Remote scoring models of rigidity and postural stability of Parkinson's disease based on indirect motions and a low-cost RGB algorithm

Background and objectives

The Movement Disorder Society's Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS III) is mostly common used for assessing the motor symptoms of Parkinson's disease (PD). In remote circumstances, vision-based techniques have many strengths over wearable sensors. However, rigidity (item 3.3) and postural stability (item 3.12) in the MDS-UPDRS III cannot be assessed remotely since participants need to be touched by a trained examiner during testing. We developed the four scoring models of rigidity of the neck, rigidity of the lower extremities, rigidity of the upper extremities, and postural stability based on features extracted from other available and touchless motions.

Methods

The red, green, and blue (RGB) computer vision algorithm and machine learning were combined with other available motions from the MDS-UPDRS III evaluation. A total of 104 patients with PD were split into a train set (89 individuals) and a test set (15 individuals). The light gradient boosting machine (LightGBM) multiclassification model was trained. Weighted kappa (k), absolute accuracy (ACC ± 0), and Spearman's correlation coefficient (rho) were used to evaluate the performance of model.

Results

For model of rigidity of the upper extremities, k = 0.58 (moderate), ACC ± 0 = 0.73, and rho = 0.64 (moderate). For model of rigidity of the lower extremities, k = 0.66 (substantial), ACC ± 0 = 0.70, and rho = 0.76 (strong). For model of rigidity of the neck, k = 0.60 (moderate), ACC ± 0 = 0.73, and rho = 0.60 (moderate). For model of postural stability, k = 0.66 (substantial), ACC ± 0 = 0.73, and rho = 0.68 (moderate).

Conclusion

Our study can be meaningful for remote assessments, especially when people have to maintain social distance, e.g., in situations such as the coronavirus disease-2019 (COVID-19) pandemic.

[Risk factor and early diagnosis of anastomotic leakage after rectal cancer surgery]

Anastomotic leakage (AL) is one of the most serious complications after sphincter- preserving surgery for rectal cancer, which can significantly prolong the length of stay of patients, increase perioperative mortality, cause dysfunction, shorten overall survival and recurrence-free survival of patients. In order to reduce the serious consequences caused by AL, prediction of AL through preoperative and intraoperative risk factors are of great importance. However, the influences of neoadjuvant chemoradiotherapy, protective stoma, laparoscopic surgery and some intraoperative manipulations on AL are still controversial. Through the auxiliary judgment of anastomotic blood supply during operation, such as indocyanine green imaging, hemodynamic ultrasound, etc., it is expected to achieve the source control of AL. Early diagnosis of AL can be achieved by attention to clinical manifestations and drainage, examination of peripheral blood, drainage and intestinal flora, identification of high risk factors such as fever, diarrhea and increased infectious indicators, and timely administration of CT with contrast enema.

Construction and validation of a novel Ferroptosis-related gene signature predictive model in rectal Cancer

Background

Rectal cancer (RC) is one of the most common malignant tumors. Ferroptosis is an iron-dependent form of cell death, which plays an important role in various cancers. However, the correlation between ferroptosis-related genes (FRGs) and prognosis in RC remains unclear.

Methods

Gene expression data from The Cancer Genome Atlas Rectum adenocarcinoma (TCGA-READ) and GSE87211 were downloaded. Clustering and functional enrichment were evaluated. A FRGs risk score was established based on the univariate Cox analysis and the Least absolute shrinkage and selection operator (LASSO) analysis. K-M analysis and ROC analysis were conducted to determine prognostic values. qRT-PCR was performed to validate levels of mRNA expression. Multivariate Cox analysis was used to build a prognostic prediction model based on the risk score.

Results

Based on FRGs, RC patients were grouped into two clusters. In the functional enrichment of differentially expressed genes between the two clusters, immune-related pathways dominated. A novel FRGs signature with 14 genes related to the overall survival (OS) of RC was established. qRT-PCR of the 14 genes identified TP63, ISCU, PLIN4, MAP3K5, OXSR, FANCD2 and ATM were overexpressed in RC tissue; HSPB1, MAPK1, ABCC1, PANX1, MAPK9 and ATG7 were underexpressed; TUBE1 had no difference. The high-risk group had a significantly lower OS than the low-risk group (P < 0.001), and ROC curve analysis confirmed the signature’s predictive capacity. Multivariate analysis demonstrated that the risk score and age were independent prognostic factors.

Conclusion

A novel FRGs model can be used to predict the prognosis in RC, as well as to guide individual treatment.

[Quality of life of patients with locally advanced rectal cancer after neoadjuvant therapy and sphincter-preserving surgery]

Objective: To investigate quality of life (QoL) of patients with locally advanced rectal cancer (LARC) who underwent low anterior resection with protective stoma under neoadjuvant therapy mode, and to explore the changes of QoL of patients from before neoadjuvant therapy to 12 months after stoma reversal. Methods: A descriptive case series study was carried out. A retrospective study was performed on patients with mid and low LARC who received complete neoadjuvant long course radiotherapy and chemotherapy, followed by radical low anterior resection (LAR) combined with protective stoma at Peking Union Medical College Hospital from December 2017 to January 2020. Inclusion criteria: (1) patients with rectal MRI assessment of mT3-4b or mN1-2 without distant metastasis (M0) before neoadjuvant therapy; (2) distance from tumor lower margin to the anal verge <12 cm; (3) rectal adenocarcinoma confirmed by biopsy before neoadjuvant therapy; (4) complete cycle of neoadjuvant therapy; (5) patients undergoing radical LAR with sphincter preservation and protective ostomy; (6) patients receiving follow-up for more than 12 months after stoma reversal. Exclusion criteria: (1) patients as grade Ⅳ to Ⅴclassified by the American Society of Anesthesiologists (ASA); (2) patients with multiple primary colorectal cancer; (3) patients with history of other malignant tumors in the past 5 years; (4) patients of emergency surgery; (5) pregnant or lactating women; (6) patients with history of severe mental illness; (7) patients with contraindication of MRI, radiotherapy, chemotherapy, or surgical treatment. A total of 83 patients were enrolled, including 51 males and 28 females with median age of 59 years and mean BMI of (24.4±3.1) kg/m(2). EORTC QLQ-CR29, international erectile function index (IIEF), Wexner constipation score and low anterior resection syndrome (LARS) score were applied to investigate the QoL of the patients before neoadjuvant therapy, 3 and 12 months after ostomy reversal, including rectal anal function and sexual function. M (P25, P75) was used for the scores of the scale. Results: (1) EORTC QLQ-CR29 score showed that before neoadjuvant therapy, before surgery, 3 months and 12 months after ostomy reversal, anxiety [64.4 (52, 0, 82.5), 75.3 (66.0, 89.5), 82.6 (78.5, 90.0), 83.6 (78.0, 91.0)] and concern about body image [76.8 (66.0, 92.0), 81.1 (76.5, 91.5), 85.5 (82.5, 94.0), 86.1 (82.0, 92.0)] were improved (all P<0.01); pelvic pain [5.4 (2.0, 8.0), 5, 0 (2.0, 7.8), 3.9 (1.0, 5.0), 3.0 (1.0, 5.0)], urinary incontinence [15.7 (7.0, 22.0), 11.1 (0, 17.5), 10.0 (0, 17.0), 9.9 (0, 16.0)], impotence [14.3 (4.2, 19.0), 12.2 (0, 16.8), 5.6 (0, 10.0), 5.2 (0.2, 8.0)], urinate [26.4 (13.0, 38.5), 13.9 (0, 20.0), 13.4 (2.5, 21.5), 13.2 (2.0, 20.0)] and mucous bloody stool [4.7 (3.0, 6.0), 2.6 (0, 5.0), 2.2 (0, 5.0), 1.9 (0, 4.0)] were improved as well (all P<0.01). The scores fluctuated in the improvement of male sexual function, abdominal pain, dry mouth, worry about body mass change, skin pain and dyspareunia, but the symptoms were significantly improved after ostomy reversal compared with before neoadjuvant therapy (all P<0.05). There were no significant changes in female sexual function, dysuria, dysgeusia and fecal incontinence after ostomy reversal compared with before neoadjuvant therapy (all P>0.05). (2) IIEF scale showed that all scores were similar before and after neoadjuvant therapy (all P>0.05). (3) Rectal and anal function scale revealed that before neoadjuvant therapy, before operation, 3 months and 12 months after stoma reversal, gas incontinence [3.1 (0, 4.0), 2.3 (0, 4.0), 1.8 (0, 4.0), 1.2 (0, 3.0)] and urgent defecation [7.2 (0, 11.0), 5.2 (0, 11.0), 2.9 (0, 9.0), 1.7 (0, 0)] were improved (all P<0.001). In terms of improving incomplete emptying sensation, the symptoms fluctuated, but the symptoms improved significantly after ostomy reversal compared with before neoadjuvant therapy (all P<0.05). While the symptoms of assistance with defecation [0 (0, 0), 0.7 (0, 1.0), 0.6 (0, 1.0), 0.7 (0, 1.0)] and defecation failure [0.2 (0, 0), 1.0 (0, 2.0), 0.8 (0, 1.5), 0.8 (0, 1.0)] showed a worsening trend (all P<0.001). Stratified analysis was performed on patients with different efficacy of neoadjuvant therapy to compare the changes in QoL before and after neoadjuvant therapy. Patients with less sensitive and more sensitive neoadjuvant therapy showed similar changes in function and symptoms. Patients with less sensitive therapy showed significant improvement in dysuria, urinary incontinence, skin pain and dyspareunia (all P<0.05), and the symptom of defecation frequency in more sensitive patients was significantly improved (P<0.05). Conclusions: For patients with LARC, neoadjuvant radiochemotherapy combined with radical LAR and protective stoma can improve QoL in many aspects. It is noted that patients show a worsening trend in the need for assistance with defecation and in defecation failure.

The Cell Cycle-Associated Protein CDKN2A May Promotes Colorectal Cancer Cell Metastasis by Inducing Epithelial-Mesenchymal Transition

Colorectal cancer (CRC) is a common gastrointestinal malignancy, and recurrence and metastasis contribute considerably to its high mortality. It is well known that the epithelial-mesenchymal transition (EMT) accelerates the rate of cancer cell dissemination and migration, thus promoting cancer metastasis. Targeted therapy is a common modality for cancer treatment, and it can play a role in inhibiting cancer progression. In this study, bioinformatics was used to search for genes associated with the prognosis of CRC. First, differential analysis was performed on colon and rectal cancer samples to obtain 2,840 and 3,177 differentially expressed genes (DEGs), respectively. A Venn diagram was then used to identify 262 overlapping genes from the two groups of DEGs and EMT-related genes. The overlapping genes were subjected to batch survival analysis and batch expression analysis successively, and nine genes were obtained whose high expression in CRC led to a poor prognosis. The least absolute shrinkage and selection operator (LASSO) prognostic model was then constructed to obtain the risk score formula. A nomogram was constructed to seek prognostic independent factors to obtain CDKN2A. Finally, CCK-8 assay, flow cytometry and western blotting assays were performed to analyze the cellular biological function of CDKN2A. The results showed that knockdown of CDKN2A expression inhibited HT-29 cell proliferation, promoted apoptosis and cell cycle progression, and affected the EMT process in CRC.

Long-term outcomes of transanal endoscopic microsurgery for the treatment of rectal neuroendocrine tumors

Background

Transanal endoscopic microsurgery (TEM) has been accepted worldwide for the treatment of local rectal lesions. We aimed to assess the efficacy and safety of TEM in the treatment of rectal neuroendocrine tumors (RNET).

Methods

A retrospective study of patients who had undergone TEM for RNET at our institution between December 2006 and June 2019 was performed. Demographic and tumor characteristics, operative and pathological details, complications, anal function questionnaires, and follow-up data were included.

Results

A total of 144 patients was included. TEM was performed as primary excision in 54 patients, after endoscopic forceps biopsy in 57 patients, and after incomplete resection by endoscopic excision in 33 patients. The median size of all primary tumors was 0.6 cm (range, 0.3–2.0 cm), and the negative resection margin was achieved in 142 (98.6%) patients. Postoperative complications (referring to only bleeding) occurred in 3 (2.1%) patients and was successfully managed with conservative method. After a median follow-up of 75.5 months after surgery, 3 patients died of other causes, and 2 patients suffered metastasis. An anal function questionnaire was posted 24 months after TEM. Among the results, 3 (2.1%) patients complained of major low anterior resection syndrome (LARS), including 1 (0.7%) who suffered from complete incontinence, while 6 (4.2%) patients had minor LARS.

Conclusions

TEM has satisfying long-term outcomes and relatively low anal function disturbance as for the treatment of small RNET. TEM also acts as a preferred salvage treatment for incomplete endoscopic excision.

Predictive ability of prognostic nutritional index in surgically resected gastrointestinal stromal tumors: a propensity score matching analysis

Prognostic nutritional index was found to be correlated with prognosis in GISTs before and after propensity score matching and its incorporation improved the prognostic stratification of NIH risk criteria.

[The development of a full-automated blood coagulation analyzer]

This paper introduces the electronic principles and systematic construction functions of a full-automated blood coagulation analyzer, which can measure the blood coagulation rightly and effectively in the clinic. by using the scattered light turbidmetry. This analyzer overcomes some shortcomings existing in other analyzers such as high price, low resolution and no quality control function.

[Expression of LIF gene during early development of mouse embryo]

Leukemia inhibitory factor (LIF) has the ability to maintain the development potential of pluripotent embryonic stem cells, suggesting that this factor might play an important role during mouse embryogenesis. By whole mount in situ hybridization on early mouse embryos, we have examined the expression pattern of the LIF gene from the two cell stage to the preimplantation blastocyst with the following results. (1) LIF transcripts were detected at all stages before implantation, but the highest level of LIF mRNA expression occurred in the blastocyst stage. (2) For the cleavage stages of mouse embryo, there was no significant distinction of the LIF gene expression level between blastomeres, but a strong signal was detectable in the cells which surrounded the blastocoel cavity of the blastocyst and most of them belonged to future extraembryonic tissues. These results suggest that a principal function of LIF in vivo may be to regulate stem cell population and to play an important role in the implantation of the blastocyst.

[Study on growth and differentiation of ES cells transfected with LIF gene]

We constructed plasmids pSVLD(+) and pSVLD(-) containing human D-form Leukemia Inhibitory Factor (LIF) cDNA sequence in sense or antisense orientation, transfected them into cells of an embryonic stem cell line ES-5, and isolated 248 pSVLD(+)-transfected and 93 pSVLD(-)-transfected G 418-resistant clones. By stepwise reducing LIF concentration in the medium, we obtained 3 pSVLD(+)-transfected clones (A 1-3) that could grow in 15% BRL-CM, including ESL(+)A 2 that could grow without LIF: we also obtained 13 pSVLD(-)-transfected clones (B 1-13) which would differentiate in 60% BRL-CM, including ESL(-)B 3 and B 5 that could not be passaged without LIF. ESL(+)A 2 and ESL(-)B 5 cells had the relatively stronger LIF mRNA or antisense LIF RNA expression, and LIF overexpression in ESL(+)A 2 cells was shown by biological assay for ES cell differentiation inhibition. ESL(+)A 2 cells could be continuously passaged for at least 13 passages without addition of exogenous LIF, retained undifferentiated morphology as well as a high growth rate, and resembled ES-5 cells in terms of stem cell characteristics and pluripotent properties, as analyzed for alkaline phosphatase activity and with staining the paraffin sections of tumor formed by inoculating ESL(+) A 2 cells into mouse. On the contrary, ESL(-) cells should be cultured in higher concentration of LIF than ES-5 cells, otherwise, would undertake extensive differentiation. By hanging drop culture for 3 days in the presence of 10(-6) mol/L RA then observing the differentiation of the formed embryonic bodies (EBs), we found that ESL(+) A 2 and ES-5 cells underwent similar morphologically differentiation, with round and epitheliallike cells occurring around the EBs; while ESL(-) B 5 cells, despite initial differentiation to round cells, differentiate into fibroblast-like and spindle shaped cells. The above results indicate that LIF overexpression in ESL(+) A 2 cells is able to completely free ES cells from the dependence on LIF-conditioned medium, and endogenous LIF gene expression, although is very low, may be indispensable for inhibiting the differentiation in vitro of ES cells; LIF overexpression might not obviously change the differentiation way of ES-5 cells, however, blocking endogenous LIF expression gives rise to the increased sensitivity of ES-5 cells to differentiate, with an altered differentiation pattern. The establishment of ESL(+) and ESL (-) cell lines provides models for further study of the growth and differentiation of ES-5 cells.

[Expression of exogenous porcine transforming growth factor beta-1 gene in ES cells and its effect on their differentiation in vitro]

A TGF-beta 1 gene expression plasmid was constructed by inserting the porcine 1.7 Kb TGF-beta 1 cDNA into BamHI site of retrovirus vector Dol. The plasmid DNA was introduced into mouse embryonic stem cells (ES-5 line) by calcium phosphate mediated transfection, and transfected ES-5 cells were then selected by stepwise increase in G418 concentration. Finally, we obtained 21 clones that could be stably grown in culture medium with G418 at 500 micrograms/ml and were designated as ES-T cells. Dot blot and Northern analysis of total RNA and polyA+ RNA extracted from those ES-T cells were shown in FIg. 2 and 3, demonstrating that 6 clones could express exogenous porcine TGF-beta 1 mRNA. The stronger hybridized signal in two clones (ES-T6 and ES-T 16) of them were further proved by southern hybridization of genomic DNA from these ES-T cells with 1.7 Kb TGF-beta 1 cDNA probe (Fig. 4). The product of TGF-beta 1 gene overexpression in ES-T 6 cells was shown in Fig. 5 and 6 by SE-LISA for TGF-beta 1 immunoreactivity to TGF-beta 1 antibodies and biological assay for CCL/64 cell growth inhibition, respectively. With respect to some biological characteristics, ES-T 6 cells, like their parent ES-5 cells, retained their pluripotent properties and positive SSEA-1 antigen (Plate I, Fig. 1). ES-T6 cells were expanded and used for studies of in vitro differentiation. Both of ES-T 6 cells and control ES-5 cells could form a lot of simple aggregates and differentiate into embryoid bodies by hanging drop culture for 3 days in the presence of retinoic acid (RA) at 10(-9) mol/L. Then individual embryoid bodies were plated on gelatinized tissue culture wells. On the third day of further culture without RA, a large amounts of epithelial-like and round cells occurred around the embryoid bodies formed either from ES-T 6 cells or ES-5 cells (Plate I, Fig. 4). However, with further culture of embryoid bodies, only the cells differentiated from ES-T6 embryoid bodies could arrange themselves and differentiate into a lot of radially arranged tubular structures (Plate II, Fig. 5). The frequency of tubular structures present in ES-T6 embryoid bodies were about 95.5%, but in ES-5 group there was only about 17.8% cases giving less defined tubular structures (Plate III, Fig. 8).(ABSTRACT TRUNCATED AT 400 WORDS)

[Studies on a new tumor marker with monoclonal antibody against human colorectal carcinoma antigen]

A hybridoma 1 G 10 clone was derived from fusion between SP 2/0- Ag14 myeloma cells and spleen cells of BALB/C mice immunized with the soluble Noridet P40 extracts from a human colonic adenocarcinoma cell line SW 620. The 1 G 10 clone was identified to be able to produce monoclonal antibody of IgG1 subclass which had sufficient titer for immunoreactivity to both extracts from SW 620 cells and surgical colonic carcinoma tissues, but no immunoreactivity to both extracts from normal adult colorectal tissues, mixed human lymphocytes and normal human serum (NHS) as well as carcinoma embryonic antigen (CEA) by enzyme-linked immunosorbent assay (ELISA). By affinity column on Sepharose 4 B coupled with 1 G 10 IgG, colonic carcinoma-associated antigen (CCA) was purified from SW 620 cell extracts and thoracic ascitic fluid of a patient with lung adenocarcinoma. Western blotting analysis with 1 G 10 IgG demonstrated that one immunoreactive bands corresponding to 55 Kd molecule was observed in the samples of ascitic fluid and SW 620 cell extracts. The 55 Kd band could be stained with Alcian blue. The immunoreactivity of CCA to 1 G 10 antibody could be abolished completely by the treatment of the antigen with NaIO4 and proteinase K. These results indicated that the determinants of CCA reacted with 1 G 10 monoclonal antibody are probably both present in polysaccharide and protein part of the molecule. The specificity of anti-CCA 1 G 10 monoclonal antibody and its possible application for clinical oncology were discussed.

[Biological characterization of a monoclonal antibody TB 21 against human transforming growth factor-beta 1]

A hybridoma TB 21 clone was derived from fusion between Sp 2/0-Ag 14 myeloma cells and spleen cells of BALB/c mice immunized with transforming growth factor-beta 1 (TGF-beta 1) purified from human platelets. The TB 21 clone was identified to produce monoclonal antibody with IgG1 subclass and had sufficient titer for immunoreactivity to both human platelets-derived TGF-beta 1 and recombinant human TGF-beta 1 by enzyme-linked immunosorbent assay (ELISA). Western blotting studies demonstrated that two immunoreactive bands corresponding to 25 Kda and 12.5 Kda molecules were observed in the sample of acid/ethanol extracts from human platelets. The affinity constant (Kaff) was determined as 1.47 x 10(8) M-1 with non-competitive ELISA. Moreover, using bioassay for the effects of TGF-beta 1 on the growth of mink lung epithelial cells (CCL/64 cell line) and fibroblast cells (NRK 49 F cell line), TB 21 IgG was shown to be able to neutralize the action of TGF-beta 1 on the growth of these target cells. Therefore, this monoclonal antibody may be a useful probe for studying the growth modulatory activity of TGF-beta 1 in a variety of cells and tissues.

[Immunohistochemical localization of transforming growth factor beta-1 during the early mouse development]

The distribution of transforming growth factor beta-1 (TGF-beta-1) in the early developing mouse embryos between day 1 and day 12 of gestation was examined by immunohistochemical techniques. Polyclonal rabbit antiserum raised against a synthetic oligopeptide identical to the N-terminal residues 1-29 of TGF-beta-1 from human platelets was used. The following results were obtained: 1. Embryonic cells of early cleavage stages (2, 4 and 8 cells) and late morulae showed positive immunofluorescent reaction without any difference in staining intensity (Plate I, Figs. 1-4). 2. Marked staining of blastocysts in toto or sections with anti-TGF-beta-1 antibodies by either immunofluorescence or immunoperoxidase reaction was also observed. Inner cell mass (ICM) cells and trophoectoderm cells were both reacted, but more intense staining was found in primary endoderm cells differentiated from ICM cells adjacent to blastocoele (Plate II, Fig. 5). 3. Scattered granules stained strongly with immunoperoxidase reaction were present in embryonic ectoderm and visceral endoderm surrounding the forming mesoderm which was only slightly stained (Plate II, Fig. 6). 4. Intense immunoperoxidase staining was also present in mesoderm of visceral yolk sac of day 8 and day 10 embryos (Plate II, Fig. 7). 5. During the formation of somites, neural tube and limb bud, remarkable staining was found in mesenchyme, individual cells of somites, mucous layer of gut tubes, heart and limb buds (Plate III, Figs. 8-10). No significant staining was seen in neural cells per se except the inner surface of neural tube. The results of present studies indicate that abundant TGF-beta-1 is present in preimplantation mouse embryos including cleavage, morulae and blastocyst stages. In postimplantation embryos, TGF-beta-1 appears to play an important role in the differentiation of endoderm and mesoderm, particularly in the development of extraembryonic tissues, and in later morphogenetic and histogenetic events involving mainly mesoderm or mesenchyme cells.

[Epidermal growth factor receptor of human liver cancer cells and its modulation by phorbol ester]

Using radioligand binding assay, the presence of epidermal growth factor (EGF) receptors in cells of two human liver cancer cell lines, BEL-7402 and SMMC-7721, was demonstrated. The ligand binding data were analyzed by a computer program. The dissociation constants (KD) of the ligand-receptor binding complex at equilibrium for 7402 and 7721 cells were 1.2 nM and 0.8 nM respectively, and their number of EGF receptors per cell were 6.2 x 10(4) and 2.5 x 10(4) respectively. After the treatment of cells with phorbol 12-myristate 13-acetate (PMA), no change either in the affinity or in the number of EGF receptors was found in 7721 cells. However, in the case of 7402 cells, while the number of receptors, like 7721 cells, remained unchanged, the affinity of EGF receptors displayed a time dependent modulation after PMA treatment. It dropped within the first hour to a KD value of 3.0 nM and then gradually returned to the normal control value at 48 hours or even slightly higher than normal (0.95 nM) at 96 hours of treatment. The modulation or down-regulation of EGF receptors by PMA in 7402 cells was paralleled by the simultaneous inhibition of DNA synthesis in these cells as evidenced from their reduction of 3H-TdR uptake. It is not clear what is the basis for the differences found between 7402 cells and 7721 cells in their number of EGF receptors per cell and their responsiveness to PMA treatment. It might be related to their difference in autocrine secretion of alpha-transforming growth factors.(ABSTRACT TRUNCATED AT 250 WORDS)

[A transforming growth factor-beta like growth factor in mouse embryonal carcinoma cells]

Our previous study indicated that polypeptides isolated from acid/ethanol extracts of solid tumors of a cloned F9-3 embryonal carcinoma cells by Bio-Gel P60 column chromatography were found to be able to stimulate anchorage independent growth of either NIH 3T3 cells or NRK 49 F cells in soft agar. The major peak of active elute had a molecular weight of about 15 kDa as determined by SDS-polyacrylamide gel electrophoresis. In the present report we further isolated and purified the active compound corresponding to molecular weight of 15 kDa by gel filteration on Bio-Gel P10 column (Fig. 1) and then by high pressure liquid chromatography (Fig. 2). It was found that the purified 15 kDa molecules showed some properties similar to transforming growth factor-beta (TGF-beta): 1. Colony-stimulating activity in soft agar can be induced in NRK 49 F cells only in the presence of mouse epidermal growth factor (EGF) (Plate I); 2. Increase in relative uptake of 3H-thymidine in NRK 49 F cells occurred in the presence of EGF, but with the same amount of EGF, not much change in 3H-thymidine incorporation could be found with further increasing amounts of purified 15 kDa molecules (Fig. 3); 3. Like human blood platelets derived TGF-beta, inhibition effect on the growth of mink lung epithelial cells (CCL/64) can also be exhibited by purified 15 kDa molecules (Fig. 4). In addition, using ELISA procedure, we have also demonstrated that the 15 kDa molecules had immunological reactivity with the antibody raised against a synthetic oligopeptide identical to the N-terminal residues 1-29 of TGF-beta 1 from human blood platelets (Fig.5). Thus, the 15 kDa molecules isolated from mouse F9-3 embryonal carcinoma cells appeared to share some common antigenic determinants with human TGF-beta 1 molecule. These results taken together provide strong support for the existence of TGF-beta like growth factor in mouse embryonal carcinoma cells.

Developmentally regulated expression of insulin-like growth factors by differentiated murine teratocarcinomas and extraembryonic mesoderm

The expression of plasma membrane receptors for insulin-like growth factors (IGFs) by PC13 embryonal carcinoma (EC) cells, and their immediate differentiated progeny PC13END was examined by binding radiolabelled IGF-I to cell monolayers. Both cell types express high-affinity IGF receptors, but the apparent number of unoccupied receptors sites falls by about 60% upon differentiation. Crosslinking studies reveal that both type 1 and type 2 IGF receptors are expressed by PC13EC cells. PC13END-cell-conditioned medium contains developmentally regulated, separable activities, one of which reacts directly with IGF-II, and the other with IGF for plasma membrane receptors. The former activity represents a soluble secreted IGF-binding protein. The latter activity is structurally and functionally similar to rat IGF-II. Polyclonal antibodies raised against purified rat IGF-II specifically recognize multiple forms of IGF in radiolabelled culture supernatants and material which closely resembles the soluble IGF-binding protein. Immunoprecipitation of radiolabelled culture supernatants with anti-rat IGF-II reveals that the differentiation of PC13EC cells is accompanied by the coexpression of IGF-like molecules and the soluble binding protein, and that IGF-like molecules are expressed by extraembryonic tissues of mesodermal origin in the early postimplantation mouse embryo. These findings show that IGF-like molecules are expressed in early mammalian development and may act in an autocrine fashion in vivo.

Cloned human teratoma cells differentiate into neuron-like cells and other cell types in retinoic acid

Single cell clones were isolated from the human teratoma line, Tera-2. The cells of three of these clones were studied. The progressively growing cells were shown to be tumorigenic, and they were characterized by the lack of expression of beta 2-microglobulin and HLA-A,B,C determinants on the cell surface. The majority of the cells expressed Thy-1 antigen and a 90 X 10(3) molecular weight protein recognized by the monoclonal antibody F10.44.2; between a third and half of the cells expressed the sugar specificities detected by the anti-SSEA-1 monoclonal antibody. In response to 5 X 10(−5) M-retinoic acid applied to cells in monolayer culture, the cells differentiated into a population of flat static cells arrested in the G1 phase of the cell cycle. A substantial proportion of these differentiated cells expressed beta 2-microglobulin and 43 X 10(3) molecular weight HLA-A,B,C polypeptides, Thy-1, SSEA-1 sugar determinants, and the 90 X 10(3) Mr protein recognized by F10.44.2. The apparent molecular weight of fibronectin secreted by the cells decreased by about 5 X 10(3) Mr to 235 X 10(3) Mr after differentiation. The progressively growing cells lacked reactivity with reagents that mark cells in the nervous system. Following aggregation and retinoic acid treatment, neuron-like cells were formed. These cells reacted with reagents that also react with human neurons in culture: they reacted with tetanus toxin, the anti-neurofilament antibodies BF10 and RT97, the anti-ganglioside, GQ1c antibody F12 A2B5, and anti-Thy-1. The progressively growing cells of these Tera-2 clones are therefore capable of forming at least two types of cell: the flat cells in monolayer cultures and the neuron-like cells. None of the cell populations reacted with the monoclonal antibody against SSEA-3 and these cloned cells are therefore distinct from previous isolates from Tera-2.

Apolipoprotein expression by murine visceral yolk sac endoderm

Apolipoprotein expression was examined in the postimplantation mouse embryo. Antibodies directed against murine Apolipoprotein AI and human low-density lipoprotein (LDL) particles specifically immunoprecipitated metabolically labelled radioactive apolipoproteins from the culture supernatant of 10.5 days post coitum (days p.c.) yolk sac visceral endoderm cultured in vitro. No evidence for apolipoprotein expression by other embryonic or extraembryonic tissues at this stage was obtained. Immunohistochemical staining at sectioned 10.5 days p.c. embryos with anti-Apolipoprotein AI antibodies revealed specific localization of immunoreactive material in the yolk sac visceral endoderm. We conclude that the yolk sac visceral endoderm is a source of lipoproteins during postimplantation embryonic development.