Utility of hospital admission for pediatric intussusceptions

Purpose

The standard practice in pediatric patients diagnosed with intussusception has been reduction via enema and admission for a period of nil per os and observation. Little data exists to support this practice. The objective of this study was to examine whether post-reduction admission to hospital is required.

Methods

A retrospective chart review was performed on all patients aged 0–18 years old with intussusception over a span of 20 years. Study included children treated for intussusception on first encounter with enema and subsequently admitted for observation. Study excluded those readmitted for recurrence after 48 h, patients whose intussusception did not reduce on first try, those lost to follow-up, and those who went to the operating room. Early recurrence was defined as recurrence within 48 h post-reduction.

Results

Out of 171 patients admitted, only one experienced an early recurrence (0.6 %). Median length of stay for all patients was 2 days. Average cost incurred per day for intussusception admission was $404.

Conclusion

Intussusception in a child that is successfully reduced via enema has a low recurrence rate and is usually followed by prompt resolution of symptoms. An abbreviated period of observation in the emergency department post-reduction may result in healthcare savings.

     

A novel fluorescent probe for imaging the process of HOCl oxidation and Cys/Hcy reduction in living cells

A new on-off-on fluorescent probe, CMOS, based on coumarin was developed to detect the process of hypochlorous acid (HOCl) oxidative stress and cysteine/homocysteine (Cys/Hcy) reduction. The probe exhibited a fast response, good sensitivity and selectivity. Moreover, it was applied for monitoring the redox process in living cells.

A new on–off–on fluorescent probe, CMOS, was designed and applied to detect the process of HOCl oxidation and Cys/Hcy reduction.

Reactive oxygen species (ROS) are indispensable products and are closely connected to various physiological processes and diseases.¹ For instance, endogenous hypochlorous acid (HOCl) as one of the most important ROS, which is mainly produced from the reaction of hydrogen peroxide with chloride catalyzed by myeloperoxidase (MPO), is a potent weapon against invading pathogens of the immune system.^2,3 However, excess production of HOCl may also give rise to oxidative damage via oxidizing or chlorinating the biomolecules.⁴ The imbalance of cellular homostasis will cause a serious pathogenic mechanism in numerous diseases, including neurodegenerative disorders,⁵ renal diseases,⁶ cardiovascular disease,⁷ and even cancer.⁸ Fortunately, cells possess an elaborate antioxidant defense system to cope with the oxidative stress.⁹ Therefore, it is necessary and urgent to study the redox process between ROS and antioxidants biosystems.Fluorescence imaging has been regarded as a powerful visual methodology for researching various biological components as its advantages of high sensitivity, good selectivity, little invasiveness and real-time detection.^10,11 To date, amounts of small molecular fluorescent probes have been reported for detection and visualization of HOCl in vivo and in vitro.^12–22,29 The designed strategies of HOCl sensitive probes are based on various HOCl-reactive functional groups, such as p-methoxyphenol,¹³p-alkoxyaniline,¹⁴ dibenzoyl-hydrazine,¹⁵ selenide,¹⁶ thioether,¹⁷ oxime,¹⁸ hydrazide,¹⁹ hydrazone.²⁰ But, many of these probes display a delayed response time and low sensitivity. And, only few fluorescent probes can be applied for investigating the changes of intracellular redox status.²¹ Besides, it''s worth noting that most of the redox fluorescent probes rely on the organoselenium compounds.²² Even though these probes are well applied for detection of cellular redox changes, excessive organic selenium is harmful to organisms and the synthesis of organoselenium compounds is high requirement and costly. Additionally, almost all the reports have only investigated the reduction effects of glutathione (GSH) as an antioxidant in the redox events. While, there are the other two important biothiols, cysteine (Cys) and homocysteine (Hcy), which not only present vital antioxidants, but also are tightly related to a wide variety of pathological effects in biosystem, such as slowed growth, liver damage, skin lesions,²³ cardiovascular,²⁴ and Alzheimer''s diseases.²⁵ However, the fluorescent probes for specially studying internal redox changes between HOCl and Cys/Hcy are rarely reported. In this respect, a novel redox-responsive fluorescent probe, CMOS, was designed and synthesized in this work, and we hope that it can be a potential tool for studying their biological relevance in living cells.Based on literature research, the aldehyde group has excellent selectivity in identification of Cys/Hcy, and the thiol atom in methionine can be easily oxidized to sulfoxide and sulfone by HOCl.^26,27 Considering these two points, we utilized 2-mercaptoethanol to protect the 3-aldehyde of 7-diethylamino-coumarin as the recognition part of HOCl, meaning that two kinds of potential recognition moieties are merged into one site. Fluorescent probe CMOS can be easily synthesized by the acetal reaction in one step (Scheme S1^†). A control molecule CMOS-2 was also prepared by 3-acetyl-7-diethylaminocoumarin (CMAC) similarly. The structure of all these compounds have been convinced by ¹H NMR, ¹³C NMR, and HR-MS (see ESI^†).As shown in Scheme 1a, we estimated that both CMOS and CMOS-2 can be rapidly oxidized in the appearance of HOCl. The oxidation product CMCHO of CMOS, which has the aldehyde moiety, can further react with Cys/Hcy to obtain the final product CMCys and CMHcy, respectively. In contrast, the oxidation product CMAC of CMOS-2 cannot combine with Cys/Hcy or other biothiols anymore (Scheme 1b).Open in a separate windowScheme 1Proposed reaction mechanism of CMOS and CMOS-2 to HOCl and Cys/Hcy.In order to confirm our design concept, the basic photo-physical characteristics of CMOS, CMCHO, CMOS-2 and CMAC were tested (Table S1, Fig. S1^†). Under the excitation wavelength 405 nm, CMOS and CMOS-2 exhibited strong fluorescence centred at 480 nm in PBS buffer solution, while the fluorescence of CMCHO and CMAC was weak around this band. The emission properties of CMOS and CMCHO were also investigated at the excitation wavelength 448 nm under the same experimental conditions as well (Fig. S2^†). After careful consideration, we chose 405 nm as the excitation wavelength in the follow-up experiments in vitro and in vivo.Next, the sensitivity of CMOS and CMOS-2 to HOCl and Cys/Hcy were investigated. As we expected, both the CMOS and CMOS-2 exhibited good response to HOCl. The fluorescence intensity of CMOS and CMOS-2 decreased gradually with addition of NaOCl (Fig. 1a, S3a^†), indicating that the fluorescence was switched off obviously in the presence of HOCl. The variation of intensity displayed good linearity with concentration of HOCl in the range of 0–20 μM (R² = 0.993, Fig. S4^†), and the detection limit of CMOS to HOCl was calculated to be 21 nM (S/N = 3). Subsequently, when Cys/Hcy was added to the final solution in Fig. 1a, the fluorescence intensity increased gradually within 180 min (Fig. 1b, S5^†). However, the fluorescence cannot be recovered by addition thiols to the CMOS-2 solution with excess HOCl (Fig. S3b^†). These results indicate that the probe CMOS can response to HOCl and Cys/Hcy in a fluorescence on-off-on manner, and can be used for monitoring the redox process with high sensitivity.Open in a separate windowFig. 1(a) Fluorescence responses of CMOS (2 μM) to different concentrations of NaOCl (0–200 μM). (b) Fluorescence responses of the CMOS solution (2 μM) with HOCl (200 μM) to Cys/Hcy (5 mM). (20 mM PBS buffer/CH₃CN, 7 : 3, v/v, pH = 7.4, λ_ex = 405 nm).To further identify the recognizing mechanism of probe CMOS, high performance liquid chromatography (HPLC) and mass spectral (MS) analysis were used to detect the redox process. Initially, probe CMOS displayed a single peak with a retention time at 3.7 min (Fig. 2a, S6^†) while reference compound CMCHO produced a single peak with a retention time at 2.5 min (Fig. 2b, S7^†). Upon the addition of HOCl to the solution of CMOS, the peak at 3.7 min weakened while 2.5 min and 2.2 min appeared (Fig. 2c). According to corresponding mass spectra, the new main peak at 2.5 min is related to compound CMCHO (Fig. S8^†). The other new peak of 2.2 min corresponds to the compound C3, which can be predicted as an intermediate in the oxidation process (Fig. S8^†).²⁸ The addition of Cys to the solution of CMCHO also caused a new peak with a retention time at 2.1 min, which has been confirmed to be the thioacetal product CMCys (Fig. S9^†). The possible sensing mechanism is depicted in Fig. S10.^†Open in a separate windowFig. 2The reversed-phase HPLC with absorption (400 nm) detection. (a) 10 μM CMOS. (b) 10 μM CMCHO. (c) 10 μM CMOS in the presence of 50 μM HOCl for 30 s. (d) 10 μM CMCHO in the presence of 1 mM Cys for 30 min. (Eluent: CH₃CN containing 0.5% CH₃COOH; 100% CH₃CN (0–7 min), 0.5 ml min⁻¹, 25 °C; injection volume, 5.0 μL).To study the selectivity of CMOS towards HOCl, we performed fluorescence response to different reactive oxygen species (ROS), reactive nitrogen species (RNS) and reactive sulfur species (RSS). As shown in Fig. 3a, CMOS exhibited significant change of fluorescence intensity only in the presence of HOCl, while other ROS and RNS, such as singlet oxygen (¹O₂), hydrogen peroxide (H₂O₂), hydroxyl radical (HO·), superoxide anion (O₂⁻), nitric oxide (NO), tert-butylhydroperoxide (t-BuOOH) and tert-butoxy radical (t-BuOO·) had no obvious fluorescence emission changes. Additionally, RSS which are abundant in biological samples, showed no influence in this process under the identical condition. The detection of reducing process was also investigated. As displayed in Fig. 3b, only cysteine and homocysteine induced excellent fluorescence recovery towards other reducing materials, such as RSS and various amino acids. Furthermore, the selectivity of CMOS-2 was also studied in the same condition. As expected, CMOS-2 could selectively detect HOCl, and not alter fluorescence intensity under various kinds of biothiols (Fig. S11^†). Therefore, our design strategy for the on–off–on probe is confirmed by results obtained above, with which CMOS can be utilized for detecting the redox process between HOCl and Cys/Hcy with high selectivity.Open in a separate windowFig. 3(a) Fluorescence response of CMOS (2 μM) to different ROS, RNS and RSS (200 μM). Bars represent emission intensity ratios before (F₀) and after (F₁) addition of each analytes. (a) HOCl; (b) KO₂; (c) H₂O₂; (d) ¹O₂; (e) HO·; (f) t-BuOOH; (g) t-BuOO·; (h) NO₂⁻; (i) NO₃⁻; (j) NO; (k) GSH; (l) Cys; (m) Hcy; (n) Na₂S; (o) Na₂S₂O₃; (p) Na₂S₂O₈; (q) NaSCN; (r) DTT; (s) Na₂SO₃. (b) Fluorescence response of the solution added HOCl in (a) to different RSS and amino acids. Bars represent emission intensity ratios before (F₂) and after (F₃) addition of each analytes (5 mM). (a) Cys; (b) Hcy; (c) Na₂S; (d) Na₂S₂O₃; (e) Na₂S₂O₈; (f) NaSCN; (g) DTT; (h) Na₂SO₃; (i) Ala; (j) Glu; (k) Gly; (l) His; (m) Ile; (n) Leu; (o) Met; (p) Phe; (q) Pro; (r) Ser; (s) Trp; (t) Vc; (u) GSH. (20 mM PBS buffer/CH₃CN, 7 : 3, v/v, pH = 7.4, λ_ex/λ_em = 405/480 nm).Subsequently, the influence of pH on probe CMOS was measured. The fluorescence intensity of CMOS and CMCHO perform no significant variances in wide pH ranges (pH = 4–11, Fig. S12a^†). Fluorescence intensity changes could be observed immediately when HOCl was added into the solution of probe CMOS, especially in alkaline condition (Fig. 4a). Considering the pK_a of HOCl is 7.6,²⁹CMOS is responsive to both HOCl and OCl⁻. Alkaline condition was also benefit for the fluorescence recovery of CMOS from Cys/Hcy (Fig. S12b^†). It is reasonable to consider that thiol atom displays higher nucleophilicity in alkaline condition. From the stop-flow test, the UV-visible absorbance of probe CMOS sharply decreased at the wavelength of 400 nm (Fig. 4b). The response time was within 10 s and the kinetic of the reaction was fitted to a single exponential function (k_obs = 0.67 s⁻¹). The ability of instantaneous response is extremely necessary to intracellular HOCl detection.Open in a separate windowFig. 4(a) Fluorescence responses of CMOS to HOCl under different pH values. Squares represent emission intensity ratios after (F₁) and before (F₀) addition of 200 μM HOCl (λ_ex/λ_em = 405/480 nm). (b) Time-dependent changes in the absorption intensity of CMOS (1 μM) before and after addition of HOCl. (20 mM PBS buffer/CH₃CN, 7 : 3, v/v, pH = 7.4, λ_abs = 400 nm).With these data in hand, we next applied CMOS for fluorescence imaging of the redox changes with HOCl and Cys/Hcy in living cells. After incubation with 5 μM CMOS at 37 °C for 30 min, intense fluorescence was observed of the SKVO-3 cells in the optical window 425–525 nm (Fig. 5a and d), indicating the probe can easily penetrate into cells. Treating the cells with 100 μM NaOCl led to remarkable fluorescence quenching as the probe sensed the HOCl-induced oxidative stress (Fig. 5b and e). After 3 min, the cells were washed with PBS buffer three times, and added 5 mM Cys/Hcy for 1 h, respectively. Then the fluorescence was recovered obviously (Fig. 5c and f). Experimental results clearly declare that the probe CMOS was successfully used to detect the process of HOCl oxidative stress and Cys/Hcy reducing repair in living cells.Open in a separate windowFig. 5Fluorescence imaging of the process of HOCl oxidative stress and thiols repair in CMOS-labeled SKVO-3 cells. Fluorescence images of SKVO-3 cells loaded with 5 μM CMOS at 37 °C for 30 min (a and d). Dye-loaded cells treated with 100 μM NaOCl at 25 °C for 3 min (b and e). Dye-loaded, NaOCl-treated cell incubated with 5 mM Cys (c), 5 mM Hcy (f) for 1 h. Emission intensities were collected in an optical window 425–525 nm, λ_ex = 405 nm, intensity bar: 0–3900.     

联合干预离子通道提高PVDF膜富集胎儿有核红细胞的效率

目的通过干预细胞膜阴离子通道(AE)和Na+/K+/2Cl-离子共转运体(NKCC),提高聚偏二氟乙烯(PVDF)膜富集脐血有核红细胞(NRBC)的效率。方法以密度为1.067的分离液分离NRBC,用AE抑制剂维拉帕米(verapamil)和NKCC抑制剂呋噻米(furosemide)联合干预,用流式细胞技术和巢式PCR观察干预前后离心法和过5μm孔径PVDF膜法富集NRBC的效率。结果最佳离心分离密度梯度为1.067。流式细胞仪检测离心分离的NRBC平均纯度为2.54%,干预后离心分离NRBC纯度为9.36%,NRBC富集率提升近3.7倍;过PVDF膜前NRBC为0.83%,过膜后NRBC为6.15%,干预后过膜将NRBC富集率提升了7.4倍。用巢式PCR检测,每ml血样中NRBC为120个时,干预后过膜的扩增条带的密度值由4.48升高至17.78,提升近4倍。结论维拉帕米和呋噻米能够通过改变脐血细胞性状,提高NRBC通过PVDF膜的效率。     

Determination of Clinical Cut-Off Values for Serum Cystatin C Levels to Predict Ischemic Stroke Risk

Background: The association between cystatin C and risk of ischemic stroke is inconsistent and the cut-off values of cystatin C are diverse in different articles. We aimed to investigate the association between cystatin C levels and the development of ischemic stroke and to explore the clinical cut-off values of serum cystatin C levels for ischemic stroke. Methods: This prospective cohort study included 7658 participants from the China Health and Retirement Longitudinal Study who were free of cardiovascular diseases and cancer at baseline. A decision-tree model was used to find reasonable cut-off values for cystatin C levels. Logistic regression models were used to analyze the association between different levels of cystatin C and the risk of ischemic stroke. Results: The whole cohort was divided into the following 3 groups according to the decision tree: group-low (<.901 mg/L), group-moderate (.901～1.235 mg/L), and group-high (>1.235 mg/L). After 4 years of follow-up, we identified 156 cases of ischemic stroke. After adjusting for potential confounding factors, the odds ratios (95% confidence intervals) of ischemic stroke were 1.637 (1.048-2.556) for group-moderate and 2.326 (1.285-4.210) for group-high) compared with the low group of cystatin C. Subgroup analyses showed that the association between cystatin C levels and the incidence of ischemic stroke was more pronounced in males or old people than in females or young people. Conclusions: We found 2 suitable cut-off values for serum cystatin C levels and found that high levels of cystatin C were associated with an increased risk of ischemic stroke.     

Radionuclide methods for diagnostics of non-rheumatic myocarditis and postmyocarditic cardiosclerosis

We compared the results of comprehensive scintigraphic examination of 35 patients with suspected myocarditis and the data of clinical, immunological, laboratory and instrumental studies. The patients were divided into 3 groups. Group 1 included 11 patients with preliminary diagnosis of acute myocarditis, group 2--11 patients with chronic myocarditis, group 3--13 patients with postmyocarditic cardiosclerosis. All patients were tested for antimyocardial antibodies, underwent 99mTc-HMPAO-labeled leukocyte and perfusion scintiography of myocardium. The study did not reveal significant differences between the three groups as regards the results of laboratory and instrumental studies. Elevated titers of antimyocardial antibodies were found in 70% of the patients in group 1, 100% in group 2, and 46% in group 3. Patients with chronic myocarditis had the highest titers of antibodies. Pathological accumulation of 99mTc-HMPAO-labeled leukocytes in myocardium was documented in 36.4 and 81.8% of the patients of groups 1 and 2 respectively. They were absent in the heart of group 3 patients. Disturbed myocardial perfusion was recorded in 45.5, 81.8 and 84.6% in groups 1, 2 and 3 respectively. The magnitude of accumulation of leukocytes was not significantly different between the groups. Results of the study suggest rather high specificity of radionuclide techniques for diagnostics of inflammatory lesions in myocardium. However, further studies are needed to confirm their sensitivity and accuracy.     

Differential inhibitor sensitivity of anaplastic lymphoma kinase variants found in neuroblastoma

Activating mutations in the anaplastic lymphoma kinase (ALK) gene were recently discovered in neuroblastoma, a cancer of the developing autonomic nervous system that is the most commonly diagnosed malignancy in the first year of life. The most frequent ALK mutations in neuroblastoma cause amino acid substitutions (F1174L and R1275Q) in the intracellular tyrosine kinase domain of the intact ALK receptor. Identification of ALK as an oncogenic driver in neuroblastoma suggests that crizotinib (PF-02341066), a dual-specific inhibitor of the ALK and Met tyrosine kinases, will be useful in treating this malignancy. Here, we assessed the ability of crizotinib to inhibit proliferation of neuroblastoma cell lines and xenografts expressing mutated or wild-type ALK. Crizotinib inhibited proliferation of cell lines expressing either R1275Q-mutated ALK or amplified wild-type ALK. In contrast, cell lines harboring F1174L-mutated ALK were relatively resistant to crizotinib. Biochemical analyses revealed that this reduced susceptibility of F1174L-mutated ALK to crizotinib inhibition resulted from an increased adenosine triphosphate-binding affinity (as also seen in acquired resistance to epidermal growth factor receptor inhibitors). Thus, this effect should be surmountable with higher doses of crizotinib and/or with higher-affinity inhibitors.     

Tyrosine phosphorylation of R3 subtype receptor‐type protein tyrosine phosphatases and their complex formations with Grb2 or Fyn

Post‐translational modification of protein tyrosine phosphatases (PTPs) is implicated in functional modulation of these enzymes. Stomach cancer–associated protein tyrosine phosphatase‐1 (SAP‐1), as well as protein tyrosine phosphatase receptor type O (PTPRO) and vascular endothelial‐protein tyrosine phosphatase (VE‐PTP) are receptor‐type PTPs (RPTPs), which belong to the R3 subtype RPTP family. Here, we have shown that the carboxyl (COOH)‐terminal region of SAP‐1 undergoes tyrosine phosphorylation by the treatment with a PTP inhibitor. Src family kinases are important for the tyrosine phosphorylation of SAP‐1. Either Grb2 or Fyn, through their Src homology‐2 domains, bound to the tyrosine‐phosphorylated SAP‐1. Moreover, both PTPRO and VE‐PTP underwent tyrosine phosphorylation in their COOH‐terminal regions. Tyrosine phosphorylation of VE‐PTP or PTPRO also promoted their complex formations with Grb2 or Fyn. Forced expression of SAP‐1, PTPRO or VE‐PTP promoted cell spreading and lamellipodium formation of fibroblasts that expressed an activated form of Ras. In contrast, such effects of non‐tyrosine‐phosphorylated forms of these RPTPs were markedly smaller than those of wild‐type RPTPs. Our results thus suggest that tyrosine phosphorylation of R3 subtype RPTPs promotes their complex formations with Grb2 or Fyn and thus participates in the regulation of cell morphology.