[Frontiers in biomedical research]

With continuous breakthroughs in basic research and technological innovation in the field of biomedicine, we have a much deeper understanding of the nature of life and disease pathogenesis. New medical technologies, medicines and medical instruments are emerging, which greatly promote diagnosis, treatment, prevention and healthy lifestyle. Focusing on international engagement together with the development needs of individual businesses is a major task for China's biomedical community in order to achieve high-quality outcomes. This paper emphasizes the need to further strengthen the cross-integration and development of medical science in China, realize the paradigm change of medical research, and promote the development and application of revolutionary medical technologies, diagnostics, drugs and medical devices. Eighteen frontier hot spots and common issues are highlighted for the field of biomedicine.

The Construction of ITP Diagnostic Modeling Based on the Expressions of Hub Genes Associated with M1 Polarization of Macrophages

Purpose

Primary immune thrombocytopenia (ITP) is an immune disease with a diagnosis of exclusion, since no validated biomarkers have been identified. In this study, we explored biomarkers associated with the development of ITP from an immune perspective to inform the clinical diagnosis.

Patients and Methods

Differentially expressed genes (DEGs) between normal and ITP samples were analyzed using limma package. Random forest algorithm and LASSO regression were further used to screen for DEGs associated with ITP. The expression of these hub genes was validated by PCR. The relationship between DEGs and immunity was explored by enrichment analysis. Immune cell infiltration in ITP was analyzed by CIBERSORT and ssGSEA, and the relationship between DEGs and infiltrating immune cells was analyzed by Spearman’s rank correlation analysis. Finally, a diagnostic model related to DEGs was constructed by the neural network, and its efficiency was detected by the ROC curve.

Results

After screening the GEO database and validation by PCR analysis, The expression of CTH and TAF8 were higher and while OSBP2 expression was lower in ITP patients compared to normal subjects (P<0.05). GO enrichment analysis showed that these DEGs were associated with inflammatory immune-related diseases, and KEGG analysis showed that they mainly regulated signaling pathways such as JAK-STAT. CIBERSORT and ssGSEA analyses showed that these DEGs were mainly associated with macrophage M1 polarization. The expression of CTH and TAF8 were positively correlated with M1 expression, while OSBP2 was negatively correlated with M1 expression. The ROC curve showed high accuracy of the neural network model [AUC= 0.939, 95% CI (0.8–1)].

Conclusion

Our results suggest that CTH, TAF8, and OSBP2 can be used as effective diagnostic biomarkers of ITP.

[Immunological research of COVID-19 and emerging infectious diseases]

Immune function plays a crucial role for the body to resist virus infection. This paper summarizes the research progress of humoral and cellular immune responses and immunopathology induced by COVID-19 patients and related virus infection, and analyzes the research and development status of COVID-19 vaccine and antibody drugs.

First Report of Trichoderma oblongisporum Causing Green Mold Disease on Lentinula edodes (shiitake) in China

Lentinula edodes (shiitake) is well known for its delicious taste and valuable medical functions, and ranked as the second most important mushroom in terms of total world production. In March 2012, a serious green mold epidemic occurred on many mushroom farms in Suizhou County of China. The infected mycelia of L. edodes in cultivated bags became rotten, yellow, wilted, and finally died, with the surfaces of the cultivated bags covered with dark green fungal colonies. At a temperature above 20°C, disease incidence was nearly 100% on some mushroom farms. Three diseased cultivated bags were collected from three different mushroom farms, and two portions at the junction of the diseased and healthy portions of the bag were plated individually on potato dextrose agar (PDA) and incubated at 25°C for 4 days. Following incubation, agar discs cut from the growing front of colonies were inoculated onto fresh PDA and subcultured to obtain putative pathogens. Three purified isolates were all whitish initially, followed by the emergence of greenish conidial clusters at the outer margin of the colony. The underside of the colony appeared pale yellow. The growth rate of the isolates was about 0.95 to 1.02 cm/day in PDA at 25°C. Aerial mycelia were floccose, white, and septate. Chlamydospores were sub-globose to broadly ellipsoidal. Conidiophore branches arose at right angles, and primary branches arose singly or in pairs. Phialides were ampulliform, 3.1 to 6.7 × 2.7 to 4.0 μm, slightly constricted at the base, swollen in the middle, and narrowed abruptly at the apex. Conidia were produced on the top of the phialides with the shape varying from ellipsoidal to oblong, 3.3 to 4.7 × 2.4 to 3.2 μm. These observations were consistent with the description of Trichoderma oblongisporum by Bissett (1). The ITS and partial tef1 were amplified from the three isolates as previously reported (2) and sequenced (KM110064 to KM110069). Nucleotide alignment showed 99% sequence identity (ITS) with two T. oblongisporum isolates (FJ623268 and DQ083020), and 88% similarity (tef1) with T. oblongisporum (AY750884). Neighbor joining tree of ITS and tef1 nucleotide sequences also showed that our three isolates had the closest relationship with the aforementioned three T. oblongisporum strains. To determine pathogenicity, a sawdust substrate was sterilized for 2 h in polyethylene bags and subsequently inoculated separately with three isolates and L. edodes strain Qiu7, which was cultivated widely in Suizhou. When the mycelia of Qiu7 colonized the bags, 10 cm³ of substrate was withdrawn from each bag. The substrate was then exposed to 10 cm³ of mycelium from each pathogen in 10 bags. A parallel inoculation with 10 cm³ of sterilized sawdust substrate without pathogen mycelia was performed as a control. The inoculated cultivated bags were kept at 25°C. After 2 months, all of the mycelia in the bags became wilted and dead, and the cultivated bags became soft, rotten, and covered with dark green fungal colonies. The controls remained uninfected. The symptoms were similar to those observed on mushroom farms. Pathogens re-isolated from all the inoculated culture bags were confirmed to be T. oblongisporum through morphological characteristics, molecular identification, and phylogenetic analysis. To our knowledge, this is the first report of T. oblongisporum causing green mold disease on L. edodes in the world. References: (1) J. Bissett. Can. J. Bot. 69:2398, 1991. (2) N. Sadfi-Zouaoui et al. Can. J. Microbiol. 55:154, 2009.

Acute management of dengue shock syndrome: a randomized double-blind comparison of 4 intravenous fluid regimens in the first hour

Dengue hemorrhagic fever is an important cause of morbidity among Asian children, and the more severe dengue shock syndrome (DSS) causes a significant number of childhood deaths. DSS is characterized by a massive increase in systemic capillary permeability with consequent hypovolemia. Fluid resuscitation is critical, but as yet there have been no large trials to determine the optimal fluid regimen. We undertook a randomized blinded comparison of 4 fluids (dextran, gelatin, lactated Ringer's, and "normal" saline) for initial resuscitation of 230 Vietnamese children with DSS. All the children survived, and there was no clear advantage to using any of the 4 fluids, but the longest recovery times occurred in the lactated Ringer's group. The most significant factor determining clinical response was the pulse pressure at presentation. A comparison of the colloid and crystalloid groups suggested benefits in children presenting with lower pulse pressures who received one of the colloids. Further large-scale studies, stratified for admission pulse pressure, are indicated.

A comparative study of ofloxacin and cefixime for treatment of typhoid fever in children. The Dong Nai Pediatric Center Typhoid Study Group

BACKGROUND

Despite concerns about safety in children, fluoroquinolone antibiotics have become the treatment of choice in patients with multidrug-resistant typhoid fever in Vietnam. However, quinolone-resistant strains of Salmonella typhi have recently been reported from Vietnam; and if quinolone resistance becomes established, alternative oral treatment options will be needed.

OBJECTIVE

Cefixime, an orally administered third generation cephalosporin, was compared with ofloxacin for the treatment of uncomplicated typhoid fever in children.

METHODS

In an open trial children with suspected typhoid fever were randomized to receive either ofloxacin (10 mg/kg/day in two divided doses) for 5 days or cefixime (20 mg/kg/day in two divided doses) for 7 days.

RESULTS

S. typhi was isolated from 82 patients (44 in the cefixime group, 38 in the ofloxacin group) and 70 (85%) of the isolates were multidrug-resistant. Median (95% confidence interval, range) fever clearance times were 4.4 (4 to 5.2, 0.2 to 9.9) days for ofloxacin recipients and 8.5 (4.2 to 9, 1.8 to 15.2) days for cefixime-treated patients (P < 0.0001). There were 11 treatment failures (10 acute and one relapse) in the cefixime group and 1 acute treatment failure in the ofloxacin group (mean difference, 22%; 95% confidence interval, 9 to 36%).

CONCLUSION

Short course treatment with cefixime may provide a useful alternative treatment in cases of uncomplicated typhoid fever in children, but it is less effective than short course treatment with ofloxacin.

Pathophysiologic and prognostic role of cytokines in dengue hemorrhagic fever

Dengue shock syndrome is a severe complication of dengue hemorrhagic fever (DHF), characterized by a massive increase in vascular permeability. Plasma cytokine concentrations were prospectively studied in 443 Vietnamese children with DHF, of whom 6 died. Shock was present in 188 children on admission to hospital, and in 71 children it developed later. Contrary to expectations, certain inflammatory markers (interleukin-6 and soluble intercellular adhesion molecule-1) were lower in the group with shock, and this may reflect the general loss of protein from the circulation due to capillary leakage. Only soluble tumor necrosis factor receptor (TNFR) levels showed a consistent positive relationship with disease severity. In patients with suspected DHF without shock, admission levels of sTNFR-75 in excess of 55 pg/mL predicted the subsequent development of shock, with a relative risk of 5.5 (95% confidence interval, 2.3-13.2). Large-scale release of soluble TNFR may be an early and specific marker of the endothelial changes that cause dengue shock syndrome.

Comparison of artemisinin suppositories, intramuscular artesunate and intravenous quinine for the treatment of severe childhood malaria

Severe malaria remains a major cause of mortality and morbidity for children living in many tropical regions. With the emergence of strains of Plasmodium falciparum resistant to both chloroquine and quinine, alternative antimalarial agents are required. The artemisinin group of compounds are rapidly effective in severe disease when given by intramuscular or intravenous injection. However, these routes of administration are not always available in rural areas. In an open, randomized comparison 109 Vietnamese children, aged between 3 months and 14 years, with severe P.falciparum malaria, were allocated at random to receive artemisinin suppositories followed by mefloquine (n = 37), intramuscular artesunate followed by mefloquine (n = 37), or intravenous quinine followed by pyrimethamine/sulfadoxine (n = 35). There were 9 deaths: 2 artemisinin, 4 artesunate and 5 quinine-treated children. There was no difference in fever clearance time, coma recovery, or length of hospital stay among the 3 groups. However, parasite clearance times were significantly faster in artemisinin and artesunate-treated patients than in those who received quinine (P < 0.0001). Both artemisinin and artesunate were very well tolerated, but children receiving these drugs had lower peripheral reticulocyte counts by day 5 of treatment than those in the quinine group (P = 0.011). No other adverse effect or toxicity was found. There was no treatment failure in these 2 groups, but 4 patients in the quinine group failed to clear their parasites within 7 d of starting treatment and required alternative antimalarial therapy. Artemisinin suppositories are easy to administer, cheap, and very effective for treating children with severe malaria. In rural areas where medical facilities are lacking these drugs will allow antimalarial therapy to be instituted earlier in the course of the disease and may therefore save lives.

Pharmacokinetics of oral artesunate in children with moderately severe Plasmodium falciparum malaria

The pharmacokinetic properties of oral artesunate (3 mg/kg) were determined in 10 Vietnamese children, aged from 6 to 15 years, with acute falciparum malaria of moderate severity. Plasma concentrations were measured using a bioassay and expressed in terms of antimalarial activity equivalent to dihydroartemisinin, the principal biologically active metabolite. Oral artesunate was absorbed rapidly with a mean time to peak plasma bioactivity of 1.7 h (95% confidence interval [95% CI] 0.8-2.6). There was wide variation in peak plasma concentrations with a mean value equivalent to 664 ng of dihydroartemisinin/mL (95% CI 387-9410, range 179-1395) and a four-fold variation in the area under the plasma concentration-time curves. Elimination from plasma was rapid with a mean (95% CI) half-life of 1.0 h (95% CI 0.8-1.4). Plasma antimalarial levels were below the limit of detection in all cases by 12 h, despite the relatively high dose of artesunate used. Oral artesunate is rapidly absorbed and rapidly eliminated in children with moderately severe malaria but there is considerable variation between individuals.

[Enhanced immune functions and antitumor activity of fibroblast-mediated interleukin-2 gene therapy]

The aim of the present study was to establish fibroblastmediated IL-2 gene therapy and to observe its antitumor effect in the mouse tumor model. The IL-2 gene-transfected fibroblasts (NIH3T3-IL-2+) secreting high level of IL-2 were encapsulated with collagen and then implanted i.p. into mice. Certain level of IL-2 could be detected in murine serum for some periods, and the splenic proliferation, NK and LAK activities, cytokine production (IFN-v, TNF, IL-2) were enhanced significantly. It was of great importance that the high endogenous LAK activity was induced. The significant therapeutic effect of i.p. implantation of NIH3T3-IL-2+ on ascitic liver carcinoma-bearing mice was observed. The better therapeutic results could be achieved. NIH3T3-IL-2+ cells were i.p. implanted in combination with i.p. injection of LAK cells. These results demonstrated that fibroblast--mediated IL-2 gene therapy has potent antitumor effect via augmentation of immune functions and the antitumor effect will be more obvious when IL-2 gene therapy is used along with the adoptive transfer of LAK cells.