儿童RRTIsT细胞亚群和NK细胞的变化分析

目的了解3～6岁儿童反复呼吸道感染（RRTIs）T细胞亚群及自然杀伤细胞（NK）的变化,指导临床预防用药,避免过度以及不当治疗。方法严格按照入选标准和剔除标准收集3～6岁儿童160例,其中：病例组73例,对照组87例。采用病例对照研究。用流式细胞仪对病例组和对照组分别进行T细胞亚群、NK细胞的检测,并对有关数据进行统计分析。结果对T细胞亚群（CD3＋、CD4＋、CD8＋、CD4＋／CD8＋）进行两独立样本的Wilcoxon秩和检验,结果表明：CD3＋（Z=-1．588,P=0．112）、CD4＋（Z=-0．541,P=0．588）、CD8＋（Z=-0．733,P=0．463）、CD4＋／CD8＋（Z=-0．315,P=0．753）病例组和对照组比较差异均无统计学意义（均P〉0．05）。对NK细胞（CD3-CD16＋CD56＋）进行t＋检验（t＇=2．779,P=0．006〈0．05;95％CI：0．674～4．003）,病例组和对照组比较差异有统计学意义。结论对RRTIs儿童检测T细胞亚群与NK细胞具有显著的临床指导意义,可避免过度使用免疫调节剂引起的用药不当。     

铂类敏感型复发性卵巢癌治疗的研究进展

卵巢癌是妇科最重要的恶性肿瘤之一,其病死率居妇科恶性肿瘤之首。随着卵巢癌复发率的逐年增高,对复发的治疗就显得尤为重要。根据病人对铂类药物的敏感性,以初次治疗(达到临床缓解)停药后6个月为界,可将复发性卵巢癌大致分为铂类敏感型和耐药型。治疗铂类敏感性复发性卵巢癌的手段很多,包括化疗、二次手术、放疗等,现对其目前的治疗及进展情况进行综述。     

Structural plasticity of 4-α-helical bundles exemplified by the puzzle-like molecular assembly of the Rop protein

The dimeric Repressor of Primer (Rop) protein, a widely used model system for the study of coiled-coil 4-α-helical bundles, is characterized by a remarkable structural plasticity. Loop region mutations lead to a wide range of topologies, folding states, and altered physicochemical properties. A protein-folding study of Rop and several loop variants has identified specific residues and sequences that are linked to the observed structural plasticity. Apart from the native state, native-like and molten-globule states have been identified; these states are sensitive to reducing agents due to the formation of nonnative disulfide bridges. Pro residues in the loop are critical for the establishment of new topologies and molten globule states; their effects, however, can be in part compensated by Gly residues. The extreme plasticity in the assembly of 4-α-helical bundles reflects the capacity of the Rop sequence to combine a specific set of hydrophobic residues into strikingly different hydrophobic cores. These cores include highly hydrated ones that are consistent with the formation of interchain, nonnative disulfide bridges and the establishment of molten globules. Potential applications of this structural plasticity are among others in the engineering of bio-inspired materials.Recurrent motifs of tertiary structure are convenient model systems for studying protein folding and potentially also for the design of bio-inspired materials. For protein design purposes, structural plasticity is an important, although poorly understood, parameter to be considered, as it is among the main reasons that the re-engineering of proteins toward novel materials is not yet satisfactorily manageable (1, 2).The present study focuses on the structural plasticity associated with the 4-α-helical bundle (4HB) motif. 4HBs consist of four amphipathic α-helices packed in a parallel or antiparallel fashion (3, 4). Their folding is largely determined by a repeating pattern of hydrophobic and hydrophilic residues, organized on the basis of seven-residue repeats (heptads) (5). Being the simplest tertiary motif, 4HBs have been subject to numerous protein-folding studies; attempts have been made to exploit them as building blocks for bio-inspired materials (6).A paradigm of a highly regular 4HB is the RNA-binding ColE1 Repressor of Primer (Rop) protein (7–9), also referred to as RNA-one-modulator (ROM). Each monomer is an α-helical hairpin consisting of two antiparallel α-helices connected by a short loop. The sequence of Rop displays a heptad repeats pattern that is interrupted only in the loop region.Structural simplicity makes Rop an attractive model system for the study of the folding of 4HBs. The loop region and the hydrophobic core have thereby attracted particular attention, as these regions are linked with the remarkable ability of Rop mutants to adopt altered topologies and properties (10–15). Striking examples of loop variants include mutant Loopless Rop (LLR), in which an uninterrupted pattern of heptad repeats is established through a five-residue deletion in the loop. In this “loopless” mutant, the α-helical hairpin of the monomer is converted into a single helix (15, 16). The complete LLR molecule is a tetramer that is completely reorganized relative to the dimeric wild-type (WT) Rop, thereby becoming a hyper-thermostable protein (16). On the other hand, establishment of an uninterrupted heptad periodicity through a two-residue insertion in the loop produces minimal changes relative to WT in terms of structure and properties (12). Thus, these two mutants with uninterrupted patterns of heptads reveal that there is a considerable structural plasticity inherent to the Rop sequence, but the relationship between heptad periodicity and the structural/physicochemical properties is complex.Extreme structural plasticity producing completely altered 4HB topologies is also associated with point mutations in the loop region. Replacement of loop residue Ala31 by Pro (17) results in a complete reorganization of the entire protein, which is converted from the canonical left-handed, all-antiparallel form into a right-handed mixed-parallel and antiparallel 4-α-helical bundle, displaying a “bisecting U” topology that is to a large extent determined by the local conformation at residue 31 (18). Mutant A31P displays two variations of the bisecting U topology; these differ in the relative juxtaposition of the α-helices (19). These conformations crystallize in different space groups (orthorhombic and monoclinic); both space groups have been occasionally observed in the same crystallization drop, indicating the coexistence of the two forms in solution. Molecular dynamics simulations for A31P have demonstrated a potential for the interconversion between the two conformations (14).Hydrophobic core mutants occasionally also display structural plasticity producing a new (“syn”) topology (20) that results from the “anti”-topology of WT through a 180° flip of one monomer around the dyad axis normal to the long axis of WT. The competition between the anti and syn topologies and the mixture of the two structures have been studied in detail for some Rop mutants (21, 22).Apart from structural plasticity, a closely related issue associated with the folding of Rop is the role of Cys residues (Cys-38 and Cys-52). Both residues are buried in the hydrophobic core and are not involved in the formation of disulfide bridges in any of the known structures of WT and its mutants. Surprisingly, however, a Cys-free variant (CYSfree) that conserves the structure, stability, and in vivo activity of WT exhibits dramatically faster unfolding kinetics (23).The present study focuses on the role of the loop region and Cys residues in the structural plasticity of Rop. To explore the conversion of the WT anti-topology into the bisecting U topology of A31P, the three double mutants D30P/A31G (PG), D30G/A31P (GP), and D30P/A31P (PP) have been constructed for loop positions 30 and 31. These mutations combine the effects of the most constrained amino acid (Pro) and of the least constrained one (Gly). In addition, the potential role of Cys residues in Rop folding is explored by following the effects of reducing agents.     

Are febrile seizures an indication for intermittent benzodiazepine treatment,and if so,in which cases?

Febrile seizures occur in ～4% of children. After a first febrile seizure, the risk of recurrence is ～40%, but excellent studies document that febrile seizures do not cause brain damage or deficits in cognition or behaviour. The risk of subsequent epilepsy is 2–4%. Prolonged febrile seizures are of concern because a child may later develop mesial temporal sclerosis and intractable epilepsy in rare cases. Most prolonged febrile seizures represent the first febrile seizure and cannot be anticipated. A first prolonged febrile seizure does not increase the risk of recurrence, but if there is a recurrence, it is more likely to be prolonged. Prevention of recurrent febrile seizures is difficult. Antipyretics are ineffective. Daily AED treatment is not often justified. Intermittent oral diazepam at the time of illness is not very successful and has significant side effects. The most optimistic study found that the number of subjects required to treat in order to prevent one recurrence was 14. Intermittent clobazam has fewer side effects than diazepam and may be somewhat effective. Rescue benzodiazepines given outside health care facilities may be effective in selected patients to prevent prolonged recurrences, although this has not been proven with rectal diazepam which has been more extensively studied than buccal or nasal midazolam. Currently, we suggest that, for children with febrile seizures, candidates for consideration for rescue benzodiazepines are those with a prolonged febrile seizure or poor access to medical care. It is possible that the use of a rescue benzodiazepine may alleviate severe parental anxiety, but this remains to be established.     

Restoring the glycosaminoglycans layer in recurrent cystitis: Experimental and clinical foundations

Restoring the bladder glycosaminoglycans layer has recently been introduced as prophylactic treatment for recurrent urinary tract infections. Herein, we analyze the latest main clinical and experimental studies to support this therapeutic option. An electronic research was carried out in the most common databases in order to identify any published studies. Retrieved studies were categorized as experimental or clinical according to their setting. For the clinical studies, the evidence level was assigned. A total of 13 laboratory studies showed how bladder glycosaminoglycans instillations act: attenuation of the inflammation process, reduction of bladder contraction amplitude and frequency, reduction of epithelium damage, and lower bacterial growth in urine and tissue samples. Likewise, two randomized clinical trials with grade 2 evidence level and two case series with grade 4 evidence level reported glycosaminoglycans as an alternative to reduce episodes and to prolong recurrence time in patients with recurrent urinary tract infections. At least 12 months of follow up was completed. No serious adverse events were reported. Compared with a placebo, in one randomized study a significantly higher maximum cystometric capacity was obtained, whereas in the other study a significant increase in quality of life scores was reported too. An improvement in the urinary symptoms score was reported by the two randomized trials. Although the clinical use of glycosaminoglycans replacement therapy for recurrent urinary tract infections is supported by a small number of clinical studies with different evidence levels, the laboratory studies show that glycosaminoglycans could have a protective role against inflammatory factors, supporting the idea “to restore the glycosaminoglycans bladder layer to prevent chronic disease course”.     

Success with plasmapheresis treatment for recurrent focal segmental glomerulosclerosis in pediatric renal transplant recipients

FSGS recurs in approximately 30% of transplanted kidneys and may lead to graft loss. We retrospectively examined the efficacy of early and intensive PP without additional IS in pediatric kidney transplant patients with recurrent FSGS at our center. Seven of 24 patients (29%) had nephrotic proteinuria and histologic evidence of FSGS recurrence within 1–5 days post‐transplantation. PP was initiated early after transplantation and initially performed daily until sustained decline in proteinuria. PP frequency was then individually tapered according to proteinuria. Recurrent FSGS in all seven patients responded to a four‐ to 32‐wk course of PP. Two of seven patients had a second recurrence of FSGS, and both recurrences remitted after an additional 3–6 wk of PP. Median observation period was 4.5 yr (0.8–16.3 yr). Complete remission of recurrent FSGS has been sustained in all seven patients, and all patients have stable graft function with recent plasma creatinine <1.5 mg/dL in six of seven patients. Most recent urine protein/creatinine is 0.13–0.61 mg/mg in six of seven patients. One patient has heavy proteinuria secondary to chronic allograft nephropathy 16 yr post‐transplant. Intensive and prolonged PP, when initiated early in the post‐operative period, is effective in treating recurrent FSGS and preventing graft loss without the use of additional immunosuppressants.     

Different expression of NOD2 in decidual stromal cells between normal and unexplained recurrent spontaneous abortion women during first trimester gestation

The NOD2 gene, encoding intracellular paternal recognition receptor (PRR) also called caspase activation and recruitment domain 15 (CARD15), is mutated in Crohn’s disease, an autoimmune-disorder. Unexplained recurrent spontaneous abortion (URSA) involved in complex auto-immune disorder. However, little is known about the expression of NOD2 protein at maternal-fetal interface with URSA patients. Our aim was to compare the expression levels of NOD2 in the decidual stromal cells (DSCs) from patients with normal pregnancy to those with unexplained recurrent spontaneous abortion (URSA) during first trimester pregnancy. Tissues and DSCs were collected from 12 patients with URSA and 26 patients with normal pregnancies that required abortion. DSCs in the normal pregnancy group showed significantly higher mRNA and protein levels of NOD2 than those isolated from the URSA group using real time PCR and in cell western. The appropriate expression of NOD2 in normal DSCs suggests that this protein may be required to sustain normal pregnancy.