matrix scoring values of position conservation, the autocross covariance of physicochemical properties, and the center motif. These features served as input for a support vector machine to predict Ca(2+)-binding residues. This method was tested on four well-established datasets using a five-fold cross-validation. The accuracies and Matthews correlation coefficients were 75.9% and 0.53 (dataset 1), 79.2% and 0.58 (dataset 2), 77.4% and 0.55 (dataset 3), and 79.1% and 0.58 (dataset 4). Comparative results show that the developed method outperforms previous methods. Based on this study, a web server was developed for predicting Ca(2+)-binding residues from any protein sequence, being publically available at http://202.207.29.245/.

Identification of complex vertebral malformation carriers in Holstein cattle in south China

Complex vertebral malformation (CVM) is a recently described monogenic autosomal recessive hereditary defect of Holstein dairy cattle that causes premature birth, aborted fetuses and stillborn calves. Guanine is substituted by thymine (G>T) in the solute carrier family 35 member A3 gene (SLC35A3). A valine is changed to a phenylalanine at position 180 of uridine 5'-diphosphate-N-acetyl-glucosamine transporter protein. CVM is expected to occur in many countries due to the widespread use of sire semen. We developed a created restriction site PCR (CRS-PCR) method to diagnose CVM in dairy cows. This was tested on 217 cows and 125 bulls selected randomly from a Holstein cattle population in south China. Five Holstein cows and five Holstein bulls were identified to be CVM carriers; the percentages of CVM carriers were estimated to be 2.3, 4.0 and 2.9% in the cows, bulls and entire Holstein cattle sample, respectively.

Verapamil, cyproheptadine, and anisodamine antagonized [Ca2+]i elevation induced by TNFalpha in a single endothelial cell

AIM

To study the effect of tumor necrosis factor alpha (TNFalpha) on intracellular free Ca2+ concentration ([Ca2+]i) and the effects of verapamil (Ver), cyproheptadine (Cyp), and anisodamine (Ani) on TNFalpha-induced [Ca2+]i changes in single endothelial cell, and to explore the mechanisms of TNFalpha-mediated shock and antishock actions of Cyp and Ani.

METHODS

Human umbilical vein endothelial cell strains (ECV304) were seeded in 35-mm tissue culture dish with 2 mL DMEM culture medium. The cultured cells were loaded by Fluo-3/AM. The spatial distribution and the dynamic changes of [Ca2+]i in single endothelial cell were determined by laser scanning confocal microscopy.

RESULTS

After stimulation with TNFalpha, [Ca2+]i in single endothelial cell rapidly increased in a concentration-dependent manner and arrived at the peak value within 60 s, afterwards, decreased and kept above the basal level. The confocal scanning image showed that [Ca2+]i elevation was more obvious in nuclear than in cytoplasma and decreased slowly. Ver (1, 2 micromol/L), Cyp (30, 60 micromol/L), and Ani (20, 40 micromol/L) markedly inhibited TNFalpha 1.2 nmol/L-induced [Ca2+]i elevation.

CONCLUSION

TNFalpha markedly induces elevation of [Ca2+]i in a single endothelial cell, it may be an important mechanism of TNFalpha-induced shock and tissue injury. That Cyp and Ani obviously suppress TNFalpha-induced [Ca2+]i elevation probably is one of the mechanisms of their antishock effects.

[Determination of residues of 20 kinds of organochlorinated pesticides in oils, fruits and vegetables by wide-bore capillary gas chromatographic column]

A rapid and high performance gas chromatographic method for the determination of 20 organchlorinated pesticides in oils, fruits and vegetables has been developed. The samples of fruits and vegetables were extracted with petroleum ether-acetone, while those of oils were extracted with acetonitrile-hexane. The extract was purified by Florisil column with ethyl ether-hexane(15:85, V/V) or ethyl ether-petroleum ether(15:85, V/V) as eluent. Chromatographic analysis was performed on wide-bore capillary column with ECD detector. Satisfactory separation and detection of these organchlorinated pesticides are presented with the proposed method. The detection limits of this method were 1.0 ng/g-20.0 ng/g(S/N = 5), the recoveries 83.2%-106.8% and the relative standard deviations 2.0%-9.5%.

The pattern of cytokine gene expression induced in rat T cells specific for myelin basic protein depends on the type and quality of antigenic stimulus

Rat T cells reactive against myelin basic protein (MBP) are exclusively, CD4+ CD8- CD45RC-, inevitably produce abundant IFN-gamma, and appear to correspond to members of the Th1 CD4+ T cell subset characterized in mice. To ascertain the basis of the pathogenic activity of these cells, we studied their pattern of cytokine expression in response to activation by distinct TCR ligands. Using RT-PCR and Northern blot assays to quantify cytokine gene production and cytokine production from intact cells, we show that (i) rat MBP-reactive T cells express IL-2, IFN-gamma, and TNF-alpha as well as IL-5 and IL-10; (ii) cytokine production is not an all or nothing phenomenon, but rather varies according to the type and dose of TCR ligand, leading to variation in the pattern of cytokine production, or dissociation between cytokine production and cell proliferation; and (iii) nonencephalitogenic T cells do not differ appreciably from their encephalitogenic counterparts in ability to produce major cytokines.

Application of dot-immunogold-silver staining in the diagnosis of clonorchiasis

All 35 confirmed clonorchiasis cases showed a positive reaction in dot-immunogold-silver staining (Dot-IGSS) with a mean serum titre of 1:1656, while none of the sera from 35 normal individuals reacted. A seroepidemiological survey of middle-school students revealed a positive rate of 17.0% (142/836), and 76.1% (105/138) of the serologically positive students were egg positive in stool examination. The egg positive rates in those with antibody at levels of 1+ to 4+ were 57.1% (28/49), 75.7% (28/37), 94.7% (36/38) and 92.9% (13/14) respectively. It is believed that Dot-IGSS can be used for the clinical diagnosis and epidemiological survey of clonorchiasis.

Heterogeneity of rat encephalitogenic T cells elicited by variants of the myelin basic protein (68-86) peptide

By immunizing Lewis rats with myelin basic protein (MBP) peptide variants derived from the major encephalitogenic epitope of guinea pig (MBP(68-88) and then isolating encephalitogenic T cells from these animals, we demonstrated that the variant peptides do not elicit the same encephalitogenic T cell subsets as those induced by the wild-type peptide or by intact MBP. Rather, the pathogenic T cells differed in clonal composition as reflected by their heterogeneous responses to a panel of variant peptides and by their T cell receptor usage. Thus, molecules mimicking the MBP(68-88) autoantigen can elicit pathogenic T cell subsets without necessarily cross-reacting with T cells specific for the original autoantigen. This suggests that a more clonally diverse group of pathogenic T cells might be involved in EAE than has been apparent from studies with intact MBP or its unaltered peptides.

The clonal composition of myelin basic protein-reactive encephalitogenic T cell populations is influenced both by the structure of relevant antigens and the nature of antigen-presenting cells

Studies of experimental autoimmune encephalomyelitis (EAE) in rodents have revealed that encephalitogenic T cell lines reactive with myelin basic protein (BP) are frequently dominated by clones expressing a restricted T cell receptor repertoire. Using the rat EAE model, we have begun to examine the basis for clonal dominance within BP-reactive T cell lines. We find that variations introduced into the standard protocol of periodic antigen stimulation produce marked shifts in the representation of different clones within encephalitogenic T cell populations. For example, altering the source of antigen-presenting cells (APC), while holding antigen (BP) constant, and substituting BP from guinea pig (GPBP) for that of the rat antigen (RBP) with constant APC, both cause shifts in the composition of the dominant clones within BP-reactive T cell lines. Our results suggest that: (i) adherence to an invariant protocol of antigen challenge may lead to an underestimation of the diversity of BP-reactive encephalitogenic T cell populations; and (ii) the minor structural differences between GPBP and RBP not only cause the weak immunogenicity of RBP but also result in the alteration of different T cell subsets. These observations indicate that apparent restrictions upon the repertoire of autoimmune T cells should be interpreted with caution when such cells are elicited by immunization with foreign antigens.

Hysteroscopic tubal catheterization and hydrotubation for treatment of infertile women with tubal obstruction

We reported the efficacy of interval hysteroscopic tubal catherization and hydrotubation for three months in 54 infertile women with tubal obstruction (102 fallopian tubes). By comparison of HSGs before and after treatment, 86 of 102 tubes (84%) showed the improvement of tubal patency (P < 0.01). 56 tubes were patent (54.9%). This method is effective for partially patent tubes (87.5%), intramural tubal obstruction (62.5%), and the obstruction at the distal portion of the fallopian tube (13.3). One -12 month follow-up after treatment, 12 of 35 women whose tubes became completely patent achieved intrauterine pregnancies.

Characterization of brain-isolated rat encephalitogenic T cell lines

In the present study, we have isolated and characterized five myelin basic protein (MBP)-reactive T cell lines directly from the brains of Lewis rats during the early paralytic phase of experimental autoimmune encephalomyelitis (EAE). Each T cell line responded to the dominant encephalitogenic epitope spanning residues 68-88, and did not react against the conserved encephalitogenic epitope [MBP(87-99)] or the nonencephalitogenic MBP epitope [MBP(50-69)]. We determined the T cell receptor (TcR) beta chain usage by polymerase chain reaction, DNA sequencing analysis and by generation of MBP-reactive hybridomas from one of the T cell lines (BT74). The results revealed that brain-infiltrating, MBP-reactive T cells freshly isolated early in the course of the disease exhibit TcR diversity.

Differential effect of human and mouse beta 2-microglobulin on the induction and the antigenic profile of endogenous HLA-A and -B antigens synthesized by beta 2-microglobulin gene-null FO-1 melanoma cells

beta 2-Microglobulin (beta 2-mu) gene-null human melanoma FO-1 cells display lower reactivity with anti-HLA class I monoclonal antibodies (mAb) following transfection with a wild-type mouse beta 2-mu gene (referred to as FO-1C cells) than following transfection with a wild-type human beta 2-mu gene (referred to as FO-1H cells). Furthermore, binding assays with a panel of anti-HLA class I mAb detected higher reactivity of FO-1C cells with mAb TP25.99 than with mAb CR1-S63, CR10-215, CR11-115, TP67, and W6/32 but similar reactivity of FO-1H cells with all the mAb tested. While mAb TP25.99 recognizes a determinant expressed on beta 2-mu-free and beta 2-mu-associated HLA class I heavy chains, the remaining mAb recognize determinants expressed only on beta 2-mu-associated HLA class I heavy chains. The differential effects of mouse and human beta 2-mu on the reactivity with anti-HLA class I mAb of FO-1 cells reflect more than one mechanism. Besides abnormalities in the processing of HLA class I heavy chains associated with mouse beta 2-mu, this molecular complex appears to be unstable on the plasma membrane of FO-1 cells. To analyze the interaction of mouse beta 2-mu with HLA-A and -B antigens, the HLA phenotype of FO-1 cells was determined, using a combination of isoelectric focusing analysis of antigens immunoprecipitated from radiolabeled cells with mAb to monomorphic determinants of HLA class I antigens, binding assays with a limited number of mAb recognizing HLA class I allospecificities, and sequence-specific oligonucleotide probe typing. Although association with mouse beta 2-mu does not cause marked differences in the expression of HLA-A25 and -B8 antigens on the cell surface of FO-1 cells, it causes a selective reduction in the expression of determinants recognized by anti-HLA-A mAb F4/72 and VF19-LL67 and by anti-HLA class I mAb W6/32 on HLA-A25 allospecificities. The differential effect of the association with mouse beta 2-mu on the antigenic profile of HLA-A25 and -B8 antigens may reflect the different characteristics of the amino acids at residue 12, which interact with residue 33 of beta 2-mu. The latter residue is the only one to differ between human and mouse beta 2-mu in the stretch of amino acids interacting with the alpha 1 and alpha 2 domains of HLA class I heavy chains.(ABSTRACT TRUNCATED AT 400 WORDS)

[Detection of interferon-gamma in malignant peritoneal effusion in ovarian cancer patients]

Concanavalin A-induced human and mouse T cell proliferation assay was used to detect the suppressive activity of ascitic fluid (AF) in ovarian cancer patients. About 80% of AF specimens were found to be suppressive. However, when later tested for AF's effect on NK cell activity, instead of suppression, marked enhancement was observed. As IL-2 was barely detectable in AF, attention was focused on interferon (IFN). Its presence was then examined and confirmed by the ability of AF to protect HEp-2 cells from the cytopathic effect of vesicular stomatitis virus (VSV). As the protective effect against VSV was abolished by low pH treatment and by anti-human interferon gamma monoclonal antibodies (MAb), the IFN identified in AF was of the gamma type (IFN-gamma). The MAb could markedly inhibit not only AF's NK-enhancing effect but T cell suppressing effect as well. After removal of the IFN-gamma from AF by affinity chromatography, both activities of AF were lost. The possible clinical implication of this new finding with regards to host's anti-tumor resistance and prognosis is discussed.

[Effects of selenium deficiency and supplementation on tumor immune response in mice]

DBA/2 mice were fed for 16 weeks with Torula yeast-based synthetic diet containing various concentrations of selenium (Se). At 13th week, the mice were immunized with syngenetic L5178 Y lymphoma cells and their specific and non-specific tumor immune responses were examined 3 weeks after immunization. The results indicated that in mice fed with a diet containing 0.007 ppm Se, the serum Se level was extremely low (0.02 micrograms/ml). These Se-deficient mice were unable to elicit normal tumor-specific immune responses. Both the specific proliferation of T cells in MLTC and tumoricidal activity of CTL were very much depressed. In addition, these mice also showed impaired NK and LAK cell activity. The effects of Se supplementation varied depending on the amount of Se given. When 0.170 ppm Se was added to the low Se diet, all the immune parameters examined were restored to the normal level. When 0.567 ppm Se was added, however, the tumor immune responses remained as low as those in Se-deficient mice. This study implies that the prevalence of primary hepatocellular carcinoma in areas where Se is deficient has a profound immunological basis. Se supplementation is obviously indicated for cancer prevention in these areas but the amount of Se supplied is crucial.

Plasma reproductive hormones in normal and vasectomized Chinese males

Plasma reproductive hormones (testosterone, LH, FSH and prolactin) were measured in 298 normal healthy males aged 30-73 years from rural areas of Sichuan Province, People's Republic of China, and in 505 similar men vasectomized between 1 year and 25 years previously. Age-related increases in LH and FSH but not in testosterone or prolactin were noted in normal men. No adverse effects of vasectomy were observed apart from a 16% increase in mean LH levels in the vasectomized compared to non-vasectomized men of similar ages.

[Influences of inflammatory macrophages on the proliferation of mouse tumor cells in vitro]

Augmented growth of tumor cells of both syngeneic and allogeneic origin was often observed when these cells were cocultured with the peritoneal inflammatory macrophages of C57BL/6 mouse, induced by thioglycollate in vitro. While large doses of macrophage-activating factor (MAF) were required for activating these inflammatory macrophages to exert the tumoricidal activity, and much less (suboptimal) doses of MAF were required for activating their cytostatic effect on tumor cells. Whether the macrophage inhibits or enhances the tumor cell proliferation, depends not only on the degree of the activation of macrophage, but also on the macrophage/tumor cell ratio.