[Conversion of serum anti-Schistosoma japonicum antibodies detected by immunological tests following treatment with praziquantel: a meta-analysis]

OBJECTIVE

To evaluate the conversion of serum antibodies against Schistosoma japonicum in humans and livestock detected by immunological tests following treatment with praziquantel.

METHODS

The studies pertaining to serological tests of schistosomiasis japonica published from 1991 to 2020 were retrieved in electronic databases, including Chinese National Knowledge Infrastructure, WanFang Data, PubMed and ScienceDirect. Data were extracted from included studies. The publication bias was assessed with funnel plots using the software RevMan version 5.3, and the conversion of antibodies against S. japonicum was evaluated through meta-analysis.

RESULTS

A total of 40 publications were included in the final meta-analysis, consisting of 33 Chinese publications and 7 English publications, and all immunological tests were performed with indirect hemagglutination test (IHA) and enzyme-linked immunosorbent assay (ELISA). Pooled analysis showed that the negative rates of serum anti-S. japonicum antibody were 45.36% [95% confidential interval (CI): (43.96%, 46.76%)] and 20.83% [95% CI: (19.69%, 21.97%)] detected by ELISA and IHA within 6 months post praziquantel treatment, 62.95% [95% CI: (61.59%, 64.31%)] and 55.61% [95% CI: (54.21%, 57.01%)] within 6 to 12 months after treatment and 85.92% [95% CI: (84.94%, 86.90%)] and 86.90% [95% CI: (85.95%, 87.85%)] over 12 months after treatment, respectively.

CONCLUSIONS

The negative rate of the serum anti-S. japonicum antibody by IHA and ELISA increased with the time of post-treatment with praziquantel. The overall negative rates of anti-S. japonicum antibody detected by IHA and ELISA are low within 12 months post praziquantel treatment. However, a high negative rate of anti-S. japonicum antibody is detected if there is no new contact with infested water after 12 months of praziquantel treatment.

[The clinic experience of implantable diaphragm pacer in a patient with high cervical spinal cord injury and literature review]

Objective: To report the use of implantable diaphragm pacer (IDP) in a patient with high cervical spinal cord injury(HCSCI). Methods: A 14-year-old male patient, who suffered from a HCSCI at C2 neurological level and had been on a ventilator for 2 years, received IDP in August 2017 at China Rehabilitation Research Center. A systematic literature review was performed on IDP in patients with HCSCI in Pubmed, CNKI, and Wanfang databases, using the keywords: phrenic nerve and electrical stimulation and spinal cord injury; IDP and spinal cord injury; breathing pacemaker system and spinal cord injury. All fields were covered from 1970/01/01 to 2018/01/01 in Pubmed, from 1981/01/01 to 2018/01/01 in CNKI, and from 1900/01/01to 2018/01/01 in Wanfang. Results: No spontaneous breathing was observed preoperatively in the patient. The electrical response of phrenic nerves was intact on the right, but unresponsive on the left. We got started with the IDP at 4 weeks after surgery. The threshold voltage of the right hemidiaphragm pacing was 0.1 V and at the level of 0.7 V with an optimal effect. No significant diaphragmatic contraction was found at left side with the extent up till 0.7 V. The maximum tidal volume was 840 ml when electrical stimulation was given at an intensity of 0.7 V bilaterally. The bilateral stimulation voltage at 0.1-0.2 V, pacing frequencies at 9 beats/min in bed, or at 12 beats/min on wheelchair, were set to maintain the tidal volume at the level of (435±32) ml. After 2-week adaptive training, the patient could wean from the ventilator for 12 hours and had a normal blood gas analysis. At 6 week after surgery, with the aid of IDP, the patient could get out in wheelchair for outdoor activities. By literature review, we found 78 English papers, including 6 clinical trials, 10 reviews, and 11 Chinese papers, consisting of 8 reviews, 1 study in animal, and 2 news reports. Extensive contents, such as preoperative evaluation, preoperative preparation, surgical procedures, complications, surgical outcomes, and animal model studies of IDP were involved. The indications of IDP reported by literature were: (1) central alveolar hypoventilation; (2) Sleep apnea syndrome (Biot's respiration); (3) Respiratory failure induced by brainstem injury or disease; (4) Respiratory failure induced by spinal cord injury or disease above C3 level. Conclusion: Our case study confirmed the therapeutic effect of IDP on patients with respiratory failure caused by HCSCI.

Wnts enhance neurotrophin-induced neuronal differentiation in adult bone-marrow-derived mesenchymal stem cells via canonical and noncanonical signaling pathways

Wnts were previously shown to regulate the neurogenesis of neural stem or progenitor cells. Here, we explored the underlying molecular mechanisms through which Wnt signaling regulates neurotrophins (NTs) in the NT-induced neuronal differentiation of human mesenchymal stem cells (hMSCs). NTs can increase the expression of Wnt1 and Wnt7a in hMSCs. However, only Wnt7a enables the expression of synapsin-1, a synaptic marker in mature neurons, to be induced and triggers the formation of cholinergic and dopaminergic neurons. Human recombinant (hr)Wnt7a and general neuron makers were positively correlated in a dose- and time-dependent manner. In addition, the expression of synaptic markers and neurites was induced by Wnt7a and lithium, a glycogen synthase kinase-3β inhibitor, in the NT-induced hMSCs via the canonical/β-catenin pathway, but was inhibited by Wnt inhibitors and frizzled-5 (Frz5) blocking antibodies. In addition, hrWnt7a triggered the formation of cholinergic and dopaminergic neurons via the non-canonical/c-jun N-terminal kinase (JNK) pathway, and the formation of these neurons was inhibited by a JNK inhibitor and Frz9 blocking antibodies. In conclusion, hrWnt7a enhances the synthesis of synapse and facilitates neuronal differentiation in hMSCS through various Frz receptors. These mechanisms may be employed widely in the transdifferentiation of other adult stem cells.

Infrared thermography to mass-screen suspected SARS patients with fever

Fever greater than 38 degrees C is a cardinal sign of patients with the severe acute respiratory syndromes (SARS). To reduce the risk of nosocomial cross infections, screening all patients and visitors who visit hospitals and clinics for fever at the entrance of every hospital building has become a standard protocol in Taiwan during the SARS epidemic from mid-April to mid-June 2003. We used a digital infrared thermal imaging (DITI) system (Telesis Spectrum 9000 MB) to conduct mass screening of patients and visitors who entered the hospital to identify those with fever. The DITI system has two components: a sensor head and a PC imaging workstation. The sensor head is an optic-mechanical device which consists of imagining optics for focusing the infrared source information on the infrared detector. The infrared images are further converted into electrical signals, which are then processed for real-time display on the monitor. During the period from April 13 to May 12 2003, 72,327 outpatients and visitors entered Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan. A total of 305 febrile patients (0.42%) was detected by infrared thermography. Among them, three probable SARS patients were identified after thorough studies including contact history, laboratory tests and radiology examinations. The findings suggests that infrared thermography was an effective and reliable tool ideal for mass-screening patients with fever in the initial phase of screening for SARS patients at a busy hospital which sees approximately 3,000 outpatients every weekday during the SARS epidemic.

Type I and II collagen regulation of chondrogenic differentiation by mesenchymal progenitor cells

Chondrogenic differentiation by mesenchymal progenitor cells (MPCs) is associated with cytokines such as transforming growth factor-beta 1 (TGF-beta1) and dexamethasone. Extracellular matrix (ECM) also regulates the differentiation by MPCs. To define whether ECM plays a functional role in regulation of the chondrogenic differentiation by MPCs, an in vitro model was used. That model exposed to dexamethasone, recombinant human TGF-beta1(rhTGF-beta1) and collagens. The results showed that MPCs incorporated with dexamethasone and rhTGF-beta1 increased proliferation and expression of glycosaminoglycan (GAG) after 14 days. Type II collagen enhanced the GAG synthesis, but did not increase alkaline phosphatase (ALP) activity. When adding dexamethasone and rhTGF-beta1 MPCs increased mRNA expression of Sox9. Incorporation with type II collagen, dexamethasone and rhTGF-beta1, MPCs induced mRNA expression of aggrecan and enhanced levels of type II collagen, and Sox9 mRNA. In contrast, incorporation with type I collagen, dexamethasone and rhTGF-beta1 MPCs reduced levels of aggrecan, and Sox9 mRNA, and showed no type II collagen mRNA. Altogether, these results indicate that type I and II collagen, in addition to the cytokine effect, may play a functional role in regulating of chondrogenic differentiation by MPCs.

Importance of planar chirality in chiral catalysts with three chiral elements: the role of planar chirality in 2'-substituted 1,1'-P,N-ferrocene ligands on the enantioselectivity in Pd-catalyzed allylic substitution

A series of novel planar chiral 2'-substituted 1,1'-P,N-ferrocene ligands 9-11, 14, and 16 were prepared with diastereopurity >99:1 and found to be effective in asymmetric allylic alkylation and amination reactions. Ligand 14 furnished the highest enantiomeric excess, 98.5% and 96.5% ee in alkylation and amination reactions, respectively. The role of planar chirality in asymmetric reactions has been examined, and decisive effects on enantioselectivity as well as the control of absolute configuration in palladium-catalyzed allylic alkylation and amination reactions were observed. To clarify why and how the planar chirality governed the stereochemical outcome, X-ray crystallographic structures of eta(3)-diphenylallyl Pd complexes, (1)H NMR, (31)P NMR spectra of palladium dichloride complexes, and eta(3)-diphenylallyl Pd complexes of three 1,1'-P,N-ferrocene ligands were analyzed with the aid of COSY and 2D NOESY experiments. All results led to the conclusion that planar chirality influences the stereochemical outcome by changing or even inverting the ratio of two rotamers because of the steric interaction between a planar chiral group and the coordination site.

Evaluation of biomechanical properties of Expanded-Polytetrafluoroethylene Soft Tissue Patch after dorsal implantation in the rat to mimic TMJ lateral reconstruction

Clinically, Gore-Tex Expanded-Polytetrafluoroethylene (E-PTFE) has been used to reconstruct the lateral temporomandibular joint (TMJ) ligament. The purpose of this study was to assess changes in the biomechanical properties of implanted E-PTFE over time with respect to tissue infiltration. Ninety-six specimens of implants were divided into four groups. Group A was the experimental group. Thirty-six autoclave-sterilized specimens were subcutaneously implanted into the backs of 36 rats. The rats were randomly sacrificed at 2 (n = 12), 7 (n = 12) and 12 (n = 12) weeks. The implants were tested for mechanical properties including maximal stress, strain and Young's modulus of elasticity (E) using the servo-hydraulic material testing system (MTS). Group B was the in vitro control group. Thirty-six specimens were placed in tissue culture media at 37 degrees C for a time period equivalent to the experimental group to simulate the effect of a moist, warm environment on biomechanical properties. Group C was the temperature and pressure control group. Twelve specimens were autoclave-sterilized to determine the changes of tensile strength under high temperature and pressure. Control group D (no treatment) was tested to determine the initial tensile strength. The results showed significantly larger maximal stress as well as an increase in E and smaller maximal strain in experimental group A than in control groups B, C and D. There was no significant difference among control groups B, C and D. Histological examination of implants at 12 weeks demonstrated that 0.2-0.3 mm of 1-mm thick implants were occupied by connective tissue from each side. It may be concluded that E-PTFE implants become stronger and less flexible after implantation in vivo.

Preferential repair of UV damage in highly transcribed DNA diminishes UV-induced intrachromosomal recombination in mammalian cells

The relationships among transcription, recombination, DNA damage, and repair in mammalian cells were investigated. We monitored the effects of transcription on UV-induced intrachromosomal recombination between neomycin repeats including a promoterless allele and an inducible heteroallele regulated by the mouse mammary tumor virus promoter. Although transcription and UV light separately stimulated recombination, increasing transcription levels reduced UV-induced recombination. Preferential repair of UV damage in transcribed strands was shown in highly transcribed DNA, suggesting that recombination is stimulated by unrepaired UV damage and that increased DNA repair in highly transcribed alleles removes recombinogenic lesions. This study indicates that the genetic consequences of DNA damage depend on transcriptional states and provides a basis for understanding tissue- and gene-specific responses to DNA-damaging agents.

Mismatch repair of heteroduplex DNA intermediates of extrachromosomal recombination in mammalian cells

Previous work indicated that extrachromosomal recombination in mammalian cells could be explained by the single-strand annealing (SSA) model. This model predicts that extrachromosomal recombination leads to nonconservative crossover products and that heteroduplex DNA (hDNA) is formed by annealing of complementary single strands. Mismatched bases in hDNA may subsequently be repaired to wild-type or mutant sequences, or they may remain unrepaired and segregate following DNA replication. We describe a system to examine the formation and mismatch repair of hDNA in recombination intermediates. Our results are consistent with extrachromosomal recombination occurring via SSA and producing crossover recombinant products. As predicted by the SSA model, hDNA was present in double-strand break-induced recombination intermediates. By placing either silent or frameshift mutations in the predicted hDNA region, we have shown that mismatches are efficiently repaired prior to DNA replication.

Site-directed mutagenesis of virtually any plasmid by eliminating a unique site

We describe an efficient site-specific mutagenesis procedure that is effective with virtually any plasmid, requiring only that the target plasmid carry a unique, nonessential restriction site. The procedure employs two mutagenic oligonucleotide primers. One primer contains the desired mutation and the second contains a mutation in any unique, nonessential restriction site. The two primers are annealed to circular single-stranded DNA (produced by heating circular double-stranded DNA) and direct synthesis of a new second strand containing both primers. The resulting DNA is transformed into a mismatch repair defective (mut S) Escherichia coli strain, which increases the probability that the two mutations will cosegregate during the first round of DNA replication. Transformants are selected en masse in liquid medium containing an appropriate antibiotic and plasmid DNA is prepared, treated with the enzyme that recognizes the unique, nonessential restriction site, and retransformed into an appropriate host. Linearized parental molecules transform bacteria inefficiently. Plasmids with mutations in the unique restriction site are resistant to digestion, remain circular, and transform bacteria efficiently. By linking a selectable mutation in a unique restriction site to a nonselectable mutation, the latter can be recovered at frequencies of about 80%. Since most plasmids share common vector sequences, few primers, targeted to shared restriction sites, are needed for mutagenizing virtually any plasmid. The procedure employs simple procedures, common materials, and it can be performed in as little as 2 days.