Dulaglutide, a long-acting GLP-1 receptor agonist, can improve hyperandrogenemia and ovarian function in DHEA-induced PCOS rats

OBJECTIVE

The purpose of this study was to explore the effect of dulaglutide on DHEA induced PCOS rats and its mechanism, to provide new drugs and research directions for clinical treatment of PCOS.

METHODS

In this study, the PCOS model was established by giving female SD rats subcutaneous injection of DHEA for 21 consecutive days. After modeling, the treatment group was injected subcutaneously with three doses of dulaglutide for 3 weeks. The model group was injected with sterile ultrapure water, and the normal group did not get any intervention. The body weight changes of rats in each group were recorded from the first day when rats received the administration of dulaglutide. Three weeks later, the rats were fasted the night after the last treatment, determined fasting insulin and fasting glucose the next day. After the rats were anesthetized by chloral hydrate, more blood was collected from the heart of the rat. The serum insulin, testosterone and sex hormone binding globulin (SHBG) levels were detected by the enzyme-linked immunoassay method. After removing the adipose tissue, the obtained rat ovary tissue was used for subsequent experimental detection, using HE staining for morphology and follicular development analysis; qRT-PCR for the detection of 3βHSD, CYP17α1, CYP19α1, and StAR gene expression in ovarian tissue; and western blotting analysis of CYP17α1, CYP19α1, StAR protein expression and insulin level to verify whether dulaglutide has a therapeutic effect on PCOS in rats.

RESULTS

After treated with different concentrations of dulaglutide, we found that the body weight of rats in the treatment groups were reduced. Compared with the rats in PCOS group, the serum androgen level of rats in the treatment groups was significantly decreased, and the serum sex hormone binding protein content was significantly increased, and there was statistically significant difference between these groups and PCOS group. In terms of protein expression and gene regulation, the expression of 3βHSD, CYP19α1 and StAR in the ovarian tissue of rats in treatment groups were decreased significantly after received the treatment of dulaglutide, and there was statistically significant difference between these groups and PCOS group. In addition, dulaglutide reduced the insulin content in the ovarian tissue of PCOS rats.

CONCLUSION

Dulaglutide may reduce the hyperandrogenemia of PCOS rats by regulating the content of serum SHBG and the expression of 3βHSD, CYP19α1, and StAR related genes and proteins, thereby inhibiting the excessive development of small follicles and the formation of cystic follicles in the ovaries of PCOS rats, thereby improving polycystic ovary in PCOS rats. In addition, dulaglutide may reduce the weight of PCOS rats, further reducing the level of high androgen in PCOS rats, and improving the morphology of their polycystic ovaries.

[Proteomic analysis of aqueous humor in acute primary angle-closure glaucoma]

Objective: To analyze the difference among expression of aqueous humor proteins in acute primary angle-closure glaucoma (APACG). Methods: Case-control study. The patients with APACG combined cataract (APACG with cataract group) and patients with cataract (cataract group), who had undertaken surgical treatment at the Tianjin Medical University Eye Hospital from October 2016 to June2017 were collected. Upon receipt of patient's consent, 50 μl of aqueous humor were collected with 1 ml syringe and No.1 needle through the surgical access during the surgery, and then injected into a sterile collection tube to be stored at -80 ℃. Those proteins extracted from aqueous humor were analyzed by quantitative proteomic mass spectrometry. The differential significance test was performed by Maxquant significances A approach. The differential proteins of the two groups were screened and determined with the conditions of P<0.05 and difference multiple>2. The functions and signal pathway of differential proteins in aqueous humor were annotated in biological big data, on the basis gene ontology (GO) and the Kyoto gene and genomic encyclopedia (KEGG) analyses. Results: There were 3 males and 7 females with an average age of (68±6) years in the APACG group. The cataract group included 2 males and 8 females with an average age of (71±8) years. There were no statistical differences in gender ratio and age between the two groups (both P>0.05). A total of 91 differential proteins were detected in this experiment, including 50 up-regulated proteins (annexinA1, vimentin, S100 calcium binding protein A8, interleukin 6, C reactive protein, laminin β2, etc.) and 41 down-regulated (keratin 85, γ-crystallin D, syntaxin-binding protein 5, semaphoring 4B, matrilin 2, cathepsin O, cadherin 4, semaphoring 3B, platelet-derived growth factor D, transforming growth factor β, etc.). On one hand, the functions of differential proteins involved in many aspects. AnnexinA1, CD163, S100 calcium-binding protein A8, C reactive protein, interleukin 6 are involved in the inflammatory reaction, cadherin 4 and laminin β2 regulate cell adhesion, matrilin 2, vimentin and laminin β2 participate in tissue fibrosis; on the other hand, KEGG analysis showed that the differential proteins participate diverse signaling pathways such as phosphatidylinositol-3-kinase-protein kinase B signaling pathway, transformation growth factor β signaling pathway, mitogen activated protein kinase signaling pathway, Toll-like receptor signaling pathway, the nuclear factor κ-light chain enhancer of the activated B cells signaling pathway, focal adhension and extracellular matrix receptor interaction pathway and so on. Conclusions: The expression of annexin A1 is significantly up-regulated in the aqueous humor in APACG, while some other factors such as transformation growth factor β, cadherin-4, and matrilin 2 are down-regulated. The change of proteins in aqueous humor is related with the outbreak of APACG. (Chin J Ophthalmol, 2019, 55: 687-694).

[Endovascular thrombectomy in patients with intracranial large artery occlusion and atrial fibrillation]

Objective: To investigate the safety and efficacy of mechanical thrombectomy in patients with atrial fibrillation complicated with acute intracranial arterial occlusion. Methods: Fifty-eight patients with atrial fibrillation complicated with acute intracranial arterial occlusion in the intervention group of East (Endovascular Therapy for Acute ischemic Stroke Trial) were analyzed. According to the TOAST (Trial of Org 10 172 in Acute Stroke Treatment) classification, patients were divided into ICAS (Intracranial Atherosclerotic Stenosis) group and cardiogenic embolism group. Clinical characteristics, treatment methods and clinical prognosis were compared between ICAS group and cardiogenic embolism group. Results: A total of 58 patients with atrial fibrillation complicated with acute intracranial arterial occlusion were included in this study, including 46 patients in the cardiogenic embolism group (79%) and 12 patients in the ICAS group (21%). The pre-hospital transport time in ICAS group was longer than that in cardiogenic embolism group (P<0.05).Patency rate in patients with atrial fibrillation complicated with acute intracranial arterial occlusion was 98.3% (57/58), The rate of patients with the 90-day function independent (mRS 0-2) was 51.7% (30/58). There were no statistically significant differences in functional independence, mortality rate, ICH and sICH at 90 days between the cardiogenic embolism group and the ICAS group. Conclusions: Mechanical thrombectomy is an effective method to treat patients with atrial fibrillation complicated with acute intracranial arterial occlusion.

[Clinical analysis of five cases of autism spectrum disorder complicated with epilepsy with chromosome copy number variation]

Objective: To explore the clinical features and genetic causes of autism spectrum disorder (ASD) patients with epilepsy. Methods: The clinical data of five patients with ASD and epilepsy admitted to Xuanwu Hospital between September 2017 and September 2018 were collected, including medical history, intelligence level, developmental level, physical examination, neuroimaging and electroencephalogram. High-throughput whole-genome sequencing was applied to five patients and their parents. Results: Of five patients, four were male and one was female. All five patients had mild mental retardation, and one patient had significant growth retardation and craniofacial deformity. The average epilepsy onset age was 6.3 years old (7 months to 16 years). The main epileptic type was tonic-clonic seizure with abnormal EEG results. All patients have a favorable response to anti-epileptic drugs. Whole-exome sequencing (WES) revealed copy number variation in all 5 patients. Among them, 3 cases were reported to be pathogenic, and 2 cases were not reported (chromosome 16p13.3 duplication and chromosome 21q22.3 deletion). Conclusions: The results of current study support that autism spectrum disorders with seizures is often associated with copy number variations, such as Williams-Beuren region duplication syndrome, chromosome 15q11.2 duplication syndrome and chromosome 15q11.2 deletion syndrome. We reported two novel copy number variations (chromosome 16p13.3 duplication and chromosome 21q22.3 deletion) in two autism spectrum disorder patients with epileptic seizures.

Cucurbitacin B inhibits cell proliferation and induces cell apoptosis in colorectal cancer by modulating methylation status of BTG3

A previous report has revealed that cucurbitacin B (CuB) inhibits cancer cell proliferation and tumorigenesis in non-small cell lung cancer (NSCLC) through epigenetic modifications of several genes. However, whether CuB regulates cell proliferation and apoptosis by altering methylation status of BTG3 in colorectal cancer (CRC) remains unknown. In the present study, the results showed that BTG3 was downregulated in CRC tissues compared with adjacent normal tissues. CuB significantly increased BTG3 levels, induced promoter demethylation, and decreased the levels of DNA methyltransferases (DNMT1, DNMT3a and DNMT3b) in both CRC cell lines (SW480 and Caco-2), and the effects of CuB were comparable with those of 5-Aza-dC. We also found that CuB inhibited cell proliferation, accompanied with decreased expression of Ki67. Furthermore, CuB treatment induced cell cycle arrest at G1 phase in SW480 and Caco-2 cells, as well as decreased levels of Cyclin D1 and Cyclin E1. Incubation with CuB promoted cell apoptosis in both CRC cell lines in vitro, accompanied with elevation of cleaved caspase-3 and cleaved PARP. BTG3 knockdown abolished the effects of CuB in CRC cells. In summary, CuB-induced proliferation inhibition and cell apoptosis may be due to the reactivation of BTG3 by promoter demethylation. CuB may be a promising agent for CRC therapy.

[Efficacy analysis of LVIS and Enterprise stent assisted coil in the treatment of vertebral artery dissection aneurysm]

Objective: To observe and evaluate the therapeutic efficacy of LVIS stent and Enterprise stent assisted coil in embolization of vertebral artery dissection aneurysm (VDA). Methods: Clinical data of 96 patients with VDAs treated by LVIS stent and Enterprise stent assisted coil were analyzed retrospectively between January, 2013 and June, 2017.Of all, the LVIS stent assisted coil was performed in 28 patients (LVIS-stent group) and Enterprise in 68 patients (Enterprise-stent group). The clinical and imaging follow-up were performed. The instant embolization rate, complications, and recurrence rate were analyzed and compared between the two groups. Results: Instant angiographic results:in the LVIS stent group, complete occlusion was achieved in 17 VDAs (60.7%), near-complete occlusion in 10VDAs (35.7%), and partial occlusion in 1 VDA (3.6%). In the Enterprise stent group, complete occlusion was achieved in 27 VDAs (39.7%), near-complete occlusion in 34VDAs(50.0%), partial occlusion in 7VDAs (10.3%). Procedure-related complications occurred in 3 patients (10.7%) in LVIS stent group and 3 patients (4.4%) in Enterprise stent group. DSA follow-up was performed during 6 to 12 months after surgery, and 10 patients with vertebral artery dissection aneurysm recurred, 2 in the LVIS group and 8 in the Enterprise stent group. The latest modified Rankin Scale score was 0 in 55 patients,1 in 13, 2 in 1, 3 in 1, and 6 in 1. Among them, all follow-up patients in the LVIS stent group had good prognosis, while in the Enterprise stent group, 50 patients (94.4%) had a good prognosis. Conclusions: The stent-assisted coils have a higher degree of embolization in the vertebral artery dissection aneurysms, a higher rate of near-total embolization, a lower incidence of neurological complications, and a good prognosis. The complete andnear-complete occlusion rates and the incidence of neurological complicationsin the LVIS group was higher than that in the Enterprise groupand the recurrence ratesin the LVIS group was lower than that in the Enterprise group,both with no statistically significant difference.

[Efficacy analysis of the endovascular treatment for 175 unruptured vertebrobasilar dissecting aneurysms]

Objective: To analyze the clinical characteristics, clinical effect and follow-up outcome of the different endovascular treatment techniques in the treatment of unruptured vertebrobasilar dissecting aneurysms (VBDAs). Methods: The clinical data of 160 consecutive patients (175VBDAs) from January 2012 to December 2016 in Beijing Tiantan hospital were retrospectively analyzed.All of the 175 aneurysms were treated with endovascular embolization, including 115 stent-assisted coils, 27 simple stents, 21 blood flow diverting devices, and 12 parent arteries occlusion.The imaging and clinical follow-up were performed after the operation. Results: Headache including cervical-occipital pain(43.1%)was the most common clinical manifestation.The incidence of perioperative complications was 3.75%, no intraoperative bleeding and no deaths.The imaging findings of 113 aneurysms were followed up for (9.9±7.3) months.Of the 71 stent-assisted coils, 62 recovered well and 9 relapsed; of the 19 aneurysms treated with simple stent, 4 recovered well, 11 improved, 2 stable and 2 relapsed; of the 15 aneurysms treated by the blood flow diverting devices, 4 recovered and 11 improved; all of the 8 aneurysms with parent arteries occlusion recovered well.A total of 144 patients were follow-up (17.3±16.6) months by the Modified Rankin Scale(mRS) score: 140 patients were 0-2 score and 4 patients were 3-6 score. Conclusions: The clinical manifestations of the unruptured VBDAs are complex, and the headache is the most common clinical symptom.Endovascular treatment for the treatment of unruptured VBDAs is safe and feasible.The principle of individualization should be followed during embolization.

Examining the effect of ions and proteins on the heat dissipation of iron oxide nanocrystals

In this paper, the effect and contribution of physiological components like ions and proteins under an applied alternating magnetic field (AMF) towards heat dissipation of superparamagnetic iron oxide nanoparticles (SPIONs) are discussed. Our results have shown that under an applied AMF, magnetic hyperthermia efficiency could be significantly enhanced if SPIONs were suspended in 1× phosphate buffered saline (PBS) compared to a suspension in de-ionized (DI) water. However, no heat enhancement was found when SPIONs were suspended in blood which is an amalgamation of physiological ions and proteins. Closer investigations have revealed that the presence of physiological ions can contribute positively to heating efficiency, and the heating efficiency increases with concentration of ions, ionic mass and solubility. However, the heating efficiency of ions can be suppressed to an insignificant level (comparable with measurement error), in the presence of physiological proteins in 1×PBS. Our electrochemical studies also showed that ionic mobility can be reduced significantly if proteins were present in the solution, thus retarding the heating efficiency.

[Urothelial carcinoma-associated 1 enhances tamoxifen resistance in breast cancer cells through competitively inhibiting miR-18a]

OBJECTIVE

To investigate how urothelial carcinoma-associated 1 (UCA1) and miR-18a modulates acquired tamoxifen resistance and the relevant mechanisms in estrogen receptor (ER) positive cancer cells.

METHODS

qRT-PCR was performed to detect UCA1 and miR-18a expression in breast cancer cells. Dual luciferase assay was performed to detect the binding between miR-18a and UCA1 3'UTR. Tamoxifen sensitive MCF-7 cells were transfected with UCA1 expression vector or miR-18a inhibitors. Tamoxifen resistant LCC9 and BT474 cells were transfected with UCA1 siRNA or miR-18a mimics. CCK-8 assay was performed to detect cell viability. Soft agar assay was performed to assess cell colony formation. Flow cytometric analysis was performed to check cell cycle distribution.

RESULTS

UCA1 was significantly upregulated in tamoxifen resistant LCC2, LCC9, and BT474 cells than in tamoxifen sensitive MCF-7 cells. UCA1 expression was significantly upregulated in MCF-7 cells after treatment with 0.1 μmol/L tamoxifen. UCA1 overexpression enhanced cell viability of MCF-7 cells after tamoxifen treatment, while UCA1 siRNA significantly suppressed viability of LCC9 and BT474 cells after tamoxifen treatment. In MCF-7 cells, compared with vector control+tamoxifen group, the average cell colony number and colony size of the UCA1+tamoxifen group was 19.0% more and 29.0% larger respectively, while the proportions of the cells in G1 phase and in S phase were 7.3% lower and 6.7% higher respectively. In BT474 cells, compared with siRNA control+tamoxifen group, the average cell colony number and colony size of the si-UCA1+tamoxifen group were 54.0% less and 42.0% smaller respectively, while the proportions of the cells in G1 phase and in S phase were 9.0% higher and 6.2% lower respectively. UCA1 directly interacted with miR-18a and reduced its expression in ER positive breast cancer cells. Knockdown of miR-18a increased viability of MCF-7 cells after tamoxifen treatment, while miR-18a overexpression significantly reduced viability of BT474 cells after tamoxifen treatment. In MCF-7 cells, compared with miRNA inhibitor control+tamoxifen group, the average cell colony number and colony size of the miR-18a inhibitor+tamoxifen group were 15.0% more and 33.0% larger respectively, while the proportions of the cells in G1 phase and in S phase were 8.8% lower and 5.3% higher respectively. In BT474 cells, compared with miRNA control+tamoxifen group, the average cell colony number and colony size of the miR-18a mimics+tamoxifen group were 47.0% less and 25.0% smaller respectively, while the proportions of the cells in G1 phase and in S phase were 13.3% higher and 7.9% lower respectively.

CONCLUSION

UCA1 can increase tamoxifen resistance of ER positive breast cancer cells via competitively inhibiting of miR-18a.

[Antibiotic resistance analysis of Streptococcus pneumoniae isolates from the hospitalized children in Shanxi Children's Hospital from 2012 to 2014]

Objective: To investigate the antibiotic resistance status of Streptococcus pneumoniae isolates from hospitalized children in Shanxi Children's Hospital. Method: E-test and Kirby-Bauer methods were applied to determine drug sensitivity of the isolates collected from the body fluid specimens of hospitalized children in Shanxi Children's Hospital from January 2012 to December 2014. The antimicrobial sensitivity and minimum inhibitory concentration (MIC) of Streptococcus pneumoniae to the conventional antibiotics were analyzed, in order to compare the annual trends of non-invasive isolates, while the differentiation of sensitivity from specimens. The comparison of rates was performed by Chi-squared test and Fisher's exact test. Result: A total of 671 isolates of streptococcus pneumoniae were obtained, which could be divided as non-invasive isolates(607), invasive isolates from non-cerebrospinal fluid(non-CSF)(40) and invasive isolates from cerebrospinal fluid(CSF)(24). The antimicrobial sensitivity(isolates(%)) of the 671 isolates were respectively vancomycin 671(100.0%), linezolid 671(100.0%), levofloxacin 665(99.1%), penicillin 595(88.7%), ceftriaxone 516(76.9%), cefotaxime 512(76.3%), sulfamethoxazole-trimethoprin(SMZ-TMP) 103(15.4%), clindamycin 28(4.2%), tetracycline 26(3.9%), erythromycin 12(1.8%). From 2012 to 2014, the susceptibility rates of non-invasive isolates to penicillin every year were 95.0%(96/101), 97.3%(110/113), 87.3%(343/393), respectively, and there was significant difference among the three years(χ(2)=13.266, P<0.05), and the values of MIC(50, )MIC(90) and the maximum values of MIC(mg/L) of penicillin were 0.064, 2.000, 6.000 in 2012, which grew up to 1.000, 3.000, 16.000 in 2014. There was no significant difference in the susceptibility rate of non-invasive isolates to ceftriaxone and cefotaxime during these three years, (χ(2)=1.172, 1.198, both P>0.05). On the other hand, the values of MIC(50, )MIC(90) and the maximum value of MIC(mg/L) of ceftriaxone and cefotaxime both increased from 0.500, 2.000, 8.000 in 2012 to 0.750, 4.000, 32.000 in 2014. There was no significant difference in the susceptibility rate of non-invasive isolates to the rest antibiotic. Based on the same examining standard of CSF, the antimicrobial sensitivity(isolates(%)) of the non-invasive isolates to ceftriaxone, cefotaxime, SMZ-TMP were respectively 281(46.3%), 278(45.8%), 78(12.9%), were significantly lower than the susceptibility rate of the invasive isolates from non-CSF (28(70%), 28(70%), 14(35%), χ(2)=8.453, 8.817, 15.094, all P<0.012 5), and lower than the invasive isolates from CSF (18(75%), 18(75%), χ(2)=7.631, 7.905, P<0.012 5; 11(45.8%), P=0.001). The sensitivity of the isolates to the rest antibiotics were similar(P>0.05). Conclusion: More than 95.0% strains of the streptococcus pneumoniae isolates from the hospitalized children in Shanxi Children's Hospital were sensitive to vancomycin, linezolid, levofloxacin, and the susceptibility rate of penicillin, ceftriaxone, cefotaxime were 88.7%, 76.9%, 76.3%. However, less than 20.0% of streptococcus pneumoniae were sensitive to erythromycin, clindamycin, SMZ-TMP and tetracycline. The susceptibility rate of penicillin of non-invasive Streptococcus pneumoniae declined by these years, and the differences to ceftriaxone and cefotaxime can be neglected, but the values of MIC(50, )MIC(90) and the maximum value of MIC of all were linearly rising. The susceptibility rate of antibiotics to ceftriaxone and cefotaxime of the non-invasive isolates was lower than the invasive isolates.

[Myoclonus and it's associated factors in Creutzfeldt-Jakob disease]

Objective: To analyze features and the related factors of myoclonus of 47 patients with probable or possible Creutzfeldt-Jakob disease (CJD). Methods: All patients diagnosed with"suspected CJD" and hospitalized in Xuanwu Hospital from January 2013 to November 2015 were included, and their clinical information and myoclonus features were analyzed. Age, clinical, course and manifestation, EEG, MRI, CSF14-3-3 features between myoclonus positive group and negative group were compared, and the correlation between myoclonus features and these factors was analyzed using Spearman correlation analyses. Results: (1) Occurrence rate of extrapyramidal symptoms (P=0.028), visual impairment (P=0.025) and dyssomnia (P=0.004) were higher in myoclonus positive group, the differences were significant. Spearman correlation analysis showed that myoclonus was related to extrapyramidal symptoms (P=0.024), visual impairment (P=0.030) and dyssomnia (P=0.001). (2) EEG features showed no significant difference between myoclonus positive and negative group. The 17 myoclonus positive patients were divided into three subgroups, typical EEG change group 52.94%(9/17), atypical EEG change group 23.53%(4/17) and no EEG change group 23.53%(4/17). Difference of myoclonus and other clinical manifestations were not significant among the three subgroups(P>0.05); correlation analysis also found no statistically significant correlation between myoclonus and EEG (P=0.201). Conclusions: Myoclonus often occurs after the damage of locomotor system (including pyramidal tract, extracorticospinal tract and cerebellum) among CJD patients, and it is related to extrapyramidal symptoms , visual impairment and dyssomnia . There is undefined correlation between myoclonus and periodic sharp wave complexes (PSWC) in EEG.

[Feature of magnetic resonance imaging in patients with Creutzfeldt-Jakob disease]

Objective: To assess the imaging features of 43 patients diagnosed as clinically possible or probable Creutzfeldt-Jakob disease (CJD) for providing referential information and experience on applications of MRI in the clinical diagnosis and treatment of CJD. Method: All patients who were diagnosed with "suspected CJD" and hospitalized in Xuanwu Hospital from January 2013 to November 2015 were collected, and their clinical information and MRI imaging features were analyzed retrospectively. Results: Totally 62 patients with "suspected CJD" were rectruited in this study, and 43 of them were diagnosied as probable and possible CJD when they were discharged.The typical MRI feature of CJD patients was "cortical ribbon" sign in MR DWI sequences and/or high signal in cortex or bilateral basal ganglia.In all patients, the simple coritcal involvement was the highest(76.47%, 26/34), followed by the cortical cortex and basal ganglia(23.53%, 8/34). MRI positive group had more prominent extrapyramidal symptoms than MRI negative group (26/31 vs 9/12, P=0.015), but no statistical difference in clinic feature was found between the group with simple cortex affected and the group with both cortex and bilateral basal ganglia affected (P>0.05). Conclusions: MRI images of patients with CJD have special characteristics and have corresponding changes when the patients are in different stages of disease. In combination with the clinical evaluation of disease progression, brain microscopic pathological changes of CJD patients can be assessed by regularly brain MRI examination.

Effects of omalizumab on T lymphocyte function in inner-city children with asthma

While omalizumab treatment of inner city children and adolescents with asthma results in improvement in clinical parameters, no change in peripheral blood T cell responses could be demonstrated. Thus, omalizumab appears not to affect T cell function.

SERS detection of R6G based on a novel graphene oxide/silver nanoparticles/silicon pyramid arrays structure

We present a novel surface-enhanced Raman scattering (SERS) substrate based on graphene oxide/silver nanoparticles/silicon pyramid arrays structure (GO/Ag/PSi). The SERS behaviors are discussed and compared by the detection of R6G. Based on the contrast experiments with PSi, GO/PSi, Ag/PSi and GO/AgA/PSi as SERS substrate, the perfect bio-compatibility, good homogeneity and chemical stability were confirmed. We also calculated the electric field distributions using Finite-difference time-domain (FDTD) analysis to further understand the GO/Ag/PSi structure as a perfect SERS platform. These experimental and theoretical results imply that the GO/Ag/PSi with regular pyramids array is expected to be an effective substrate for label-free sensitive SERS detections in areas of medicine, food safety and biotechnology.

Microstructure, mechanical properties and superelasticity of biomedical porous NiTi alloy prepared by microwave sintering

Porous NiTi alloys were prepared by microwave sintering using ammonium hydrogen carbonate (NH4HCO3) as the space holder agent to adjust the porosity in the range of 22-62%. The effects of porosities on the microstructure, hardness, compressive strength, bending strength, elastic modulus, phase transformation temperature and superelasticity of the porous NiTi alloys were investigated. The results showed that the porosities and average pore sizes of the porous NiTi alloys increased with increasing the contents of NH4HCO3. The porous NiTi alloys consisted of nearly single NiTi phase, with a very small amount of two secondary phases (Ni3Ti, NiTi2) when the porosities are lower than 50%. The amount of Ni3Ti and NiTi2 phases increased with further increasing of the porosity proportion. The porosities had few effects on the phase transformation temperatures of the porous NiTi alloys. By increasing the porosities, all of the hardness, compressive strength, elastic modulus, bending strength and superelasticity of the porous NiTi alloys decreased. However, the compressive strength and bending strength were higher or close to those of natural bone and the elastic modulus was close to the natural bone. The superelastic recovery strain of the trained porous NiTi alloys could reach between 3.1 and 4.7% at the pre-strain of 5%, even if the porosity was up to 62%. Moreover, partial shape memory effect was observed for all porosity levels under the experiment conditions. Therefore, the microwave sintered porous NiTi alloys could be a promising candidate for bone implant.

A sero-epidemiological survey of Chinese Babesia motasi for small ruminants in China

Babesia motasi BQ1 (Lintan) was first isolated from Haemaphysalis qinghaiensis collected in Gannan Tibet Autonomous Region, Gansu province in April 2000. In this study, a total of 3,204 serum samples from small ruminants in 22 provinces located in different districts of China were tested for antibodies against merozoite antigens from cultured B. motasi BQ1 (Lintan) by enzyme-linked immunosorbent assay. This method can survey the prevalence of low-pathogenic Chinese B. motasi. The results of this survey indicated that the average positive rate was 43.5 %, and the positive rates of investigated provinces were significantly different from 6.1 to 91.0 %, and the infections had been found in all provinces investigated. Our data provide large important information regarding the current sero-prevalence of B. motasi in China.

Allergen-specific IgE as a biomarker of exposure plus sensitization in inner-city adolescents with asthma

BACKGROUND

Relationships among allergen-specific IgE levels, allergen exposure and asthma severity are poorly understood since sensitization has previously been evaluated as a dichotomous, rather than continuous characteristic.

METHODS

Five hundred and forty-six inner-city adolescents enrolled in the Asthma Control Evaluation study underwent exhaled nitric oxide (FE(NO)) measurement, lung function testing, and completion of a questionnaire. Allergen-specific IgE levels and blood eosinophils were quantified. Dust samples were collected from the participants' bedrooms for quantification of allergen concentrations. Participants were followed for 12 months and clinical outcomes were tracked.

RESULTS

Among sensitized participants, allergen-specific IgE levels were correlated with the corresponding settled dust allergen levels for cockroach, dust mite, and mouse (r = 0.38, 0.34, 0.19, respectively; P < 0.0001 for cockroach and dust mite and P = 0.03 for mouse), but not cat (r = -0.02, P = 0.71). Higher cockroach-, mite-, mouse-, and cat-specific IgE levels were associated with higher FE(NO) concentrations, poorer lung function, and higher blood eosinophils. Higher cat, dust mite, and mouse allergen-specific IgE levels were also associated with an increasing risk of exacerbations or hospitalization.

CONCLUSIONS

Allergen-specific IgE levels were correlated with allergen exposure among sensitized participants, except for cat. Allergen-specific IgE levels were also associated with more severe asthma across a range of clinical and biologic markers. Adjusting for exposure did not provide additional predictive value, suggesting that higher allergen-specific IgE levels may be indicative of both higher exposure and a greater degree of sensitization, which in turn may result in greater asthma severity.

Childhood Asthma Control Test and airway inflammation evaluation in asthmatic children

BACKGROUND

The Childhood Asthma Control Test (C-ACT) has been proposed as a tool in assessing the level of disease control in asthmatic children. To evaluate the position of C-ACT in the clinical management of asthmatic children, in relationship to the level of airway inflammation as assessed by fractional exhaled nitric oxide (FeNO) and with lung function.

METHODS

A total of 200 asthmatic children were included in the study: 47 children with newly diagnosed asthma ('New') and without any regular controller therapy; and 153 children with previously diagnosed asthma, treated according to GINA guidelines, and evaluated during a scheduled follow-up visit ('Follow-up'). Childhood Asthma Control Test, FeNO and lung function [forced expiratory volume 1 (FEV1) and forced vital capacity (FVC)] were evaluated.

RESULTS

In New vs Follow-up participants, C-ACT score (P < 0.001), FVC (P < 0.005) and FEV1 (P < 0.05) were significantly lower, and FeNO (P = 0.011) were significantly higher. In New, but not in Follow-up participants, significant correlations were observed between C-ACT score and FeNO (r = -0.51; P < 0.001), FEV1 (r = 0.34; P = 0.022) and FEV1/FVC (r = 0.32; P = 0.03). This lack of correlation in Follow-up visits seemed attributable to dissociation between inadequately controlled asthma by C-ACT ratings with normalization of other measures such as FeNO levels.

CONCLUSIONS

This study confirms and expands the concept that C-ACT is complementary to, but not a substitute for, other markers of disease control in asthmatic children, especially in the context of follow-up visits.

Biological potency of German cockroach allergen extracts determined in an inner city population

BACKGROUND

Cockroach allergy is an important cause of inner city asthma. To perform valid studies on the diagnosis and treatment of cockroach allergy, biological potencies of test extracts need to be established, and a surrogate in vitro test for biological potency should be chosen.

METHODS

Sixty-two cockroach-allergic adult subjects were recruited for quantitative skin testing with three commercial German cockroach extracts. The intradermal D50 values were determined using linear interpolation, and the biologic potencies were determined from D50 data. The extracts were also analysed for relative potency, using a competition ELISA, and for specific allergen content, using a two-site ELISA.

RESULTS

Estimates of each extract's D50 were analysable in 48-55 subjects, with D50s between 10.3 and 11.8. All three extracts were bioequivalent using pre-set criteria. The biological potencies of the extracts were 1738-8570 bioequivalent allergy units (BAU)/mL (geometric mean=3300), and these relative potencies were similar to those estimated by competition ELISA and specific allergen content. IgE against cockroach allergens were detected in sera from 34 subjects with analysable D50s, and 17 subjects had IgE directed against specific cockroach allergens. Although the presence of anti-Bla g 5 correlated with the subjects' skin test responses for 2/3 extracts, no single allergen was immunodominant. Antibody responses among the subjects were heterogeneous.

CONCLUSIONS

Although commercial cockroach extracts are relatively low in potency, immunotherapeutic doses should be achievable. Biological potency may be estimated using D50 testing, a combination of specific allergen determinations, or by an overall potency assay such as the competition ELISA.

CAPSULE SUMMARY

The biological potency of three German cockroach allergen extracts, determined in an inner city population, was 1738-8570 BAU/mL. No one allergen was immunodominant, and surrogate in vitro testing methods were examined.

At least two genetically distinct large Babesia species infective to sheep and goats in China

A fatal disease of sheep and goats in the northern part of China has been reported to be due to Babesia ovis. However, some characteristics of the causative agent in recent reports are not in accordance with the original attributes ascribed to this parasite. Therefore, the 18S small subunit ribosomal RNA (18S rRNA) genes of a number of Babesia isolates in China were sequenced and compared with that of other Babesia and Theileria species in an attempt to clarify their taxonomic position. In the present study, seven Babesia isolates were collected from distinct areas of northern China, and the 18S rRNA genes were amplified and sequenced. The phylogenetic trees were inferred based on 18S rRNA gene sequences of the Chinese ovine Babesia isolates and some of ovine Babesia and Theileria species available in GenBank. In the phylogenetic tree, Babesia sp. isolates from Madang, Tianzhu, Lintan, Ningxian, Hebei and Liaoning all grouped with B. motasi with 88.2-99.9% identity, while Babesia sp. Xinjiang grouped in a separate clade between B. ovis and B. crassa with 79.7-81.2% identity. The results indicated that there are at least two distinct Babesia species groups-B. motasi and Babesia sp. Xinjiang, the latter was distinctly different from other ovine Babesia isolates from China with less than 86.6% identity.

[The characteristic infrared spectra of alpha,alpha'-dioxoketene cyclic dithioacetals]

The characteristic infrared spectra of the five alpha,alpha'-dioxoketene cyclic dithioacetals such as carbonyl, double bond of carbon and carbon, single bond of carbon and sulfur etc have been studied. It is specially important that the changing rules with the change of chemical structure have been discussed.

Allergy and asthma prevention: the cup half full

Lack of an effective approach to atopic disease prevention is implicit in the global rise in asthma and allergy prevalence over the last 10-20 years. Indeed, asthma appears to be the most common chronic disease of childhood, allergies seem more common than not, and recent evidence suggests that this atopic disease burden is influencing adult prevalence of these conditions as well. Thus, the time seems right for prevention. Considering our current understanding of asthma and allergy pathogenesis, numerous strategies of atopic disease prevention can be envisioned. These strategies can be organized as follows: (1) allergen avoidance; (2) anti-inflammatory pharmacotherapy; (3) inhibition of Th2-type immune development by Th1-type cytokine induction; and (4) dietary and environmental approaches to atopic disease prevention.

Endotoxin: friend or foe?

Endotoxin in our living environment has been of increasing interest to our global community of allergists. Initially and largely studied for its capacity to mediate septic shock (and earning its "-toxin" suffix), we have since come to understand that endotoxin in the dust of many occupational settings also is an occult respiratory culprit, inducing airflow obstruction and aggravating asthma and allergies. More recently, environmental endotoxin has been implicated as a microbial exposure in early childhood that may have an atopy-protective effect by augmenting early Th1-type immune development. Although seemingly paradoxical, endotoxin's dual nature ultimately may serve to enlighten our understanding of how such bioactive exposures can interact with and guide our immune systems in both health and disease.

Metropolitan home living conditions associated with indoor endotoxin levels

BACKGROUND

Household endotoxin exposure in allergy and asthma has been gaining attention for its dual potential to exacerbate these conditions in individuals with established disease and to abrogate atopy before disease onset.

OBJECTIVE

We sought to better understand the home environmental and lifestyle factors influencing house dust endotoxin levels.

METHODS

From the homes of 86 infants with wheeze in metropolitan Denver, Colorado, house dust endotoxin (detected with a standardized Limulus Amebocyte Lysate assay) and common indoor allergen (Fel d 1, Can f 1, Der p 1, Der f 1, and Bla g 1) contents were quantified. Comprehensive home environment and lifestyle questionnaires were completed during home visits by trained study staff and parents.

RESULTS

House dust endotoxin levels were associated with only 2 home environmental features: animals in the home and the presence of central air conditioning. The strongest positive associations were found with animals in the home. Interestingly, the homes without cats or other animals revealed a negative correlation between house dust Fel d 1 and endotoxin (P =.03). Central air conditioning, especially during months of typical use, was associated with lower house dust endotoxin levels. No significant associations between house dust endotoxin levels and home dampness, number of household inhabitants or young children, cleaning frequency, or presence of tobacco smokers in the home were found.

CONCLUSIONS

Indoor endotoxin exposure can be increased by the presence of animals in the home and decreased with central air conditioning. In some homes without animals, where allergen exposure adequate for sensitization still occurs, there are lower levels of house dust endotoxin. Therefore in homes without animals, factors that influence allergen and endotoxin levels in house dust probably differ. Households with detectable allergen levels but low endotoxin levels may provide a predisposing environment for animal allergen sensitization.

The natural history of peanut allergy in young children and its association with serum peanut-specific IgE

OBJECTIVES

To observe the nature and frequency of adverse reactions caused by accidental peanut exposure in young children with clinical peanut hypersensitivity and to determine the value of serum peanut-specific IgE levels during follow-up.

STUDY DESIGN

Eighty-three children with clinical peanut hypersensitivity diagnosed before their fourth birthdays were contacted yearly to track adverse peanut reactions. Serum peanut-specific IgE levels were determined in 51 of 83 subjects.

RESULTS

Fifty-eight percent (31/53) of subjects followed up for 5 years experienced adverse reactions from accidental peanut exposure. Regardless of the nature of their initial reaction, the majority with subsequent reactions (52%, 31/60) experienced potentially life-threatening symptoms. The group with isolated skin symptoms (11/51, 22%) had lower serum peanut-specific IgE levels than the group with respiratory and/or gastrointestinal symptoms (40/51, 78%) (median: 1.25 kU(A)/L vs 11. 65 kU(A)/L, P =.004, Wilcoxon rank sums test). Despite this, there was no threshold level below which only skin symptoms appeared to occur. Four selected subjects had negative double-blind placebo-controlled food challenge responses to peanuts during follow-up.

CONCLUSIONS

The majority of children with clinical peanut hypersensitivity followed up for 5 years will have adverse reactions from accidental peanut exposure. Symptoms experienced during subsequent adverse peanut reactions may not be consistent with symptoms reported during initial reactions. Therefore proper education regarding peanut avoidance and treatment of adverse reactions is necessary in all cases of clinical peanut hypersensitivity. Young children who are allergic to peanuts can lose clinical hypersensitivity.

Allergy and asthma: classic TH2 diseases (?)

More than a decade of cytokine immunology has revealed a central role for pro-allergic TH2-like cytokines in the immune pathogenesis of allergic diseases and asthma. Of these, IL-4, IL-5, and IL-13 are produced mostly by T lymphocytes; more recently, numerous other immune cell types have been found capable of producing these cytokines as well, although their role in mediating atopic disease pathogenesis is less well understood. In contrast, the counterregulatory cytokine IFN-gamma can inhibit both the production and activities of the pro-allergic cytokines; therefore, central to the atopic diseases is a paradigm of cytokine imbalance, with overproduction of the TH2-like cytokines, and a relative deficiency of IFN-gamma production. Intriguing recent evidence is that all humans are TH2-like cytokine "skewed" at birth, due to maternal-fetal immune biology imperatives. However, further investigations suggest that IFN-gamma is likely to be pro-inflammatory in many if not most aspects of chronic allergic inflammation. Therefore, our understanding of these "classic TH2" diseases evolves, with important insights that will serve to optimize therapeutic strategies and investigations in the new millennium.

Relation between house-dust endotoxin exposure, type 1 T-cell development, and allergen sensitisation in infants at high risk of asthma

BACKGROUND

Bacterial endotoxin is known to induce interferon gamma and interleukin 12 production, and therefore has the potential to decrease allergen sensitisation. To find out the role of early chronic endotoxin exposure in the development of allergen sensitisation and asthma, we compared concentrations of endotoxin in house dust with allergen sensitisation in infants at high risk for developing asthma.

METHODS

61 infants 9-24 months old with at least three physician-documented episodes of wheezing were studied. Concentrations of house-dust endotoxin and allergens were measured in the infants' homes. Allergen sensitisation was measured by skin-prick testing with a panel of common inhalant and food allergens. In a subset of these infants, proportions of T lymphocytes producing interferon gamma, and interleukins 4, 5, and 13 were calculated by cell-surface and intracellular cytokine staining, with flow cytometry.

FINDINGS

House-dust endotoxin concentrations ranged from 104 to 10,000 endotoxin units (EU) per mL (geometric mean 912 EU/mL). Concentrations did not vary significantly over a 6-month interval. Ten infants (16%) were sensitised to at least one allergen. The homes of allergen-sensitised infants contained significantly lower concentrations of house-dust endotoxin than those of non-sensitised infants (mean 468 vs 1035 EU/mL, respectively; p=0.01). Increased house-dust endotoxin concentrations correlated with increased proportions of interferon-gamma-producing CD4 T cells (p=0.01). Such concentrations did not correlate with proportions of cells that produced interleukins 4, 5, or 13.

INTERPRETATION

This study may provide the first direct in-vivo evidence that indoor endotoxin exposure early in life may protect against allergen sensitisation by enhancing type 1 immunity.

Sequence heterogeneity in Ig kappa transcripts from single B lymphocytes

Individually amplified kappa cDNA molecules from single B lymphocytes revealed sequence heterogeneity and aberrantly spliced products. The nature and frequency of the base changes and their absence from similarly amplified beta2 microglobulin transcripts indicate that they were not derived by Taq polymerase misincorporations or by a general infidelity in RNA polymerase. The trinucleotide sequences in which the base changes occurred are disfavored targets of the somatic hypermutation mechanism that modifies antibody variable (V) region genes during immunity. Taken together with the observation that the transcript alterations were absent from the kappa Ig gene, this suggests that somatic mutations were acquired by the kappa gene and rapidly repaired following limited transcription. Preferential repair of mutations located in specific trinucleotide contexts could be the basis for some of the microsequence-specific bias in mutation frequencies observed in antibody V region genes.

Alterations in glycosyltransferases during myeloid and monocytoid differentiation of HL-60 cells

HL-60, a human promyelocytic leukemia cell line, can be differentiated to myeloid lineage by all- trans retinoic acid (ATRA), dimethylsulfoxide (DMSO) and n -butyric acid (n -BA), or to monocytoid(monocytic/macrophagic) lineage by phorbol-12-myristate-13-acetate (PMA) and ganglioside GM(3). The activity alterations of N -acetylglucosaminyltransferase III and V (GnT-III, GnT-V) as well as alpha-1,6-fucosyl-tranferase (alpha1,6 Fuc T) were studied during the differentiation of HL-60 cells by the above-mentioned five inducers using the fluorescence (PA)-labeled glycan-HPLC method for GnT assays and biotin-labeled glycan-LCA affinity chromatography combined with the HRP-avidin colorimetric method for alpha1,6 Fuc T assay. It was observed that after 3 days, all three enzymes decreased in HL-60 cells induced by 1 micromol/l ATRA and 0.6 mmol/l n-BA, while GnT-III and alpha1,6 Fuc T increased, but GnT-V still decreased after induction by 1% DMSO. GnT-V and alpha1,6 Fuc T declined, while GnT-III was elevated after induction by 0.1 micromol/l PMA for 3 days. In contrast, GnT-III increased after the treatment with 50 micromol/l GM(3)for 3 or 6 days, but GnT-V was not appreciably changed and alpha1,6 FucT was elevated after 6 days of GM(3)treatment. It may be concluded that the decrease of GnT-V is the common change in myeloid differentiation and the increase of GnT-III is the general alteration in monocytoid differentiation. The changes in the activities of glycosyltransferases were consistent with the structural changes in surface N -glycans previously found in our laboratory, i.e. that the antennary number of N -glycans decreased during myeloid differentiation by ATRA, and the amount of bisecting GlcNAc in N -glycans increased during monocytoid differentiation by PMA.

Molecular pathogenesis of root dentin caries

Human dentin has a higher content of organic matrix and more non-ideal hydroxyapatite than human enamel. Ultrastructural studies indicate that root caries involves both mineral dissolution and breakdown of the organic matrix. Factors involved in the root caries process seem more complicated than those in enamel caries. Moreover, the distinct roles of acids and enzymes and the sequence of events in the root caries process are not well-understood. Although Streptococcus mutans and Actinomyces viscosus are considered to be major pathogenic micro-organisms of root caries, their roles in degradation of the organic matrix components of root dentin need clarification. The purpose of this paper is to review the basic composition of root dentin and the roles of acids and both endogenous and bacterial enzymes in the root caries process.

Clinical practice guidelines for the management of chronic sinusitis in children

Chronic sinusitis in children is a common and vexing disease for clinicians and the public. There are insufficient data in the literature to develop an evidence-based clinical guideline. Experience in managing pediatric chronic sinusitis has been gained through a multidisciplinary clinic at our institution during the past 3 years. A panel of experts was formed, and with the guidance of a guideline methodologist, the development of a rigorous outcome-based guideline was undertaken. Symptom-improvement and recurrence estimates for a variety of medical and surgical treatments were assessed. Wide probability estimates were made by the panelists in most cases. Although we refrained from making specific recommendations, we developed a ranked series of practical treatment options taking into account side effects and costs.

Modification of pentasaccharide core of surface N-glycans during differentiation of HL-60 cells

All-trans retinoic acid (ATRA) or phorbol-12-myristate-13-acetate (PMA) are two representative inducers which induce the differentiation of HL-60 cells to myelocytes and monocytes respectively. Structural modifications of the pentasaccharide core portion of N-glycans on cell surface glycoproteins during differentiation of HL-60 cells induced by these two agents and the enzymatic mechanism of the structural modifications were studied. Both ATRA and PMA enhanced the incorporation of [3H]-labeled mannose into N-glycans of glycoproteins from cell surface. By using E-PHA and WGA lectin affinity chromatography to analyze [3H]-N-glycans prepared from the surface of control, ATRA- and PMA-treated cells, it was found that the content of bisecting GlcNAc (bis-GlcNAc) attached to the core of N-glycans decreased in ATRA-treated cells, but increased in PMA-treated cells. Since GlcNAc T-III is the enzyme responsible for the synthesis of bis-GlcNAc, the change of bis-GlcNAc was consistent with the alteration of GlcNAc T-III activities in ATRA- and PMA-treated cells. Core alpha-1,6 fucose of surface N-glycans decreased during differentiation which was determined by AAL affinity chromatography. This was also compatible with the reduced activity of alpha-1,6 Fuc T. the enzyme catalyzing the synthesis of core Fuc, in ATRA- and PMA-treated cells. The increase of GlcNAc T-III activity and bis-GlcNAc content in N-glycans may be related to cell adhesion observed in monocytic differentiation.

Influence of whey and purified whey proteins on neutrophil functions in sheep

The effects of ruminant whey and its purified fractions on neutrophil chemotaxis and superoxide production in sheep were studied. Both colostral whey and milk whey were found to inhibit chemotaxis regardless of whether they were autologous or homologous, but the inhibitory effects were abolished by washing neutrophils with culture medium before their use in the chemotaxis assay. Colostral whey and milk whey also inhibited the chemotactic activity of zymosan-activated serum. Whey fractions of various degrees of purity such as lactoferrin, lactoperoxidase, lactoferrin-lactoperoxidase, alpha-lactalbumin, bovine serum albumin and whey protein concentrate were then studied. While none of these proteins showed any effects on chemotaxis, lactoferrin-lactoperoxidase and whey protein concentrate were found to have an enhancing effect on superoxide production in a dose-dependent manner. Our results provide information on the modulatory role of ruminant milk proteins in inflammatory responses and warrant future investigation.

Modulation of immune responses by bovine beta-casein

The present reports the influence of bovine beta-casein on in vitro and in vivo immune responses. Bovine beta-casein showed an inhibitory effect on ovine neutrophil chemotaxis but had an enhancing effect on superoxide production by neutrophils. In response to mitogenic stimulation, the proliferative response of both T and B lymphocytes was significantly enhanced by beta-casein. While beta-casein had no significant effects on IFN gamma production by ovine blood lymphocytes, and TNF alpha production and MCH Class II antigen expression by ovine bronchoalveolar macrophages, it enhanced IL-1 beta production by the macrophages, beta-casein also had no influence on bovine NK cell activity against a virally-infected cell line. Interestingly, beta-casein was found to reduce the adjuvant effect of matrix immune stimulating complexes (ISCOM) on anti-ovalbumin antibody response in mice when given intramuscularly. Taken together, the results suggest that bovine beta-casein had selective modulating effects in vitro on both innate and adaptive immune responses in ruminants, whereas systemic administration of beta-casein, that might have a depressive effect on adjuvant activity, requires further study.

Tracing the development of single memory-lineage B cells in a highly defined immune response

To study the development of B lymphocyte memory, we identified and isolated splenic B cells expressing a highly defined antibody variable region that constitutes a reproducible and predominant component of the memory antibody response to p-azophenylarsonate (Ars). Isolation was achieved during the primary immune response by surface staining and flow cytometry using a specific anti-idiotypic antibody called E4, which recognizes this canonical V region, encoded by one set of V gene segments. The isolated E4+ cells displayed all of the phenotypic characteristics of germinal center centrocytes, including a low level of surface Ig, a lack of surface IgD, a high level of receptor for peanut agglutinin, and expression of mutated antibody V genes. E4+ B cells were first detected in the spleen 7-8 d after primary immunization, reached peak numbers from days 10-13, and waned by day 16. Surprisingly, at their peak, E4+ cells comprised only 40,000 of all splenocytes, and half of these failed to bind Ars. Using this number, we estimate the total number of Ars-specific memory-lineage cells in the spleen to be no more than 50,000 (0.1%) at any one time, and presumably far fewer that are committed to the memory pool. Chromosomal copies of rearranged V genes from single E4+ cells were amplified by nested PCR, and the amplified products were sequenced directly without cloning, using standardized conditions that disclose virtually no Taq polymerase errors. V gene sequence analyses of E4+ cells isolated from single mice confirmed their canonical nature and revealed that they were derived from few precursors. In the average mouse, the E4+ pool was derived from fewer than five canonical precursors. Somatic mutations were found within the V genes of almost all cell isolates. At day 13, a significant fraction of E4+ cells had mutations known to increase antibody affinity for Ars, suggesting they were products of at least one cycle of post-mutational antigen-driven selection. However, the lack of shared mutations by clonally related cells indicated that the selective expansion of mutant subclones typical of memory responses had not yet taken place. This was supported by the observation that half of the E4+ cells failed to bind Ars. Collectively, our results indicate that the memory compartment is a highly selected entity, even at relatively early stages of the primary immune response when somatic mutation and clonal selection are still in progress. If germinal centers are the source of memory B cells, our data suggest that B cell memory may be derived from only a small fraction of all germinal centers.

Amplification of genes, single transcripts and cDNA libraries from one cell and direct sequence analysis of amplified products derived from one molecule

We report a procedure to generate and amplify cDNA libraries and to amplify and sequence genes and single RNA transcript molecules from the same cell without cloning. An absence of cloning steps minimizes potential sources of contamination, which can be especially problematic when working at the single cell level. Potential contamination is further reduced by an absence of any purification step prior to PCR amplification. Amplifications are designed to minimize the production of aberrant molecules in favor of full-length products, which is especially advantageous when generating cDNA libraries. Genes are amplified from isolated single nuclei, which are segregated from cytoplasmic lysates by microcentrifugation. Specific cDNA, total cDNA or both are synthesized from aliquots of the cytoplasmic lysate, and single cDNA molecules are isolated from others of the same species by limiting dilution prior to PCR amplification. In this way, the frequency of amplified products provides for a direct calculation of cDNA copy number by a Poisson analysis. Incorporation errors by Taq DNA polymerase occur at a low frequency and can be eliminated by sequencing independently amplified cDNA molecules from the same cell. Single molecule amplifications provide sufficient material for numerous (approximately 150) direct DNA sequencing reactions. The limiting dilution approach also permits sequence information to be obtained from a single cDNA, when highly related transcripts derived from distinct genes are present in the same cell and simultaneously amplified with the same primers. In sum, this method provides for a maximum amount of nucleic acid information to be extracted from one cell. It has a wide range of applications to studies of the immune system where, to a first approximation, each lymphocyte has a unique receptor identity, where specific states of differentiation may be difficult to assess in a mixed cell population, and where cell immortalization procedures are not always possible nor practical.

Diaphragmatic flutter presenting as inspiratory stridor

Diaphragmatic flutter is a rarely reported disorder in which the diaphragm involuntarily contracts at a rapid rate. We report a unique case in which diaphragmatic flutter was associated with inspiratory stridor and was severely disabling. A new approach to the treatment of this condition, phrenic nerve crush, provided an optimal outcome, with resolution of symptoms and the return of normal diaphragmatic function. Pathophysiology and treatment of this condition are discussed.

Phylogenetic relationships among two species of golden monkey and three species of leaf monkey inferred from rDNA variation

Restriction maps of rDNA repeats of five species of Colobinae and three outgroup taxa, Hylobates leucogenys, Macaca mulatta, and Macaca irus, were constructed using 15 restriction endonucleases and cloned 18S and 28S rRNA gene probes. The site variation between Rhinopithecus roxellana and Rhinopithecus bieti is comparable to that between Presbytis françoisi and Preshytis phayrei, implying that R. bieti is a valid species rather than a subspecies of R. roxellana. Phylogenetic analysis on the 47 informative sites supports the case for Rhinopithecus being an independent genus and closely related to Presbytis. Furthermore, branch lengths of the tree seem to support the hypothesis that the leaf monkeys share some ancestral traits as well as some automorphic characters.

Multiple genotypes of mitochondrial DNA within a horse population from a small region in Yunnan Province of China

mtDNA genotypes of six domestic horses (three adult short horses whose heights are under 1 m and three common domestic horses) from a small region of 15 km2 in Malipo county of Yunnan province of China were investigated by the technique of restriction fragment length polymorphism (RFLP) with 16 restriction endonucleases which recognize 6-bp sequences. An average of 56 fragments for an individual was obtained. Unlike other domestic animals, this population of horses exhibits high mtDNA genetic diversity. Each of the six horses has a specific mtDNA genotype showing a pattern of multiple maternal origins, as suggested by fossil and literature records. We think the population of horses is an amazing seed-resource pool of horses and hence deserves to be paid more attention from the view of conservation genetics. However, it is also remarkable that we did not find any typical mtDNA genetic markers which would discriminate between short horses and common domestic horses.

Image scanning ellipsometry for measuring nonuniform film thickness profiles

A novel technique to measure the two-dimensional (2-D) thickness profile of a nonuniform, thin film, from several nanometers to several micrometers, in a steady state as well as in a transient state has been developed and tested. Image scanning ellipsometry (ISE) is a full-field imaging technique that one can use to study every point on the surface simultaneously with high spatial resolution and thickness sensitivity, i.e., it can measure and map the 2-D film thickness profile. The primary purpose of this paper is to present the basic concept of ISE and a demonstration of its use.

Sequencing heavy- and light-chain variable genes of single B-hybridoma cells by total enzymatic amplification

We have devised a protocol to obtain accurate and complete sequences of the immunoglobulin heavy- and light-chain variable-region (VH and VL) genes of single B-hybridoma cells that express defined V genes. The amplification achieved ranges from 2 x 10(13)- to 1 x 10(14)-fold. Only one potential Taq DNA polymerase error was observed in 7590 nucleotides of sequence, thus permitting the identification of naturally occurring somatic mutations. The two-step nature of the amplification protocol provides sufficient DNA for a minimum of 160 sets of sequencing reactions of both the VH and VL genes from one cell without cloning. The amplification of relatively long segments of DNA in the first step of the protocol permits second-step amplification and sequencing of regions that flank VH and VL codons. Fractionating cellular lysates prior to the first step of amplification permits the separate amplification of V genes on opposite sister chromatids and possibly on opposite strands of the same DNA duplex. Accurate sequencing of VH and VL genes of defined germ-line origin that are expressed by single B cells taken directly from the animal is thus made feasible by this approach.