[Incidence and prognosis of olfactory and gustatory dysfunctions related to infection of SARS-CoV-2 Omicron strain: a national multi-center survey of 35 566 population]

Objective: This cross-sectional investigation aimed to determine the incidence, clinical characteristics, prognosis, and related risk factors of olfactory and gustatory dysfunctions related to infection with the SARS-CoV-2 Omicron strain in mainland China. Methods: Data of patients with SARS-CoV-2 from December 28, 2022, to February 21, 2023, were collected through online and offline questionnaires from 45 tertiary hospitals and one center for disease control and prevention in mainland China. The questionnaire included demographic information, previous health history, smoking and alcohol drinking, SARS-CoV-2 vaccination, olfactory and gustatory function before and after infection, other symptoms after infection, as well as the duration and improvement of olfactory and gustatory dysfunction. The self-reported olfactory and gustatory functions of patients were evaluated using the Olfactory VAS scale and Gustatory VAS scale. Results: A total of 35 566 valid questionnaires were obtained, revealing a high incidence of olfactory and taste dysfunctions related to infection with the SARS-CoV-2 Omicron strain (67.75%). Females(χ2=367.013, P<0.001) and young people(χ2=120.210, P<0.001) were more likely to develop these dysfunctions. Gender(OR=1.564, 95%CI: 1.487-1.645), SARS-CoV-2 vaccination status (OR=1.334, 95%CI: 1.164-1.530), oral health status (OR=0.881, 95%CI: 0.839-0.926), smoking history (OR=1.152, 95%CI=1.080-1.229), and drinking history (OR=0.854, 95%CI: 0.785-0.928) were correlated with the occurrence of olfactory and taste dysfunctions related to SARS-CoV-2(above P<0.001). 44.62% (4 391/9 840) of the patients who had not recovered their sense of smell and taste also suffered from nasal congestion, runny nose, and 32.62% (3 210/9 840) suffered from dry mouth and sore throat. The improvement of olfactory and taste functions was correlated with the persistence of accompanying symptoms(χ2=10.873, P=0.001). The average score of olfactory and taste VAS scale was 8.41 and 8.51 respectively before SARS-CoV-2 infection, but decreased to3.69 and 4.29 respectively after SARS-CoV-2 infection, and recovered to 5.83and 6.55 respectively at the time of the survey. The median duration of olfactory and gustatory dysfunctions was 15 days and 12 days, respectively, with 0.5% (121/24 096) of patients experiencing these dysfunctions for more than 28 days. The overall self-reported improvement rate of smell and taste dysfunctions was 59.16% (14 256/24 096). Gender(OR=0.893, 95%CI: 0.839-0.951), SARS-CoV-2 vaccination status (OR=1.334, 95%CI: 1.164-1.530), history of head and facial trauma(OR=1.180, 95%CI: 1.036-1.344, P=0.013), nose (OR=1.104, 95%CI: 1.042-1.171, P=0.001) and oral (OR=1.162, 95%CI: 1.096-1.233) health status, smoking history(OR=0.765, 95%CI: 0.709-0.825), and the persistence of accompanying symptoms (OR=0.359, 95%CI: 0.332-0.388) were correlated with the recovery of olfactory and taste dysfunctions related to SARS-CoV-2 (above P<0.001 except for the indicated values). Conclusion: The incidence of olfactory and taste dysfunctions related to infection with the SARS-CoV-2 Omicron strain is high in mainland China, with females and young people more likely to develop these dysfunctions. Active and effective intervention measures may be required for cases that persist for a long time. The recovery of olfactory and taste functions is influenced by several factors, including gender, SARS-CoV-2 vaccination status, history of head and facial trauma, nasal and oral health status, smoking history, and persistence of accompanying symptoms.

[Deep neck space infections: a retrospective cohort study of surgical risk factors]

Objective: To explore risk factors affecting treatment for deep neck space infections (DNSIs) so as to provide guidance for appropriate early managements. Methods: A retrospective cohort study was conducted on inpatients with DNSIs admitted to the Department of Otolaryngology, Head and Neck Surgery, Affiliated Hospital of Qingdao University from March 2013 to February 2021. Patients were divided into surgical and non-surgical groups based on whether they had surgery or not. Information collected included demographic data, disease-related signs and symptoms, treatment history, systemic comorbidities, imaging data and laboratory indicators. Hypothesis testing, univariate Logistic regression and multivariate Logistic regression were used for data processing. Resuts A total of 61 patients were included, including 37 males and 24 females, aged 6-96 years. There were 35 cases (57.4%) in the surgical group and 26 cases (42.6%) in the non-surgical group. Multivariate analysis showed that risk factors for surgery as followings: neck dyskinesia (OR=0.03, 95%CI: 0.00-0.24), dysphagia (OR=0.10, 95%CI: 0.02-0.72), serum white blood cell count≥16.74×10⁹/L (OR=1.18, 95%CI: 1.01-1.39) and interspace gas (OR=0.03, 95%CI: 0.00-0.30). Conclusion: Clinicians should be alert to these risk factors for surgery in the course of treatment and timely surgical treatment for patients who meet the conditions.

Essential signals in publication trends and collaboration patterns in global Research Integrity and Research Ethics (RIRE)

Amid an increasingly demanding research environment, there has been a growing interest in studies concerning Research Integrity and Research Ethics (RIRE). Between 1990 and 2020, over 9700 publications were published to address problematic research conduct such as falsification, plagiarism, and related protocols and standards. In this work, country-level trends and collaborative structures are examined with respect to economic group. Our results showed that RIRE publications are predominantly led by the West, with North America and Western Europe contributing the most. While there is interest within growing economies such as China, the pace is not comparable to its overall publications. However, international collaborations on RIRE grew to account for nearly 30% of all publications on the subject in 2020. Although there is a stronger preference for high income countries to collaborate with other high income countries, we observe a rise in partnerships between high-/middle-income and middle-/lower-income co-authorship pairs in the last decade. These trends point to a maturing global community with distributed knowledge transfer, towards more unified international standards for research ethics and integrity.

[Transoral endoscopic resection of benign tumors in parapharyngeal space via medial pterygomandibular raphe approach]

Objective: To explore the surgical methods and effects of transoral endoscopic resection of benign tumors in parapharyngeal space via medial pterygomandibular raphe approach. Methods: The clinical data of 23 patients who underwent resection of benign tumors in parapharyngeal space by endoscopic medial pterygomandibular raphe approach from January 2016 to July 2020 in the Department of Otorhinolaryngology Head and Neck Surgery, the Affiliated Hospital of Qingdao University were analyzed retrospectively. There were 14 males and 9 females with a median age of 43 years. The tumors were located in the anterior space of the styloid process in 13 cases and in the posterior space in 10 cases. The smallest tumor volume was 7.3 ml and the largest was 80.2 ml. The preoperative imaging features, the characteristics and risks of this approach in the operation were analyzed, and the feasible mode of operation was explored. Results: All patients completed the operation successfully. The intraoperative blood loss was 20 to 50 ml, with an average of 28.3 ml. The operation time was 40 to 110 min, with an average of 75.4 min. The incision length was 2 to 4 cm, with an average of 3.0 cm. The postoperative pain score was 2 to 4, with an average of 3.2. The postoperative hospital stay was 4 to 9 d, with an average of 6.7 d. Postoperative pathological diagnosis included pleomorphic adenoma (n=12), neurilemmoma (n=10) and basal cell adenoma (n=1). The patients were followed up for 6 to 60 months. There was no postoperative complication such as infection or serious bleeding, and there was no tumor recurrence after operation. Conclusion: Endoscopic resection of benign tumor in parapharyngeal space via medial pterygomandibular raphe approach is a safe, effective, and minimally invasive surgical method for the treatment of tumors in parapharyngeal space.

[Application of endoscopic resection of benign tumor in infratemporal fossa]

Objective: To explore the application of endoscopy and clinical effect of endoscopic resection of benign tumor in infratemporal fossa. Methods: The clinical data of 11 patients with benign tumors in infratemporal fossa admitted to the Department of Otorhinolaryngology Head and Neck Surgery and Skull Base Surgery of the Affiliated Hospital of Qingdao University from January 2016 to September 2018 were retrospectively analyzed. There were 6 males and 5 females, with the age ranging from 11 to 63 years old. The main clinical manifestations were pharyngeal foreign body sensation, submaxillary pain, maxillofacial numbness and tongue numbness. Imaging examination showed that the tumor was round and had a clear boundary with the surrounding tissue. All the patients underwent endoscopic surgery. Appropriate surgical approach was selected according to the location of the tumor and its relationship with the internal carotid artery. The endoscopic surgical approaches included trans-oropharyngeal approach in 7 cases, trans-lateral pterygomandibular raphe approach in 1 case and trans-medial pterygomandibular raphe approach in 3 cases. The pathological results, prognosis, complications and relapse of patients were summarized through descriptive statistics. Results: The tumors were completely resected under endoscope in all patients, and there was no significant complication occurred after surgery. The average pain VAS score was 3.1 after surgery and average hospital stay was 5.9 d. The postoperative pathological diagnoses consisted of 6 cases of pleomorphic adenoma, 4 cases of neurilemmoma and 1 case of basal cell adenoma. All patients were followed up regularly from 6 to 39 months without recurrence of tumor. Conclusion: Endoscopic resection of benign tumors in infratemporal fossa has the advantages of minimal damage, rapid recovery, few complications, and definite curative effect, which can be used as an important alternative for surgical treatment of benign tumors.

[Clinical analysis of transnasal endoscopic repair of cerebrospinal fluid rhinorrhea]

Objective:To summarize the common clinical types of cerebrospinal fluid（CSF） rhinorrhea and key points of transnasal endoscopic repair of CSF rhinorrhea. To evaluate clinical effects. Method:In 29 patients with cerebrospinal fluid rhinorrhea, 9 patients with traumatic CSF rhinorrhea, 10 patients with spontaneous CSF rhinorrhea, 7 patients with CSF rhinorrhea after tumour excision, and 3 patients with iatrogenic CSF rhinorrhea. All the 29 patients were treated with transnasal endoscopic repair of CSF rhinorrhea. Result:There were 25 patients were successfully repaired at one time. Three patients developed intracranial infection and 2 patient developed pneumocephalus after surgery, all of them were cured with conservative treatment. All the patients who were followed-up for more than half a year had no recurrence. Conclusion:Transnasal endoscopic repair of CSF rhinorrhea is safe and effective, the success rate of operation is high, it is not easy to recur, and the complications are few. It can be used as the first choice for repairing of CSF rhinorrhea and effective prevention measures. Accurate location of leak, appropriate repair, effective reconstruction of the skull base, continuous drainage of the lumbar cistern when necessary and active prevention of intracranial infection are critical to the success of operation.

[Analysis of clinical features of respiratory epithelial adenomatoid hamartoma in the nasal cavity]

Objective: To analyze the clinical features of respiratory epithelial adenomatoid hamartoma (REAH) in the nasal cavity. Methods: Clinical datas of 23 patients, who were hospitalized in Department of Otorhinolaryngology Head and Neck Surgery, the Affiliated Hospital of Qingdao University, from February 2016 to February 2018 with histopathologically proved REAH in the nasal cavity were reviewed. There were 18 males and 5 females, with the age range from 16 to 71 years old. The most common area, main symptoms, surgical methods and follow-up results were analyzed. Results: The most common area was olfactory cleft (21 cases), and the mainly symptom was nasal congestion (18 cases). All the patients received transnasal endoscopic surgery and had no recurrence during following-up from three months to one year. Conclusions: The most common area of REAH in the nasal cavity is the olfactory cleft. Histopathological result is needed to make a definite diagnosis. Complete surgical resection is the main treatment.

[Clinical analysis of orbital complications due to rhinosinusitis in 28 cases]

Objective: To investigate the clinical characteristics of orbital complications due to rhinosinusitis and to provide the basis for the diagnosis and treatment of this disease. Methods: Retrospectively analyzed the clinical data of 28 patients with orbital complications due to rhinosinusitis who were admitted into the Affiliated Hospital of Qingdao University, Department of Otorhinolaryngology from August 2009 to April 2017. In all 28 cases, there were 1 case with preseptal cellulites, 9 cases with orbital cellulites, 13 cases with subperiosteal orbital abscess and 5 cases with orbital abscess. Among all the patients, 9 were younger than 14. Two patients were in ages from 14 to 17 and 7 patients were at or above 18 years. Absolute medicine therapy was performed on 8 patients and combined therapy of operation and pharmacotherapy on 20 patients. Results: The patients were followed up for 2 to 19 months. Both the general symptoms and ocular symptoms disappeared and nasal ventilation function recovered well. Conclusions: The treatment for orbital complications of rhinosinusitis includes absolute medicine therapy and combined therapy of operation and pharmacotherapy. And the selection of treatment depends on disease stage. Timely diagnosis and reasonable treatment would be beneficial in the recovery of patients.

Characterization of spark plasma sintered Ag nanopowders

The low temperature sintering behaviour of nanocrystalline Ag powder (with an average size of 70 nm) was characterized. Using spark plasma sintering (SPS), the Ag nanopowders can be successfully sintered at low pressure for only 5 min without external heating, and the sintering density increases and porosity decreases significantly with increase in the sintering temperature. Nanoindentation has been used to characterize the SPS sintered Ag samples. The mechanisms of the low sintering temperature behaviour of the nano-Ag powder and the nanoscale mechanical performance have been discussed. Compression tests were also used to characterize the mechanical properties of the sintered Ag sample with a maximum strain up to 15%.

The chemical characterization of tribofilms using XANES — Interaction of nanosize calcium-containing detergents with zinc dialkyldithiophosphate

A Plint friction and wear tester was used to investigate the effect of several calcium-containing detergents on the tribological and tribochemical performance of a zinc dialkyldithiophosphate (ZDDP) lubricating oil additive in a low-sulfur base stock, 100N. Thus, the friction and wear behavior of a steel-on-steel contact lubricated by 100N oil containing ZDDP alone and ZDDP–detergent mixtures at 100 °C was evaluated in a pin-on-disc configuration. The wear scar width of the upper steel pins was determined using an optical microscope, while the tribofilms formed on the lower steel discs were analyzed using X-ray absorption near edge structure (XANES) spectroscopy and X-ray photoelectron spectroscopy (XPS). At the same time, the thermal-oxidation films of the oil blends containing different additives were also prepared on the same steel discs and analyzed using XANES spectroscopy for comparative studies. It was found that in simple formulations the three kinds of calcium-containing detergents improved the friction-reducing and antiwear abilities of the 100N base stock. This was related to the individual tribochemical reactions and the deposition (in one case) of nanosized CaCO3 on the rubbing steel surface, indicating that the calcium-containing detergent had a synergistic antiwear performance with the ZDDP tested in the present work. Moreover, the calcium-containing detergents contributed to retarding the thermo-oxidation and friction-induced decomposition of ZDDP in 100N oil and influenced the composition and thickness of the tribofilms, which could be dependent on the molecular structures of the detergents and directly related to the tribochemistry of ZDDPs in mineral oil. The rubbing of the steel–steel pair at 100 °C was more beneficial for the deposition of nanosized calcium carbonate on the steel surface than heating at 150 °C. The calcium-containing detergents alone in the base stock also experienced tribochemical reactions, leading to obvious changes in the oxidation state of S in the corresponding tribofilms. Therefore, it was supposed that the tribochemical reactions of the ZDDP and detergents together with the deposition of nanosized CaCO3 on the rubbing steel surfaces accounted for the good antiwear performance of the blended oils.Key words: ZDDP, detergent, thermal film, tribofilm, tribochemistry, XANES, XPS.

Expression of Schwann cell-specific proteins and low-molecular-weight neurofilament protein during regeneration of sciatic nerve treated with neurotrophin-4

Neurotrophin-4 acts as a potent survival factor for subpopulations of motoneurons. To investigate its effect on Schwann cell sheath and axonal proteins during peripheral nerve regeneration, sciatic nerves in adult rats were transected and repaired, and fibrin glue containing neurotrophin-4 injected around the repair site. At 5, 15, 30 and 60 days after repair, 5-mm nerve segments distal to the repair were collected, and western blotting was used to measure myelin-associated glycoprotein, myelin basic protein and low-molecular-weight neurofilament protein. In control groups these dramatically declined at 5 and 15 days then increased from 30 and 60 days. However, in the neurotrophin-4 group there was a significant increase (to several times basal values) in myelin-associated glycoprotein and myelin basic protein at 5-15 days. The relatively small increases (<7%) in Schwann cell numbers suggest that this is mainly due to increased synthesis per cell. The neurotrophin-4 group also showed a small but significant increase at 15 days in low-molecular-weight neurofilament protein, which however remained much lower than basal. We conclude that neurotrophin-4 regulates the expression of myelin-associated glycoprotein, myelin basic protein, and to a lesser extent low-molecular-weight neurofilament protein, during peripheral nerve regeneration.

Altered glycosylation in inflammatory bowel disease: a possible role in cancer development

Ulcerative colitis and Crohn's disease (together known as Inflammatory Bowel Disease or IBD) are both associated with increased risk for colorectal cancer. Although it is conventional to emphasise differences between IBD-associated and sporadic colon cancer, such as a lower rate of Adenomatosis Polyposis Coli mutations and earlier p53 mutations, IBD-associated cancer has a similar dysplasia-cancer sequence to sporadic colon cancer, similar frequencies of major chromosomal abnormalities and of microsatellite instability and similar glycosylation changes. This suggests that IBD-associated colon cancer and sporadic colon cancer might have similar pathogenic mechanisms. Because the normal colon is arguably in a continual state of low-grade inflammation in response to its microbial flora, it is reasonable to suggest that both IBD-associated and sporadic colon cancer may be the consequence of bacteria-induced inflammation. We have speculated that the glycosylation changes might result in recruitment to the mucosa of bacterial and dietary lectins that might otherwise pass harmlessly though the gut lumen. These could then lead to increased inflammation and/or proliferation and thence to ulceration or cancer. The glycosylation changes include increased expression of onco-fetal carbohydrates, such as the galactose-terminated Thomsen-Friedenreich antigen (Gal beta1,3GalNAc alpha-), increased sialylation of terminal structures and reduced sulphation. These changes cannot readily be explained by alterations in glycosyltransferase activity but similar changes can be induced in vitro by alkalinisation of the Golgi lumen. Consequences of these changes may be relevant not only for cell-surface glycoconjugates but also for intracellular glycoconjugates.

Interaction between bacterial peptides, neutrophils and goblet cells: a possible mechanism for neutrophil recruitment and goblet cell depletion in colitis

Goblet cell depletion occurs in various forms of colitis, but its mechanism is unknown. We have investigated two linked hypotheses: (i) that bacterial peptides, such as formyl-methionyl-leucyl-phenylalanine (fMLP), interact with epithelial cells inducing the release of chemokines, including interleukin-8 (IL-8), which in turn leads to the recruitment of neutrophils which release mucin secretagogues; (ii) that fMLP acts directly on epithelial cells to cause mucus secretion. Studies were performed to measure the effects of fMLP on the synthesis and secretion of IL-8 and mucus by the goblet cell differentiated colon cancer cell lines HT29-MTX (methotrexate-conditioned HT29 colonic adenocarcinoma cell line) and LS174T, and to assess the effects of neutrophil-derived secretagogues on goblet cell secretion in these cell lines. fMLP (0.1 microM) increased the secretion of IL-8 by 105% (P<0.0001) in HT29-MTX cells and by 401% (P<0.0001) in LS174T cells. fMLP also increased the synthesis and secretion of mucins by these cell lines, with maximal effects of 65% above control values for synthesis (P<0.01) and 73% for secretion (P<0.01). A dose-related increase (up to 67%; P<0.01) in mucin secretion was demonstrated in HT29-MTX cells in response to incubation with supernatant from activated neutrophils. This effect was largely (83%; P<0.02) inhibited by ICI 200,355, a specific inhibitor of neutrophil elastase. In conclusion, the bacterial peptide fMLP and neutrophil elastase are both potent mucus secretagogues for colon epithelial cells. fMLP also elicits release of the potent neutrophil chemoattractant IL-8 from colon epithelial cells. These findings support the hypothesis that the mucosal inflammation and mucus depletion seen in ulcerative colitis could result from interaction between bacterial peptides and the mucosa.

Cell surface-expressed Thomsen-Friedenreich antigen in colon cancer is predominantly carried on high molecular weight splice variants of CD44

Increased mucosal expression of TF, the Thomsen-Friedenreich oncofetal blood group antigen (galactose beta1-3 N-acetylgalactosamine alpha-) occurs in colon cancer and colitis. This allows binding of TF-specific lectins, such as peanut agglutinin (PNA), which is mitogenic to the colorectal epithelium. To identify the cell surface TF-expressing glycoprotein(s), HT29 and Caco2 colon cancer cells were surface-labeled with Na[(125)I] and subjected to PNA-agarose affinity purification and electrophoresis. Proteins, approximately 110-180 kDa, present in HT29 but not Caco2 were identified by Western blotting as high molecular weight splice variants of CD44 (CD44v). Selective removal of TF antigen by Streptococcus pneumoniae endo-alpha-N-acetylgalactosaminidase substantially reduced PNA binding to CD44v. Immunoprecipitated CD44v from HT29 cell extracts also expressed sialyl-Tn (sialyl 2-6 N-acetylgalactosaminealpha-). Incubation of PNA 15 microg/ml with HT29 cells caused no additional proliferative effect in the presence of anti-CD44v6 mAb. In colon cancer tissue extracts (N = 3) PNA bound to CD44v but not to standard CD44. These data show that CD44v is a major PNA-binding glycoprotein in colon cancer cells. Because CD44 high molecular weight splice variants are present in colon cancer and inflammatory bowel disease tissue but are absent from normal mucosa, these results may also explain the increased PNA reactivity in colon cancer and inflammatory bowel disease. The coexpression of oncofetal carbohydrate antigens TF and sialyl-Tn on CD44 splice variants provides a link between cancer-associated changes in glycosylation and CD44 splicing, both of which correlate with increased metastatic potential.

Opposite effects on human colon cancer cell proliferation of two dietary Thomsen-Friedenreich antigen-binding lectins

Increased cell surface expression of the Thomsen-Friedenreich antigen (TF antigen, Galbeta1-3GalNAcalpha-) is a common feature in malignant and pre-malignant epithelia. Our previous studies have shown that dietary TF-binding lectins from peanut (Arachis hypogea) and edible mushroom (Agaricus bisporus) produce marked but different effects on human intestinal epithelial cell proliferation. This study investigates the proliferative effects of the other two known dietary TF-binding lectins: jacalin (Artocarpus integrifolia, JAC) and amaranth lectin (Amaranthus caudatus, ACA). JAC produced dose-dependent and non-cytotoxic inhibition of proliferation in HT29 human colon cancer cells with maximal effects of 46 +/- 4% at 20 microg/ml, whereas ACA produced dose-dependent stimulation of proliferation with maximal effects of 22 +/- 3% at 20 microg/ml when assessed both by incorporation of [3H]thymidine into DNA and by cell counting. The lectin-mediated effects were inhibitable by the presence of appropriate Galbeta1-3GalNAc-expressing glycoproteins but differences existed between JAC and ACA in their patterns of inhibition by such substances. Ligand binding equilibrium studies using iodinated lectins revealed different Kd of the two lectins for HT29 cell surface glycoproteins. Lectin blots of cell membrane extracts showed different binding patterns in all the four TF-binding lectins. These results provide further evidence that dietary TF-binding lectins can have marked effects on the proliferation of human malignant gastro-intestinal epithelial cells and hence may play a role in intestinal cancer development, and also show that the biological effects of dietary lectins cannot be predicted solely from their carbohydrate binding properties.

Neurotrophin-4 delivered by fibrin glue promotes peripheral nerve regeneration

Neurotrophin-4 (NT-4) is a recently identified neurotrophic factor with potential trophic effects on subpopulations of neurons. Little is known about its role in peripheral nerve regeneration following nerve injury. To investigate this, 48 Sprague-Dawley rats underwent left sciatic nerve transection and immediate repair. Fibrin glue mixed with either NT-4 or vehicle (control) was injected around the nerve repair site. Nerve regeneration was assessed both functionally and histomorphometrically. The results showed that the NT-4-treated group had a significant increase compared with the control in the regeneration distance at 5 days. The sciatic function index was significantly greater in the NT-4 group from 40 to 60 days after nerve repair. Morphometric analysis revealed that nerves treated with NT-4 had significant improvement in the number of regenerated axons, axonal diameter, and myelin thickness. These results suggest that NT-4 is a potent factor improving rat sciatic nerve regeneration.

Intracellular trafficking and release of intact edible mushroom lectin from HT29 human colon cancer cells

Our previous studies have shown that the Galbeta1-3GalNAcalpha- (Thomsen-Friedenreich antigen)-binding lectin from the common edible mushroom Agaricus bisporus (ABL) reversibly inhibits cell proliferation, and this effect is a consequence of inhibition of nuclear localization sequence-dependent nuclear protein import after ABL internalization [Yu, L.G., Fernig, D.G., White, M.R.H., Spiller, D.G., Appleton, P., Evans, R.C., Grierson, I., Smith, J.A., Davies, H., Gerasimenko, O.V., Petersen, O.H., Milton, J.D. & Rhodes, J.M. (1999) J. Biol. Chem. 274, 4890-4899]. Here, we have investigated further the intracellular trafficking and fate of ABL after internalization in HT29 human colon cancer cells. Internalization of 125I-ABL occurred within 30 min of the lectin being bound to the cell surface. Subcellular fractionation after pulse labelling of the cells with 125I-ABL for 2 h at 4 degrees C followed by culture of the cells at 37 degrees C demonstrated a steady increase in radioactivity in a crude nuclear extract. The radioactivity in this extract reached a maximum after 10 h and declined after 20 h. Release of ABL from the cell, after pulse labelling, was assessed using both fluorescein isothiocyanate-labelled ABL and 125I-ABL and was slow, with a t1/2 of 48 h. Most of the 125I-ABL both inside cells and in the medium remained intact, as determined by trichloroacetic acid precipitation and SDS/PAGE, and after 48 h only 22 +/- 2% of ABL in the medium and 14 +/- 2% inside the cells was degraded. This study suggests that the reversibility of the antiproliferative effect of ABL is associated with its release from cells after internalization. The internalization and subsequent slow release, with little degradation of ABL, reflects the tendency of lectins to resist biodegradation and implies that other endogenous or exogenous lectins may be processed in this way by intestinal epithelial cells.

Modulation of retinal pigment epithelial cell behavior by Agaricus bisporus lectin

PURPOSE

To determine whether Agaricus bisporus lectin (ABL) binds retinal pigment epithelial cells (RPEs), to conduct a preliminary viability study of RPEs exposed to ABL, and to evaluate the effects of ABL on RPE proliferation and RPE-mediated matrix contraction in vitro.

METHODS

Using cultured bovine RPEs, immunohistochemistry was used to study ABL binding. Morphologic and trypan blue exclusion techniques were used for toxicity studies. The effect of ABL on RPE proliferation was investigated by [methyl-3H]-thymidine incorporation. The effect of ABL on RPE-mediated matrix contraction was evaluated with RPE-populated three-dimensional collagen matrices.

RESULTS

ABL bound to RPE cells. This binding was inhibited by asialomucin. No change in RPE morphology or trypan blue exclusion compared with controls was observed in RPEs incubated with 5 to 60 microg/ml ABL for 3 days. Twenty-four-hour incubations of RPEs with ABL significantly inhibited RPE proliferation in a dose-dependent way, 40 microg/ml ABL inhibited proliferation by 83% (SE 14, P<0.05). ABL showed a dose-dependent significant inhibition of RPE-mediated collagen matrix contraction over 3 days, with 93% inhibition compared with controls by 40 microg/ml lectin (P<0.05). The inhibitory effect of ABL on proliferation and gel contraction was partly reversible after eliminating ABL from the culture medium.

CONCLUSIONS

Bovine RPE cells bind ABL, and preliminary evaluations suggest that levels of ABL that are nontoxic to the cells potently inhibit RPE proliferation and RPE-mediated matrix contraction. ABL deserves further investigation as a potential inhibitor of RPE proliferation and cell-mediated matrix contraction in anomalous reparative processes such as proliferative vitreoretinopathy and as a laboratory tool for RPE behavioral studies.

Edible mushroom (Agaricus bisporus) lectin, which reversibly inhibits epithelial cell proliferation, blocks nuclear localization sequence-dependent nuclear protein import

The Galbeta1-3GalNAcalpha (TF antigen)-binding lectin (ABL) from the common edible mushroom (Agaricus bisporus) has a potent anti-proliferative effect without any apparent cytotoxicity. This unusual combination of properties prompted investigation of its mechanism of action. In contrast to soluble lectin, agarose-immobilized, and hence noninternalizable ABL had no effect on proliferation of HT29 colon cancer cells. Electron microscopy of HT29 cells incubated with fluorescein- and gold-conjugated ABL showed internalization of the lectin into endocytotic vesicles and multivesicular bodies. Confocal microscopy showed perinuclear accumulation of fluorescein isothiocyanate-conjugated lectin, which also inhibits HT29 cell proliferation, raising the possibility that the lectin might interfere with nuclear pore function. Transport of heat shock protein 70 into the nucleus in response to heat shock was blocked by preincubation of HT29 cells for 6 h with 40 micrograms/ml ABL. In digitonin-permeabilized cells, nuclear uptake of bovine albumin conjugated to a nuclear localization sequence (NLS)-containing peptide was also inhibited by a 15-min preincubation with 40-100 micrograms/ml ABL. In contrast, serum-stimulated nuclear translocation of mitogen-activated protein kinase, which is NLS-independent, was not affected by pretreatment of cells with the lectin. These results suggest that the anti-proliferative effect of ABL is likely to be a consequence of the lectin trafficking to the nuclear periphery, where it blocks NLS-dependent protein uptake into the nucleus.

Stimulation of proliferation in human colon cancer cells by human monoclonal antibodies against the TF antigen (galactose beta1-3 N-acetyl-galactosamine)

In many tissues, the TF (Thomsen-Friedenreich) blood group antigen (Galbeta1-3GalNAc alpha-) behaves as an onco-foetal carbohydrate antigen, showing increased expression in malignancy and hyperplasia. Dietary lectins which bind the TF antigen have marked effects on proliferation of epithelial cells without cytotoxicity. This led us to speculate that anti-TF antibodies, including those that naturally occur in humans, might have similar effects. Five anti-TF antibodies, TF2 (human), TF5 (human), 5A8 (mouse), 8D8 (mouse) and BM22 (mouse), but not TFI (human) or 49H.9 (mouse), showed marked dose-dependent stimulation (95-192%) of [3H]thymidine incorporation by HT29 human colon cancer cells. Similar stimulation of proliferation of HT29 cells by these monoclonal antibodies (MAbs) was found when cell count assessment was used. Antibody-stimulated proliferation was inhibited by co-incubation with glycoproteins expressing Galbeta1-3GalNAc alpha- (asialo glycophorin or [Galbeta1-3GalNAc alpha-O-p-aminophenyl]n-human serum albumin). A proliferative effect of these antibodies was also demonstrated on human colon cancer cell lines LS174T and HT29-MTX but not on Caco-2 cells. Although immunoblotting showed similar binding patterns of all the antibodies on HT29 cell membrane extracts, there was little correlation between cell surface binding assessed by immunofluorescence and proliferative response, and internalization of the biotinylated antibody TF5 was demonstrated by confocal microscopy. Our results provide further evidence that cell surface glycoproteins which express TF antigen may play an important role in the regulation of cell proliferation and also suggest that human anti-TF antibodies may have proliferative effects on cells which express TF antigen.

Stimulation of colonic mucin synthesis by corticosteroids and nicotine

1. We speculated that corticosteroids might cause beneficial stimulation of mucus synthesis, since this is a known action of carbenoxolone, itself a corticosteroid, and has also been proposed as a possible mechanism for the protective effect of smoking on ulcerative colitis. We have therefore compared the effects of corticosteroids including carbenoxolone, and nicotine on mucin synthesis, assessed by incorporation of N-[3H]acetylglucosamine into mucin by colonic epithelial biopsies in culture. 2. In histologically normal biopsies from the left colon, hydrocortisone and prednisolone caused a very marked concentration-dependent increase in mucin synthesis, with maximal effect (580 and 300% of control values respectively) at 6 mumol/l [P < 0.001, n = 35 biopsies (seven patients)] and 1.5 mumol/l [P < 0.001, n = 35 (seven patients)] respectively. The maximal effect of hydrocortisone was significantly greater than that of prednisolone (P < 0.05). Carbenoxolone, 0.17 mmol/l, also increased mucin synthesis in the left colon by 242% [P < 0.05, n = 15 (three patients)]. In contrast, these corticosteroids caused only a small, non-significant increase in mucin synthesis in the histologically normal right colon; fludrocortisone, 2 and 20 mumol/l, and aldosterone, 0.1-10 mumol/l, had no effect. Nicotine significantly increased mucin synthesis (180-220% of control values) between 62.5 nmol/l and 6.25 mumol/l (P < 0.05 at all concentrations) in both the right and left colon. In biopsies from the relatively uninvolved right colon of patients with ulcerative colitis, corticosteroids and nicotine caused relatively smaller increases in mucin synthesis. 3. The marked stimulation of mucin synthesis by corticosteroids suggests that this may account, at least in part, for their therapeutic effect in ulcerative colitis.

'Sticky' neutrophils, pathergic arthritis, and response to heparin in pyoderma gangrenosum complicating ulcerative colitis

Pyoderma gangrenosum is strongly associated with inflammatory bowel disease and exhibits pathergy, occurring at sites of previous minor trauma. A patient is presented with a 21 year history of extensive ulcerative colitis, who developed pyoderma gangrenosum and arthralgia while receiving high dose corticosteroids for active ulcerative colitis. The arthralgia exhibited pathergy affecting particularly the left temporomandibular joint, which was stressed by an asymmetric bite, and the left elbow, which had been fractured many years previously. This prompted the hypothesis that neutrophils in this condition may be marginated, as a result of increased stickiness of either the neutrophil or the vascular endothelium. The introduction of heparin therapy was associated with rapid resolution of the arthralgia, pyoderma gangrenosum, and ulcerative colitis.