[The cases of tracing the source of patients infected with Omicron variant of SARS-CoV-2 based on wastewater-based epidemiology in Shenzhen]

Wastewater-based epidemiology (WBE) is an emerging discipline, which has been applied to drug abuse tracking and infectious disease pathogen surveillance. During the COVID-19 epidemic, WBE has been applied to monitor the epidemic trend and SARS-CoV-2 variants etc. In order to detect hidden COVID-19 cases and prevent transmission in the community, wastewater surveillance system for monitoring SARS-CoV-2 RNA was developed in Shenzhen. The sewage sampling sites were set up in key places such as the port areas, urban villages and residential communities of Futian, Nanshan, Luohu and Yantian districts. From July 26 to November 30, 2022, a total of 369 sewage sampling sites were set up, covering 1.93 million people. Continuous sampling was carried out for 3 hours in the peak period of water use every day. Sewage virus enrichment and SARS-CoV-2 nucleic acid detection were carried out by polyethylene glycol precipitation method and RT-qPCR, and a positive water sample disposal process was molded. This article aims to introduce the case of source tracing of COVID-19 infected patients based on urban sewage in Shenzhen. The sewage monitoring of Honghu water treatment plant in Luohu District played an early warning role, and the source of infection was traced. In the disposal of positive water samples in Futian South Road, Futian District, the important experience of monitoring point layout was obtained. In the sewage monitoring of Nanshan village, Nanshan District, the existence of occult infection was revealed. Sharing the experience of tracing the source of COVID-19 patients to avoid the spread of COVID-19 in the community based on wastewater surveillance of SARS-CoV-2 RNA in Shenzhen, and summarizing the advantages and application prospects of sewage surveillance can provide new ideas for monitoring emerging or re-emerging pathogens that are known to exhibit gastrointestinal excretion in the future.

Zoledronic Acid Accelerates Bone Healing in Carpal Navicular Fracture via Silencing Long Non-coding RNA Growth Arrest Specificity 5 to Modulate MicroRNA-29a-3p Expression

Carpal navicular fractures are the most common carpal fractures. This study intends to explore the specific mechanism of Zoledronic Acid (ZA) in carpal navicular fracture healing via long non-coding RNA (lncRNA) growth arrest specificity 5 (GAS5) to mediate microRNA (miR)-29a-3p. A fractured rat model was constructed. Two weeks later, a subcutaneous injection of systemic ZA was implemented, and an injection of plasmid vectors interfered with GAS5 or miR-29a-3p expression was performed on the fracture site. Osteocalcin (OCN) and bone morphogenetic protein-2 (BMP-2) were determined, as well as serum levels of alkaline phosphatase (ALP), osteopontin (OPN) and osteoprotegerin (OPG) and bone mineral density. MC3T3-E1 cells were transfected with plasmid vectors interfering with GAS5 or miR-29a-3p, and cell proliferation and apoptosis were analyzed. GAS5 and miR-29a-3p expression in fractured rats was tested, together with their binding relationship. ZA promoted OCN and BMP-2 expression, increased bone mineral density and serum levels of ALP, OPN and OPG in fractured rats. GAS5 was upregulated and miR-29a-3p was down-regulated in fractured rats. Downregulation of GAS5 or upregulation of miR-29a-3p further promoted bone healing in fractured rats. GAS5 targets miR-29a-3p, and down-regulation of miR-29a-3p can reverse the effect of down-regulation of GAS5 on bone healing in fractured rats. ZA promoted the proliferation of MC3T3-E1 cells and inhibited apoptosis by regulating the GAS5/miR-29a-3p axis. ZA regulates miR-29a-3p expression by down-regulating GAS5 to promote carpal navicular fracture healing, promote MC3T3-E1 cell proliferation, and inhibit cell apoptosis.

[Effects of acute paraquat poisoning on cognitive ability in humans]

Objective: To explore the effects of acute paraquat poisoning on cognitive function of patients through neuropsychologic test. Methods: In June 2019, 36 patients with acute paraquat poisoning in the emergency department of a provincial hospital in Hebei Province were selected as the case group. 36 healthy individuals were selected as control group. The cognitive function and depressive state were assessed by mini mental state scale, auditory word learning test, digit span test, connection test, Boston Naming Test and geriatric depression scale. Results: The results of Mini-Mental State examination showed that the total score of the case group was lower than that of the control group, the difference was statistically significant (P<0.05) . The results of the Auditory Vocabulary Learning test showed that the scores of delayed recall, clue recall, corrective ability and semantic learning strategies of the case group were significantly lower than those in the control group (P<0.05) . There was no significant difference in the scores of immediate memory between the two groups (P>0.05) . The scores of Digit Span test and Boston Naming test in the control group were higher than those in the case group, the Trail Making test time in the control group was shorter than that in the case group, and the differences were statistically significant (P<0.05) . Conclusion: Acute paraquat poisoning can impair human cognitive ability to a certain extent.

Are glutamate transporters neuroprotective or neurodegenerative during cerebral ischemia?

The accumulation of glutamate (Glu) in the synaptic cleft during cerebral ischemia triggers the death of neurons, causing mental or physical handicap. However, the mechanisms of the alteration in Glu homeostasis and the imbalance between the release and clearance of Glu in ischemia are not yet completely understood. Additionally, the role of Glu transporters in regulating Glu concentration in the synaptic cleft is controversial. This review aims to provide readers with an in-depth understanding of Glu transporters in the early or later stages of ischemic events, or in mild or severe cerebral ischemia via alteration of Glu transporter expression, reversal of Glu transporters function, and trafficking between membrane and cytoplasm, to further clarify whether the Glu transporters are neuroprotective or neurodegenerative during cerebral ischemia. We provide the insights for deeper understanding of the mechanism of Glu transporters regulation after different periods and severities of cerebral ischemia.

1H nuclear magnetic resonance-based plasma metabolomics provides another perspective of response mechanisms of newborn calves upon the first colostrum feeding

The first meal of a neonatal calf after birth is crucial for survival and health. Blood IgG levels remarkably increase in neonatal calves after the first colostrum feeding. However, there is little comprehensive information on blood small-molecule metabolites in neonatal calves at that time. In this study, the changes in plasma metabolites of neonatal calves after the initial colostrum feeding were first examined with comprehensive 1H nuclear magnetic resonance (NMR). Sixteen plasma samples obtained from 8 calves before and after feeding were analyzed with 1H NMR. Multivariate analyses revealed a significant difference in metabolic profiles. After feeding, acute phase N-acetylated glycoproteins and 13 other plasma metabolites decreased, whereas 19 plasma metabolites increased. Metabolomics pathway analysis of these metabolites revealed that a global metabolic response on the first colostrum feeding was reflected by alterations of 13 metabolic pathways including lipid, carbohydrate, and amino acid metabolism in neonatal calves. These results suggested that besides meeting energy demand, a 4.0 L of high-quality colostrum feeding within 4 h after birth had a positive effect on relieving the postnatal stress in neonatal calves. This study provides another perspective of response mechanisms of newborn calves upon the first colostrum feeding.

Metabolomics and pathway analyses to characterize metabolic alterations in pregnant dairy cows on D 17 and D 45 after AI

Nutrient flow to the embryo and placenta is crucial for proper development and growth during pregnancy. In this study, a metabonomic analysis was undertaken to better understand global changes in pregnant dairy cows on D 17 and D 45 after timed artificial insemination (AI). Metabolic changes in the blood plasma of pregnant dairy cows were investigated using HPLC-MS and a multivariate statistical analysis. Changes in metabolic networks were established using the MetPA method. Alterations in six metabolic pathways were found on D 17 and D 45, including variations in the level of alpha-linolenic acid metabolism, glycerophospholipid metabolism, pentose and glucuronate interconversions, glycerolipid metabolism, folate biosynthesis, and tyrosine metabolism. In addition to these pathways, 9 metabolic pathways were markedly altered on D 45. These pathways included changes in the one-carbon pool caused by folate; phenylalanine, tyrosine and tryptophan biosynthesis; thiamine metabolism; pantothenate and CoA biosynthesis; purine metabolism; inositol phosphate metabolism; amino sugar and nucleotide sugar metabolism; pentose phosphate; and the TCA pathway. The combination of metabonomics and network methods used in this study generated rich biochemical insight into possible biological modules related to early pregnancy in dairy cows.

Significant genetic differentiation of Gobiopterus lacustris, a newly recorded transparent goby in China

In our recent survey, the transparent small Lacustrine goby, Gobiopterus lacustris had reported as the endemic species of Luzon, Philippines, was identified as an abundant species in mangroves of Leizhou Peninsula, China. Here, high diversity and significant differentiation of five sites of samples representing the west and east populations were revealed by mitochondrial DNA sequences. Five haplotypes of 56 cytochrome oxidase subunit I (Cox1) with the lengths of 623 base pairs (bp) have the high pairwise identity (>98.8%). Moreover, a total of 31 haplotypes for 129 partial D-loop regions were clustered into two clades corresponding to the east and west sampling sites. The strong population structure was confirmed (ΦST = 0.43017, p < .0001) with high haplotype diversity (h = 0.880 ± 0.017) and low nucleotide diversity (p=.00484). Moreover, both the mismatch distribution analysis and neutral test of D-loop revealed that the west group might experience a recent demographic expansion. Lastly, the isolation-with-migration analysis supported the expansion and indicated that the east-west split happened at approximately 7.1 kyr ago. Given the distribution and diversity, G. lacustris could be a good model for the study of the sea-level fluctuations and coast evolution of the South China Sea.

[Analysis of type C behavior in patients with oral lichen planus]

OBJECTIVE

To assess type C behavior in patients with oral lichen planus (OLP) in order to provide basis for clinical prevention, treatment and psychological intervention of OLP.

METHODS

Type C behavior scale was used on 85 OLP patients and 85 control patients, who were in accordance with the inclusion criteria, in order to investigate their type C behavior. The scale included 9 items: anxiety, depression, anger, anger toward inside (anger-in), anger toward outside (anger-out), reasoning, domination, optimism, and social support. Scores of the 9 items between OLP patients and control group were calculated under the instruction of the scale and were statistically analyzed, and OLP group was further stratified statistically by sex, reticulate-erosive-ulcerative (REU) pathological type and course of diseases, and the scores of each group were analyzed and compared.

RESULTS

Among the 85 OLP patients, there were more females, more non-erosive lesion type, and the most common site for OLP was the buccal mucosa. The scores of the type-C behavior questionnaire for anxiety, depression, anger and optimism were respectively 43.01±7.47, 44.02±7.61, 21.56±5.26, 22.15±4.00 among the OLP patients and were 37.94±8.70, 39.58±7.35, 18.12±5.39, 24.05±3.23 among control group, with significant differences(P<0.05 for all) between the two groups. The female OLP patients had higher anxiety, depression, anger scores (43.21±6.97, 44.29±7.54, 21.64±5.09) and lower reasoning, domination, optimism scores (39.12±5.66, 16.29±3.95, 22.05±4.12) with significant differences (P<0.05 for all) compared with those of the female controls. The scores between male patients and male controls showed no significant difference. The patients with erosive lesions had higher anger score (22.94±5.26) than that of the patients without erosive lesions(20.60±5.03), with a significant difference(P<0.05). With the development of the disease, the tendency of anxiety and depression of the patients were more obvious, while optimism scores remained declining. The patients suffering more than 3 years of OLP had higher anger-toward-outside scores (17.36±3.35) than the patients suffering less than 3 years of OLP (15.19±3.99), with a significant difference (P<0.05).

CONCLUSION

OLP patients showed an obvious type C behavior characteristic, especially in anxiety, depression, anger and low optimism. This research provides the C behavior characteristic of OLP for further psychological consultation or intervention during OLP treatment.

[Statins in periodontitis therapy]

Statins inhibit the activity of enzyme 3-hydroxy-3-methyl-acetyl coenzyme A reductase and further inhibit cholesterol synthesis. Statins are the most widely used cholesterol-lowering drugs in clinical practice. Studies have found that statins also play a positive role in periodontitis treatment. In this paper, we reviewed the functions of statins in bone metabolism and anti-inflammation in periodontitis. In addition, the application of statins as a local drug delivery system in the treatment of periodontitis was described.

Identification of low potassium stress-responsive proteins in tobacco (Nicotiana tabacum) seedling roots using an iTRAQ-based analysis

Potassium is one of the three main mineral nutrients, and is vital for leaf growth and the quality of tobacco (Nicotiana tabacum) plants. In recent years, the isobaric tags for relative and absolute quantitation (iTRAQ) method has been one of the most popular techniques for quantitative proteomic analysis. In this study, we used iTRAQ to compare protein abundances in the roots of control and low potassium-treated tobacco seedlings, and found that 108 proteins were differentially expressed between the two treatments. Of these, 34 were upregulated and 74 were downregulated, and 39 (36%) were in the chloroplasts. Kyoto Encyclopedia of Genes and Genomes pathway enrichment results suggested that metabolic pathways were the dominant pathways (10 upregulated and 14 downregulated proteins). Ten proteins involved in the pyruvate metabolism pathway increased their expression levels, and 17 upregulated proteins were enriched in the ribosomes category. To evaluate correlations between protein and gene transcript abundances, the expression patterns of 12 randomly chosen genes were examined. A quantitative real-time polymerase chain reaction revealed that the 12 genes were induced after low potassium treatment for 3, 6, 12, and 24 h. Our results demonstrate that low potassium levels affect protein profiles in tobacco roots.

[Clinical characters of pre-malignant and malignant polyp in postmenopausal women and the diagnostic value of hysteroscopy]

OBJECTIVE

To investigate the clinical characteristics of pre-malignant and malignant polyps in postmenopausal patients and to evaluate the diagnositic value of hysteroscopy in this disease.

METHODS

From June 2005 to October 2014, 403 postmenopausal patients with polyps were treated in the Gynecologic Minimally Invasive Center, Beijing Obstetrics and Gynecology Hospital. There were 27 patients including 22 patients with pre-malignant and 5 patients with malignant polyps. All malignant lesions were endometrioid adenocarcinoma. The clinical data were retrospectively analyzed. Based on pathology, the diagnostic value of hysteroscopy was evaluated.

RESULTS

(1) CLINICAL CHARACTERISTICS: there were 27 cases with pre-malignant and malignant polyps (group 1) and 376 cases with benign polyps (group 2). Compared the two groups, the average age was (60±8) vs (58±6) years old, the period of menopause was (9.8±8.1) vs (8.3±6.9) years. Thirteen cases (48.1%, 13/27) in group 1 and 159 cases (42.3%, 159/376) in group 2 had clinical symptoms including postmenopausal bleeding and vaginal discharge. Twelve cases (44.4%, 12/27) in group 1 and 140 cases (37.2%, 140/376) in group 2 were with hypertension. Five cases (18.5%, 5/27) in group 1 and 43 cases (11.4%, 43/376) in group 2 were with diabetes. The measures above were no significant differences (P>0.05) (2) Ultrasound features: the average thick of endometrium in group 1 and group 2 were respectively (1.3±0.7) and (0.8±0.4) cm, which had statistical significance (t=4.98, P=0.001). (3) Hysteroscopic diagnosis: the average diameters of polyp in group 1 and group 2 were respectively (2.4±1.0) and (1.6±1.0) cm, which had statistical significance (t=2.93, P=0.004). Six cases in group 1 were diagnosed by hysteroscopy including 4 cases of malignant polyp and 2 cases of pre-malignant polyp. The sensitivity, specificity, positive predictive value, negative predictive value and the accuracy were 22.2% (6/27), 100.0% (376/376), 100.0% (6/6), 94.7% (376/397) and 94.8% (382/403), respectively.

CONCLUSIONS

Pre-malignant and malignant endometrial polyps are more common in the subjects with the larger diameters and the thicker endometrium. All polyps should be under complete resection by hysteroscopy and through pathology examination.

Genetic diversity analysis of fruit characteristics of hawthorn germplasm

One hundred and six accessions of hawthorn intraspecific resources, from the National Germplasm Repository at Shenyang, were subjected to genetic diversity and principal component analysis based on evaluation data of 15 fruit traits. Results showed that the genetic diversity of hawthorn fruit traits varied. Among the 15 traits, the fruit shape variable coefficient had the most obvious evaluation, followed by fruit surface state, dot color, taste, weight of single fruit, sepal posture, peduncle form, and metula traits. These are the primary traits by which hawthorn could be classified in the future. The principal component demonstrated that these traits are the most influential factors of hawthorn fruit characteristics.

Quantitative trait locus analysis of grape weight and soluble solid content

A grapevine hybrid population was derived from a crossing of the early-maturing female parent cultivar '87-1' and the late-maturing male parent cultivar '9-22'. A total of 149 plants were selected from the hybrid population as the mapping population, and after sequence-related amplified polymorphism and simple-sequence repeat marker analysis were conducted we constructed molecular genetic maps of the parents. The molecular linkage map of '87-1' had 19 linkage groups that contained 188 markers, with an average interval of 5.7 cM and a total distance of 1074.5 cM; the '9-22' map had 19 linkage groups that contained 175 markers, with an average interval of 7.8 cM and a total distance of 1100.2 cM. The molecular linkage map of both parents had 19 linkage groups that contained 251 markers, with an average interval of 5.0 cM and a total distance of 1264.2 cM. We used the interval mapping method to conduct a quantitative trait locus (QTL) analysis of grape weight and soluble solid content of the mapping population. Six QTLs were related to grape weight, and the average contribution to the phenotypic variance was between 11.3 and 33.0%. Seven QTLs were related to soluble solid content, and the average contribution to the phenotypic variance was between 15.7 and 55.8%.

Antioxidant and lipid-regulating effects of probucol combined with atorvastatin in patients with acute coronary syndrome

OBJECTIVE

To investigate the effects of probucol combined with atorvastatin on the serum oxidation index and lipid levels in patients diagnosed with acute coronary syndrome (ACS).

METHODS

We randomly assigned 126 ACS patients (77 males and 49 females) to the control group (atorvastatin 20 mg/day, n=62) or the treatment group (atorvastatin 20 mg/day and probucol 750 mg/day, n=64). All the patients were followed up for 12 weeks. As oxidization indices, we measured the serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), oxidized LDL (ox-LDL), and paraoxonase-1 (PON1) before and after treatment. We also monitored the adverse effects of the drugs during the treatment.

RESULTS

At baseline, there were no obvious differences (P>0.05) between the two groups (including age, gender, etc.). After 12 weeks of treatment, the ox-LDL levels in the treatment group were significantly lower while PON1 levels were significantly higher than those in the control group. There were no statistically significant difference between the two groups with respect to the side effects (P<0.05).

CONCLUSIONS

The combined use of atorvastatin and probucol in ACS patients could reduce ox-LDL expression and increase PON1 expression more effectively than use atorvastatin alone.

Cladosporium cladosporioides Identified in China on Tobacco Seeds

Tobacco (Nicotiana tabacum L.) is a leafy, annual, solanaceous plant grown commercially for its leaves. China is the biggest single tobacco market and accounts for more than 40% of the global tobacco consumption (1). Tobacco seed harvested in Guiyang, Guizhou Province, China, are commonly contaminated or infected by various fungal pathogens, which can cause abnormal seedlings with dark brown lesions and stunting of roots and decayed seeds. In 2013, five samples of 500 seeds from tobacco cv. Guiyan 4 were tested for germination on moistened paper on petri dishes. On average, 35% of the seeds from all five samples developed into abnormal seedlings or were decayed and were plated onto potato dextrose agar media and grown for 5 days at 25°C in darkness to confirm the presence of a pathogen. However, one fungus was isolated from an average of 10% of the 500 seeds sampled. It was identified morphologically as Cladosporium cladosporioides (Fresen.) de Vries based on the velvety olive-brown with almost black reverse colony color and dimensions and color of conidia and conidiophores. Conidia formed in long branched chains that readily disarticulate, single celled, elliptical to limoniform, 2 to 8 (avg. 4.3) × 2 to 3 (avg. 2.1) μm. Conidia were pale to olive brown and smooth to verruculose. Ramoconidia were 0 to 1 septate, 7 to 14 (avg. 9.2) × 2 to 4 (avg. 2.6) μm, smooth or sometimes minutely verruculose. Conidiophores were pale to olive brown, macro- and micronemateus, smooth or sometimes verruculose, and of various lengths up to 320 μm long and 2 to 5 μm wide. Primer pair ITS1 and ITS4 was employed to amplify the regions of ITS1-5.8s-ITS2 of the pathogens. Sequences of all three isolates (G3, G10, and G18) (Accession Nos. KF841547, KF841554, and KF841560) were identical to each other and to four sequences in GenBank (JX230994.1, JQ768317.1, JQ768322.1, and AB763555.1). Pathogenicity of the three isolates of C. cladosporioides was verified on tobacco seedlings of 3-week-old grown on wet filter paper in the petri dishes (9 cm in diameter). For each isolate, 20 seedlings incubated in one plate were inoculated with 0.5 ml of a suspension of 10⁵ conidia/ml. Twenty seedlings were treated with sterile water as control treatment. After inoculation, the petri dishes were incubated at 25°C, 100 to 120 μEm^-2 S^-1, RH > 80%, and 16 h light per day for disease development. At 96 h after inoculation, symptoms comprising medium brown to black lesions on the roots were clearly visible on inoculated plants but not on the control plants. All seedlings inoculated died 9 days after inoculation whereas control seedlings remained symptomless. Re-isolation attempts on PDA from roots demonstrated C. cladosporioides to be present in symptomatic seedlings but not in roots of the control plants. Moreover, the characteristics of the cultured fungi were exactly the same as those originally isolated. Isolates G3, G10, and G18 (KF841547, KF841554, and KF841560) were deposited with the Tobacco Diseased Fungi, Guizhou Academy of Tobacco Sciences, Guizhou, China. Previously, C. cladosporioides has also been isolated from macadamia (Macadamia integrifolia Maiden & Betche) racemes in South Africa (4), from diseased papaya (Carica papaya L.) in Taiwan province of China (2), and from seeds of Amaranthus spp. in Poland (3). To the best of our knowledge, this is the first report of C. cladosporioides causing seed disease on tobacco in China and the disease should be considered in existing disease management practices. References: (1) British American Tobacco Annual Report, 8, 2012. (2) R. S. Chen, et al. Plant Dis. 93:426, 2009. (3) W. Pusz. Phytopathologia 54:15, 2009. (4) N. van den Berg et al. Plant Dis. 92:484, 2008.

A comparative study of locoregionally advanced nasopharyngeal carcinoma treated with intensity modulated irradiation and platinum-based chemotherapy

PURPOSE

To investigate the prognosis of three subgroups of locoregionally advanced nasopharyngeal carcinoma treated with intensity-modulated radiotherapy and platinum-based chemotherapy.

PATIENTS AND METHODS

Hundred and eighty-one consecutive patients with locoregionally advanced untreated nasopharyngeal carcinoma were retrospectively divided into three subgroups: locally advanced group (T3-4N0-1M0), regionally advanced group (T1-2N2-3M0) and the mixed group (T3-4N2-3M0). They were all treated with definitive intensity-modulated radiotherapy and platinum-based chemotherapy. Their prognosis were investigated and compared. Multivariate analysis was applied to identify the independent risk factors of study endpoints.

RESULTS

The 3-year locoregional control rates for locally advanced group, regionally advanced group, and the mixed group were 91.5%, 90.6% and 84.3% respectively, no significant difference was observed (P=0.656, P=0.429). The 3-year distant metastasis-free survival rates were 89.6%, 75.7% and 76.3%, respectively. The distant metastasis-free survival rate of the locally advanced group was significantly higher than the other two subgroups (P=0.028, P=0.028). The 3-year progression-free survival rates were 85.5%, 67.9% and 67.1% respectively with significance also favoring the locally advanced group (P=0.043, P=0.023). Nodal stage and the performance status were the independent risk factors of distant metastasis in the observed period.

CONCLUSIONS

In the context of intensity-modulated radiotherapy and platinum-based chemotherapy, the locally advanced group had a better prognosis compared with the regionally advanced group and the mixed group. Treatment stratification may be based on nodal stage.

Isolation and characterization of microsatellite DNA loci from the peanut worm, Sipunculus nudus

Sipunculus nudus, the peanut worm, is the best known species in its genus. This unsegmented subtidal marine worm is consumed in some parts of Asia and is also used as fish bait. We found 20 microsatellite DNA markers for S. nudus. The number of alleles per polymorphic locus ranged from two to seven in a sample of 39 individuals. Observed and expected heterozygosities per polymorphic locus varied from 0.103 to 1.000 and from 0.307 to 0.771, respectively. Five loci showed significant departure from Hardy-Weinberg equilibrium after sequential Bonferroni's correction. No significant linkage disequilibrium between pairs of loci was found. These microsatellite markers will provide useful tools for investigating genetic population structure, population history and conservation management of S. nudus.

[Screening for genes associated with cardiac fibrosis induced by aldosterone]

AIM

To investigate differently expressed genes associated with cardiac fibrosis induced independently by aldosterone.

METHODS

Fetal cardiac fibroblasts (FCFs)were isolated and cultured. Total RNA was extracted 8 hours after aldosterone administration. Then gene chips were used to screen these RNA samples. Some of candidate genes were confirmed by RT-PCR and Western blot.

RESULTS

Differently expressed 1519 genes were screened. Up-regulated genes were 714 while down-regulated genes were 805. The expression of CCL7, MMP-26 and IL31RA was tested by RT-PCR and western blot, the results is identical with those by gene chips.

CONCLUSION

Gene chip can efficiently single out differently expressed genes induced dependently by aldosterone in FCFs. CCL7, MMP-26 and IL31RA may be associated with cardiac fibrosis induced by aldosterone.

DNA barcoding, phylogenetic relationships and speciation of snappers (genus Lutjanus)

The phylogenetic relationships of 13 snapper species from the South China Sea have been established using the combined DNA sequences of three full-length mitochondrial genes (COI, COII and CYTB) and two partial nuclear genes (RAG1, RAG2). The 13 species (genus Lutjanus) were selected after DNA barcoding 72 individuals, representing 20 species. Our study suggests that although DNA barcoding aims to develop species identification systems, it may also be useful in the construction of phylogenies by aiding the selection of taxa. Combined mitochondrial and nuclear gene data has an advantage over an individual dataset because of its higher resolving power.

Microsatellite analysis of genetic diversity and phylogenetic rela-tionship of nine species of grouper in genus Epinephelus

Thirteen microsatellite markers of Epinephelus awoara previously discovered by our lab were selected to analyze the genetic diversity and phylogenetic relationship of nine species of grouper (E. awoara, E. merra, E. fario, E. fasciatus, E. lanceolatus, E. akaara, E. septemfasciatus, E. coioides and E. fuscoguttatus) from South China Sea. The results showed that the number of total alleles of these 13 microsatellite loci was 84 in these fishes, the mean number of alleles ranged from 2.69 to 5.38, mean polymorphism information content (PIC) ranged from 0.1976 to 0.4267, mean observed heterozygosity (Ho) from 0.4615 to 0.6239, mean expected heterozygosity (He) from 0.3510 to 0.4754 and mean Hardy-Weinberg departure value (D) from 0.1097 to 0.2836, respectively. All of these indicated that genetic diversity of the nine species of grouper was at a medium level. Two NJ dendrograms showed that E. coioides, E. fuscoguttatus and E. lanceolatus were grouped together, while E. awoara, E. akaara and E. septemfasciatus were in a second group, and E. merra, E. fasciatus and E. fario were in a third group which had a relatively closed relationship with the second group. The dendrograms could also support a conclusion that Promicrops lanceolatus (E. lanceolatus) should be included in genus Epinephelus.

Rapid isolation and characteristics analysis of microsatellites from Lutjanus russelli

The (CA)n DNA sequences in Lutjanus russelli were isolated through PCR arrays, and the characteristics of the microsatellite were analyzed. DNA was extracted from a sample of Lutjanus russelli, and digested with Hae+Dra. The fragments were ligated to pUCm-T vector and transferred into DH5alpha to construct a genomic library. The positive clones were isolated with universal M13 reverse and forward primers, M13 forward primer and the simple sequence repeats (SSRs) probes (CA)15, M13 reverse primer and (CA)15. After twice isolation, 121 positive clones, whose PCR products with M13 forward primer and probes (CA)15 or M13 reverse primer and (CA)15 were smaller than those with universal M13 reverse and forward primers probably contained microsatellites, were obtained. Then, 53 (CA)n(n> or =7) microsatellites were obtained by sequencing. The repeat length mainly distributed in 7-15(80.77%). Besides (CA)n repeats, other repeat motifs, such as An, (CAC)n and (AACA)n, were also obtained. Scorable and constant amplification of DNA fragments were observed with 48 pairs of SSR primers designed from the flank sequences. This research makes a positive contribution to explorating genomes of Lutjanus russelli, offers genetic tools to examine the genetic variations and constructs genetic linkage map.

[Linkage analysis and mutation detection of GRIA3 in Smith--Fineman--Myers syndrome]

To determine the role of GRIA3 in the etiology of Smith--Fineman--Myers syndrome (SFMS), polymorphic short tandem repeats within GRIA3 gene were genotyped by PCR and denaturing polyacrylamide gel electrophoresis to test linkage between GRIA3 and the gene responsible for SFMS. The open reading frame of GRIA3 was detected for mutation by PCR amplification and direct sequencing in affected and normal males from SFMS family. One of the two short tandem repeats was informative in SFMS family. Tight linkage between SFMS locus and GRIA3 gene was established by STR3 within GRIA3 gene. No disease--causing mutation was found within the open reading frame of GRIA3 gene. The disease in SFMS family from Shandong (China) is not caused by the mutation within open reading frame of GRIA3 gene.

Activator protein-1 transcription factor mediates bombesin-stimulated cyclooxygenase-2 expression in intestinal epithelial cells

Colorectal carcinogenesis is a complex, multistep process involving genetic alterations and progressive changes in signaling pathways regulating intestinal epithelial cell proliferation, differentiation, and apoptosis. Although cyclooxygenase-2 (COX-2), gastrin-releasing peptide (GRP), and its receptor, GRP-R, are not normally expressed by the epithelial cells lining the human colon, the levels of all three proteins are aberrantly overexpressed in premalignant adenomatous polyps and colorectal carcinomas of humans. Overexpression of these proteins is associated with altered epithelial cell growth, adhesion, and tumor cell invasiveness, both in vitro and in vivo; however, a mechanistic link between GRP-R-mediated signaling pathways and increased COX-2 overexpression has not been established. We report that bombesin, a homolog of GRP, potently stimulates the expression of COX-2 mRNA and protein as well as the release of prostaglandin E(2) from a rat intestinal epithelial cell line engineered to express GRP-R. Bombesin stimulation of COX-2 expression requires an increase in [Ca(2+)](i), activation of extracellular signal-regulated kinase (ERK)-1 and -2 and p38(MAPK), and increased activation and expression of the transcription factors Elk-1, ATF-2, c-Fos, and c-Jun. These data suggest that the expression of GRP-R in intestinal epithelial cells may play a role in carcinogenesis by stimulating COX-2 overexpression through an activator protein-1-dependent pathway.

Hypersulfated low molecular weight heparin with reduced affinity for antithrombin acts as an anticoagulant by inhibiting intrinsic tenase and prothrombinase

In buffer systems, heparin and low molecular weight heparin (LMWH) directly inhibit the intrinsic factor X-activating complex (intrinsic tenase) but have no effect on the prothrombin-activating complex (prothrombinase). Although chemical modification of LMWH, to lower its affinity for antithrombin (LA-LMWH) has no effect on its ability to inhibit intrinsic tenase, N-desulfation of LMWH reduces its activity 12-fold. To further explore the role of sulfation, hypersulfated LA-LMWH was synthesized (sLA-LMWH). sLA-LMWH is not only a 32-fold more potent inhibitor of intrinsic tenase than LA-LMWH; it also acquires prothrombinase inhibitory activity. A direct correlation between the extent of sulfation of LA-LMWH and its inhibitory activity against intrinsic tenase and prothrombinase is observed. In plasma-based assays of tenase and prothrombinase, sLA-LMWH produces similar prolongation of clotting times in plasma depleted of antithrombin and/or heparin cofactor II as it does in control plasma. In contrast, heparin has no effect in antithrombin-depleted plasma. When the effect of sLA-LMWH on various components of tenase and prothrombinase was examined, its inhibitory activity was found to be cofactor-dependent (factors Va and VIIIa) and phospholipid-independent. These studies reveal that sLA-LMWH acts as a potent antithrombin-independent inhibitor of coagulation by attenuating intrinsic tenase and prothrombinase.

Roles of gastrointestinal hormones in pancreatic cancer

Several gastrointestinal (GI) hormones, such as gastrin, cholecystokinin, and bombesin, have been reported to affect the development of pancreatic cancer. The receptors for these hormones are found in normal and neoplastic pancreatic cells. Activation of these receptors enhances pancreatic carcinogenesis and promotes the growth of established pancreatic carcinoma either in vitro or in vivo. On the other hand, some studies have shown that these GI hormones may have no effect or may play an inhibitory role in the development of pancreatic cancer. The reasons for the apparent discrepancies in the published literature are discussed in this review. In recent years, increasing emphasis has been placed on the effects of GI hormones on cancer invasion and metastasis. As the transition from noninvasion to the invasive state is the crucial event in cancer development, further investigation of the way in which GI hormones affect the invasion and metastasis of pancreatic cancer may be important for the development of new therapeutic approaches with eventual clinical utility.

Insulin-like growth factor-I promotes multidrug resistance in MCLM colon cancer cells

Insulin-like growth factor-I (IGF-I) is known as a potent mitogen for a variety of cell types, including colon cancer cell lines. The objective of this study was to determine the effect of IGF-I on cell death induced by cytotoxic agents actinomycin D (Act-D), lovastatin (LOV), and doxorubicin (DOX) in the MCLM mouse colon cancer cell line, and the mechanisms involved. Subconfluent monolayer MCLM cells were treated with IGF-I (25 ng/ml) for 12 h in serum-free media. Various concentrations of cytotoxic agents then were added to the cells that were incubated continually at 37 degrees C for 24 h. Cell survival was determined with the MTT (3-[4-5-dimenthylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay, which assesses mitochondrial function in living cells. The mRNA expression for multidrug resistance gene-1 (mdr-1), c-H-ras, and manganese superoxide dismutase (MnSOD) in cells treated with IGF-I was examined by Northern blot or RNase protection assays. The levels of p-glycoprotein, a drug efflux pump encoded by the mdr-1 gene, were assessed by Western immunoblotting. Results demonstrated that 1) IGF-I significantly inhibited the cell death and apoptosis of MCLM cells treated with Act-D, LOV, or DOX; 2) IGF-I increased mRNA expression for mdr-1, c-H-ras, and MnSOD; 3) the p-glycoproteins in cells treated with IGF-I or stably transfected with c-H-ras were elevated when compared with control. These results suggest that IGF-I protects MCLM cells against death induced by cytotoxic agents; this acquired drug resistance may be mediated by multiple mechanisms, including promoting expression of mdr-1, c-H-ras, and MnSOD; whereas, the p-glycoprotein level stimulated by IGF-I may result partly from the increase of c-H-ras in the cells.

Regulation of growth of human gastric cancer by gastrin and glycine-extended progastrin

BACKGROUND & AIMS

Gastrin (G-17) stimulates the growth of certain gastric and colon cancers mostly through gastrin/cholecystokinin (CCK)-B receptors. Glycine-extended gastrin (Gly-G) stimulates growth of a rat pancreatic acinar cell line; however, the effect of Gly-G on human gastric cancers is not known. The purpose of this study was to characterize the trophic effect of G-17 and Gly-G on two human gastric cancer cell lines, AGS and SIIA.

METHODS

Binding analyses were performed, and cell growth was assessed by counting cells over a time course.

RESULTS

G-17 stimulated growth of both AGS and SIIA cells. In AGS cells, gastrin/CCK-B receptor antagonists inhibited the effect of G-17 and competitively antagonized 125I-G-17 binding, whereas the CCK-preferring (CCK-A) receptor antagonists had no effect. In contrast, CCK-A receptor antagonists inhibited the stimulatory effect of G-17 in SIIA cells, whereas CCK-B receptor antagonists had no effect. Gly-G stimulated the growth of AGS and SIIA cells; neither the CCK-B nor the CCK-A receptor antagonists blocked this effect.

CONCLUSIONS

G-17 stimulates proliferation of AGS cells through the CCK-B receptor; however, G-17-mediated growth of SIIA acts through a CCK-A-like receptor. Furthermore, Gly-G stimulates growth of human gastric cancer cell lines, possibly through a receptor other than the CCK-B or CCK-A receptor.

Insulin-like growth factor-II expression in carcinoma in colon cell lines: implications for autocrine actions

BACKGROUND

In the gastrointestinal tract, insulin-like growth factor-II (IGF-II) messenger RNA (mRNA) is localized mainly in mesenchymal cells, and is more abundant in the fetus than in the adult. The purposes of this study are to characterize the gene expression of IGF-II at the mRNA and protein level in seven different epithelial cell lines derived from colon carcinomas and to determine the action of IGF-II and IGF-receptors on a colon carcinoma cell line.

STUDY DESIGN

Insulin-like growth factor-II mRNAs were examined by Northern analysis; conditioned media from colon carcinoma cells were concentrated, chromatographed, and examined by a specific IGF-II radioreceptor assay. Insulin-like growth factor receptors were examined by radioligand binding assays. The mitogenic role of IGF-II was determined by a 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay.

RESULTS

Multiple sizes of IGF-II mRNAs were expressed in all colon carcinoma cell lines tested (six human cell lines: HCT116, COLO 205, COLO 320 DM, LoVo, DLD-1, and HT29, and one mouse cell line: MC-26). In the conditioned media of COLO 205 and HCT116 cells, 7.5 kilodaltons IGF-II and high molecular form (IGF-II and IGF binding protein complex) were detected. Both Type I and Type II IGF receptors were present on COLO 205 cells whose growth was stimulated by IGF-II. Addition of anti-IGF-I receptor and anti-IGF-II antibody in the cell culture significantly depressed growth of the COLO 205 cell line in the presence or absence of exogenous IGF-II.

CONCLUSIONS

Insulin-like growth factor-II mRNAs are expressed in human and mouse colon carcinoma cell lines, which may induce production of a significant amount of biologically active IGF-II protein. The IGF-II secreted by COLO 205 cells may stimulate cell growth in an autocrine fashion through the Type I IGF receptors.

Differential regulation by TGF-beta 1 and insulin of insulin-like growth factor binding protein-2 in IEC-6 cells

The purposes of this study were to determine the regulation of insulin-like growth factor binding protein-2 (IGFBP-2) in IEC-6 cells by transforming growth factor-beta 1 (TGF-beta 1) and insulin and to determine whether IGFBP-2 mediated the growth-inhibitory action on the cells. Utilizing Western ligand blot analysis, we found that TGF-beta 1 at concentrations of 0.5, 1.0, and 2 ng/ml significantly increased levels of 32-kDa IGFBP in the conditioned medium (CM) of IEC-6 cells in a dose-dependent fashion and that low doses of insulin (1.0 and 5.0 microgram/ml) also increased IGFBP levels in the CM of IEC-6 cells, but a high dose of insulin (10 micrograms/ml) depressed IGFBP release in the CM. Immunoblotting has shown that the IGFBP of 32 kDa was IGFBP-2 and further confirmed the above results. IGFBP-2 mRNA levels were stimulated by TGF-beta 1 (2.0 ng/ml) and suppressed by insulin (5.0 micrograms/ml). In addition, des (1-3) IGF-I (50 ng/ml) and insulin stimulated the proliferation of IEC-6 cells. Anti-IGFBP-2 antibodies partially blocked the inhibitory role in IEC-6 cell growth evoked by des (1-3) IGF-I. These findings suggest that the upregulation of IGFBP-2 by TGF-beta 1 occurs, at least in part, at the level of mRNA, whereas the regulation by insulin appears to be at a posttranslational level, and that the TGF-beta 1-stimulated production of IGFBP may contribute to the growth-inhibitory action in intestinal epithelial cells.

A study of the cytotoxicity of malignant pleural effusion lymphocytes and LAK cells against autologous tumor cells

The cytotoxicity of malignant pleural effusion lymphocytes (MPEL) against autologous tumor cells (ATC) were compared with that of peripheral blood lymphocytes (PBL). It was demonstrated that the cytotoxicity of PBL was higher than that of MPEL (P < 0.001), but the cytotoxicity and expansion of MPEL-activated by rIL-2 was much higher than that of PBL activated by rIL-2 (LAK cells) (P < 0.001). This shows that local immune reaction of the pleural cavity of patients with malignant pleural effusion was in the state of suppression. MPEL activated are better effector cells than LAK cells in tumor adoptive immunotherapy.

Insulin-like growth factors enhance phagocytosis by human neutrophils in vitro

Polymorphonuclear neutrophils (PMNs) were isolated from human blood, and PMN phagocytosis was assessed by measuring the chemiluminescence (CL) response in the presence of ZAP (opsonized zymosin particles containing luminol). The administration of 6.5 nM of insulin-like growth factor I (IGF-I), des(1-3)-IGF-I, IGF-II or insulin to PMNs for 20 min resulted in significant increases of the CL response for all test preparations. Des(1-3)-IGF-I, a truncated IGF-I with low affinity binding to IGF binding proteins (IGFBPs), was the most potent CL stimulator. The CL production evoked by 6.5 nM of des(1-3)-IGF-I was inhibited significantly by both 0.25 and 1.0 nM of EGTA (Ca2+ chelator), or 10 microM nifedipine (Ca2+ channel inhibitor), pertussis toxin (0.05 and 1.0 micrograms/ml) or cholera toxin (5 micrograms/ml). These results suggest that IGF-I and its homologues are potent stimulators of phagocytosis and that this action is modulated by IGFBP, and may require extracellular Ca2+ and/or IGF-I receptor G-protein coupling.

In vivo mitogenic effects of estradiol on colon cancers: role of gastrin and gastrin receptors

We have previously reported mitogenic effects of gastrin on a mouse colon cancer (MC-26) cell line in vivo. The present studies were undertaken to determine if gonadal hormones can influence the mitogenic response of MC-26 cells to gastrin. The female gonadal hormone, estradiol (E2), was determined to be as mitogenic as pentagastrin (PG) for the growth of MC-26 tumors in mice; the mitogenic effects of E2 and PG were not additive. Female gonadal hormones were furthermore as effective as PG in maximally up-regulating gastrin receptor (GR) concentrations on MC-26 tumor membranes, which was confirmed in autoradiographic studies. Since PG and E2 had similar and non-additive trophic effects it was hypothesized that gastrin may be mediating the trophic effects of E2. Serum gastrin concentrations were significantly increased in E2 treated ovariectomized mice that correlated with an increase in tumor weights; E2 however was ineffective in stimulating the release of gastrin from perfused rat stomachs indicating that the increase in serum gastrin concentration on long-term treatment with E2 was mediated by some other mechanism. Saturable high-affinity E2 binding sites were not measured in MC-26 cells and tumors, supporting the possibility that mitogenic effects of E2 were probably mediated via indirect mechanisms. In summary our results indicate that both E2 and PG are equally mitogenic for colon cancer cells in vivo which may explain the sex- and age-related discrepancy in the incidence of human colon cancers.

Insulinlike growth factor-binding protein modulates the growth response to insulinlike growth factor 1 by human gastric cancer cells

BACKGROUND

This study determined whether the resistance to the mitogenic effect of insulinlike growth factor 1 (IGF-1) in AGS (we found that IGF-1 had almost no effect on the growth of AGS) cells is caused by the absence of IGF-1 receptor on the cells or by the interference of endogenous IGFs and IGF-binding protein (IGFBP).

METHODS

IGF-1 receptors were examined by radioligand binding assay. The protein in conditioned medium and the molecular weight of IGF-1 receptors on AGS cells were determined by affinity cross-linking with 125I-IGF-1 followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Messenger RNAs for IGF-1, IGF-2, and IGFBP-4 were detected by Northern analysis.

RESULTS

AGS cells possessed a single class of high-affinity binding sites for IGF-1 (dissociation constant [Kd], 0.51), with a binding capacity approximately 4 x 10(4) sites per cell. The size of the alpha subunit of IGF-1 receptors on cell membranes was approximately 130 kilodaltons. des (1-3) IGF-1, a truncated IGF-1 with very low affinity to IGFBPs, stimulated AGS cell growth in dose-dependent fashion. The medium conditioned by AGS cells contained IGFBPs of 27-32 and 37-42 kilodaltons. AGS cells expressed messenger (mRNA) RNAs for IGF-2 and IGFBP-4 but not for IGF-1, whereas another gastric carcinoma cell line (SIIA), whose growth is stimulated by IGF-1, expressed mRNA IGF-2 but did not express mRNA for IGF-1 or IGFBP-4:

CONCLUSIONS

The relative absence of growth response of AGS cells to IGF-1 is due to the endogenously produced IGFBPs sequestering IGF-1 and preventing receptor interaction.

[Potentiated polarized liquid therapy and heart emergency]

Kalium and Magnesium ions are important cations in human body, both of them take part in many processes of metabolism in coordination. Injection of Kalii L-aspartatis and Magnesii L-aspartatis added to polarized liquid (GIK-Glucose, Insulin, Kalii Chlorid) might potentiate its effect and reduce carbon dioxide and ammonia in blood. 72 patients with various heart emergencies and other critical diseases were treated with potentiated polarized liquid (GIKL) with remarkable efficacy. A preliminary study on its clinical use and mechanism was carried out.

A novel bombesin receptor antagonist (2258U89), potently inhibits bombesin evoked release of gastrointestinal hormones from rats and dogs, in vitro and in vivo

Several bombesin-receptor antagonists are available that inhibit secretory and growth effects of bombesin, in vitro. In the present study, we examined the effects of a new class of bombesin receptor antagonists (modified GRP(15-27) peptides, with D-Pro26 and D-Ala24 moieties), on bombesin mediated effects, in vivo and in vitro. Of the 10 different compounds tested, BW-10 or 2258U89 ([de-NH2)Phe19,D-Ala24,D-Pro26 psi(CH2NH)Phe27]-GRP(19-27)) was most potent towards inhibiting bombesin binding to rat pancreatic acinar cancer cells with an ID50 of 0.5 nM. BW-10 (1 and 10 nM) significantly inhibited the gastrin response to 1 nM bombesin, from isolated rat stomach, in vitro, in a dose-dependent fashion. BW-10 (10-100 nmol/kg) was equally effective at significantly inhibiting bombesin evoked gastrin release in anesthetized rats, in vivo. [D-Phe6]Bombesin(6-13)-propylamide (BIM), a member of another class of antagonists, reported previously to be the most potent antagonist, in vitro, on the other hand, enhanced bombesin provoked gastrin release in rats. The antagonistic effects of BIM, in vivo, may thus be more selective. Intravenous infusion of BW-10 (10 nmol/kg/h) partially depressed gastrin and pancreatic polypeptide and completely abolished insulin released in response to bombesin, in conscious dogs. These results suggest that BW-10 functions as one of the most potent bombesin receptor antagonists, in vitro and in vivo, which could potentially be used as a therapeutic compound in treatment of some human diseases.

Characterization of insulinlike growth factor I receptors in human colon cancer

A possible role of insulinlike growth factor I (IGF-I) and IGF-I receptors in the proliferation of human colon cancer has, to the best of the authors' knowledge, not been examined as yet. To determine a role of IGF-I in colon cancer, several human colon cancer cell lines and colon cancers were screened for specific binding to 125I-IGF-I. Almost all the human colon cancer cells examined were variably positive for specifically binding 125I-IGF-I. Almost half the colon cancer cell lines examined showed significant growth response to 6.6 nmol/L IGF-I. Dose-dependent growth effects of exogenously added IGF-I (0.05-3.3 nmol/L) were shown in a representative human colon cancer cell line (Colo-205). To determine if IGF-I binding sites on colon cancer cells were similar or different from that described on other cells, the binding affinity, binding specificity, and molecular size of the IGF-I binding sites were characterized in representative human colon cancer cell lines (HCT-116 and Colo-205). The optimal binding assay conditions for measuring maximum number of 125I-IGF-I binding sites on the cells, in vitro, were determined and found to be similar to that described on other cells. Scatchard analysis of the specific binding data showed the presence of a single class of high-affinity binding sites [disassociation constant (Kd) = approximately 1.0-2.0 nmol/L], with a binding capacity of 1.0-2.0 x 10(5) sites per cell. The molecular weight of IGF-I receptors on cell membranes was determined by gel electrophoresis of the affinity cross-linked proteins, followed by autoradiography. A single band of binding proteins with a molecular mass of approximately 300 kilodaltons was evident under nonreducing conditions and separated out into two bands of approximately 240 and approximately 130 kilodaltons under reducing conditions. The 130-kilodalton band represents the alpha subunit of IGF-I receptors, and the 240-kilodalton band may represent aggregates of the receptor subunits that were not reduced completely. The widespread existence of high-affinity binding sites for IGF-I in established human colon cancer cell lines and freshly resected human colon cancers and the proliferative effect of IGF-I in several colon cancer cell lines, in vitro, reflect that IGF-I may be an important endocrine/paracrine/autocrine factor in the growth regulation of colon cancers in situ.

Specific binding and growth effects of bombesin-related peptides on mouse colon cancer cells in vitro

In the present study, we characterized specific binding of bombesin (BBS)/gastrin-releasing peptide (GRP) to mouse colon cancer (MC-26) cells. MC-26 cells were inoculated into male BALB/c mice subdermally, and tumors were harvested from mice 21-28 days postinoculation. Tumor membranes were analyzed for binding to GRP-related peptides, using either 125I-GRP or 125I-tyrosine4-BBS. Under optimal binding assay conditions, BBS displaced specific binding of both 125I-GRP and 125I-tyrosine4-BBS in a dose-dependent manner, and a curvilinear displacement resulted. Specific binding data, analyzed by either a Scatchard or a Lineweaver-Burk plot, demonstrated presence of 2 classes of specific binding sites, arbitrarily named type I and type II sites. Type I sites had a high binding affinity [Kd 0.45 +/- 0.05 nM (SE)] and a relatively low capacity (226 +/- 27 fmol/mg membrane protein), whereas type II sites had a 10-20-fold lower binding affinity and approximately 6-7-fold higher capacity. BBS/GRP binding sites were specific for GRP-related peptides and demonstrated no significant binding affinity for all other unrelated peptides tested. Relative binding affinity of GRP analogues was in the order of GRP (14-27) greater than neuromedin C greater than or equal to BBS greater than or equal to GRP (1-27) greater than neuromedin B (for the later, P greater than 0.05 versus other peptides). Two BBS receptor antagonists, [D-Arg1,D-trp7,9,Leu11]-substance P (spantide) and [Leu13-psi-(CH2NH)Leu14]BBS also inhibited specific binding of 125I-GRP in a dose-dependent manner. Molecular weight of GRP/BBS binding proteins on tumor membranes was determined by cross-linking methods. A major molecular form (greater than 80-90%) (Mr approximately 75,000) and a minor Mr approximately 180,000 band were evident, both under reducing and nonreducing conditions. BBS (0.5-50 nM) demonstrated a significant dose-dependent growth effect on MC-26 cells in vitro, in terms of [3H]thymidine and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide uptake; these studies indicate that the BBS/GRP binding sites on MC-26 cells may serve as functional receptors and mediate the growth effects of BBS on MC-26 cells.

Role of gastrin in bombesin-stimulated somatostatin release

The intermediary pathways in the bombesin-induced somatostatin release were examined in isolated perfused rat stomach obtained from male rats that were fasted overnight. The stomachs were perfused by way of the celiac artery. On coinfusion of 1.0 mumol/L tetrodotoxin and 1 nmol/L bombesin, a significant depression in release of somatostatin was observed compared with that observed with bombesin alone. The 5-minute integrated somatostatin response after treatment with tetrodotoxin and bombesin was 173% +/- 14% of basal, which was significantly lower than that observed with bombesin alone (394% +/- 59% of basal, P less than 0.05) but significantly higher than that observed with medium-199 alone (95% +/- 7% of basal, P less than 0.05); this indicated that approximately 70% of the bombesin-stimulated somatostatin release was indirectly mediated through neural pathways, while a significant (approximately 30%) segment of it was mediated by nonneural mechanisms. To test if the 30% somatostatin release was secondary to gastrin release in response to bombesin, gastrin antiserum and bombesin (1 nmol/L) were coadministrated in the presence or absence of tetrodotoxin (1 mumol/L). Gastrin antiserum alone did not significantly affect basal release of somatostatin but caused a significant inhibition (approximately 23%) of bombesin-provoked somatostatin release. Coadministration of gastrin antiserum and tetrodotoxin attenuated bombesin-stimulated somatostatin release. Gastrin (1 mumol/L) alone significantly stimulated somatostatin release (150% +/- 10% of basal), which was completely attenuated in the presence of gastrin antiserum. Tetrodotoxin did not affect bombesin-elicited gastrin release, confirming that bombesin-stimulated gastrin release was directly mediated. To determine the nature of the neural pathways mediating the bombesin-induced somatostatin release, atropine (100 nmol/L) was used. Atropine inhibited bombesin-induced somatostatin release to the same extent as tetrodotoxin, indicating that cholinergic pathways mediated bombesin-induced somatostatin release. These results show that almost all the somatostatin response to bombesin is indirectly mediated, and is composed of a major neural (cholinergic) and a minor nonneural pathway. The nonneural mechanism appears to be contributed primarily by gastrin released in response to bombesin, which apparently has a short paracrine positive feedback effect on somatostatin release.

Growth-promoting effects of gastrin on mouse colon cancer cells in vitro: absence of autocrine effects

We have previously demonstrated trophic effects of gastrin on mouse colon cancer (MC-26) cells, in vivo, and demonstrated the presence of gastrin receptors (GR) on these cells. The cellular and intracellular mechanism by which gastrin expresses trophic effects on colon cancer cells is, however, as yet unknown. For us to start investigating the possible mechanisms involved, it was important that we first develop an in vitro model, in which gastrin expresses its trophic effects directly on the MC-26 cells. The growth-promoting effects of gastrin on the MC-26 cells were examined in various in vitro culture models, in terms of [3H]thymidine incorporation and cell number. A significant trophic effect of gastrin could be demonstrated on quiescent cells in culture, in the absence of serum. The optimal cell-culture conditions for observing trophic effects of gastrin were defined and included a 24-h period of rapid growth of MC-26 cells in serum-supplemented normal growth medium, followed by a 24-h period of culture in serum-free medium containing an optimal dose (1.0 mM) of thymidine, to achieve growth-arrest of the cells. Addition of gastrin (0.5 to 25 nM) to the quiescent, growth-arrested cells resulted in significant dose-dependent increases in both the incorporation of [3H]thymidine uptake by the cells, and a significant increase in cell number. The concentration of GR on the growth-arrested quiescent MC-26 cells in culture was significantly increased compared to the GR concentration on the control, asynchronized cells. The increased presence of GR on the growth-arrested, synchronized MC-26 cells may have allowed us to observe a significant trophic effect of gastrin on the MC-26 cells, in vitro itself. To determine if gastrin was functioning as an autocrine growth factor for MC-26 cells, we examined the effect of gastrin antibodies on the growth of MC-26 cells; no significant effect of the antigastrin IgG on the growth of MC-26 cells was observed.