[Determination of methyl isobutyl ketone in urine by headspace coupled with gas chromatography-mass spectrometry].

Objective: To establish a method for the determination of methyl isobutyl ketone (MIBK) in urine samples by headspace-gas chromatography-mass spectrometry. Methods: Automatic headspace sampling technique was adopted to optimize the headspace conditions (headspace bottle heating temperature and equilibration time) and gas chromatographic conditions. A total of 5 ml samples were taken and added with 3.0 g ammonium sulfate into a 20 ml headspace bottle. After heated at 60 ℃ for 30 mins, gas from the upper part of headspace bottle was injected into gas chromatography with an injection volume of 100 µl. The target was separated by HP-5MS UI (30 m×0.25 mm×0.25 µm) capillary column and then detected by mass spectrometry detector. The retention time and external standard method were used for qualitative and quantitative analysis of MIBK in samples, respectively. Results: The standard curve of MIBK showed significant linearity between 20.0-1 000.0 µg/L. The standard curve was y=62.9x-652.5, and the correlation coefficient r=0.9998. The detection limit of MIBK was 5.0 µg/L and the quantification limit of MIBK was 16.0 µg/L. The average recovery rate was 95.3%~100.2% at three spiked concentrations of low (50.0 µg/L) , medium (200.0 µg/L) and high (500.0 µg/L) . The intra-day and inter-day precisions were 1.7%~3.8% (n=6) and 1.2%~4.0% (n=6) respectively. This method was stable for the determination of MIBK, and the urine could be kept 14 d at -20 ℃ without significantly loss. Conclusion: This method is proved to be simple, practical and highly sensitive. It can satisfy the request for the determination of urine samples of workers exposed to MIBK.

[Meta-analysis on the contents of trace elements in workers with occupational exposure to lead].

Objective: To quantitatively evaluate the content differences of trace elements in workers with occupational exposure to lead. Methods: In January 2021, relevant literatures on the contents of trace elements in workers with occupational exposure to lead published from 1990 to 2020 were searched through CNKI, Wanfang, VIP, PubMed, web of science and Embase. Screened and extracted the literatures, and evaluated the quality of the included literatures with Newcastle Ottawa Scale. Meta analysis was performed with Review Manager 5.3 software, and standardized mean difference (SMD) and its 95% confidence interval were used as effect indicators. Results: A total of 20 literatures were included, and the quality scores were 5-7. The results of Meta-analysis showed that compared with the control group, the contents of blood zinc (SMD=-1.01, 95%CI: -1.53, -0.49) , hair zinc (SMD=-0.17, 95%CI: -0.33, -0.01) , hair copper (SMD=-0.50, 95%CI: -1.01, 0) , hair iron (SMD=-3.91, 95%CI: -5.80, -2.03) and hair manganese (SMD=-1.09, 95%CI: -2.02, -0.15) in occupational lead exposure group were significantly lower (P<0.05) . Compared with the control group, the content of cobalt in hair of occupational lead exposure group (SMD=1.41, 95%CI: 0.72, 2.10) was higher, and the difference was statistically significant (P<0.05) . There was no significant difference in the contents of blood chromium, blood copper, blood iron, blood manganese, blood selenium and hair nickel between the two groups (P>0.05) . Conclusion: Workers with occupational exposure to lead have abnormal trace elements.

miR-17-5p knockdown inhibits proliferation, autophagy and promotes apoptosis in thyroid cancer via targeting PTEN.

Thyroid cancer is one common endocrine malignancy with various pathological types. MicroRNAs (miRNAs) play essential roles in development, prognosis and treatment of thyroid cancer. However, the role of miR-17-5p in thyroid cancer progression and its mechanism remain poorly understood. The expressions of miR-17-5p and phosphatase and tensin homolog (PTEN) were measured in thyroid cancer tissues and cells by quantitative real-time polymerase chain reaction or western blot. Cell proliferation and apoptosis were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay and flow cytometry, respectively. The protein levels of biomarkers in autophagy or protein kinase B (AKT)/mechanistic target of rapamycin (mTOR) pathway were analyzed by western blot. The interaction between miR-17-5p and PTEN was probed by luciferase activity assay. We found that miR-17-5p expression was elevated and PTEN level was reduced in thyroid cancer tissues and cells compared with their corresponding controls. Knockdown of miR-17-5p or overexpression of PTEN suppressed cell proliferation and autophagy but promoted apoptosis in thyroid cancer cells. PTEN was indicated as a target of miR-17-5p and its interference reversed abrogation of miR-17-5p-mediated inhibition of proliferation and autophagy and increase of apoptosis. Moreover, downregulation of miR-17-5p impeded the activation of AKT/mTOR pathway in thyroid cancer cells, which was attenuated by silencing PTEN. Our data supported that knockdown of miR-17-5p upregulated PTEN expression, therefore leading to suppression of the malignancy of thyroid cancer and inactivation of AKT/mTOR pathway, providing a novel avenue for treatment of thyroid cancer.

[Clinical characteristics and risk factors analysis of intracranial and extracranial arterial dissection].

Objective: To compare and analyze the clinical features and potential risk factors of intracranial and extracranial arterial dissection. Methods: A total of 241 consecutive patients with cervicocerebral artery dissection (CAD) in the First Affiliated Hospital of Zhengzhou University from 2010 to 2019 were observed. The 241 CAD patients were divided into extracranial artery dissection group (EAD) (n=81) and intracranial artery dissection group (IAD) (n=160), clinical characteristics and risk factors were compared between the two groups. Results: Compared with EAD, the National Institute of Health Stroke Scale (NIHSS) score was higher in patients with ischemic stroke in the IAD group (P=0.015). Patients with IAD were more likely to present with headache (58.8% vs 37.0%, P<0.001), and dissection Aneurysms (76.3% vs 38.3%, P<0.001). Patients with EAD more likely to have a history of mild head and neck injuries (11.1% vs 4.4%, P=0.047) and often involved the anterior circulation (77.8% vs 20.0%, P<0.001). Multivariate Logistic regression analysis showed differences in a history of minor head and neck trauma (OR=3.53, 95%CI 1.04-11.97, P=0.042), anterior circulation involvement (OR=0.09, 95%CI 0.05-0.19, P<0.001), dissection aneurysms (OR=4.98, 95%CI 2.80-8.84, P<0.001), headache (OR=2.42, 95%CI 1.39-4.20, P=0.002) remained significant, and the NHISS score lost its significance. Conclusions: EAD often involves the anterior circulation and a history of mild injury to the head and neck. IAD is more prone to exhibit headache symptoms, and it is more likely to form a dissection aneurysm, and the symptoms of ischemic stroke are more severe.

[Determination of the butanone in urine by gas chromatography with precolumn derivation].

Objective: To establish a method for determination of the butanone in urine by gas chromatography (GC) with pre-column derivation. Methods: For detecting of butanone in urine, potassium iodide and potassium dichromate were added into urine under acidic condition, sample derivatization was undertaken in 50 ℃ water bath for 60 min and the iodine butanone was extracted with n-hexane. After the sodium thiosulfate solution was used to remove excess iodine, urine samples were centrifuged at 10000 r/min for 5 min, then the supernatant was analyzed using temperature rising programming with the Agilent Hp-5 column (30 m×0.32 mm, 0.25 µm) and electron capture detector (ECD) as the detector. The detector temperature was 300 ℃, the inlet temperature was 200 ℃, and the carrier gas was nitrogen. Results: For detecting of butanone in urine, potassium iodide and potassium dichromate were added for derivatization under the acidic condition. After extraction and centrifugation, the supernatant directly put through column and detected by ECD. In present study, the sample pretreatment condition was optimized, the relative standard deviations of intra-day and inner-day, the spiked samples and its recovery were evaluated for analyzing the accuracy of the proposed method. Conclusion: This method has proved to be simple, efficient and highly sensitivity, it can be utilized for butanone detection in occupational population.

[Applications of the Fe(3)O(4) nanocomposite modified by Humic Acid in determination of S-phenylmercapturic acid in urine by dispersive solid-phase extraction and HPLC].

Objective: To establish a method for determination the S-phenylmercapturic acid in urine by dispersive solid-phase extraction using Humic Acid/Fe(3)O(4) magnetic nanocomposite as adsorbent. Methods: The 5 ml of urine samples were adjusted to pH 1.0 and extracted by Fe3O4@HA. Then the analytes were separated on EC-C(18) capillary column and detected by HPLC-VWD. The S-phenylmercapturic acid was characterized by the retention time and quantified by peak area and external standard method. Results: The standard curves of SPMA showed significant linearity between 0.04~1.00 mg/L (r=0.999 7) . The average recovery was 94.2%~102.4%. The intra-day and inter-day precisions (RSD) were 2.9~6.7% (n=6) and 3.1~7.5% (n=6) respectively. The detect limit of SPMA was 0.012 g/L (S/N=3) . Conclusion: This method is simple, rapid, sensitive and accurate. It is applicable for determination of SPMA in the urine of works who were exposed to benzene.

[Simultaneous determination of trichloroethylene and trichloroethanol in blood by liquid-liquid extraction-gas chromatography].

Objective: To establish a method for determing the trichloroethylene(TCE)and trichloroethanol(TCOH)in blood samples by liquid-liquid extraction-gas chromatography with electron capture detector. Methods: With this method,ether was used as extraction solvent and trichloromethane was used as an internal standard. The whole blood sample was extracted with ether, and dehydrated by anhydrous sodium sulfate. Then the analytes were separated on HP-5 capillary column(30m×0.32mm×0.15µm)and detected byECD.The retention time was for qualitative analysis and the internal standard was for quantitation. Results: The standard curves of TCE and TCOH showed significant linearity between 95.5µg/L-7640.0µg/L(r=0.9997)and 19.0µg/L-1520.0µg/L(r=0.9992). The average recovery was 95.5%-103.6%.The intra-day and inter-day precisions(RSD)were 2.5%-6.8%(n=6)and 1.6%-4.3%(n=6) respectively. The detect limit of TCE and TCOH were 2.10 µg/L and 0.56µg/L(S/N=3)respectively.The blood can be kept 7 days at-20℃ refrigerator without significantly loss. Conclusion: This method is proved to be simple,practical and highly sensitive. It can satisfy the request for the determination of blood samples of humans exposed to TCE.

[Epidemiological characteristics of notifiable infectious diseases in Beijing, 2021].

Objective: To understand the epidemiological characteristics of notifiable infectious diseases reported in Beijing in 2021 under the influence of the novel coronavirus pneumonia epidemic prevention and control policy, and provide reference evidence for the prevention and control of notifiable infectious diseases. Methods: Descriptive epidemiological methods were used to analyze the morbidity of notifiable infectious diseases reported in Beijing in 2021, with software R 4.1.2 for data process and ArcGIS 10.8 for visualization. Results: The morbidity of notifiable infectious diseases in Beijing in 2021 was 290.51/100 000, a decrease of 43.29% compared with 2020 and a decrease of 71.45% compared with the average during 2017-2019. The top 5 reported diseases with high morbidity were other infectious diarrhea, influenza, hand foot and mouth disease, pulmonary tuberculosis and syphilis. From the perspective of transmission route, intestinal infectious diseases were the main diseases, accounting for 50.15% (31 898/63 601) of the total cases. From the perspective of pathogens, viral infectious diseases were the main diseases, accounting for 59.63% (25 259/42 356) of the total cases. The laboratory diagnosis rate of notifiable infectious diseases reported in Beijing increased from the average of 16.47% (36 289/220 371) during 2017-2019 to 35.36% (22 490/63 601) in 2021. The laboratory diagnosis rate of parasitic infectious diseases was 83.33%. The districts with high incidence of intestinal infectious diseases were Pinggu, Miyun and Fengtai; Natural foci and insect borne infectious diseases were mainly reported in Yanqing, Mentougou, Fangshan and Daxing. Conclusion: The morbidity of notifiable infectious diseases in Beijing in 2021 showed a decrease trend. The laboratory confirmation rate of reported notifiable infectious disease cases increased, and there were great differences in the laboratory confirmation rate among different diseases. It is very necessary to improve the laboratory confirmation rate of the cases. The diseases with different transmission routes showed different geographical distributions. It is necessary to conduct the targeted prevention and control of infectious diseases in different areas.

Development of a new peptide-bead coupling method for an all peptide-based Luminex multiplexing assay for detection of Plasmodium falciparum antibody responses.

Using a recombinant protein antigen for antibody testing shows a sum of antibody responses to multiple different immune epitopes existing in the protein antigen. In contrast, the antibody testing to an immunogenic peptide epitope reflects a singular antibody response to the individual peptide epitope. Therefore, using a panel of peptide epitopes provides an advantage for profiling multiple singular antibody responses with potential to estimate recent malaria exposure in human infections. However, transitioning from malaria immune epitope peptide-based ELISA to an all peptide bead-based multiplex Luminex assay presents some challenges including variation in the ability of different peptides to bind beads. The aim of this study was to develop a peptide coupling method while demonstrating the utility of these peptide epitopes from multiple stage antigens of Plasmodium falciparum for measuring antibodies. Successful coupling of peptide epitopes to beads followed three steps: 1) development of a peptide tag appended to the C-terminus of each peptide epitope consisting of beta-alanine-lysine (x 4)--cysteine, 2) bead modification with a high concentration of adipic acid dihydrazide, and 3) use of the peptide epitope as a blocker in place of the traditional choice, bovine serum albumin (BSA). This new method was used to couple 12 peptide epitopes from multiple stage specific antigens of P. falciparum, 1 Anopheles mosquito salivary gland peptide, and 1 Epstein-Barr virus peptide as an assay control. The new method was applied to testing of IgG in pooled samples from 30 individuals with previously repeated malaria exposure in western Kenya and IgM and IgG in samples from 37 U.S. travelers with recent exposure to malaria. The new peptide-bead coupling method and subsequent multiplex Luminex assay showed reliable detection of IgG to all 14 peptides in Kenyan samples. Among 37 samples from U.S. travelers recently diagnosed with malaria, IgM and IgG to the peptide epitopes were detected with high sensitivity and variation. Overall, the U.S. travelers had a much lower positivity rates of IgM than IgG to different peptide epitopes, ranging from a high of 62.2% positive for one epitope to a low of only 5.4% positive for another epitope. In contrast, the travelers had IgG positive rates from 97.3% to 91.9% to various peptide epitopes. Based on the different distribution in IgM and IgG positivity to overall number of peptide epitopes and to the number of pre-erythrocytic, erythrocytic, gametocytic, and salivary stage epitopes at the individual level, four distinct patterns of IgM and IgG responses among the 37 samples from US travelers were observed. Independent peptide-bead coupling and antibody level readout between two different instruments also showed comparable results. Overall, this new coupling method resolves the peptide-bead coupling challenge, is reproducible, and can be applied to any other immunogenic peptide epitopes. The resulting all peptide bead-based multiplex Luminex assay can be expanded to include other peptide epitopes of P. falciparum, different malaria species, or other diseases for surveillance, either in US travelers or endemic areas.

Associations of oral and intestinal florae and serum inflammatory factors with pathogenesis of oral cancer.

OBJECTIVE: The aim of this study was to explore the effects of oral and intestinal florae and serum inflammatory factors on the pathogenesis of oral cancer. PATIENTS AND METHODS: Oral cancer patients and healthy subjects in our hospital were enrolled in disease group (n=50) and control group (n=50), respectively. Oral flora of subjects was collected using the sterile cotton swab. Microbial deoxyribonucleic acid (DNA) was extracted for Polymerase Chain Reaction (PCR) amplification and sequencing. Subsequently, the feces were also collected from patients, and sent to the company for analysis of microbial composition via sequencing. In addition, the levels of serum inflammatory factors tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), IL-6, and IL-1ß in disease group and control group were detected via enzyme-linked immunosorbent assay (ELISA). RESULTS: The number of patients with a history of drinking (p=0.040) and betel nut chewing (p=0.000) in the disease group was larger than that in the control group, and the difference was statistically significant. In terms of oral flora distribution, the ratios of dominant bacteria Staphylococcus and Rothia were 64% and 50% in disease group, which were significantly higher than those in the control group (24% and 18%) (p=0.023 and 0.034). In terms of intestinal flora distribution, the abundance of intestinal florae (Flavobacteriaceae, Sphingobacteriales, Rikenella, Pseudomonadales, Tetragenococcus and Acinetobacter) in the disease group was remarkably higher than that in the control group (p<0.05). However, the abundance of Vagococcus and Pediococcus in control group was significantly higher than that in the disease group (p<0.05). Among intestinal flora, Firmicutes exhibited a highly positive correlation with Bacteroides (r=0.341, p=0.023), and a highly negative correlation with Ruminococcus (r=-0.832, p=0.000). Bacteroides had a highly negative correlation with Lactobacillus (r=-0.763, p=0.000) and Enterococcus (r=-0.461, p=0.000). In disease group, the levels of TNF-α (p=0.021), IL-8 (p=0.000), and IL-1ß (p=0.000) were evidently higher than those in the control group [(23.51±2.14) ng/L vs. (12.34±2.45) ng/L, (89.75±4.29) ng/L vs. (43.23±3.25) ng/L, (42.25±3.25) ng/L vs. (15.32±1.47) ng/L]. However, there was no statistically significant difference in IL-6 level between the two groups (p=0.217). CONCLUSIONS: Oral and intestinal florae and serum inflammatory factors are associated with the pathogenesis of oral cancer.

Sequential treatment by polidocanol and radiofrequency ablation of large benign partially cystic thyroid nodules with solid components: Efficacy and safety.

PURPOSE: The purpose of this study was to retrospectively evaluate the efficacy and safety of a sequential treatment including percutaneous polidocanol sclerotherapy and radiofrequency ablation (RFA) in terms of volume reduction and complication rate in large, benign, partially cystic thyroid nodules with solid components. MATERIALS AND METHOD: From April 2017 to April 2019, 46 patients with 47 large benign partially cystic thyroid nodules underwent sequential treatment. There were 14 men and 32 women with a mean age of 49.9±11.5 (SD) years (range: 18-75 years). The volume of initial nodules was 12.7±12.3 (SD) mL (range: 2.16-75.62mL). Volume reduction after percutaneous polidocanol sclerotherapy and further RFA was evaluated respectively. Patients had clinical and ultrasound evaluations at a follow-up time of 12.1±5.3 (SD) months (range: 1.5-23.9 months). Technical success and complications were accessed retrospectively. RESULTS: After unsatisfying results with polidocanol sclerotherapy alone the 46 patients with 47 large benign partially cystic thyroid nodules had further RFA. Mean volume reduction of 47 nodules was 90.5±11.3 (SD) % (range: 43.9-99.3%) one month after RFA, 94.9±6.2 (SD) % (range: 66.9-99.5%) three months after RFA, and 95.8±5.5 (SD) % (range: 71.0-99.8%) six months after RFA. No recurrence or nodule enlargement after RFA was observed at the last follow-up. The complication rate of RFA was 12.5% (8/46 patients), with minor complications only. CONCLUSIONS: The sequential treatment regimen, including percutaneous polidocanol sclerotherapy and RFA, is an appropriate and safe treatment strategy for large benign partially cystic thyroid nodules with solid components.

[Post-discharge growth of extremely premature infants within corrected age of 24 months].

Objective: To demonstrate the post-discharge catch-up growth of extremely premature infants (EPI) within 24 months of corrected age. Methods: This study retrospectively collected the anthropomorphic measurements of 311 EPI who visited Shenzhen Maternity and Child Healthcare Hospital from August 2013 to April 2020. These infants were stratified according to gestational age at birth (GA): 23-24+6weeks, 25-26+6weeks, 27-27+6weeks; and birth weight:<750 g, 750-999 g, ≥1 000 g. The anthropomorphic measurements, including weight, length, and head circumference for age, were recorded timely from discharge to 24 months of corrected age. And the growth curve stratified by GA and birth weight were fitted in both chronological age and corrected age, which were then compared with the World Health Organization Child Growth Standards for term infant (2006 version), to investigate the catch-up growth pattern of EPI. And appropriate catch-up was defined as the measurements reached the 25th percentile of WHO growth curve. Results: In these 311 EPI, 184 were males and 127 females, with gestational age of 23-27+6 weeks and birth weight of 480-1 430 g. Regardless of the GA and birth weight, the growth curves fitted in corrected age failed to overlap with that in chronological age by 24 months of corrected age. The growth velocity of weight, length and head circumference in both corrected and chronological age were all positively correlated with GA and birth weight: the 27-27+6weeks group showed a preferable growth pattern than the 25-26+6weeks group, and the curve of the 23-24+6weeks group was most unfavorable; and the same pattern was observed between the subgroups of different birth weight. Furthermore, the GA had more significant impact on the catch-up growth pattern than birth weight did. When assessed with corrected age curve, the weight and length of both male and female EPIs achieved appropriate catch-up by 24 months, as well as the head circumference of girls; whereas, boys' head circumference reached appropriate catch-up at the corrected age of 9 months, but fell behind the 25th percentile after that. However, when assessed with chronological age curve, both boys and girls failed to achieve appropriate catch-up in weight, length and head circumference by age 24 months. And no matter in corrected or chronological age, all physical measurements of girls were lower than those of boys. Conclusions: The rapid catch-up growth of EPI happens within 6 months of corrected age. The lower the birth weight and gestational age, the lower the physical measurements at each corresponding month of age, and the longer it takes to achieve appropriate catch-up. Gestational age has a greater impact on the longitudinal catch-up growth than birth weight does. And girls generally grow slower than boys in either correct or actual age. Before 24 months of corrected age, the growth should be assessed with corrected age rather than chronological age.

Daily trimethoprim-sulfamethoxazole prophylaxis rapidly induces corresponding resistance among intestinal Escherichia coli of HIV-infected adults in Kenya.

BACKGROUND: Trimethoprim-sulfamethoxazole (TMP-SMZ) has been recommended by World Health Organization (WHO) as daily prophylaxis for Africans with AIDS to prevent opportunistic infections. Daily TMP-SMZ may reduce its susceptibility to commensal intestinal Escherichia coli (E coli), increasing the burden of TMP-SMZ-resistant pathogens. METHODS: Participants received either daily TMP-SMZ (CD4 <350 cells/mm(3)) or daily multivitamins (MVIs; CD4 > or =350 cells/mm(3)) for 6 months. Stool was collected at baseline, 2 weeks, 2 months, and 6 months. A random E coli was tested for susceptibility. RESULTS: Baseline prevalence of TMP-SMZ resistance ranged from 71% to 81% and was not different across CD4 strata. At 2 weeks, prevalence of TMP-SMZ-resistant E coli increased significantly from 78% to 98% (P < .001) among persons taking daily TMP-SMZ and did not change among persons taking MVIs. CONCLUSIONS: Daily prophylaxis with TMP-SMZ induced in vivo resistance to the drug after 2 weeks. Empiric therapy for diarrhea with agents other than TMP-SMZ should be considered for HIV-infected persons receiving daily TMP-SMZ prophylaxis.

Predicted and observed alleles of Plasmodium falciparum merozoite surface protein-1 (MSP-1), a potential malaria vaccine antigen.

The 19-kDa antigenic domain of Plasmodium falciparum merozoite surface protein (MSP)-1 is a potential malaria vaccine candidate. Based on the amino acid substitution, four known alleles, E-TSR (PNG-MAD20 type), E-KNG (Uganda-PA type), Q-KNG (Wellcome type), and Q-TSR (Indo type) of this domain have been identified. Using single or double crossover recombinational events, we predicted the existence of additional alleles of this antigen. The presence of the predicted alleles was determined in parasite isolates from western Kenya, by undertaking a cross-sectional and a longitudinal study. Of the ten predicted alleles, we have revealed the presence of three new alleles: E-KSG-L (Kenya-1 type); E-KSR-L (Kenya-2 type); and E-KNG-F (Kenya-3 type). The results of this study suggest that it may be possible to predict the complexity of the genetic makeup of natural parasite populations.

Comparative flow cytometric analysis of term placental intervillous and peripheral blood from immediate postpartum women in Western kenya.

Understanding maternal immune responses in the placenta is critical for management of pregnancy failures and haematogenous infections during pregnancy. However, it is unknown whether maternal placental intervillous blood (IVB) mononuclear cell populations are distinct from those found in maternal peripheral blood (PB). In this study, cell populations in the IVB and PB from immediate postpartum women were compared by flow cytometry. While levels of B and CD4+ and CD8+ T lymphocytes were similar, IVB contained significantly higher levels of monocytes (10.9+/-5.9 versus 5.5+/-2.5 per cent, respectively) and natural killer cells (14.3+/-9.6 versus 5.9+/-3.2 per cent, respectively) than the PB. Expression of the early activation marker CD69 was increased on T cells in the IVB, whereas levels of HLA-DR, a late activation marker, were similar between IVB and PB. These results suggest that maternal cells that circulate through the intervillous compartment may be subject to local influences that affect their distribution, phenotype and function. Further comparative study of these blood compartments will be necessary to elucidate the mechanisms by which the local placental milieu influences the IVB.

Diversity in the immunodominant determinants of the circumsporozoite protein of Plasmodium falciparum parasites from malaria-endemic regions of Papua New Guinea and Brazil.

To determine the nature and extent of variation in the T cell sites of the Plasmodium falciparum circumsporozoite (CS) protein, a candidate antigen in the development of a malaria vaccine, we cloned and sequenced 69 recombinant clones of the CS protein gene representing 18 and 17 P. falciparum isolates from infected individuals from Madang, Papua New Guinea (PNG), a holoendemic malaria region, and Paragaminos and Jacunda, Brazil, relatively low endemic regions, respectively. As previously known, the amino acid sequence polymorphism was restricted to the three immunodominant regions of the protein, Th1R-N1, Th2R, and Th3R. While some of the observed nonsilent mutations in the T cell determinants of the CS protein were similar to those previously identified, we have found new amino acid changes in each of the polymorphic sequences in parasites from PNG and Brazil. A comparison of the CS epitope sequences of parasites from PNG and Brazil with the previously known CS epitope sequences of parasites from Brazil and The Gambia showed the following: 1) polymorphism was found in the Th1R-N1, Th2R, and Th3R region; however, while amino acid substitutions in the Th1R-N1 and Th2R region tended to be conservative, the substitutions found in the Th3R region were not, suggesting that the Th3R epitope may be rapidly evolving to allow parasites to escape host antiparasite cytotoxic T cell-enforced immune responses, and 2) the CS proteins of P. falciparum from high malaria-transmission regions (PNG and The Gambia) appear more polymorphic than the CS proteins of parasites from relatively low malaria-endemic regions in Brazil, where P. falciparum infection has been recently established.

Differential effect and interaction of monocytes, hyperimmune sera, and immunoglobulin G on the growth of asexual stage Plasmodium falciparum parasites.

Using a flow cytometry-based parasite growth inhibition assay (GIA) and an antibody-dependent cellular inhibition (ADCI) assay, we have assessed the differential effect and interaction of monocytes, immune sera, and purified immunoglobulins from Kenyan adults on the growth of Plasmodium falciparum parasites in vitro. We found that monocytes from 14 different normal, healthy, non-malaria-exposed donors had varying effects on parasite growth, i.e., inhibition or enhancement of parasitemia, suggesting heterogeneity in anti-parasitic activities of monocytes from individual donors. Twenty-two serum samples collected from clinically immune adults from western Kenya inhibited growth of P. falciparum after 48 hr in culture. In contrast, all IgG preparations, except one, purified from the same serum samples enhanced parasite growth. In ADCI experiments, of the 22 purified IgG samples used, 11 showed ADCI activities with specific growth inhibition (SGI) of more than 10%, with the highest at 27.6%, and the remaining 11 IgG samples had an SGI of less than 10%. Our results also showed that the ratio of IgG1 to IgG3 antibodies, as determined by an indirect immunofluorescence assay, was higher in the high ADCI response group than in the low response group, suggesting that a higher concentration of IgG1 antibodies with a higher IgG1/IgG3 ratio might be associated with ADCI activities. The present study has resulted in the development of simple, reproducible flow cytometry-based GIA and ADCI assays, and also provides baseline information for further investigation of the role of ADCI activity in naturally acquired immune protection against malaria.

A prospective, controlled, double-blind, cross-over study of tripterygium wilfodii hook F in treatment of rheumatoid arthritis.

A polyglycosides of Tripterygium wilfodii hook F (TWH) preparation with a code name of T2 is used in the present double-blind, controlled, cross-over study on the treatment of 70 cases of rheumatoid arthritis (RA). An impressive curative effect of T2 is confirmed much more convincingly by the present study than that by the previously reported clinical open trials. The adverse reactions and the probable pharmacological mechanism of T2 are also discussed.

[Observation on interleukin-2 in mice infected with Plasmodium yoelii].

C57BL/6J, NIH and ICR mice were inoculated with nonlethal P. yoelii (BY 265 strain) and NIH mice which had recovered from primary infection were reinoculated with the same parasite. The parasitemia of the mice was observed and IL-2 production by spleen lymphocytes of the mice upon Con A or P. yoelii antigen stimulation was detected at different intervals throughout primary infection and reinfection. The IL-2 level was measured by the microassay based on incorporation of H-TdR into CTLL2. The main results were as follows: (1) There were marked differences in both the Con A-induced IL-2 production and the parasitemia between C57BL/6J, NIH and ICR mice. The Con A-induced IL-2 levels (means +/- SE of SI) in C57BL/6J, NIH and ICR mice before primary infection were 223.7 +/- 19.32, 122.12 +/- 28.91 and 7226 +/- 30.60 respectively. The maximum parasitemia (means SE of %) in C57BL/6J, NIH and ICR mice after primary infection were 2.7% +/- 0.29%, 14.50% +/- 2.75% and 31.30% +/- 1.80% separately. It suggests that the innate Con A-induced IL-2 levels in the three strains of mice might be one of the factors influencing their susceptibility to P. yoelii primary infection. (2) There was significant depression in the capacity of releasing IL-2 upon Con A stimulation 3, 10 and 15 days after NIH mice had been inoculated with P. yoelii; after that, it was followed by the gradual resumption of the Con A-induced IL-2 production. P. yoelii antigen-induced IL-2 was only detected by d34 after inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)