[Explore the safety and efficiency of mild myopia retention in patients with myopia and presbyopia].

Objective: To explore the corrective effects of a personalized corneal refractive surgery design that retains mild myopia in patients over 40 years old with refractive errors and presbyopia. Methods: A retrospective case series study was conducted, including 60 patients (120 eyes) over 40 years old who underwent corneal refractive surgery at Peking Union Medical College Hospital l from January 2023 to December 2023. The patients were divided into two groups based on their preference: Group A (retained mild myopia) and Group B (fully corrected), with 30 patients (60 eyes) in each group. Preoperative and postoperative visual acuity, subjective refraction, slit-lamp examination, corneal topography, and intraocular pressure were assessed at 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months after surgery. The effectiveness and safety indices were calculated based on visual acuity before and after surgery. The National Eye Institute Refractive Quality of Life questionnaire was used to evaluate patient satisfaction and postoperative visual symptoms. Results: There were no significant differences in preoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent (SE), corneal thickness, and intraocular pressure between the two groups (all P>0.05). At the final follow-up, the proportions of eyes with UDVA≥0.8 and≥1.0 were 93.3% (56/60) and 60.0% (36/60) in Group A, and 100% (60/60) and 83.3% (50/60) in Group B, respectively. The SE was significantly different between Group A [(-0.35±0.52) D] and Group B [(-0.07±0.55) D] (P<0.05). Near visual acuity was better in Group A than in Group B (P<0.05). The effectiveness indices were 0.96±0.23 and 0.99±0.12, and the safety indices were 1.02±0.11 and 1.02±0.07 for Groups A and B, respectively. Both groups had high overall satisfaction, but Group A had higher scores for near vision, reading, and computer screen viewing. Conclusion: The personalized corneal refractive surgery design that retains mild myopia provides good corrective effects for patients over 40 years old with refractive errors, improving patient satisfaction and quality of life.

[Outcome of 126 adolescent and adult T-cell acute leukemia/lymphoma patients and the prognostic significance of early T-cell precursor leukemia subtype].

Objective: To evaluate the clinical characteristics of T-cell acute leukemia/lymphoma (T-ALL) and explore the prognosis significance of early T-cell precursor leukemia/lymphoma. Methods: A cohort of 126 patients diagnosed with T-ALL from 2008 to 2014 in West China Hospital, Sichuan University were enrolled in this study. They were further categorized by immunophenotype according to the expression of T-cell lineage markers CD1a, CD8, CD5 and one or more stem cell or myeloid markers. The laboratory indicators and prognosis factors were also statistically analyzed. Results: Of all patients, the ratio of male to female was 2.5∶1, with the median age of 25 years old (range 14 to 77) . The percentage of ETP-ALL was up to 47.6%. T-ALL patients showed higher ratio in first clinical remission rate (CR(1)) than T-LBL ones (64.4% vs 30.8%, P=0.032) . Group with WBC count higher than 50×10(9)/L at presentation showed higher ration of achieving CR(1) than those lower than 50×10(9)/L (78.4% vs 50.9%, P=0.010) . In comparison with the non-ETP-ALL, ETP-ALL patients had older age of onset (P<0.001) , lower WBC count (P<0.001) , lower risk of CNS involvement (10.0% vs 30.2%, P=0.009) and slightly inferior overall survival (P=0.073) . T-cell lineage markers CD1a(-), CD8(-) and CD4(-) positive patients had higher CR(1) than their corresponding negative ones (P=0.002, P=0.000, P=0.001) , while CD33(-) and CD56(-) positive patients had lower ratio of achieving CR(1) than their negative ones, respectively (P=0.035, P=0.035) . Conclusion: Flow cytometry and associated markers for immunophenotyping was of significance in the diagnosis and prognosis monitoring of T-ALL/LBL. The percentage of ETP-ALL/LBL subtype was high in Chinese adolescent and adult T-ALL patients. ETP-ALL/LBL was a high risk subtype, which needs more precise standard for diagnosis and advanced therapies for better outcome.

MIR-92 stimulates VEGF by inhibiting von Hippel-Lindau gene product in epithelial ovarian cancer.

The molecular mechanisms underlying regulation of vascular endothelial growth factor (VEGF) in epithelial ovarian cancer (EOC) remain poorly defined. VEGF, a potent angiogenic factor, is up-regulated in a variety of cancers and contributes to angiogenesis in tumor tissues. The level of VEGF correlates with progression of malignancy. We previously reported that miR-92 is abnormally elevated in the plasma of EOC patients. Here, we tested the hypothesis that miR-92 inhibits von Hippel-Lindau gene product (VHL), a tumor suppressor gene, and in turn de-represses HIF-1α, a known key transcription factor for VEGF, to stimulate VEGF expression. Using a variety of biomedical methods including Western blot, RT-PCR, gene silencing, luciferase assay, and chromatin immunoprecipitation in both surgically-resected specimens and EOC cell culture, we established that EOC cells have elevated levels of HIF-1α and miR-92 expression, but the expression of VHL is reduced. We further demonstrated that miR-92 can target the VHL transcript to repress its expression. We also found that stabilized HIF-1α can form an active complex with transcriptional coactivator p300 and phosphorylated-STAT3 at the VEGF promoter to stimulate its expression. In addition, matrix metalloproteinases MMP-2 and MMP-9 are positively regulated by HIF-1α. These results suggest that miR-92 can potentially be considered as a novel therapeutical target in treatment of EOS.

[Comparison of the effects of 0.1% bromfenac sodium eye drops and corticosteroids after small incision lenticule extraction].

Objective: To study the safety, efficacy and tolerability of the usage of 0.1% bromfenac sodium eye drops in small incision lenticule extraction (SMILE). Methods: Prospective case control study. Three groups were observed, including 60 patients (60 eyes) undergoing SMILE for myopia. After surgery, 20 patients (20 eyes) were treated with 0.1% bromfenac sodium eye drops twice daily for 10 days, 20 patients (20 eyes) were treated with topical compound tobramycin eye drops 4 times daily for 10 days, and 20 patients (20 eyes) were treated with topical compound tobramycin eye drops 4 times daily for 3 days and 0.1% bromfenac sodium eye drops twice daily thereafter for 7 days. All of the patients were examined preoperatively and at 1 day, 10 days, 1 month and 3 months postoperatively, including visual acuity, intraocular pressure, topography and adverse reactions. The differences among the 3 groups were analyzed by the single factor analysis of variance. Results: There was no significant difference among the 3 groups in the uncorrected visual acuity at 10 days, 1 month and 3 months postoperatively (F=0.77, 0.30, 0.36. P=0.47, 0.75, 0.69) . The intraocular pressure in the dexamethasone group at 10 days, 1 month and 3 months postoperatively was higher than the other two groups with no significant difference (F=0.56, 0.98, 0.63. P=0.57, 0.38, 0.54) . The surface asymmetry index of patients was 0.33±0.10, 0.50±0.17 and 0.55±0.21 in the bromfenac sodium group, 0.33±0.08, 0.49±0.16 and 0.60±0.37 in the dexamethasone-bromfenac sodium group, and 0.31±0.12, 0.52±0.23 and 0.55±0.19 in the dexamethasone group; preoperatively and at 1 and 3 months, respectively. There was no significant difference among the 3 groups in the surface asymmetry index at 1 and 3 months postoperatively (F=0.09, 0.21. P=0.91, 0.81) . The surface regularity index of patients was 0.15±0.12, 0.34±0.18 and 0.40±0.18 in the bromfenac sodium group, 0.18±0.17, 0.33±0.26 and 0.33±0.26 in the dexamethasone-bromfenac sodium group, and 0.30±0.25, 0.41±0.28 and 0.34±0.29 in the dexamethasone group preoperatively and at 1 and 3 months, respectively. There was no significant difference among the 3 groups in the surface regularity index at 1 and 3 months postoperatively (F=0.74, 0.39. P= 0.48, 0.68) . In the bromfenac sodium group, one patient complained of binocular visual fatigue at 10 days, and one patient complained of dryness in one eye at 1 and 3 months. Conclusion: Bromfenac sodium eye drops can be used to replace corticosteroids after SMILE procedure with high safety and good tolerance. Satisfactory recovery of visual acuity, intraocular pressure and ocular surface could be achieved. (Chin J Ophthalmol, 2017, 53: 18-22).

High glucose level induces cardiovascular dysplasia during early embryo development.

The incidence of gestational diabetes mellitus (GDM) has increased dramatically amongst multiethnic population. However, how gestational diabetes mellitus damages the developing embryo is still unknown. In this study, we used yolk sac membrane (YSM) model to investigate angiogenesis in the developing chick embryo. We determined that in the presence of high glucose, it retarded the growth and extension of the embryonic vascular plexus and it also reduced the density of the vasculature in yolk sac membrane model. Using the same strategy, we used the chorioallantoic membrane (CAM) as a model to investigate the influence of high glucose on the vasculature. We established that high glucose inhibited development of the blood vessel plexus and the blood vessels formed had a narrower diameter than control vessels. Concurrent with the abnormal angiogenesis, we also examined how it impacted cardiogenesis. We determined the myocardium in the right ventricle and left atrium were significantly thicker than the control and also there was a reduction in glycogen content in cardiomyocytes. The high glucose also induced excess reactive oxygen species (ROS) production in the cardiomyocytes. We postulated that it was the excess reactive oxygen species that damaged the cardiomyocytes resulting in cardiac hyperplasia.

Effects of cochlear ablation on amino acid concentrations in the chinchilla posteroventral cochlear nucleus, as compared to rat.

Using a microchemical approach, we measured changes of amino acid concentrations in the chinchilla caudal posteroventral cochlear nucleus (PVCN) after cochlear ablation to determine to what extent slow decreases of glutamate and aspartate concentrations after carboplatin treatment resulted from slower effects of cochlear damage in chinchillas than in rats and guinea pigs, as opposed to effects of carboplatin treatment being slower than those of cochlear ablation. Our results indicate that both factors are involved: decreases of glutamate and aspartate concentrations after cochlear ablation are much slower in chinchillas than in rats and guinea pigs, but they are much faster than the decreases after carboplatin treatment. Further, aspartate and glutamate concentrations in the chinchilla caudal PVCN decreased by larger amounts after cochlear ablation than in rats or guinea pigs, and there was a transient increase of aspartate concentration at short survival times. Detailed mapping of amino acid concentrations in the PVCN of a chinchilla with 1 month survival after cochlear ablation and a rat with 7 days' survival indicated that the reductions of glutamate and aspartate occurred throughout the PVCN but were somewhat larger in ventral and caudal parts in chinchilla. Any decreases in the adjacent granular region were very small. There were also sustained bilateral decreases in concentrations of other amino acids, notably GABA and glycine, in the caudal PVCN of cochlea-ablated chinchillas but not rats. The effects of cochlear ablation on the concentrations of most of these other amino acids in chinchilla caudal PVCN differed from those of carboplatin treatment. Thus, although a major effect of auditory nerve damage on the cochlear nucleus-decreases of glutamate and aspartate concentrations-occurs across species and types of lesions, the details of timing and magnitude and the effects on other amino acids can vary greatly.

Expression of hepatitis B virus X protein is closely correlated with the high periportal inflammatory activity of liver diseases.

Hepatitis B virus X (HBx) protein is a multifunctional protein that exerts dual activity on cell proliferation and death. Although HBx is thought to be a major determinant that leads to hepatocellular carcinoma, its pathophysiological role in humans remains to be established. Attempts have been made to evaluate the role of HBx in liver specimens derived from patients with chronic B viral hepatitis and hepatocellular carcinoma. Among 25 paired liver specimens of hepatocellular carcinoma and corresponding nontumour liver tissues, HBx mRNA was hardly detected and was significantly lower than other HBV transcripts. An immunohistochemical study demonstrated that expression of HBx protein was also lower than other HBV gene products. Interestingly, however, expression of HBx protein changed with the progression of chronic hepatitis. HBx was expressed in 5.0% of patients with chronic hepatitis without cirrhosis but increased to 44.8% in chronic hepatitis with cirrhosis. In contrast, only one (3.7%) of 27 hepatocellular carcinomas showed HBx positivity whereas 29.6% of surrounding nontumour tissues was still HBx-positive. These results suggest that HBx may play a major role at the promotion stage of carcinogenesis. Noticeably, HBx-positive cells were preferentially localized in the periportal region of chronic hepatitis or periphery of cirrhotic nodules where high necroinflammatory activity was accompanied. We found a positive correlation between HBx expression and periportal inflammatory activity (P < 0.001). Thus, HBx may potentiate cell destruction and regeneration of liver that provide an opportunity for the accumulation of genetic mutations, which contribute to multistep hepatocarcinogenesis.

Chemotherapeutic drug, adriamycin, restores the function of p53 protein in hepatitis B virus X (HBx) protein-expressing liver cells.

Hepatitis B virus X (HBx) protein implicated in the development of liver cancer may inhibit the function of p53 tumor suppressor protein through cytoplasmic retention of p53 protein. Here, we attempt to investigate whether the functional inhibition of p53 protein by HBx protein is reversible. First, we provide the evidence for the association of endogenous p53 protein with HBx by co-immunoprecipitation in stable Chang cells that express HBx protein in an inducible manner (ChangX-34). By immunofluorescence microscopy, the major location of p53 protein of ChangX-34 cells was confirmed at the nuclear periphery as well as in the cytoplasm where HBx protein is mainly expressed. Surprisingly, anticancer drug, adriamycin induces the nuclear translocation of p53 protein sequestered in the cytoplasm. This change is accompanied by the restoration of p53 activity, which results in increased transcriptional activity at the p53-responsive DNA elements as well as increase of p21WAF1 mRNA expression. Further, we observed the induction of cell death and G1 arrest in these cells upon adriamycin treatment regardless of HBx expression. Together, we demonstrate that functional inhibition of p53 protein through its cytoplasmic retention by HBx protein is reversible. These results may be extended into other tumors of which p53 activity is modulated by viral oncoproteins.

A rat model for radiation-induced proctitis.

Radiation proctitis is a frequent acute complication encountered with pelvic irradiation. This study was aimed at establishing the optimal radiation dose for radiation-induced proctitis in rats. Female Wistar rats were used. The rectal specimens were examined morphologically at 5th and 10th day following 10-30 Gy irradiation in single fraction. With increasing dose, mucosal damage became worse, and there was a prominent reaction after > or =15 Gy. We selected 17.5 Gy as an optimal dose for radiation proctitis and examined specimens at day 1-14 and at week 4, 6, 8, and 12 after 17.5 Gy. The rectal mucosa revealed characteristic histological changes with time. An edema in lamina propria started as early as 1-2 days after irradiation and progressed into acute inflammation. On day 7 and 8, regeneration was observed with or without ulcer. Four weeks later, all regeneration processes have been completed with end result of either fibrosis or normal appearing mucosa. This study showed that the radiation injury of the rectum in rat develops in dose-dependent manner as it has reported in previous studies and suggested that 17.5 Gy in single fraction is the optimum dose to evaluate the protective effect of various medications for radiation proctitis in face of the clinical situation.

Tc-99m MIBI SPECT is useful for noninvasively predicting the presence of MDR1 gene-encoded P-glycoprotein in patients with hepatocellular carcinoma.

PURPOSE: Resistance to chemotherapeutic drugs continues to be one of the major unsolved problems in the treatment of cancer. Multidrug resistance is defined as the ability of cells exposed to a single drug to develop resistance to a broad range of structurally and functionally unrelated drugs as a result of enhanced outward transport of drugs mediated by P-glycoprotein that is encoded by multidrug resistance genes. Recent evidence has shown that Tc-99m MIBI is a suitable transport substrate for P-glycoprotein. A potential advantage of Tc-99m MIBI SPECT is its superiority to diagnose noninvasively the presence of P-glycoprotein overexpression in vivo. In this study, the authors determined the association of enhanced MIBI efflux in Tc-99m MIBI SPECT with overexpression of P-glycoprotein in hepatocellular carcinoma. MATERIALS AND METHODS: Thirty-five patients with hepatocellular carcinoma were enrolled in the study. Tc-99m MIBI SPECT was performed 10 minutes after intravenous injection of 20 mCi Tc-99m MIBI. All patients had liver biopsy or surgery within 1 week of MIBI imaging. Immunohistochemical study of the biopsy or resected hepatocellular carcinoma specimens was performed using the avidin-biotin-peroxidase technique with monoclonal antibody JSB-1 directed against P-glycoprotein. RESULTS: On Tc-99m MIBI SPECT, 30 of 35 (85.7%) patients with hepatocellular carcinoma had no Tc-99m MIBI uptake in tumor lesions, whereas five patients with hepatocellular carcinoma had Tc-99m MIBI uptake in tumor lesions. P-glycoprotein expression was observed in tumor tissues of all the patients without Tc-99m MIBI uptake, whereas among the five patients with Tc-99m MIBI uptake, no P-glycoprotein expression was seen in tumor lesions (P < 0.015). CONCLUSION: Tc-99m MIBI SPECT is useful for noninvasively predicting the presence of MDR1 gene-encoded P-glycoprotein in patients with hepatocellular carcinoma.

Pollen ablation of transgenic tobacco plants by expression of the diphtheria toxin A-chain gene under the control of a putative pectin esterase promoter from Chinese cabbage.

We previously showed that a 383 bp (-274 to approximately +109) promoter of a pollen-specific gene, GBAN215-6, had a property of a late gene in pollen development in transgenic tobacco plants. It drove GUS gene expression from uninucleate microspores to pollen tube growth of trinucleated cells. To more precisely characterize the specificity of the promoter, we placed the diphtheria toxin A-chain (DTx-A) coding region under the control of the GBAN215-6 promoter. Transgenic tobacco plants containing the GBAN215-6/DTx-1 were phenotypically normal until an early stage of flowering. The dehisced anthers do not contain pollen grains and the filament length of stamen was shorter than that of normal plants. Microscopic examination showed that ablation of pollen by the expression of DTx-A was variable. The transgenic tobacco plants containing one copy of the DTx-A gene show 50% aborted and 50% normal pollen, which suggests that this gene acts gametophytically. However, most of the transgenic plants with high copy number were male-sterile. When these male-sterile tobacco plants were backcrossed as female with pollen from wild-type tobacco plants, the fruit capsule sizes and seed yields of the next generation (BC1 lines) were severely reduced and the segregation of male-sterile to fertile plants in BC1 seeds was not Mendelian.

Tubular adenoma of the gallbladder with spindle cell metaplasia.

We report four cases of tubular adenoma of the gallbladder with spindle cell metaplasia. Three patients had solitary polyps in the gallbladder and the fourth had multiple (three) polyps. Only one patient who had a polyp of larger size had abdominal pain. Histologically, these tubular adenomas had characteristic morular foci composed of short spindle cells. These spindle cell components lacked intercellular bridges or cytoplasmic keratinization. Immunohistochemically, the spindle cells stained positively for one or more cytokeratins and negatively for vimentin, muscle actin and S-100 protein. Spindle cells are considered to represent the metaplastic component of the adenoma cells.

Cyclin E expression in benign and malignant epithelial neoplasms of the gallbladder.

Cyclins are the regulatory subunits of cyclin-dependent kinase and play an important role in cell proliferation. Many tumors, such as colon, breast and gastric carcinomas are known to be involved in the deregulation or amplification of cyclins, especially cyclin E, which involves the restriction point of G1-S transition. We investigated the expression of cyclin E in benign and malignant epithelial tumors of the gallbladder and compared the results with the activity of cell proliferation by the Ki67 antigen using immunohistochemical staining. Cyclin E was expressed in the adenocarcinoma tissue in 33.3% of patients (4 out of 12 cases), whereas only one out of 8 cases of adenoma expressed cyclin E (12.5%). There was a correlation between cyclin E expression and the Ki67 labeling index. These results suggest that the high expression of cyclin E in adenocarcinoma of the gallbladder is related to a high rate of cell proliferation.

Gastric metastasis of mammary signet ring cell carcinoma--a differential diagnosis with primary gastric signet ring cell carcinoma.

Metastasis of breast carcinoma to the stomach is relatively uncommon, although metastasis to other organs such as lung, bone, and lymph nodes is not rare. It may cause difficulty in differentiating from primary gastric carcinoma. We report a case of signet ring cell carcinoma of the breast with metastasis to the stomach with illustrations of histologic findings of both lesions. The results of immunohistochemical stainining with GCDFP-15 (gross cystic disease fluid protein-15), that can be used to differentiate primary gastric signet ring cell carcinoma and metastatic mammary signet ring cell carcinoma, are described.

Promoter sequences of two homologous pectin esterase genes from Chinese cabbage (Brassica campestris L. ssp. pekinensis) and pollen-specific expression of the GUS gene driven by a promoter in tobacco plants.

The promoter regions of two genomic clones, GBAN215-6 and GBAN215-12 from Chinese cabbage (Brassica campestris L. ssp. pekinensis), were sequenced. The nucleotide sequences of their promoter regions were compared with that of the Bp19 pollen-specific gene of Brassca napus. High nucleotide sequence homologies were observed among these three genes in the region between 210 bp upstream and the putative transcription start site. A sequence motif TGTGGTG, which is similar to that of the PB core motif (TGTGGTT) of two tomato pollen-specific genes, LAT52 and LAT56, was present in these two cloned genes. To determine regulatory sequences responsible for the anther-specific expression of the gene BAN215-6, two recombinant plasmids, pBPE3 (-274- + 109) and pBPE4 (-816- + 109) containing different lengths of the promoter fused with the GUS gene, were constructed and introduced into tobacco plants by Agrobacterium-mediated transformation. The result showed that the 383 bp (-274- + 109) of the BAN215-6 promoter region was sufficient for the anther-specific expression of the GUS gene. The GUS expression in a tobacco plants transformed with these constructs was first detected in uninucleate microspores and persisted at in vitro germinated pollen tubes. The expression level was increased during anther development, reaching the highest level in mature pollens.

Pancreatic serous cystadenoma mimicking pseudocyst.

The serous cystadenoma of the pancreas is a rare lesion that is usually found incidentally. It is mostly observed as a spongy microcystic mass but rare variants such as macrocystic, unicystic, or multicentric are also seen. We recently experienced a unique case of unicystic serous cystadenoma mimicking a pseudocyst. It was grossly a unilocular cyst with surrounding dense fibrosis resembling a pseudocyst. Microscopically, the cyst was partly lined by low columnar-to-cuboidal cells with clear cytoplasm containing glycogen.

Protease-activated lymphoid cell and hepatocyte recognition site in the preS1 domain of the large woodchuck hepatitis virus envelope protein.

A site capable of strictly host- and cell type-specific recognition was identified in the preS1 domain of woodchuck hepatitis virus (WHV) through the use of antipeptide antisera generated against the extreme N-terminal fragment of the large virus envelope protein. The crucial determinant of this binding site was mapped to amino acids 10-13. Although a synthetic analogue of the site was highly immunogenic, natural WHV envelope did not display the site activity unless it was modified by proteolysis or acidic pH treatment, indicating an internal location of the determinant in viral envelope. Synthetic peptides encompassing the sequence of this site bound woodchuck lymphoid cells and hepatocytes in a species-restricted manner which followed characteristics of a specific ligand-receptor interaction, although their ability to interact with lymphoid cells was considerably greater than that for hepatocytes. In WHV-infected animals, a natural antibody to the identified cryptic cell-binding site arose independently of that directed against epitopes of unmodified virus envelope and its appearance constituted the earliest immunovirological indicator of virus invasion. Our results demonstrated that the preS1 domain of the large WHV envelope protein is endowed with the species- and cell type-specific recognition site which is protected against antibody surveillance by the natural tertiary structure of the protein and we suggest that proteolytic cleavage is required to induce the binding activity.

Mitogenic properties of Ukrain (NSC-6315170) on human peripheral blood monocytes: clinical implications.

Using a cell-proliferation assay, the authors examined and compared the mitogenic effects of Ukrain and phytohaemagglutinin (PHA) on human peripheral blood mononuclear cells (PBMCs), as well as their synergic effects. It was found that even a short period of pretreatment of the cell with Ukrain had a potent synergic effect on PHA mitogenesis resulting in significantly higher cell stimulation indices than those of PHA alone. Moreover, it was found that a short period of PHA treatment of the cells is almost imperative for Ukrain to exert its mitogenic effects. The mitogenic effect of Ukrain on human PBMCs is consistent with a previous clinical report which found that circulating lymphocytes were significantly increased in cancer patients treated with Ukrain. Thus the in vitro assay used in these studies may serve as a prognostic assay for potential patient responsiveness to Ukrain treatment, as well as a clinical parameter during Ukrain therapy.

Identification and characterization of the cell surface 70-kilodalton sialoglycoprotein(s) as a candidate receptor for encephalomyocarditis virus on human nucleated cells.

The attachment of encephalomyocarditis (EMC) virus to human nucleated cells susceptible to virus infection was examined with HeLa and K562 cell lines. Both cell types showed specific virus binding competitively blocked by unlabeled virions. The number of binding sites for EMC virus on HeLa and K562 cells were approximately 1.6 x 10(5) and 3.5 x 10(5) per cell, respectively, and dissociation binding constants were 1.1 and 2.7 nM, respectively. Treatment of cells with cycloheximide after pretreatment with trypsin eliminated EMC virus attachment, suggesting that the virus-binding moiety is proteinaceous in nature. Digestion of cells, cell membranes, and sodium deoxycholate-solubilized cell membranes with proteases or neuraminidases or treatment of cells with lectins demonstrated that the EMC virus-cell interaction is mediated by a sialoglycoprotein. Proteins with a molecular mass of 70 kDa were isolated from detergent-solubilized cell membranes of both HeLa and K562 cells by EMC virus affinity chromatography. The purified proteins, as well as their 70-kDa-molecular-mass equivalents detected in intact surface membranes of HeLa and K562 cells, specifically bound EMC virus in a virus overlay protein blot assay, whereas membranes from nonpermissive K562 D clone cells did not. Western immunoblot analysis with glycophorin A-specific antibody confirmed that the identified 70-kDa binding site on K562 cells is not glycophorin A, which is the EMC virus receptor molecule on virus-nonpermissive human erythrocytes (HeLa cells do not express glycophorin A). These results indicate that EMC virus attachment to permissive human cells is mediated by a cell surface sialoglycoprotein(s) with a molecular mass of 70 kDa.

Localization of vitronectin- and fibronectin-receptors on cultured human glioma cells.

Utilizing a human astrocyte-derived glioma cell line, we have demonstrated the presence of a vitronectin receptor, alpha v beta 3, and a fibronectin receptor, alpha 5 beta 1, on the surface of the cells spreading on the respective adhesion molecules by immunohistochemical analyses. By phase-contrast microscopy, these receptors were found to be expressed predominantly in the focal contact-like area, suggesting that they were involved in the spreading of the cells upon contact with these adhesion molecules. Interestingly, they appeared to have differential functions and roles as integrins as evidenced by different time-dependent distribution profiles on the cell surface in the serum-containing medium. Furthermore, both vitronectin and fibronectin seem to have chemotactic effects onto the glioma cells as observed in a Boyden chamber study. Although these receptors are not expected to be present on the surface of astrocytes under physiological conditions, they may be expressed thereon and involved in gliosis when the cerebral vasculature is traumatized and, thereby, blood proteins, including vitronectin and fibronectin, come into contact with the astrocytes.