A novel MRI-based diagnostic model for predicting placenta accreta spectrum

Objective To develop and evaluate a diagnostic model based on MRI signs for predicting placenta accreta spectrum. Materials and Methods A total of 155 pregnant women were included in this study, randomly divided into 104 cases in the training set and 51 cases in the validation set. There were 93 Non-PAS cases, and 62 cases in the PAS group. The training set included 62 Non-PAS cases and 42 PAS cases. Clinical factors and MRI signs were collected for univariate analysis. Then, binary logistic regression analysis was used to develop independent diagnostic models with clinical relevant risk factors or MRI signs, as well as those combining clinical risk factors and MRI signs. The ROC curve analysis was used to evaluate the diagnostic performance of each diagnostic model. Finally, the validation was performed with the validation set. Results In the training set, four clinical factors (gestity, parity, uterine surgery history, placental position) and 11 MRI features (T2-dark bands, placental bulge, T2 hypointense interface loss, myometrial thinning, bladder wall interruption, focal exophytic mass, abnormal placental bed vascularization, placental heterogeneity, asymmetric placental thickening/shape, placental ischemic infarction, abnormal intraplacental vascularity) were considered as risk factors for PAS. The AUC of the clinical diagnostic model, MRI diagnostic model, and clinical + MRI model of PAS were 0.779, 0.854, and 0.874, respectively. In the validation set, the AUC of the clinical diagnostic model, MRI diagnostic model, and clinical + MRI model of PAS were 0.655, 0.728, and 0.735, respectively. Conclusion Diagnosis model based on MRI features in this study can well predict placenta accreta spectrum.

[Efficacy of cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy for pseudomyxoma peritonei]

Objective: To evaluate the efficacy and safety of cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) in the treatment of pseudomyxoma peritonei (PMP). Methods: In this descriptive case series study, we retrospective analyzed the records of PMP patients treated with CRS and HIPEC between January 2013 and June 2023 at Affiliated Cancer Hospital and Institute of Guangzhou Medical University. The inclusion criteria were as follows: (1) Aged 18 to 75 years and nonpregnant women. (2) Histologically confirmed diagnosis of pseudomyxoma peritonei. (3) Karnofsky Performance Scale (KPS)>70. (4) The functions of major organs such as the heart, liver, lungs, and kidneys can tolerate major surgery for long periods of time. (5) No evidence of extra-abdominal metastasis. Patients with extensive intra-abdominal adhesions or severe infectious diseases were excluded. The main outcomes were overall survival (OS) and postoperative major complications. The postoperative major complications were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (version 5.0). We used the peritoneal cancer index (PCI) score to quantitatively assess the peritoneal metastases and the completeness of cytoreduction (CCR) score at the end of surgery (CCR-0 and CCR-1 considered to be complete CRS). Results: A total of the 186 PMP patients with a median age of 56 (interquartile range extremes (IQRE), 48-64) years were included, 65 (34.9%) males and 121 (65.1%) females. The median peritoneal cancer index (PCI) score was 28 (20-34). Appendiceal origin accounted for 91.4%. Histological types were low grade in 99 patients (53.2%), high grade in 57 patients (30.6%), and 55 patients (29.6%) received complete cytoreduction (CCR-0/1). The median operative duration was 300 (211-430) minutes for all patients. Treatment-related 30-day mortality was 2.7%; 90-day mortality 4.3%; reoperation 1.6%; and severe morbidity 43.0%. Within the entire series, anemia(27.4%), electrolyte disturbance(11.6%), and hypoalbuminemia(7.5%) were the most frequent major complications (grade 3-4). The incidences of gastrointestinal anastomotic leakage, abdominal bleeding, and abdominal infection were 2.2%, 2.2%, and 4.3%, respectively. After a median follow-up of 38.1 (95%CI:31.2-45.1) months, the 5-year OS was 50.3% (95%CI: 40.7%-59.9%) with a median survival time of 66.1 (95%CI: 43.1-89.1) months. The survival analysis showed that patients with pathological low grade, low PCI, and low CCR score had better survival with statistically significant differences (all P<0.05). Further stratified into complete and incomplete CRS subgroups, the 5-year OS of the CCR-0 and CCR-1 subgroups was 88.9% (95%CI: 68.3%-100.0%) and 77.6% (95%CI: 62.7%-92.5%), respectively; and 42.0% (95%CI: 29.5%-54.5%) in the CCR-2/3 subgroup. Conclusions: CRS and HIPEC may result in a long-term survival benefit for PMP patients with acceptable perioperative morbidity and mortality. This strategy, when complete CRS is possible, could significantly prolong survival for strictly selected patients at experienced centers.

Pathogenic analysis of suspected COVID-19 patients in a SARS-CoV-2 non-epidemic area of China

OBJECTIVE

The aim of this study is to find the distributions of pathogens in 164 suspected COVID-19 patients from the outpatient clinic of Shenjing Hospital of China Medical University from 24th January, 2020, to 29th February of 2020.

PATIENTS AND METHODS

164 COVID-19 suspected patients were from the Shengjing Hospital of China Medical University. Oropharyngeal swab specimens were acquired by respiratory doctors under standardized conditions. Specific nucleic acids of SARS-CoV-2, influenza A and B, respiratory syncytial virus A and B, adenovirus, parainfluenza virus, along with pneumonic mycoplasma were detected by real-time fluorescence PCR. Symptomatic, epidemiologic, laboratory and radiological data of the patients were obtained from the electronic medical record system of our hospital.

RESULTS

Among the 164 patients, 3 were positive for SARS-CoV-2, 15 were positive for other respiratory viruses and 16 were positive for pneumonic mycoplasma. Of the positive patients above, 1 patient was co-infected with SARS-CoV-2 and adenovirus, and 1 was co-infected with influenza B and pneumonic mycoplasma. The 3 SARS-CoV-2 infected patients were clinically diagnosed as COVID-19 because they meet the diagnostic criteria listed in "Chinese Clinical Guidance for COVID-19 Pneumonia diagnosis and treatment", including epidemic history, symptom and pathogenic detection, as well as abnormalities of the laboratory and radiological data. However, the clinical characteristics of COVID-19 patients were non-specific compared to those of the patients infected with other respiratory viruses.

CONCLUSIONS

The endemic common respiratory pathogens are more prevalent than SARS-CoV-2 in the SARS-CoV-2 non-epidemic areas of this research. Detection of the pathogen is the unique means for definite COVID-19 diagnosis.

Prevalence of Cognitive Frailty Phenotypes and Associated Factors in a Community-Dwelling Elderly Population

OBJECTIVES

Cognitive frailty was notable target for the prevention of adverse health outcomes in future. The goal of this study was to use a population-based survey to investigate cognitive frailty phenotypes and potentially sociodemographic factors in elderly Chinese individuals.

DESIGN

Cross-sectional study.

SETTING

General community.

PARTICIPANTS

A total of 5328 elderly adults (aged 60 years or older, mean age 71.36 years) enrolled in the Shanghai study of health promotion for elderly individuals with frailty.

MEASUREMENTS

The 5-item FRAIL scale and the 3-item Rapid Cognitive Screen tools were used to assess physical frailty and cognitive impairment, including dementia or mild cognitive impairment (MCI). Physical frailty was diagnosed by limitations in 3 or more of the FRAIL scale domains and pre-physical frailty by 1-2 limitations. Subjective cognitive decline (SCD) and pre-MCI SCD, was diagnosed with two self-report measures based on memory and other cognitive domains in elderly adults.

RESULTS

Of the participating individuals, 97.17% (n= 5177, female 53.4%) were eligible. Notably, 9.67%, 41.61% and 35.20% of participants were MCI, SCD and pre-MCI SCD; 35.86% and 4.41% exhibited physical pre-frailty and frailty; and 19.86% and 6.30% exhibited reversible and potential reversible cognitive frailty. Logistic regression analyses indicated that physical frailty phenotypes were significantly associated with MCI with SCD, and pre-MCI with SCD. Older single females with a high education level were more likely to exhibit the reversible cognitive frailty; and younger elderly individuals with a middle education level were at lower risk for potentially reversible cognitive frailty.

CONCLUSIONS

The prevalence of pre-physical and reversible cognitive frailty was high in elderly individuals and age was the most significant risk factor for all types of frailty phenotypes. To promote the rapid screening protocol of cognitive frailty in community-dwelling elderly is important to find high-risk population, implement effective intervention, and decrease adverse prognosis.

Associations of Preoperative Irisin Levels of Paired Cerebrospinal Fluid and Plasma with Physical Dysfunction and Muscle Wasting Severity in Residents of Surgery Wards

BACKGROUND

Myokine Irisin has been proposed to regulate metabolic homeostasis, which is related to chronic diseases or physical activity. However, whether irisin levels in paired cerebrospinal fruid (CSF), plasma and their ratio of inpatients, could use as biomarkers, and be independently related to the varying physical dysfunction, muscle wasting severity and chronic diseases with varying severe degrees, remain largely elusive.

METHODS

We conducted an observational study to assess the independent associations between irisin levels in paired cerebrospinal fruid (CSF), plasma and their ratio, and the independence in activities of daily life (ADLs), muscle wasting severity and chronic diseases with varying severe degrees among elderly Chinese in-patient subjects.

RESULTS

Among 217 inpatients in surgery wards with a mean age of 68.07 years (±15.94years), 31.3% of women and 68.7% of men were included in the study. Bivariate correlation analysis showed that Log transformed CSF and plasma irisin levels and their ratio were potential associated with age, fat%, muscle wasting time, ADLs, number of multimorbidity, the severity of bone mass loss and anemia. Regression models analysis indicated that CSF and plasma irisin levels and their ratio in inpatient individuals were independently associated with the independence in ADLs. Plasma irisin levels were independently related to the change of muscle wasting use.

CONCLUSIONS

Collectively, the evaluation of paired plasma and CSF irisin levels, and their ratio in in-patient individuals is intriguing candidates for the susceptibility of the independence in ADLs. Plasma irisin levels were positively associated with indepedence in ADLs, negatively related to muscle wasting severity, and could use as biomarkers for muscle wasting severity.

Dosimetry study of 18F-FMISO + PET/CT hypoxia imaging guidance on intensity-modulated radiation therapy for non-small cell lung cancer

OBJECTIVES

This study was to evaluate the feasibility of simultaneous integrated boost on tumor hypoxia area by studying the dosimetric change of hypoxia imaging guidance on intensity-modulated radiation therapy for non-small cell lung cancer (NSCLC).

METHODS

Five NSCLC patients with large hypoxic volume participated in this study. FDG PET/CT images were fused with CT localization images to delineate gross tumor volume. FMISO PET/CT images were fused with CT localization images to delineate hypoxic biological target volume (BTV) (tissue maximum ratio ≥ 1.3) by threshold. BTV was irradiated with 72, 78 and 84 Gy, respectively, 30 times. The dosimetry differences were compared in target volume and organ at risk between simultaneous integrated boost plans and conventional radiotherapy plans.

RESULTS

Dosages on BTV of NSCLC hypoxic area were increased to 72, 78 and 84 Gy, respectively, by simultaneous integrated boost intensity-modulated radiation therapy. There was no obvious difference in dosage distributions on original target volume compared with those in conventional radiotherapy. Dosages on main organ at risk in chest met the dosimetric constraint, and there was no significant difference compared with those in conventional radiotherapy.

CONCLUSION

It is feasible in dosiology that the dosages in NSCLC hypoxic area were added to 72, 78 and 84 Gy by simultaneous integrated boost with the guidance of ¹⁸F-FMISO PET/CT.

The Presence of MMP-20 Reinforces Biomimetic Enamel Regrowth

Biomimetic synthesis of artificial enamel is a promising strategy for the prevention and restoration of defective enamel. We have recently reported that a hydrogel system composed of chitosan-amelogenin (CS-AMEL) and calcium phosphate is effective in forming an enamel-like layer that has a seamless interface with natural tooth surfaces. Here, to improve the mechanical system function and to facilitate the biomimetic enamel regrowth, matrix metalloproteinase-20 (MMP-20) was introduced into the CS-AMEL hydrogel. Inspired by our recent finding that MMP-20 prevents protein occlusion inside enamel crystals, we hypothesized that addition of MMP-20 to CS-AMEL hydrogel could reinforce the newly grown layer. Recombinant human MMP-20 was added to the CS-AMEL hydrogel to cleave full-length amelogenin during the growth of enamel-like crystals on an etched enamel surface. The MMP-20 proteolysis of amelogenin was studied, and the morphology, composition, and mechanical properties of the newly grown layer were characterized. We found that amelogenin was gradually degraded by MMP-20 in the presence of chitosan. The newly grown crystals in the sample treated with MMP-20-CS-AMEL hydrogel showed more uniform orientation and greater crystallinity than the samples treated with CS-AMEL hydrogel without MMP-20. Stepwise processing of amelogenin by MMP-20 in the CS-AMEL hydrogel prevented undesirable protein occlusion within the newly formed crystals. As a result, both the modulus and hardness of the repaired enamel were significantly increased (1.8- and 2.4-fold, respectively) by the MMP-20-CS-AMEL hydrogel. Although future work is needed to further incorporate other enamel matrix proteins into the system, this study brings us one step closer to biomimetic enamel regrowth.

Low-grade Albuminuria Associated with Subclinical Left Ventricular Diastolic Dysfunction and Left Ventricular Remodeling

AIMS

Low-grade albuminuria (LGA) has been shown to be associated with increased risk for cardiovascular disease. Our study investigated the relationship between normal urinary albumin-to-creatinine ratios (UACRs) and subclinical left ventricular (LV) diastolic dysfunction and remodeling in diabetics and non-diabetics.

METHODS

A total of 888 diabetic and 208 non-diabetic patients with normal UACRs (< 30 mg/g) from Fuzhou, Fujian Province, China were examined. The subjects were stratified into quartiles based on their respective UACR levels. LV diastolic function was defined by early diastolic transmitral velocities (E)/average early diastolic annular velocities (average e), accompanied by average e. LV remodeling was defined by LV mass indexed to body surface area and relative wall thickness based on 2-dimensional and Doppler echocardiography.

RESULTS

UACR was independently associated with cardiac diastolic function as defined by E/e and average e (OR=1.042, P=0.001) and LV remodeling (OR=1.037, P=0.001) in all participants. Diabetic patients in the highest quartile of UACR demonstrated a greater risk of developing LV diastolic dysfunction by a magnitude of 1.625 (OR=1.625, P=0.037) than patients in the lowest quartile; those in the third and highest quartiles demonstrated a greater risk of LV remodeling by a magnitude of 1.729-1.994 compared to the lowest quartile (OR=1.729, P=0.027 and OR=1.994, P=0.005, respectively). The association between UACR and subclinical diastolic dysfunction was most prevalent in younger, non-obese, non-hypertensive females or patients who had experienced diabetes for fewer than 10 years. The association between UACR and LV remodeling was most prevalent in non-obese, older males, in patients with normal low-density lipoprotein levels, in patients who had experienced diabetes for fewer than 10 years, and in patients without hypertension.

CONCLUSION

UACR was associated with subclinical LV diastolic dysfunction and remodeling in both patients with and without Type 2 diabetes. We conclude that LGA may also be a marker for subclinical cardiovascular damage in Type 2 diabetics.

123 EFFECTS OF TAURO URSODEOXYCHOLIC ACID ON DEVELOPMENT OF BOVINE EMBRYOS FROM IN VITRO FERTILIZATION

Endoplasmic reticulum stress (ERS) is a novel apoptotic pathway and plays an important role for embryonic development. Tauro ursodeoxycholic acid (TUDCA) is a specific chemical chaperone that can inhibit ERS. In this study, we investigated the effects of TUDCA on the development and mRNA expression of ERS-related genes in bovine embryos from IVF in order to improve the efficiency of embryo in vitro culture. Bovine oocytes collected from ovaries at slaughter were cultured in the maturation medium (TCM-199 + 26.2 mmol L–1 NaHCO3 + 5 mmol L–1 HEPES + 5% fetal bovine serum) for 24 h and fertilized in vitro with bovine sperm. After fertilization, the embryos were respectively placed into the medium (TCM-199 + 3% fetal bovine serum) containing different concentrations of TUDCA (0, 100, 250, 500, 1000 μmol L–1) and cultured in the 5% CO2 at 38.5°C. Blastocyst development was evaluated after 7 days of culture, and then the total cell number and apoptosis index of blastocysts were detected with TUNEL. In addition, X-box binding protein 1 (XBP-1) of embryos at 2-cell, 4-cell, morula, and blastocyst stages was detected with RT-PCR, and the change of the mRNA expression of ERS-related (Grp78, Ire1, Chop) and apoptosis-related (Bax, Bcl-2) genes in blastocyst collected at 7 days of culture were analysed by QRT-PCR. A total of 1336 oocytes were used in this study, and each experimental group comprised 6 replicates. The results revealed that the splicing of XBP-1 was present during the development of bovine embryos, and especially obvious at the 4-cell, morula, and blastocyst stages. When embryos were cultured in medium with different concentrations of TUDCA, compared with the control group (0 μmol L–1), more embryos developed to blastocyst stage with 500 μmol L–1 TUDCA (31.86 ± 7.32% v. 21.11 ± 8.05%; P < 0.05), but the cleavage rate was not significantly different among groups (P > 0.05). The result for TUNEL found that when adding 500 μmol L–1 TUDCA to culture, the bovine embryos significantly improved the total cell number of blastocysts (110. ± 15.21 v. 102.3 ± 8.62; P < 0.05), and the apoptosis index of blastocysts was markedly decreased (3.71 ± 0.91 v. 5.36 ± 1.92; P < 0.05) relative to the control group. Moreover, the result of QRT-PCR analysis showed that treating embryos with 500 μmol L–1 TUDCA significantly reduced the mRNA expression level of Ire1 and Chop genes (P < 0.05) and up-regulated the expression of anti-apoptotic Bcl-2 gene (P < 0.05), while down-regulated the expression of pro-apoptotic Bax gene (P < 0.05). Furthermore, XBP-1 splicing in blastocysts also abated after embryos were treated with 500 μmol L–1 TUDCA. In conclusion, ERS occurs in bovine embryos during in vitro culture, but treating embryos with 500 μmol L–1 TUDCA may reduce ERS to facilitate embryonic development. This work was funded by the China High Technology Development Program (2011AA100607), China Natural Science Foundation (31072033), and Guangxi Science Foundation (2011GXNSFA018084, 2012GXNSFFA060004).

MicroRNA-21 regulates T-cell apoptosis by directly targeting the tumor suppressor gene Tipe2

MicroRNAs (MiRs) are short noncoding RNAs that can regulate gene expression. It has been reported that miR-21 suppresses apoptosis in activated T cells, but the molecular mechanism remains undefined. Tumor suppressor Tipe2 (or tumor necrosis factor-α-induced protein 8 (TNFAIP8)-like 2 (TNFAIP8L2)) is a newly identified anti-inflammatory protein of the TNFAIP8 family that is essential for maintaining immune homeostasis. We report here that miR-21 is a direct target of nuclear factor-κB and could regulate Tipe2 expression in a Tipe2 coding region-dependent manner. In activated T cells and macrophages, Tipe2 expression was markedly downregulated, whereas miR-21 expression was upregulated. Importantly, Tipe2-deficient T cells were significantly less sensitive to apoptosis. Conversely, overexpression of Tipe2 in EL-4 T cells increased their susceptibility to activation-induced apoptosis. Therefore, Tipe2 provides a molecular bridge between miR-21 and cell apoptosis; miR-21 suppresses apoptosis in activated T cells at least in part through directly targeting tumor suppressor gene Tipe2.

BubR1 deficiency results in enhanced activation of MEK and ERKs upon microtubule stresses

Disruption of microtubules activates the spindle checkpoint, of which BubR1 is a major component. Our early studies show that BubR1 haplo-insufficiency results in enhanced mitotic slippage in vitro and tumorigenesis in vivo.

OBJECTIVE

Given that both MAPKs/ERKs and MEK play an important role during mitosis, we investigated whether there existed regulatory relationship between the MAPK signalling pathway and BubR1.

METHOD AND RESULTS

Here, we have demonstrated that BubR1 deficiency is correlated with enhanced activation of MEK and ERKs after disruption of microtubule dynamics. Specifically, treatment with nocodazole and paclitaxel resulted in hyper-activation of ERKs and MEK in BubR1(+/-) murine embryonic fibroblasts (MEF) compared to that of wild-type MEFs. This enhanced activation of ERKs and MEK was at least partly responsible for more successful proliferation completion when cells were treated with nocodazole. BubR1 knockdown via RNAi resulted in enhanced activation of ERKs and MEK in HeLa cells, correlating with inhibition of PP1, a negative regulator of MEK. Moreover, when BubR1 was partially inactivated due to premature missegregation of chromosomes after Sgo1 depletion, phosphorylation of ERKs and MEK was enhanced in mitotic cells; in contrast, little, if any activated ERKs and MEK were detected in mitotic cells induced by nocodazole. Furthermore, BubR1, activated ERKs and activated MEK all localized to spindle poles during mitosis, and also, the proteins physically interacted with each other.

CONCLUSION

Our studies suggest that there exists a cross-talk between spindle checkpoint components and ERKs and MEK and that BubR1 may play an important role in mediating the cross-talk.

The relationship between polymorphisms of HCMV UL144 ORF and clinical manifestations in 73 strains with congenital and/or perinatal HCMV infection

Human cytomegalovirus (HCMV) displays genetic variability and can cause a wide range of diseases in neonates. To explore the relationship between polymorphisms and clinical manifestations, the UL144 genes from 73 clinical strains were sequenced. All of the strains, which came from 70 infants with suspected congenital and/or perinatal HCMV infection, were non-passage strains. Among them, 23 strains were from surgery specimens, and the others were from urine samples. Clinically, 12 infants displayed asymptomatic infection and 58 patients displayed symptomatic infection. The results showed that 36 patients (49.3%) were infected with strains belonging to UL144 group G1 (G1a 33/36, G1b 3/36), 19 patients (28.8%) were infected with strains belonging to group G2, and 15 patients (21.9%) were infected with strains belonging to group G3. This result indicated that UL144 group G1 was the predominant genotype in congenital and/or perinatal HCMV infection in northern China. Compared with the distribution pattern of strains in UL144 genotypes of data from Chicago, Iowa and Texas, and Japan by chi-square test, the difference was statistically significant. This suggested that the distribution pattern of strains in UL144 genotype was related to geographic location. However, no linkage was observed between the UL144 genotypes and the severity and/or outcome of HCMV disease.

Sequence variability of the human cytomegalovirus UL141 Open Reading Frame in clinical strains

Human cytomegalovirus (HCMV) displays genetic polymorphisms. HCMV disease and tissue tropism may be related to specific genomic variability among strains. This work analyzed the genetic polymorphism of UL141 open reading frame (ORF), one of the genes in HCMV UL/b' region, from 21 clinical strains. 8 previously published UL141 sequences in the GenBank were used for sequence comparison. Detailed sequence analysis showed that the UL141 gene was highly conserved at both the nucleotide and amino acid level. The coding regions were identical in size. The nucleotide and amino acid sequence identities among all strains were 96.9-100% and 97.6-100%, respectively.

Ligustrazini inhibits endotoxin induced PAI-1 expression in human umbilical vein endothelial cells

Plasminogen activator inhibitor 1 (PAI-1) is one of important coagulant factors. Endotoxin lipopolysaccharide (LPS) induces thrombosis by stimulating PAI-1 secretion of vascular cells (EC). Using sandwich enzyme-linked immunosorbent assay (ELISA) and Northern blot, was investigated the effects of Chinese medicine ligustrazini on PAI-1 expression in EC and LPS-stimulated EC. The results showed that ligustrazini inhibited both basal and LPS-induced PAI-1 mRNA expression in EC. The effect of ligustrazini on LPS-induced PAI-1 secretion worked in a dose-dependent manner. This study provided theoretic and experimental evidence for use of ligustrazini against septic shock and cardiovascular diseases.

Scanning FCS, a novel method for three-dimensional particle tracking

We describe a novel method to track fluorescent particles in three dimensions with nanometre precision and millisecond time resolution. In this method, we use our two-photon excitation microscope. The galvomotor-driven x–y scanning mirrors allow the laser beam to move repetitively in a circular path with a radius of half the width of the point spread function of the laser. When the fluorescent particle is located within the scanning radius of the laser, the precise position of the particle in the x–x plane can be determined by its fluorescence intensity distribution along the circular scanning path. A z-nanopositioner on the objective was used to change the laser focus at two planes (half width of the point spread function apart). The difference of the fluorescence intensity in the two planes is used to calculate the z-position of the fluorescent particle. The laser beam is allowed to scan multiple circular orbits before it is moved to the other plane, thus improving the signal to noise ratio. With a fast feedback mechanism, the position of the laser beam is directed to the centre of the fluorescent particle, thus allowing us to track a particle in three dimensions. In this contribution we describe some calibration experiments performed to test the three-dimensional tracking capability of our system over a large range.

Effects of the flavonoid baicalin and its metabolite baicalein on androgen receptor expression, cell cycle progression and apoptosis of prostate cancer cell lines

Recent studies on the Chinese herbal medicine PC SPES showed biological activities against prostate cancer in vitro, in vivo and in patients with advanced stages of the disease. In investigating its mode of action, we have isolated a few of the active compounds. Among them, baicalin was the most abundant (about 6%) in the ethanol extract of PC SPES, as determined by HPLC. Baicalin is known to be converted in vivo to baicalein by the cleavage of the glycoside moiety. Therefore, it is useful to compare their activities in vitro. The effects of baicalin and baicalein were studied in androgen-positive and -negative human prostate cancer lines LNCaP and JCA-1, respectively. Inhibition of cell growth by 50% (ED(50)) in LNCaP cells was seen at concentrations of 60.8 +/- 3.2 and 29.8 +/- 2.2 microM baicalin and baicalein, respectively. More potent growth inhibitory effects were observed in androgen-negative JCA-1 cells, for which the ED(50) values for baicalin and baicalein were 46.8 +/- 0.7 and 17.7 +/- 3.4, respectively. Thus, it appears that cell growth inhibition by these flavonoids is independent of androgen receptor status. Both agents (1) caused an apparent accumulation of cells in G(1) at the ED(50) concentration, (2) induced apoptosis at higher concentrations, and (3) decreased expression of the androgen receptor in LNCaP cells.

Protein folding pathways of adenylate kinase from E. coli: hydrostatic pressure and stopped-flow studies

Adenylate kinase (AKe) from E. coli is a small, single-chain, monomeric enzyme with no tryptophan and a single cysteine residue. We have constructed six single-Trp mutants of AKe to facilitate optical studies of these proteins and to specifically examine the interrelationship between their structure, function, dynamics, and folding reactions. In this study, the effects of hydrostatic pressure on the folding reactions of AKe were studied. The native structure of AKe was transformed to a non-native, yet pressure stable, conformation by hydrostatic pressure of about 300 MPa. This pressure lability of AKe is rather low for a monomeric protein and presumably may be attributed to substantial conformational flexibility and a correspondingly large volume change. The refolding of AKe after pressure-induced denaturation was reversible under ambient conditions. At low temperature (near 0 degrees C), the refolding process of pressure-exposed AKe mutants displayed a significant hysteresis. The observation of a slow refolding rate in the 193 region and a faster folding rate around the active site (86, 41, 73 regions) leads us to suggest that in the folding process, priority is afforded to functional regions. The slow structural return of the 193 region apparently does not hinder the more rapid return of enzymatic activity of AKe. Circular dichroism studies on the pressure-denatured Y193W mutant show that the secondary structure (calculated from far-UV spectra) returned at a rapid rate, but the tertiary structure alignment (calculated from near-UV spectra) around the 193 region occurred more slowly at rates comparable to those detected by fluorescence intensity. Denaturation of AKe mutants by guanidine hydrochloride and subsequent refolding experiments were also consistent with a much slower refolding process around the 193 region than near the active site. Fast refolding kinetic traces were observed in F86W, S41W, and A73W mutants using a fluorescence detection stopped-flow rapid mixing device, while only a slow kinetic trace was observed for Y193W. The results suggest that the differences in regional folding rates of AKe are not derived from the specific denaturation methods, but rather are inherent in the structural organization of the protein.

Base sequence effects in bending induced by bulky carcinogen-DNA adducts: experimental and computational analysis

The covalent binding of bulky mutagenic or carcinogenic compounds to DNA can lead to bending, which could significantly alter the interactions of DNA with critical replication and transcription proteins. The impact of adducts derived from the highly reactive bay region enantiomeric (+)- and (-)-anti-7,8-diol-9,10-epoxide derivatives of benzo[a]pyrene (BPDE) are of interest because the (+)-7R,8S,9S,10R-anti-BPDE enantiomer is highly tumorigenic in rodents, while the (-)-7S,8R,9R,10S-anti-BPDE enantiomer is not. Both (+)- and (-)-anti-BPDE bind covalently with DNA predominantly by trans addition at the exocyclic amino group of guanine to yield 10S (+)- and 10R (-)-trans-anti-[BP]-N(2)-dG adducts. We have synthesized a number of different oligonucleotides with single (+)- and (-)-trans-anti-[BP]-N(2)-dG adducts (G) in the base sequence context XG*Y, where X and Y are different DNA bases. The G* residues were positioned at or close to the center of 11 base pair ( approximately 1 helical turn) or 16 base pair ( approximately 1.5 turns) duplexes. All bases, except for X and Y and their partners, were identical. These sequences were self-ligated with T4 ligase to form multimers that yield a ladder of bands upon electrophoresis in native polyacrylamide gels. The extent of bending in each oligonucleotide was assessed by monitoring the decrease in gel mobilities of these linear, self-ligated oligomers, relative to unmodified oligonucleotides of the same base sequence. The extent of global bending was then estimated using a sequence-specific three-dimensional model from which the values of the base-pair step parameter roll adjacent to the lesion site could be extracted. We find that (+)-trans-anti-[BP]-N(2)-dG adducts are considerably more bent than the (-) isomers regardless of sequence and that A-T base pairs flanking the [BP]-N(2)-dG lesion site allow for local flexibility consistent with adduct conformational heterogeneity. Interestingly, the fit of computed versus observed gel mobilities using classical reptation treatments requires enhancement of unmodified DNA flexibility in gels, compared to aqueous salt solution. The differences in bending between the two stereoisomeric adduct duplexes and the observed base sequence context effects may play a significant role in the differential processing of these lesions by cellular replication, transcription, and repair enzymes.

Micronuclei assay by laser scanning cytometry

BACKGROUND

The micronuclei (MN) assay is used to assess the chromosomal/mitotic spindle damage induced by ionizing radiation or mutagenic agents in vivo or in vitro. Because visual scoring of MN is cumbersome semi-automatic procedures that relay either on flow cytometry or image analysis were developed: both offer some advantages but also have shortcomings.

METHODS

In the present study laser scanning cytometer (LSC), the instrument that combines analytical capabilities of flow and image cytometry, has been adapted for quantitative analysis of MN. The micronucleation of human breast carcinoma MCF-7 and leukemic HL-60 and U-937 cells was induced by in vitro treatment with mitomycin C. Cellular DNA was stained with propidium iodide (PI), protein was counterstained with fluorescein isothiocyanate (FITC). Two approaches were used to detect MN: (a) the threshold contour was set based on the data from the photosensor measuring red fluorescence of PI and MN were identified on the bivariate PI versus PI/FITC fluorescence distributions by their characteristic position; (b) the threshold contour was set on the data from the sensor measuring FITC fluorescence which made it possible, using the LSC software dedicated for FISH analysis, to assay both the frequency and DNA content of individual MN within each measured cell.

RESULTS

The capability of LSC to relocate MN for visual examination was useful to confirm their identification. Visual identification of MN combined with their multiparameter characterization that took into an account their DNA content and protein/DNA ratio made it possible establish the gating parameters that excluded objects that were not MN; 93.3+/-3.3 events within the selected gate were MN. It was also possible to successfully apply FISH software to characterize individual cells with respect to quantity of MN residing in them. The percentage of MN assayed by LSC correlated well with that estimated visually by microscopy, both for MCF-7 (r = 0.93) and HL-60 cells (r = 0.87).

CONCLUSIONS

LSC can be used to obtain unbiased estimate of MN frequencies. Unlike flow cytometry, it also allows one to characterize individual cells with respect to frequency and DNA content of MN residing in these cells. These analytical capabilities of LSC may be helpful not only to score MN but also to study mechanisms by which clastogenic agents induce MN.

[Experimental study of compound salvia injection in preventing and treating chronic nephrotoxicity induced by cyclosporin A in rats]

OBJECTIVE

To explore the mechanism of protective effect of Compound Salvia Injection (CSI) on experimental cyclosporin A induced nephrotoxicity.

METHODS

Rats were on low-salt diet and cyclosporin A (CsA) was administered once a day through gastrogavage at dosage of 30 mg/kg.d for 28 days. Expression of the mRNA for intrarenal transforming growth factor-beta 1 (TGF-beta 1) and renin was measured by reverse transcription-polymerase chain reaction (RT-PCR). Intrarenal expression of TGF-beta 1 and Collagen IV was determined by immunohistochemical assays. The effects of CSI on these changes were also evaluated.

RESULTS

Chronic CsA-induced nephropathy might be correlated to TGF-beta 1 and renin mRNA up-regulation as well as matric proteins accumulation in interstitium. CSI could reduce these changes.

CONCLUSION

Decreased CsA-related TGF-beta 1 and renin upregulation expression and accumulation of matrix proteins in the kidney might be related to the protective mechanism of CSI on CsA-induced chronic nephrotoxicity.

[Amino acid sequence analysis of peptides that can react to the nuclear localization signals of human cytomegalovirus PPUL44]

OBJECTIVE

To find the peptides that have strong binding ability to the nuclear localization signals (NLS) of human Cytomegalovirus (HCMV) PPUL44 protein, and to analyze their amino acid sequences.

METHODS

Peptide clones that have binding ability to the NLSs were selected from a random peptide display library by using synthesized HCMV PPUL44 NLSA and NLSB respectively. The DNA sequences of these clones were detected by using "ABI Prism BigDye Terminator Cycle Sequencing Ready Reaction Kit". The amino acid sequences of the clones were analyzed for their homology, and the homologous sequences were compared with known sequences in protein bank.

RESULTS

The peptides that can bind to the HCMV PPUL44 NLSA(named as bNLSApep) have higher homologous amino acid sequence to importin alpha subunit, the bNLSApep48 sequence AVVTPVLTEILK is more similar to the sequence of the importin alpha subunit Arm 7 from amino acid 18 to 29, ANIFPVLTEILQ; The bNLSBpep 39 is similar to the sequence of all 8 Arm regions of importin alpha subunit from amino acid 10 to 21.

CONCLUSION

It is possible that the HCMV PPUL44 NLSA is a specific recognition site by importin alpha subunit, it can bind to the Arm 7 region of importin alpha subunit; HCMV PPUL44 NLSB is a non-specific recognition site for importin alpha subunit. This study provided an experimental data for the proposal that the Arm repeat region of importin alpha subunit is the binding region of NLS.

Multiparameter analysis of progeny of individual cells by laser scanning cytometry

BACKGROUND

Effectiveness of antitumor drugs to suppress unrestricted proliferation of cancer cells is commonly measured by cell clonogenicity assays. Assays of clonogenicity are also used in studies of stem/progenitor cells and in analysis of carcinogenic transformation. The conventional assays are limited to providing information about frequency of colonies (cloning efficiency) and do not reveal the qualitative (phenotype) attributes of individual colonies that may yield clues on mechanisms by which cell proliferation was affected by the studied agent.

METHODS

Laser scanning cytometry (LSC) was adapted to identify and characterize size and phenotype of colonies of MCF-7 cells growing in microscope slide chambers, untreated and treated with the cytotoxic ribonuclease, onconase (Onc). Individual colonies were located and data representing each colony were segmented based on >650-nm fluorescence excited by a He-Ne laser of the cells whose protein was stained with BODIPY 630/650-X. The DNA of the cells was stained with propidium iodide (red fluorescence) whereas specific proteins (estrogen receptor [ER] or tumor suppressor p53) were detected immunocytochemically (green fluorescence), each excited by an Ar ion laser.

RESULTS

A plethora of attributes of individual colonies were measured, such as (a) morphometric features (area, circumference, area/circumference ratio, DNA or protein content per area ratio), (b) number of cells (nuclei), (c) DNA content, (d) protein content and protein/DNA ratio, and (e) expression of ER or p53 per colony, per total protein, per nucleus or per DNA, within a colony. Also cell cycle distribution within individual colonies and heterogeneity of colonies with respect to all the measured features could be assessed. The colonies growing in the presence of Onc had many of the above attributes different than the colonies from the untreated cultures.

CONCLUSIONS

Analysis of the features of cell colonies by LSC provides a wealth of information about the progeny of individual cells. Changes in colony size and phenotype, reflecting altered cell shape, cell size, colony protein/DNA ratio, and expression of individual proteins, may reveal mechanisms by which drugs suppress the proliferative capacity of the cells. This may include inducing growth imbalance and differentiation and modulating expression of the genes that may be associated with cell cycle, apoptosis, or differentiation in a progeny of individual cells. Extensions of LSC may make it applicable for automatic analysis of cloning efficiency and multiparameter analysis of cell colonies in soft agar. Such analyses may be useful in studies of the mechanisms and effectiveness of antitumor drugs, in the field of carcinogenesis, and for analyzing primary cultures and assessing tumor prognosis and drug sensitivity. The assay can also be adapted to analysis of microbial colonies.

[Molecular cloning of EXT2 and EXT4 gene]

Hereditary multiple exostose(EXT) is an autosomal dominant disorder of skeletal system. Three genetic loci have been identified at 8q24.1(EXT1), 11p11(EXT2) and 19p(EXT3) respectively. In this paper, EXT2 gene was cloned with positional cloning and homologous screening. SSCP and sequencing analysis have been done in 37 EXT patients who came from 20 EXT families, 2 mutations of insertion were tested in 2 patients. This confirmed that the gene cloned in this paper was EXT2 gene which locus at 11p11. Additionally EXT4 gene was cloned with homologous screening and located at 1p36.1 with FISH in this paper.

[A study on the mechanism of anisodamine against thrombosis]

OBJECTIVE

To investigate the effects and the mechanism of Chinese herb anisodamine on PAI-1 expression in LPS stimulated endothelial cells (ECs).

METHODS

Human umbilical vein endothelial cells (HUVECs) were cultured by trypsin digestion method. PAI-1 protein in HUVEC conditioned medium was measured by sandwich enzyme-linked immunosorbent assay (ELISA), and PAI-1 mRNA expression in HUVEC was determined by Northern blot analysis. HUVEC nuclear factor-kappa B (NF-kappaB) nuclear translocation was assessed by immunocytochemistry technique.

RESULTS

LPS treatment of cultured HUVECs resulted in a significant increase of PAI-1 protein as well as mRNA expression by these cells. However, when HUVECs were incubated with LPS plus anisodamine, the upregulation of PAI-1 by LPS was significantly abated. The expression of PAI-1 protein and mRNA was decreased by 30% and 24% respectively compared with LPS treatment alone. Moreover, anisodamine was able to decrease the basal level of PAI-1 protein and mRNA by 74% and 70% respectively. Furthermore, anisodamine could block LPS induced NF-kappaB of HUVECs nuclear translocation.

CONCLUSION

Anisodamine inhibits both basal and LPS-induced PAI-1 protein as well as mRNA expression in ECs. The inhibition of anisodamine on LPS-induced PAI-1 in ECs may take place via the NF-kappaB pathway.

Mechanism of ligustrazini against thrombosis

OBJECTIVE

To investigate the mechanism of Chinese medicine ligustrazini against thrombosis, and the effects of ligustrazini on plasminogen activator inhibitor (PAI-1) expression in normal endothelial cells and lipopolysaccharide (LPS) stimulated endothelial cells.

METHODS

Human umbilical vein endothelial cells (HUVECs) were cultured by trypsin digestion method. PAI-1 protein in HUVEC conditioned medium was measured by Sandwich enzyme-linked immunosorbent assay (ELISA), and PAI-1 mRNA expression was determined by Northern blot analysis. Using electrophoretic mobility shift assay (EMSA), we observed HUVEC nuclear factor-kappa B (NF-kappa B) nuclear translocation.

RESULTS

LPS treatment of cultured HUVECs resulted in a significant increase in PAI-1 protein and mRNA expression by these cells. However, when HUVECs were incubated with LPS plus ligustrazini, the upregulation of PAI-1 by LPS was abated. Moreover, ligustrazini could decrease the basal level of PAI-1 protein and mRNA in HUVECs as compared with control. Nuclear extracts prepared from HUVECs stimulated by LPS demonstrated that binding to the NF-kB oligo nucleotide increased as compared with the unstimulated cells, but ligustrazini did not change those binding in the absence or presence of LPS.

CONCLUSIONS

Ligustrazini inhibited both basal and LPS-induced PAI-1 protein and mRNA expression in endothelial cells, and the modulation of PAI-1 in HUVECs by ligustrazini might have other mechanisms rather than NF-kB pathway.

[Identification of mutations in the human EXT1 and EXT2 genes]

OBJECTIVE

To investigate further the genetic basis of hereditary multiple exostoses (EXT) and provide useful information for gene diagnosis of the disease.

METHODS

Polymerase chain reaction-single strand conformation polymorphism was used to examine the entire coding regions of EXT(1) gene on chromosome 8 and EXT(2) gene on chromosome 11 for mutation in thirty EXT families. Mutations were further identified by sequencing.

RESULTS

Two frameshift mutations were identified in two unrelated EXT families. One was the deletion of one base(T) in exon 6 of the EXT(1) gene, and the other was the deletion of four bases (tgtt) in exon 2 of the EXT(2) gene. Both of the mutations resulted in a frameshift and premature termination of translation.

CONCLUSION

EXT is a genetically heterogeneous bone disorder caused by the mutation of EXT tumor suppressor gene. These results could be directly applied in the genetic counseling and prenatal genetic diagnosis of EXT.

Stimulation of tissue factor expression in human microvascular and macrovascular endothelial cells by cultured vascular smooth muscle cells in vitro

The effect of conditioned media obtained from different smooth muscle cells (SMC) on tissue factor (TF) expression in endothelial cells (EC) in vitro was investigated. We could show that conditioned media from cultured human aortic SMC, human umbilical artery SMC or human umbilical vein SMC all resembling the synthetic phenotype of SMC induced TF activity in human umbilical vein EC and human skin microvascular EC in a dose- and time-dependent fashion. This induction was also seen at the level of specific TF mRNA as evidenced by Northern blotting. The TF inducing activity was heat-labile and acid-stable and had an approximate molecular mass of 38 kD. This activity was found to be distinct from known inducers of TF expression in EC such as interleukin-1, tumor necrosis factor-alpha, bacterial lipopolysaccharide or vascular endothelial growth factor. Such as factor, if released by SMC in vivo, could contribute to the activation of EC under conditions such as when EC are in close contact with SMC of the synthetic (nondifferentiated) phenotype seen in processes like vessel development or neo-intima formation.

[Molecular cloning and characterization of novel protein kinase gene DYRK3]

OBJECTIVE

To isolate full length cDNA of a novel protein kinase and to deduce the protein kinase's classification position and functions.

METHODS

cDNA libraries gDNA library was screened with a partial cDNA clone which is homologous to human protein kinase DYRK2 as probe. FISH mapping was performed.

RESULTS

Two full length cDNAs of a novel protein kinase from human muscle cDNA library and human testis cDNA library were isolated. The full length cDNA from muscle has an open reading frame which is predicted to encode a protein of 588 amino acid residues and the cDNA from testis to encode a protein of 568 amino acid residues.

CONCLUSION

Because the sequence from the 27th codon to the 3' end of the cDNA from muscle is identical to that from the 7th codon to the 3' end of the cDNA from testis, they should be different transcripts of the same gene. As the gene is highly homologous to human protein kinase DYRK2, the present authors termed the gene DYRK3. DYRK3 is homologous to many serine/threonine protein kinases such as yeast Yak1, human Clk1, human Mnb, drosophila melanogaster Mnb and Cdk2. DYRK3 should belong to the Clk family in CMGC group of serine/threonine protein kinase. DYRK3 has been mapped to chromosome 1q32 by FISH.

[Effect of human recombinant gamma-interferon on proliferative activity of human laryngeal cancer cell lines]

The effect of human on PCNA expressions of HEP-2 lines was investigated using LSAB (Labelled streptacidin biotin method) with monoclonal antibody Ki-67 (anti-PCNA). The results showed that the PCNA expression which reflects the proliferative activity of cells was dependent on dose of rhu-IFN-gamma in HEP-2 cell lines. Thus, our data suggest that rhu-IFN-gamma might be useful in the treatment of laryngeal cancer because it provides effective cytostatic.

Very low density lipoprotein and oxidized very low density lipoprotein induce monocyte chemotactic protein 1 in rabbit aortic smooth muscle cells

OBJECTIVE

To understand whether very low density lipoprotein (VLDL) and oxidatively modified very low density lipoprotein (OX-VLDL) can stimulate vascular smooth muscle cells (SMCs) to express high level of monocyte chemotactic protein (MCP-1) mRNA.

METHODS

LDL and VLDL were isolated from normal blood donors by density gradient ultracentrifugation and oxidatively modified by adding CuCl2 and incubation at 37 degrees C for 24 hours. Rabbit aortic SMCs were cultured by a substrate-attached explant method, and their total RNA was extracted by guanidinium isothiocyanate method. The expression of MCP-1 mRNA in SMCs was examined by dot blotting analysis using a probe of gamma-22P-end-labeled 35-mer oligonucleotide.

RESULTS

Dot blotting analysis showed that cultured SMCs can express MCP-1 mRNA and the level of MCP-1 mRNA was increased significantly in SMCs after 24-hour coculture with VLDL (6-fold) and OX-VLDL (20-fold).

CONCLUSIONS

VLDL and OX-VLDL both can induce MCP-1 mRNA expression in cultured rabbit aortic SMCs and the latter is more effective than the former.

Differential expression of mast cell growth factor receptor (c-kit) by peritoneal connective tissue-type mast cells and tissue culture-derived mast cells

The peritoneal cavity of the mouse is a major source of connective tissue-type mast cells (CTMCs). Flow cytometric analysis using biotinylated recombinant murine mast cell growth factor (rMuMGF) showed that 1 to 3% of the cells in the peritoneal cavity exhibited MGF receptor (MGFR) (or c-kit). CTMCs were the only cell types expressing MGFR in the peritoneal cavity, and every one of them expressed MGFR. More than half the peritoneal CTMCs retained the potential to proliferate in the presence of recombinant murine interleukin 3 (rMuIL-3), rMuIL-4, and rMuMGF and gave rise to pure, alcian blue-positive "mast cells," which actively expressed c-kit transcripts and MGFR. Flow cytometric analysis and receptor assay carried out at 4 degrees C showed that the number of MGFRs on culture-derived mast cells (CDMCs) was one-third that of peritoneal CTMCs (6 x 10(4) vs. 1.8 x 10(5) MGFR/cell). At 37 degrees C, the total number of membrane MGFRs detected in CDMC was two to three times more than that detected at 4 degrees C, indicating that nearly 70% of total MGFR in CDMCs, compared with only 40% in peritoneal CTMCs, existed as "cryptic sites" unable to interact with exogenous ligand at 4 degrees C. Thus, diminished expression of MGFR is one of the phenotypic characteristics associated with CDMCs.

Construction of polyepitope fusion antigens of human cytomegalovirus ppUL32: reactivity with human antibodies

We have previously shown that single linear epitopes of the major human cytomegalovirus (HCMV) antigens, expressed as fusion proteins or synthesized as oligopeptides, can be valuable diagnostic material in the serology of HCMV infection (M. P. Landini, M. X. Guan, G. Jahn, W. Lindenmaier, M. Mach, A. Ripalti, A. Necker, T. Lazzarotto, and B. Plachter, J. Clin. Microbiol. 28:1375-1379, 1990; M. P. Landini, T. Lazzarotto, A. Ripalti, M. X. Guan, and M. La Placa, J. Clin. Microbiol. 27:2324-2327, 1989; A. Ripalti, M. P. Landini, E. S. Mocarski, and M. La Placa, J. Gen. Virol. 70:1247-1251, 1989). In this work we addressed the question of whether the expression of more than one linear epitope on a single fusion protein could increase the reactivity of genetically engineered antigenic material with human antibody. To answer this question we fused sequences expressing two different epitopes contained in the basic phosphoprotein of 150 kDa encoded by UL32 (M. S. Chee, A. T. Bankier, S. Beck, R. Bohni, C. M. Brown, T. Cerny, T. Hornsel, C. A. Hutchinson, T. Kouzarides, J. A. Martignetti, and B. G. Barrell, Curr. Top. Microbiol. Immunol. 154:125-169, 1990; G. Jahn, T. Kouzarides, M. Mach, B.-C. Scholl, B. Plachter, B. Traupe, E. Preddie, S. C. Satchwell, B. Fleckenstein, and B. G. Barrell, J. Virol. 61:1358-1367, 1987), ppUL32, which was repeatedly shown to be the strongest immunogen present in the viral particle. We also made fusions with sequences expressing a single epitope repeated once, twice, or three times. The different fusion proteins were tested with HCMV-positive human sera. We found that fusion proteins expressing different epitopes together were recognized by a larger number of serum specimens and with more intense reactions in Western blot (immunoblot) experiments. We also found evidence that expression on the same polypeptide of the two distinct epitopes produced a stronger antigen than the mere addition of two fusion proteins which each carried one copy of one of these epitopes. Furthermore, we found that while the same epitope expressed two or three times on the same fusion protein was not better recognized by immunoglobulin G than the single epitope, immunoglobulin M reactivities to the double and triple epitopes were enhanced.

Prokaryotic expression of a large fragment of the most antigenic cytomegalovirus DNA-binding protein (ppUL44) and its reactivity with human antibodies

We isolated and characterized from a lambda gt11 expression library clones expressing portions of human cytomegalovirus (HCMV)-p52. This nonstructural viral protein is encoded by UL44 and is known to be one of the best IgM reactive antigens. The reactivity of these clones was studied with human antibody and the gene fragment coding for the most immune-reactive portion of p52 (aa 202-434) was cloned in a prokaryotic expression vector, pROS, which overexpresses the antigen as a fusion protein to a truncated molecule of beta-galactosidase.

Up-regulation of granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors in murine peritoneal exudate macrophages by both GM-CSF and IL-3

Murine peritoneal exudate macrophages (PEM) display multiple CSF receptors. In this study, the expression of granulocyte-macrophage (GM)-CSF receptors in PEM was studied. PEM displayed over 5000 single type, high affinity GM-CSF receptors/cell with a Kd = 38 to 42 pM and an apparent molecular mass of 86,000 Da. Treatment of PEM with low, but not high, concentrations of recombinant murine (rMu) GM-CSF continuously for 24 h resulted in a marked up-regulation of GM-CSF receptors in PEM. A similar up-regulation of GM-CSF receptors also was detected in PEM cultures treated with rMuIL-3 (1-100 ng/ml) for 24 h or longer, regardless the doses of rMuIL-3 added in this case. Scatchard analysis of equilibrium binding showed that the enhanced binding activities in both cases were due to an increase in total number of GM-CSF receptors rather than changes in receptor affinity. Contrariwise, treatment with recombinant human macrophage-CSF (greater than 100-1000 ng/ml) partially inhibited the expression of GM-CSF receptors in PEM. Removal of rMuGM-CSF from culture medium 24 h after treatment led to a further up-regulation of GM-CSF receptors over a 4 to 24-h period, depending on the doses of initial treatment. On the other hand, removal of rMuIL-3 from culture medium after prolonged treatment did not result in further increase in GM-CSF receptors. The protein synthesis inhibitor cycloheximide abrogated GM-CSF receptor up-regulation induced by both rMuIL-3 and rMuGM-CSF, whereas actinomycin D inhibited only the second (8-24 h) phase of GM-CSF receptor up-regulation induced by exposure to high concentrations rMuGM-CSF (10 ng/ml). These findings suggest that rMuGM-CSF and rMuIL-3 up-regulate GM-CSF receptors in PEM in part through similar or identical metabolic pathways and provide further evidence of a close linkage between IL-3 and GM-CSF receptors.

Up-regulation of granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors in murine peritoneal exudate macrophages by both GM-CSF and IL-3

Murine peritoneal exudate macrophages (PEM) display multiple CSF receptors. In this study, the expression of granulocyte-macrophage (GM)-CSF receptors in PEM was studied. PEM displayed over 5000 single type, high affinity GM-CSF receptors/cell with a Kd = 38 to 42 pM and an apparent molecular mass of 86,000 Da. Treatment of PEM with low, but not high, concentrations of recombinant murine (rMu) GM-CSF continuously for 24 h resulted in a marked up-regulation of GM-CSF receptors in PEM. A similar up-regulation of GM-CSF receptors also was detected in PEM cultures treated with rMuIL-3 (1-100 ng/ml) for 24 h or longer, regardless the doses of rMuIL-3 added in this case. Scatchard analysis of equilibrium binding showed that the enhanced binding activities in both cases were due to an increase in total number of GM-CSF receptors rather than changes in receptor affinity. Contrariwise, treatment with recombinant human macrophage-CSF (greater than 100-1000 ng/ml) partially inhibited the expression of GM-CSF receptors in PEM. Removal of rMuGM-CSF from culture medium 24 h after treatment led to a further up-regulation of GM-CSF receptors over a 4 to 24-h period, depending on the doses of initial treatment. On the other hand, removal of rMuIL-3 from culture medium after prolonged treatment did not result in further increase in GM-CSF receptors. The protein synthesis inhibitor cycloheximide abrogated GM-CSF receptor up-regulation induced by both rMuIL-3 and rMuGM-CSF, whereas actinomycin D inhibited only the second (8-24 h) phase of GM-CSF receptor up-regulation induced by exposure to high concentrations rMuGM-CSF (10 ng/ml). These findings suggest that rMuGM-CSF and rMuIL-3 up-regulate GM-CSF receptors in PEM in part through similar or identical metabolic pathways and provide further evidence of a close linkage between IL-3 and GM-CSF receptors.

Transforming growth factor-beta 1 bifunctionally regulates murine macrophage proliferation

Transforming growth factor-beta (TGF-beta) is a family of polypeptide growth factors with multiple functional activities. Recent studies suggest that TGF-beta is a selective inhibitor of hematopoietic cells. In this report, we study the effect of TGF-beta 1 on the proliferation of murine peritoneal exudate macrophages (PEM) in response to purified murine recombinant granulocyte-macrophage colony-stimulating factor (rMuGM-CSF) and human recombinant M-CSF (rHuM-CSF). In mice, PEM and other types of tissue macrophages display multiple types of receptors for CSFs and respond to them, either alone or in combination, to undergo extensive proliferation in vitro. Recombinant human TGF-beta 1 (rHuTGF-beta 1) (0.1 to 1.0 ng/mL) markedly enhanced the growth of PEM in response to rMuGM-CSF but inhibited their responsiveness to rHuM-CSF. Similar effects of rHuTGF-beta 1 were also detected using murine pulmonary alveolar macrophages (PAM) and bone marrow-derived macrophages (BMDM). Receptor binding assays using iodinated rMuGM-CSF and rHuM-CSF showed that rHuTGF-beta 1 treatment greatly enhanced the expression of GM-CSF receptors in PEM, in a time- and dose-dependent manner, suggesting a possible mechanism for the synergistic effect of TGF-beta 1. On the other hand, the expression of M-CSF receptors was not affected by TGF-beta 1 treatment. Analysis by mRNA PCR showed that the synergistic effect of TGF-beta 1 is not due to autocrine CSFs produced by treated cells. Our results suggest that TGF-beta 1 is an important regulator of macrophage proliferation. Depending on the types of CSFs present, TGF-beta 1 may act either as a growth promoter or inhibitor.