A novel artificial intelligence-assisted "vascular-healing" diagnosis for prediction of future clinical relapse in patients with ulcerative colitis: a prospective cohort study

BACKGROUND AND AIMS

Image-enhanced endoscopy (IEE) has attracted attention as a method for detecting inflammation and predicting outcomes in patients with ulcerative colitis (UC); however, the procedure requires specialist endoscopists. Artificial intelligence (AI)-assisted IEE may help non-experts to provide objective accurate predictions using optical imaging. We aimed to develop a novel AI-based system using 8853 images from 167 patients with UC to diagnose "vascular-healing" and establish the role of AI-based vascular-healing for predicting the outcomes of patients with UC.

METHODS

This open-label, prospective cohort study analyzed data for 104 patients with UC in clinical remission. Endoscopists performed colonoscopy using the AI system, which identified the target mucosa as AI-based vascular-active or vascular-healing. Mayo endoscopic subscore (MES), AI outputs, and histological assessment were recorded for six colorectal segments from each patient. Patients were followed-up for 12 months. Clinical relapse was defined as a partial Mayo score >2 RESULTS: The clinical relapse rate was significantly higher in the AI-based vascular-active group [23.9% (16/67)] compared with the AI-based vascular-healing group [3.0% (1/33)] (P=0.01). In a sub-analysis predicting clinical relapse in patients with MES ≤1, the area under the curve for the combination of complete endoscopic remission and vascular-healing (0.70) was increased compared with that for complete endoscopic remission alone (0.65).

CONCLUSIONS

AI-based vascular healing diagnosis system may potentially be used to provide more confidence to physicians to accurately identify patients in remission of UC who would likely relapse rather than remain stable.

Effectiveness of endoscopic resection for colorectal neoplasms in ulcerative colitis: a multicenter registration study

BACKGROUND AND AIMS

Patients with ulcerative colitis (UC) are at risk of developing colorectal cancer. The feasibility of endoscopic resection (ER) for UC-associated neoplasia has been suggested, but its efficacy and safety remain unclear. We aimed to assess the efficacy and safety of ER for colorectal neoplasms in patients with UC.

METHODS

This was a retrospective, multicenter cohort study of patients with UC who initially underwent ER or surgery for colorectal neoplasms between April 2015 and March 2021. Patients who had prior colorectal neoplastic lesions were excluded.

RESULTS

Among 213 men and 123 women analyzed, the mean age at UC onset was 41.6 years, and the mean age at neoplasia diagnosis was 56.1 years for 240 cases of total colitis, 59 cases of left-sided colitis, 31 cases of proctitis, and 6 cases of segmental colitis. EMR was performed for 142 lesions, and endoscopic submucosal dissection (ESD) was performed for 96 lesions. The perforation rate was 2.5% for all 238 lesions removed by ER and 6.3% for the 96 lesions removed by ESD. Among 146 ER lesions followed up with endoscopy, the local recurrence rate was 2.7%. The incidence of metachronous neoplasia after ER was 6.1%. All patients were followed a median of 34.7 months after initial treatment, and 5 died (all surgical cases). Overall survival was significantly higher in the ER group than in the surgery group (P = .0085).

CONCLUSIONS

ER for colorectal neoplasms in UC may be acceptable in selected cases, although follow-up for metachronous lesions is necessary.

Use of advanced endoscopic technology for optical characterization of neoplasia in patients with ulcerative colitis: Systematic review

OBJECTIVES

Advances in endoscopic technology, including magnifying and image-enhanced techniques, have been attracting increasing attention for the optical characterization of colorectal lesions. These techniques are being implemented into clinical practice as cost-effective and real-time approaches. Additionally, with the recent progress in endoscopic interventions, endoscopic resection is gaining acceptance as a treatment option in patients with ulcerative colitis (UC). Therefore, accurate preoperative characterization of lesions is now required. However, lesion characterization in patients with UC may be difficult because UC is often affected by inflammation, and it may be characterized by a distinct "bottom-up" growth pattern, and even expert endoscopists have relatively little experience with such cases. In this systematic review, we assessed the current status and limitations of the use of optical characterization of lesions in patients with UC.

METHODS

A literature search of online databases (MEDLINE via PubMed and CENTRAL via the Cochrane Library) was performed from 1 January 2000 to 30 November 2021.

RESULTS

The database search initially identified 748 unique articles. Finally, 25 studies were included in the systematic review: 23 focused on differentiation of neoplasia from non-neoplasia, one focused on differentiation of UC-associated neoplasia from sporadic neoplasia, and one focused on differentiation of low-grade dysplasia from high-grade dysplasia and cancer.

CONCLUSIONS

Optical characterization of neoplasia in patients with UC, even using advanced endoscopic technology, is still challenging and several issues remain to be addressed. We believe that the information revealed in this review will encourage researchers to commit to the improvement of optical diagnostics for UC-associated lesions.

Beyond complete endoscopic healing: Goblet appearance using an endocytoscope to predict future sustained clinical remission in ulcerative colitis

OBJECTIVES

Complete endoscopic healing, defined as Mayo endoscopic score (MES) = 0, is an optimal target in the treatment of ulcerative colitis (UC). However, some patients with MES = 0 show clinical relapse within 12 months. Histologic goblet mucin depletion has emerged as a predictor of clinical relapse in patients with MES = 0. We observed goblet depletion in vivo using an endocytoscope, and analyzed the association between goblet appearance and future prognosis in UC patients.

METHODS

In this retrospective cohort study, all enrolled UC patients had MES = 0 and confirmed clinical remission between October 2016 and March 2020. We classified the patients into two groups according to the goblet appearance status: preserved-goblet and depleted-goblet groups. We followed the patients until March 2021 and evaluated the difference in cumulative clinical relapse rates between the two groups.

RESULTS

We identified 125 patients with MES = 0 as the study subjects. Five patients were subsequently excluded. Thus, we analyzed the data for 120 patients, of whom 39 were classified as the preserved-goblet group and 81 as the depleted-goblet group. The patients were followed-up for a median of 549 days. During follow-up, the depleted-goblet group had a significantly higher cumulative clinical relapse rate than the preserved-goblet group (19% [15/81] vs. 5% [2/39], respectively; P = 0.02).

CONCLUSIONS

Observing goblet appearance in vivo allowed us to better predict the future prognosis of UC patients with MES = 0. This approach may assist clinicians with onsite decision-making regarding treatment interventions without a biopsy.

Real-Time Artificial Intelligence-Based Optical Diagnosis of Neoplastic Polyps during Colonoscopy

Real-Time AI-Based Diagnosis of Neoplastic PolypsColonoscopists diagnosed small colonic polyps as benign or malignant on the basis of their appearance. The results were compared in real time to see if CADx could distinguish among polyps requiring removal. For standard visual inspection versus CADx, we determined sensitivity for diagnosis (88.4% vs. 90.4%) and high confidence in assessment (74.2% vs. 92.6%).

Evaluation in real-time use of artificial intelligence during colonoscopy to predict relapse of ulcerative colitis: a prospective study

BACKGROUND AND AIMS

The use of artificial intelligence (AI) during colonoscopy is attracting attention as an endoscopist-independent tool to predict histologic disease activity of ulcerative colitis (UC). However, no study has evaluated the real-time use of AI to directly predict clinical relapse of UC. Hence, it is unclear whether the real-time use of AI during colonoscopy helps clinicians make real-time decisions regarding treatment interventions for patients with UC. This study aimed to establish the role of real-time AI in stratifying the relapse risk of patients with UC in clinical remission.

METHODS

This open-label, prospective, cohort study was conducted in a referral center. The cohort comprised 145 consecutive patients with UC in clinical remission who underwent AI-assisted colonoscopy with a contact-microscopy function. We classified patients into either the Healing group or Active group based on the AI outputs during colonoscopy. The primary outcome measure was clinical relapse of UC (defined as a partial Mayo score >2) during 12 months of follow-up after colonoscopy.

RESULTS

Overall, 135 patients completed the 12-month follow-up after AI-assisted colonoscopy. AI-assisted colonoscopy classified 61 patients as the Healing group and 74 as the Active group. The relapse rate was significantly higher in the AI-Active group (28.4% [21/74]; 95% confidence interval, 18.5%-40.1%) than in the AI-Healing group (4.9% [3/61]; 95% confidence interval, 1.0%-13.7%; P < .001).

CONCLUSIONS

Real-time use of AI predicts the risk of clinical relapse in patients with UC in clinical remission, which helps clinicians make real-time decisions regarding treatment interventions. (Clinical trial registration number: UMIN000036650.).

Combined endocytoscopy with pit pattern diagnosis in ulcerative colitis-associated neoplasia: Pilot study

OBJECTIVES

Ulcerative colitis-associated neoplasias (UCAN) are often flat with an indistinct boundary from surrounding tissues, which makes differentiating UCAN from non-neoplasias difficult. Pit pattern (PIT) has been reported as one of the most effective indicators to identify UCAN. However, regenerated mucosa is also often diagnosed as a neoplastic PIT. Endocytoscopy (EC) allows visualization of cell nuclei. The aim of this retrospective study was to demonstrate the diagnostic ability of combined EC irregularly-formed nuclei with PIT (EC-IN-PIT) diagnosis to identify UCAN.

METHODS

This study involved patients with ulcerative colitis whose lesions were observed by EC. Each lesion was diagnosed by two independent expert endoscopists, using two types of diagnostic strategies: PIT alone and EC-IN-PIT. We evaluated and compared the diagnostic abilities of PIT alone and EC-IN-PIT. We also examined the difference in the diagnostic abilities of an EC-IN-PIT diagnosis according to endoscopic inflammation severity.

RESULTS

We analyzed 103 lesions from 62 patients; 23 lesions were UCAN and 80 were non-neoplastic. EC-IN-PIT diagnosis had a significantly higher specificity and accuracy compared with PIT alone: 84% versus 58% (P < 0.001), and 88% versus 67% (P < 0.01), respectively. The specificity and accuracy were significantly higher for Mayo endoscopic score (MES) 0-1 than MES 2-3: 93% versus 68% (P < 0.001) and 95% versus 74% (P < 0.001), respectively.

CONCLUSIONS

Our novel EC-IN-PIT strategy had a better diagnostic ability than PIT alone to predict UCAN from suspected and initially detected lesions using conventional colonoscopy. UMIN clinical trial (UMIN000040698).

Changes in atrial natriuretic peptide and brain natriuretic peptide associated with hypobaric hypoxia-induced pulmonary hypertension in rats

Experimental pulmonary hypertension induced in a hypobaric hypoxic environment (HHE) is characterized by structural remodeling of the heart and pulmonary arteries. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) both have diuretic, natriuretic, and hypotensive effects, and both are involved in cardiovascular homeostasis as cardiac hormones. To study the effects of HHE on the natriuretic peptide synthesis system, 170 male Wistar rats were housed in a chamber at the equivalent of the 5500-m altitude level for 1-12 weeks. After 1 week of HHE, pulmonary arterial pressure was significantly raised, and the ratio of left ventricle plus septum over right ventricle of the heart showed a significant decrease (compared with those of ground-level control rats). In both ventricular tissues, the expression of ANP messenger (m)RNA and BNP mRNA increased after exposure to HHE. The amounts of ANP and BNP had decreased significantly in right atrial tissue at 12 weeks of HHE (compared with those of the controls), whereas in ventricular tissues at the same time point, both levels had increased significantly. In in situ hybridization and immunohistochemical studies, the staining of the mRNAs for ANP and BNP and of ANP and BNP themselves was more intense in both ventricular tissues after exposure to HHE than before (i.e., in the controls). The results suggest that, in response to HHE, the changes in ventricular synthesis are similar for ANP and BNP. These changes may play a role in modulating pulmonary hypertension in HHE. However, under our conditions, pulmonary hypertension increased progressively throughout the HHE period.

Detection of kinases that phosphorylate 14-3-3 binding sites of Raf-1 using in situ gel kinase assay

Raf-1 is a serine/threonine protein kinase that plays a critical role in mitogenic signal transduction. Raf-1 activation requires 14-3-3 binding to Raf-1 as an essential step. This binding is regulated through phosphorylation of Ser259 and Ser621 of Raf-1, each constituting part of the consensus motif for the binding of Raf-1 to 14-3-3. However, Raf-1 kinase kinase(s) that phosphorylates these sites remains unknown. In this report, we detected Raf-1 kinase kinase activity using recombinant glutathione-S-transferase-Raf-1 fusion proteins as substrate of in situ gel kinase assay. Ser259 was phosphorylated by a kinase with a molecular weight of 90 kDa, which was suggested to be Rsk judging from the molecular size, the time course of activation after EGF stimulation and the elution pattern from an anion-exchange column. The Raf-1 fragment containing Ser621 was phosphorylated by kinases with molecular weights of 85, 60, 50 and 48 kDa but not by the kinase that phosphorylates Ser259. These results suggest that although Ser259 and Ser621 lie in the same amino acid sequence motif for 14-3-3 binding, these two regulatory sites for this binding are phosphorylated by different protein kinases.

Expression and electrophysiological function of actin in chick cerebellar neurons

Among several monoclonal antibodies obtained by immunizing Balb/c mice with cerebellar synaptic membrane fractions from E20 chick embryos, the antibody, named M35, suppressed Ca-spikes in immature cultured chick cerebellar neurons. M35 immunoprecipitated 43 kDa protein from a 125I-labeled embryonic crude cerebellar membrane fraction. Immunohistochemically, the M35 antigen was expressed most intensively in Purkinje cells, but its expression was limited to highly motile structures at developmental neuronal remodeling. Electrophysiologically, M35 facilitated current responses to AMPA and inhibited the responses to GABA in cultured cerebellar Purkinje neurons. The several peptides derived from the affinity-purified 43 kDa protein were found to have homologous amino acid sequences to non-muscle actins. These results suggest that the antigen recognized by M35 may play an essential role probably as membrane ion channels modulating synaptic functions in not only the development and growth but also the neuronal activity of chick cerebellar Purkinje cells.

Regulation of the gene promoter for extracellular signal-regulated protein kinase 2 by transcription factors NF-Y and Sp3

We have previously shown that the maximal promoter activity of the gene for extracellular signal-regulated protein kinase 2 (ERK2; also known as p42 mitogen-activated protein kinase) resides in the 371 bp 5'-flanking sequence. In the present study we defined roles for a CCAAT box and two adjacent GC boxes in the activity of this promoter. Deletion analysis and DNase I footprinting of this 371 bp region indicated that the CCAAT box at -64 and GC boxes at -86 and -39 are crucial for promoter activity. Electrophoretic mobility-shift assays showed that transcription factor NF-Y/CBF binds to the CCAAT box. Sp1 and Sp3, members of the Sp family of transcription factors, bind to the GC boxes of the ERK2 promoter. The binding of Sp3 was predominant over that of Sp1. Disruption by mutation of any of the CCAAT box and GC boxes similarly decreased promoter activity. These three cis elements exhibited a moderate synergy in promoter function. The transactivating role of NF-Y was corroborated by the finding that a dominant-negative form of NF-YA diminished the promoter activity. These results provide clues for refining our understanding of not only the regulation of expression of the gene for ERK2 but also mechanisms by which NF-Y and Sp1/Sp3 regulate transcription.

Expression of endothelin-1 in rats developing hypobaric hypoxia-induced pulmonary hypertension

Experimental pulmonary hypertension induced in a hypobaric hypoxic environment (HHE) is characterized by structural remodeling of the heart and pulmonary arteries. Endothelin-1 (ET-1), a 21-amino acid peptide, is a novel and long-lasting vasoconstrictor that increases pulmonary arterial pressure in both in vivo and in vitro experiments. To study the effects of HHE on ET-1 activity in the lungs, 59 male rats were subjected to the equivalent of an altitude of 5500 m for 1 to 4 weeks. In rats exposed to HHE, the mean pulmonary arterial pressure increased significantly from 15.2+/-0.3 (ground level) to 30.6+/-1.5 mm Hg (5500-m level) at 4 weeks, whereas their mean systemic arterial pressure remained normal. The levels of ET-1 mRNA and protein, measured respectively by Northern blot analysis and enzyme immunoassay, increased rapidly in the lungs on exposure to HHE. By in situ hybridization and immunohistochemistry, respectively, ET-1 mRNA and protein were detected in control rats in nonciliated bronchiolar epithelial cells and alveolar epithelial cells, as well as in the endothelial cells of pulmonary arteries, but minimally in the smooth muscle cells of pulmonary arteries. ET-1 mRNA- and protein-reactive smooth muscle cells in pulmonary arteries and ET-1 mRNA-reactive airway epithelial cells were significantly more abundant in rats exposed to HHE than in ground level controls. These results suggest the possibility that in smooth muscle cells in pulmonary arteries and airway epithelial cells, ET-1 may play an autocrine or paracrine role in the remodeling of blood vessels during the development of the pulmonary hypertension that is induced by HHE.

Expression of C-type natriuretic peptide during development of rat lung

C-type natriuretic peptide (CNP), recently found to be secreted from vascular endothelial cells, is now viewed as a novel endothelium-derived relaxing peptide. However, the distribution and expression of CNP during cardiopulmonary development is unclear. To follow changes in the expression of CNP during lung development, we examined rat embryos and neonates using Northern blot analysis and in situ hybridization for CNP mRNA and radioimmunoassay and immunohistochemistry for CNP protein. A substantial expression of CNP mRNA was first detected on postnatal day 2, and it thereafter remained fairly steady. The level of CNP protein also increased rapidly after postnatal day 1, reaching a settled level on postnatal day 4. CNP protein and mRNA were detected in the endothelium and smooth muscle cells of blood vessels and in bronchial airway and alveolar epithelia. Immunoreactivity for CNP protein in the endothelium of blood vessels increased to an intense level after the saccular stage. These results suggest that the changes in CNP levels may be related to the occurrence of pulmonary vasodilation after birth.

Thrombopoietin expression in normal and hypobaric hypoxia-induced thrombocytopenic rats

Thrombopoietin (TPO) is important as the physiologic regulator of platelet production. High-altitude hypoxia is a well-known cause of polycythemia and thrombocytopenia in animals. Fifty-two Wistar rats were housed for 0.5 to 21 days in a mechanical chamber in an environment equivalent to that found at 5500 m to determine (a) the cellular localization of TPO and (b) whether the decreased platelet and megakaryocyte counts in rats exposed to a hypobaric hypoxic environment (HHE) are associated with an altered TPO mRNA expression. In normal rats, there were high levels of TPO mRNA in the liver and kidney, intermediate levels in the brain and large intestine, and low levels in the skeletal muscle and small intestine. TPO mRNA and protein were expressed in Purkinje cells and neuronal cells in the brain, in proximal tubular cells and the mesangial cells of the glomeruli in the kidney, in hepatocytes and biliary duct epithelial cells, in absorptive epithelial cells in the large intestine, in the epidermis, and in the lung. The platelet count in the blood and megakaryocyte counts in the bone marrow and spleen were all decreased significantly after 5 or more days of exposure to HHE. In major producers such as the liver and kidney and in minor producers such as the brain, TPO mRNA levels, which tended to be decreased after 0.5 to 3 days of exposure to HHE, had returned to normal by about Day 5 or 7. Thus, during the HHE period with a decreased platelet count, no changes in TPO mRNA levels were detected in these three organs. In conclusion, we have demonstrated that TPO production occurs in various types of cells. In HHE, however, factors other than TPO may be involved in hypobaric hypoxia-induced thrombocytopenia in rats.

Tissue factor is associated with the nonbacterial thrombotic endocarditis induced by a hypobaric hypoxic environment in rats

High-altitude hypoxia causes a hypercoagulable state. In our previous study on the blood coagulation system in rats, nonbacterial thrombotic endocarditis (NBTE) developed after 4-12 weeks' exposure to the equivalent of 5500 m in altitude. We hypothesized that TF (tissue factor)-producing cells in the cardiac valves might be induced by the hypobaric hypoxic environment (HHE) and then trigger NBTE. A total of 170 male Wistar rats were housed in a chamber at the equivalent of 5500 m altitude for 1-12 weeks. We measured TF activity in the plasma and studied morphological changes in the mitral valves using immunohistochemical and immunoelectrical methods for TF protein and in situ hybridization for TF mRNA. After 4 weeks or more of exposure to HHE, 28 of the 56 surviving rats had developed NBTE. After 4-8 weeks' exposure to HHE, the plasma TF activity level was significantly higher than in control rats. There was a significant correlation between plasma TF activity and the incidence of NBTE. After 1 weeks' exposure to HHE, immunoreactivity for TF protein was detected in foamy macrophages and stromal cells in the cardiac valves. In rats with NBTE, TF protein was present in foamy macrophages and spindle stromal cells and focally present in the extracellular matrix. TF mRNA was detected in some foamy macrophages within the thrombus, TF protein was localized to the rough endoplasmic reticulum and plasma membrane of many macrophages, some fibroblasts, and a few endocardial cells. TF is associated with the pathogenesis of the NBTE induced by exposure to HHE. The accumulation of TF-producing macrophages during exposure to HHE may be responsible for initiating thrombus formation.

The mouse extracellular signal-regulated kinase 2 gene. Gene structure and characterization of the promoter

ERK2 (extracellular-signal regulated kinase 2, also known as p42 mitogen-activated protein kinase) is an integral member of the mitogen-activated protein kinase cascade that is crucial for many cellular events such as proliferation and differentiation. Here, we determined the genomic organization of the Erk2 gene and characterized its promoter. The Erk2 gene spans over 60 kilobases, and the coding region is split into eight exons. In the coding region, exon-intron organization was exactly conserved between the two mouse genes for ERK2 and ERK1 except one junction shifted by one nucleotide. Primer extension and S1 nuclease analyses identified two major transcription start sites located at -219 and -223 relative to the translation start site. The 5'-flanking sequence lacked TATA box but contained a CCAAT box located approximately 60 base pairs upstream of transcription start sites. Sequencing of the 5'-flanking region also revealed potential cis-acting elements for multiple transcriptional regulatory factors including Sp1, zif268, Ets, CREB, and PuF sites. The promoter activity of the 5'-flanking region was examined using chloramphenicol acetyltransferase as a reporter gene. Transient transfection experiments using Chinese hamster ovary cells defined a maximal promoter activity in a 371-base pair region immediately upstream of the translation start site. Furthermore, we demonstrated, using mouse P19 embryonal carcinoma cells, that this 371-base pair sequence is likely to be sufficient to confer the transcriptional activation of the ERK2 promoter during the retinoic acid-induced differentiation of P19 cells.

Lactacystin increases LDL receptor level on HepG2 cells

Low density lipoprotein (LDL) receptor expression is regulated by proteolysis of transcription factors, sterol regulatory element binding proteins. To investigate the involvement of proteasome in this regulatory process, the effect of lactacystin, a specific proteasome inhibiton of microbial origin, was tested on LDL receptor expression on HepG2 cells. The addition of lactacystin to the cell culture increased the number of LDL receptors, indicating that proteasome plays a down-regulatory role in LDL receptor expression.

Gene expression of TGF-alpha, EGF and IL-6 in cultured renal tubular cells and renal cell carcinoma

BACKGROUND

Renal cell carcinoma (RCC) is thought to arise from the renal tubular cells (RTC). Assuming that proliferating RTC imply a premalignant change of RTC into RCC, messenger RNA expressions of growth factors in cultured RTC were compared to both cultured and frozen noncultured RCC.

METHODS

The expression of transforming growth factor-alpha (TGF-alpha), epidermal growth factor (EGF), EGF receptor (EGFR) and interleukin-6 (IL-6) were studied in surgically obtained RCC (n = 17), cultured RCC (n = 10), and autologous cultured RTC (n = 15). Quantitation of the PCR product was performed using a computer image analyzer which evaluated the intensity of each cytokine relative to beta-actin.

RESULTS

TGF-alpha, EGFR and IL-6 were detected in most of the cultured RTC, and both cultured and noncultured RCC were also expressed at high levels. In contrast to a high positivity of TGF-alpha, EGF was not strongly positive in all specimens.

CONCLUSIONS

Our results show that there is a predominant autocrine production of TGF-alpha in RCC and RTC, suggesting that TGF-alpha plays a distinct role in the proliferation of these cells. These studies also indicate that the mechanisms of proliferation and cytokine production of RCC and RTC are similar.

Identification of the proteolytic enzyme which cleaves human p75 TNF receptor in vitro

The extracellular domains of the human 55 and 75 kD TNF receptors (p55 and p75 TNF-R) are proteolytically cleaved to produce 30 and 40 kD soluble fragments, respectively. In this study, the enzymatic activity involved in the cleavage of human p75 TNF-R, named TNF-R releasing enzyme (TRRE), was identified in the culture supernatant of PMA-stimulated THP-1 cells using an activity assay system established by our group. When THP-1 cells were stimulated with PMA, TRRE was released rapidly into the supernatant, reaching maximal activity within 3 hours. The release of TRRE into the culture supernatant depended on the concentration of PMA and FCS. TRRE activity was partially inhibited by chelating agents, suggesting that TRRE may be a metallo-protease-like enzyme. This is the first successful attempt to establish a stable TRRE source with a reliable assay system.

Immunohistochemical analysis of the nm23 gene product (NDP kinase) expression in astrocytic neoplasms

The expression levels of nm23-H1 have been reported to correlate with the metastatic potential of some tumours. We have treated a child with a rare case of astrocytoma with diffuse osteoblastic metastases. We therefore decided to examine the expression of the nm23 gene product in 24 gliomas in order to clarify the association of its expression with the clinical features of the disease. A polyclonal antibody against a GST/nm23-H1 fusion protein was raised in rabbits. Twenty-four specimens, including 5 recurrent gliomas and one extraneural metastasis, were obtained from 19 patients treated surgically between 1990 and 1993 in our hospital. Immunohistochemical staining was performed on paraffin sections using an avidin-biotinyl peroxidase complex method. Of the 24 astrocytic neoplasms, 3 (12.5%) specimens from one patient with diffuse bony metastases stained intensely with nm23-H1. Two specimens obtained from glioblastoma multiforme patients stained weakly. The other 19 specimens were negative for nm23-H1 expression. Little or no nm23 expression was observed in adjacent nontumourous cerebral tissues. The results suggest that high levels of nm23 expression might correlate with extraneural metastatic potential in astrocytic neoplasms.

Potentiating effects of methamphetamine on the hyperactivity of microencephalic rats treated prenatally with methylazoxymethanol: possible implication of hyperdopaminergia

Microencephalic rats induced by methylazoxymethanol (MAM) were observed to have notable hyperactivity compared to control rats, as measured by several behavioral parameters in an automated field apparatus. Acute injection of the stimulant drug, methamphetamine (MAP), produced an increase in the incidence of locomotion and rearing in control rats, and this stimulatory effect of MAP on motor activity was markedly potentiated in MAM rats. Chronic MAP treatment did not change D1 or D2 dopamine receptor densities in either control or MAM rats. From these results, it was suggested that augmented dopaminergic functions may contribute to the hyperactivity seen in MAM rats.

Immunohistochemical analysis of nm23/NDP kinase expression in human lung adenocarcinoma: association with tumor progression in Clara cell type

Levels of nm23-H1/nucleoside diphosphate kinase (NDP kinase) expression have been reported to correlate inversely with metastatic potential in some tumors but not in others. Whether or not nm23 gene product is associated with metastatic potential in lung cancer is not clear as yet. We therefore immunohistochemically examined the expression of nm23 gene products in primary lung adenocarcinomas according to cytologic subtypes in order to clarify the association of its expression with the clinical features of the disease. Seventy-two (64.9%) of the 111 lung adenocarcinomas were positive for nm23 protein. In lung adenocarcinoma of Clara cell type, high levels of nm23 expression were associated with advanced pathologic stage, positive lymph node status, and poorer prognosis (P < 0.05). However, no correlation with clinical outcome was observed in other cell types. Our data suggest that higher levels of nm23 expression are associated with tumor progression in lung adenocarcinoma of Clara cell type.

Adenovirus and protein kinase C have distinct molecular requirements for regulating epidermal growth factor receptor trafficking

The ligand-activated tyrosine kinase receptor for epidermal growth factor (EGF) is down-regulated by an integral membrane protein coded for by the E3 early transcription unit of group C adenoviruses. The E3 protein appears to block recycling of constitutively internalized receptors, causing them instead to traffic to lysosomes where they are degraded. Expression of functional EGF receptors is also regulated by protein kinase C (PKC), which directly phosphorylates the EGF receptor at Thr-654. The goal of this study was to determine potential interactions between PKC and the E3 protein, since membrane-bound PKC activity is elevated by the adenovirus E1A protein. Our results show that although tumor promoters which activate PKC cause a coordinate induction of E3 protein synthesis and EGF receptor degradation, the E3 protein-induced pathway for receptor down-regulation functions independently of PKC and other kinases that are inhibited by staurosporine. This suggests that in contrast to other mechanisms that modulate receptor expression (i.e., ligand and PKC), the E3 protein is not regulated by phosphorylation but is constitutively active. We also report that adenovirus-mediated degradation is the preferred pathway in infected cells stimulated with 12-O-tetradecanoylphorbol-13-acetate (TPA) to induce receptor recycling.

Immunohistochemical analysis of cathepsin B expression in human lung adenocarcinoma: the role in cancer progression

Production of cathepsin B by tumor cells has been linked to metastatic potential in several experimental models. Sections of 95 primary lung adenocarcinomas were examined for expression of cathepsin B using a standard avidin-biotin immunohistochemical technique. Staining for cathepsin B was observed in 22.1% of all cases and 28.0% of those of the Clara cell type. In Clara cell adenocarcinomas, cathepsin B expression correlated with positive lymph node status, presence of distant metastases, and poor prognosis (P < 0.05). However, no correlation with clinical outcome was observed in other cell types. Our data suggest that cathepsin B may be involved in invasion and metastasis in Clara cell lung adenocarcinoma.

Role of threonine residues in regulation of the epidermal growth factor receptor by protein kinase C and mitogen-activated protein kinase

Epidermal growth factor (EGF) receptor tyrosine kinase activity is down-regulated by a number of growth-modulating agents that activate protein kinase C and/or mitogen-activated protein (MAP) kinases. Although the mechanism is unclear, it has been hypothesized that phosphorylation of specific threonine residues leads to inhibition of the EGF receptor tyrosine kinase. Two sites phosphorylated on the EGF receptor in response to phorbol esters are possible mediators of this effect: threonine 654, the target of protein kinase C, and threonine 669, the target of MAP kinase and the major site of phosphorylation on the EGF receptor. In order to investigate the role of these residues in receptor regulation, we substituted glutamic acid to mimic the negative charge introduced by phosphorylation at these sites. The wild-type and mutant receptor cDNAs were then transfected into CHO cells that lack endogenous EGF receptor. The EGF binding properties of the mutant receptors were similar to those of the wild-type EGF receptors. EGF stimulated tyrosine kinase activity and DNA synthesis in cells expressing both mutant receptors, indicating that the mutant EGF receptors are biologically active. Treatment of cells with phorbol esters inhibited the high affinity EGF binding and tyrosine kinase activities of both mutant and wild-type EGF receptors. These results indicate that acidic residues at either the Thr-654 or Thr-669 site modulate but do not block EGF receptor signalling. Furthermore, this data demonstrates that the mutant EGF receptors are still a target for inhibition by phorbol esters. Thus, events other than phosphorylation of Thr-654 or Thr-669 appear to be required for receptor down-regulation by protein kinase C or MAP kinase.

cDNAs and deduced amino acid sequences of subunits in the binding component of mouse bactericidal factor, Ra-reactive factor: similarity to mannose-binding proteins

The complement-dependent bactericidal factor, Ra-reactive factor, binds specifically to Ra polysaccharide, which is common to some strains of Gram-negative enterobacteria, and its is a complex of proteins composed of a polysaccharide-binding component and a component that is presumably responsible for the complement activation. The former component consists of two different 28-kDa polypeptides, P28a and P28b. We determined the partial amino acid sequences of P28a and P28b, and the results indicated that these polypeptides were similar to two species of mannose-binding protein, MBP-C and MBP-A (alternative names, liver and serum mannan-binding proteins, respectively), which have been isolated from rat liver and/or serum [Drickamer, K., Dordal, M. S., & Reynolds, L. (1986) J. Biol. Chem. 261, 6878-6887; Oka, S., Itoh, N., Kawasaki, T., & Yamashina, I. (1987) J. Biochem. 101, 135-144]. Thus, we cloned the respective cDNAs, using as probes synthetic oligonucleotides for which the sequences had been deduced from the amino acid sequences of P28a and P28b and of rat MBP cDNAs. The primary structures of P28a and P28b deduced from the cloned cDNAs are homologous to one another. They have three domains, a short NH2-terminal domain, a collagen-like domain, and a domain homologous to regions of some carbohydrate-binding proteins, as has been reported for rat MBPs. Southern and Northern blotting analyses using these cDNAs indicated that the P28a and P28b polypeptides are the products of two unique mouse genes which are expressed in hepatic cells.

Organ-specific occurrence and expression of the isoforms of nonspecific lipid transfer protein in castor bean seedlings, and molecular cloning of a full-length cDNA for a cotyledon-specific isoform

Four kinds of nonspecific lipid transfer proteins (nsLTP) were purified from different organs of castor bean (Ricinus communis L.) seedlings. Amino acid compositions and amino-terminal sequences of the four nsLTPs were determined and compared with those of castor bean isoforms, nsLTP-A, -B, and -C, previously reported [Takishima et al. (1986) Biochim. Biophys. Acta 870, 248-255; Takishima et al. (1988) Eur. J. Biochem. 177, 241-249]. Two isoforms from the cotyledons were identified as nsLTP-A and -C, one isoform from the endosperms as nsLTP-B, and the other was a new isoform from the axes. This new isoform was named nsLTP-D and its amino acid sequence was determined. These results demonstrated organ-specific occurrence of the nsLTP isoforms in castor bean seedlings. The isoforms nsLTP-A, -B, -C, and -D showed similar transfer activity not only for phosphatidylcholine and phosphatidylethanolamine but also for monogalactosyldiacylglycerol, although the homology among their amino acid sequences ranged from 70 to 30%. Two cDNA clones (pnsLTP-C and pnsLTP-D) for nsLTPs of castor bean seedlings were isolated and sequenced. pnsLTP-C was the cDNA clone for nsLTP-C expressed in the cotyledons, and pnsLTP-D was that for nsLTP-D in the axis. A coupled in vitro transcription-translation analysis of both cDNA clones revealed that pnsLTP-C encodes the full-length of nsLTP-C precursor (pro-nsLTP-C), while pnsLTP-D encodes a part of nsLTP-D precursor. PronsLTP-C contained a 24-amino acid pre-sequence preceding the mature nsLTP-C (92 amino acids).(ABSTRACT TRUNCATED AT 250 WORDS)

The primary structure of Aspergillus niger acid proteinase A

The complete amino acid sequence of the acid proteinase A, a non-pepsin type acid proteinase from the fungus Aspergillus niger var. macrosporus, was determined by protein sequencing. The enzyme was first dissociated at pH 8.5 into a light (L) chain and a heavy (H) chain, and the L chain was sequenced completely. Further sequencing was performed with the reduced and pyridylethylated or aminoethylated derivative of the whole protein, using peptides obtained by digestions with Staphylococcus aureus V8 protease, trypsin, chymotrypsin, and lysylendopeptidase. The location of the two disulfide bonds was determined by analysis of cystine-containing peptides obtained from a chymotryptic digest of the unmodified protein. These results established that the protein consists of a 39-residue L chain and a 173-residue H chain that associate noncovalently to form the native enzyme of 212 residues (Mr 22,265). This is, to our knowledge, the first time that such a protein with a rather short peptide chain associated noncovalently has been found. No sequence homology is found with other acid or aspartic proteinases, except for Scytalidium lignicolum acid proteinase B, an enzyme unrelated to pepsin by sequence, which has about 50% identity with the present enzyme. These two enzymes, however, are remarkably different from each other in some structural features.

Purification and partial sequencing of inhibitory factor on renal membrane adenylate cyclase in pancreatic cancer extract: identity with histones H1b or H1d

Inhibitory activity on renal membrane adenylate cyclase (AC) has previously been found in the extract of a pancreatic cancer associated with humoral hypercalcemia of malignancy (HHM). AC inhibitor was purified employing inhibition of AC activity of renal membrane stimulated by forskolin as its index. N-terminal 9 residues and a digested fragment of purified protein (14 residues) were completely consistent with that of histones H1b and H1d. Not only histone H1 but also histones H2A, H2B and H3 from calf thymus inhibited AC activity. These results indicate that the AC inhibitor in the pancreatic cancer extract is histone H1b or H1d and histones H2A, H2B and H3 also have an AC inhibitory activity.

Epidermal growth factor (EGF) receptor T669 peptide kinase from 3T3-L1 cells is an EGF-stimulated "MAP" kinase

The epidermal growth factor (EGF) receptor is both an activator and a target of growth factor-stimulated kinases involved in cellular signaling. Threonine-669 (T669) of the EGF receptor is phosphorylated in response to a wide variety of growth-modulating agents. MAP kinase is similarly phosphorylated as well as stimulated by growth activators, including EGF. To determine whether a MAP-type kinase is responsible for T669 kinase activity in EGF-stimulated 3T3-L1 cells, we partially purified and characterized the T669 peptide kinase. The results indicate that a MAP kinase phosphorylates the T669 peptide and raise the possibility that this enzyme may participate in a feedback loop, being activated by the EGF receptor and in turn phosphorylating the receptor.

Thapsigargin, a novel promoter, phosphorylates the epidermal growth factor receptor at threonine 669

Thapsigargin, a protein kinase C-independent tumor promoter, can negatively regulate the epidermal growth factor (EGF) receptor through inhibition of high affinity EGF binding and EGF-stimulated tyrosine kinase activity. In contrast to activators of protein kinase C, thapsigargin does not induce significant phosphorylation of threonine 654. However, thapsigargin does stimulate phosphorylation of the EGF receptor at other serine and threonine residues. We now identify threonine 669 as the major site of phosphorylation on the EGF receptor resulting from thapsigargin treatment. These results raise the possibility that phosphorylation of threonine 669 may mediate changes in the binding and kinase state of the EGF receptor.

Amino acid sequences of two nonspecific lipid-transfer proteins from germinated castor bean

The amino acid sequence of two nonspecific lipid-transfer proteins (nsLTP) B and C from germinated castor bean seeds have been determined. Both the proteins consist of 92 residues, as for nsLTP previously reported, and their calculated Mr values are 9847 and 9593 for nsLTP-B and nsLTP-C, respectively. The sequences of nsLTP-B and nsLTP-C, compared to the known sequence of nsLTP-A from the same source, are 68% and 35% similar, respectively. No variation was found at the positions of the cysteine residues, indicating that they might be involved in disulfide bridges.

The structure of jack bean urease. The complete amino acid sequence, limited proteolysis and reactive cysteine residues

The amino acid sequence of jack bean urease has been determined. The protein consists of a single kind of polypeptide chain containing 840 amino acid residues. The subunit relative molecular mass calculated from the sequence is 90,770, indicating that urease is composed of six subunits. Out of 25 histidine residues in urease, 13 were crowded in the region between residues 479 and 607, suggesting that this region may contain the nickel-binding site. Limited tryptic digestion cleaved urease at two sites, Lys-128 and Lys-662. Proteolytic products were not dissociated and retained full enzymatic activity. Five tryptic peptides containing the reactive cysteine residues were isolated and characterized with the aid of sulfhydryl-specific reagents, N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine and N-(7-dimethylamino-4-methyl-3-coumarinyl)-maleimide. The reactive cysteine residues were located at positions 59, 207, 592, 663, and 824. The possibility that Cys-59, Cys-207, Cys-663, and Cys-824 are involved in the urease activity of the enzyme has been eliminated. Cys-592, which is essential for enzymatic activity, is located in the above-mentioned histidine-rich region.

On the activities of parathyroid hormone-like factor and transforming growth factors in extract of pancreatic cancer associated with humoral hypercalcemia of malignancy

Extract of exocrine pancreatic cancer associated with humoral hypercalcemia of malignancy was examined for biological activities of PTH-like factor and transforming growth factor (TGFA and TGFB), both of which are possible causes of hypercalcemia. The crude extract had both PTH-like and TGF activities. On Bio Gel P-60 column chromatography, PTH-like and TGFA activities were eluted at around 10 kD, whereas TGFB activity was eluted at around void fractions, 10 kD and 6 kD. Liver extract, used as a control material, exhibited only TGFB activity at around 6 kD. CM-cellulose column chromatography of 10 kD fractions resulted in a subtle distinction between PTH-like activity and TGF activities. Further fractionation of the peak with PTH-like activity on reverse-phase high performance liquid chromatography separated PTH-like activity distinctly from TGFB activity. TGFA activity was lost through the procedure. It was concluded that the exocrine pancreatic cancer associated with hypercalcemia produced not only PTH-like activity but also TGFA and TGFB activities. Several chromatographic analyses suggested that PTH-like activity and at least TGFB activity stem from distinct molecules and that the PTH-like factor has no significant TGFB activity intrinsically.

A spin-label study of the effects of drugs on calcium release from isolated sarcoplasmic reticulum vesicles

The effects of caffeine, thymol, and procaine on calcium release from fragmented sarcoplasmic reticulum (FSR) from rabbit skeletal white muscle were investigated by the spin label method at the organellar level. Two thiol-directed spin labels, 4-maleimide-2,2,6,6-tetramethylpiperidinooxyl and 4-(2-iodoacetamide)-2,2,6,6-tetramethylpiperidinooxyl, were used for the labeling of SR proteins. The ratio (W/S) of the weakly (W) and strongly (S) immobilized ESR signals was measured for the maleimide and iodoacetamide labeled FSR. The two labels gave different W/S values, which means that the two labels report conformational changes at different loci of SR proteins. The dependences of the W/S ratios on the concentration of the drugs showed that conformational changes of SR proteins induced by these drugs are not the same. From measurements of the distribution of 5-doxyldecanoic acid methylester between the lipid and water phases, it was found that the conformational changes of the SR proteins caused by thymol or procaine induced a disorder in local regions of the phospholipid bilayers of FSR, while such disordering was not induced by caffeine. On the other hand, caffeine and thymol showed definite effects on calcium release from FSR, while procaine did not. These results indicate that the effects of the drugs on the protein conformations can be well characterized at the organellar level by means of the spin label technique and that some specific changes in the conformations of SR proteins are necessary for calcium release from FSR.

On the overshoot of calcium accumulation in fragmented sarcoplasmic reticulum induced by thymol

The mechanism was studied of the overshoot of calcium accumulation in fragmented sarcoplasmic reticulum (FSR) which is observed when the active transport of calcium into FSR is performed in the presence of thymol; the amount of calcium in FSR increases steeply during the first minute of the reaction and then decreases markedly. In contrast to this behavior, the amount of calcium in FSR increases monotonically and then reaches saturation in the absence of thymol. It is shown that the amount of calcium accumulated in FSR is determined by the balance between the rapid influx and efflux of calcium, and that both processes are depressed by thymol. The overshoot of calcium accumulation can be explained as follows: thymol so markedly depresses the efflux of calcium uncoupled with Ca2+-ATPase activity that the amount of calcium is increased in FSR in spite of partial deactivation of Ca2+-ATPase. However, the state of the FSR membrane is rapidly changed when the concentration of accumulated calcium exceeds a certain critical value. Concomitant with this change, the calcium permeability of the membrane is increased, leading to a decrease in the amount of accumulated calcium. The effects of magnesium and temperature on the overshoot of calcium accumulation can be accounted for by this proposed mechanism.