Optimum treatment strategy for superficial esophageal cancer: endoscopic mucosal resection versus radical esophagectomy

This study was designed to determine the optimum treatment for a superficial esophageal cancer involving the mucosal or submucosal layer of the esophagus. The subjects were 150 patients with a superficial esophageal cancer who underwent endoscopic mucosal resection (EMR) or esophagectomy in Kurume University Hospital from 1981 to 1997. The mortality and morbidity rates, survival rate, and recurrence rate were retrospectively compared for (1) 35 patients who underwent EMR and 37 patients who underwent esophagectomy for a mucosal esophageal cancer and (2) 45 patients who underwent extended radical esophagectomy and 33 patients who underwent less radical esophagectomy for a submucosal esophageal cancer. Among the 72 patients with a mucosal cancer, lymph node metastasis/recurrence was observed in only one (1%); whereas of 78 patients with a submucosal cancer it was observed in 30 (38%). Among patients with a mucosal cancer the mortality and morbidity rates after EMR were lower than for those after esophagectomy. The survival rate after EMR was the same as that after esophagectomy. No recurrence was observed after either treatment modality. Among the patients with a submucosal cancer, the survival rate was higher and the recurrence rate lower after extended radical esophagectomy; than after less radical esophagectomy; the mortality and morbidity rates after extended radical esophagectomy were the same as those after less radical esophagectomy. Multivariate analysis demonstrated that the treatment modality (EMR versus esophagectomy) did not influence the survival of patients with a mucosal esophageal cancer, whereas it strongly influenced the survival of patients with a submucosal esophageal cancer. We concluded that EMR was the mainstay of treatment for a mucosal esophageal cancer, and extended radical esophagectomy was the mainstay of treatment for a submucosal esophageal cancer.

[Clinical characteristics of ventricular tachycardia and ventricular fibrillation in exercise stress testing]

OBJECTIVES

Ventricular tachycardia (VT) and ventricular fibrillation (Vf) induced in exercise stress testing should be treated urgently, although the occurrence of arrhythmia is rare. The conditions for the onset of arrhythmia and the clinical characteristics of VT and Vf patients in exercise stress testing were studied.

METHODS

Fifty-nine patients (mean age 54 +/- 17 years, 41 males, 18 females) with VT (succession of 3 or more ventricular premature beats) or Vf induced in exercise stress testing were selected from 7,594 patients with consecutive treadmill stress testing in our hospital from January 1993 to February 1998.

RESULTS

The incidence of exercise-induced VT or Vf was 0.8%, and there were no fatal accidents in all tests. Among the 59 patients with exercise-induced VT or Vf, 52 patients had non-sustained VT, 5 had sustained VT, and 2 had Vf. Of the 59 patients, 23 had rhythm or conduction disturbances, 14 had coronary artery disease, 13 had cardiomyopathy, and 9 had valvular heart disease. The VT or Vf incidence in coronary artery disease was 0.2%, and in valvular heart disease was 10.8%. VT or Vf occurred at over 80% of maximum heart rate exercise intensity in 40 patients, including 4 with sustained VT and 2 with Vf, of the 59 patients. Also, in 9 VT patients including the 4 sustained VT patients, VT occurred in the exercise recovery period within 2 min after the exercise. Although VT disappeared spontaneously in 52 non-sustained VT and 3 sustained VT patients, intravenous injection of lidocaine was needed in 2 sustained VT patients and direct current defibrillator was needed in 2 Vf patients. Furthermore, only one non-cardiac death was observed in the follow-up period of average 42 months.

CONCLUSIONS

Our results showed clinical characteristics and incidence of VT or Vf similar to past reports. Furthermore, all sustained VT and Vf patients, who should be treated urgently, had a past history of ventricular premature beats or VT. Our data suggest that VT and Vf could occur during the recovery period, especially in patients with documented ventricular tachyarrhythmias when the stress intensity has reached the critical level in the exercise tolerance test.

Development of the insulin-like growth factor-I assay system

A high speed full automatic ELISA system for measurement of insulin-like growth factor-I (IGF-I) was established by using magnetic particle-linked monoclonal antibody and enzyme-labeled monoclonal antibody. A standard curve was obtained, and the effect of dilution on the assay system was investigated. An IGF-I spike recovery test of human serum samples and a study of the correlation with a radioimmunoassay system were performed, and good results were obtained from all studies. The assay range was 0.5-50 ng/ml, and the time required for the full automatic measurement was 15 minutes. This assay system will play a central role in the clinical approach to IGF-I.

Additivity of the proliferative effects of HGF/SF and EGF on hepatocytes

The additivity of DNA synthesis induced by hepatocyte growth factor/scatter factor (HGF/SF) and epidermal growth factor (EGF) was revealed in periportal hepatocytes (PPH), perivenous hepatocytes (PVH), and primary hepatocytes. Furthermore, additivity of the signal transduction pathway of HGF/SF and EGF was investigated (i.e., the activity of mitogen-activated protein kinase (MAPK) induced by HGF/SF and EGF), but it was not seen in PPH, PVH, or primary hepatocytes, although wortomannin, a PI 3-kinase inhibitor, abolished the additivity. The additivity of DNA synthesis induced by HGF/SF and EGF was not related to hepatocyte heterogeneity, but to a difference in the signal transduction pathway, probably another pathway that is different from the classical MAPK (MAPK/ERK1,2) path.

[New trends in neoadjuvant chemoradiotherapy for locally-advanced esophageal cancer: esophagectomy--is it necessary?]

In responders to neoadjuvant chemoradiotherapy for locally-advanced esophageal cancer, there was no significant difference in the long-term outcome between patients who underwent esophagectomy and those who did not. Esophagectomy might be unnecessary for patients who achieve a complete response with chemoradiotherapy for an esophageal cancer, in cases when salvage surgery is considered in order to treat any future recurrence.

Radical esophagectomy and secondary anastomosis for high-risk patients with intrathoracic esophageal carcinoma

OBJECTIVE

We have often conducted esophageal reconstruction via a thoracic subcutaneous route in high-risk patients to avoid major complications following anastomotic leakage. This type of reconstruction is nonphysiological, however, and presents a poor cosmetic appearance. In better risk patients, therefore, we usually conduct gastric-tube replacement via a posterior mediastinal route. We have recently begun gastric-tube replacement via the posterior mediastinal route with secondary anastomosis for high-risk patients to avoid anastomotic leakage.

RESULTS

From 1996 to 1999, secondary anastomosis was conducted in 25 patients with different degrees of risk--10 with diabetes mellitus, 7 with liver dysfunction, 3 with simultaneous laryngeal and/or pharyngeal cancer, 2 each with induction chemoradiotherapy, cardiac failure, renal dysfunction, respiratory failure, and cardiorespiratory dysfunction, and 1 with cerebral infarction. 6 patients had with multiple combined diseases. Secondary anastomosis was conducted 3-12 weeks (mean: 5.5 weeks) after esophagectomy. Stomach-tube necrosis was not seen in any of the 25 patients undergoing this 2-step procedure. Anastomosis leakage was seen in 5 of the 25 patients (20%), but was slight, in all but 1.

CONCLUSION

Our 2-step procedure has the following advantages: low risk of anastomotic leakage, radical surgery for esophageal cancer, the potential for early adjuvant therapy after esophagectomy, easy and early training in swallowing, and no cosmetic problem. Its disadvantages are prolonged hospitalization, multiple surgery, and esophageal stoma formation. Secondary anastomosis thus appears helpful in treating high-risk patients with advanced esophageal cancer.

Chronic inhalation toxicity and carcinogenicity studies of 3-chloro-2-methylpropene in BDF1 mice

Chronic toxicity and carcinogenicity studies of 3-chloro-2-methylpropene (CMP), which has been widely used as an insecticide and chemical intermediate, were carried out in BDF1 mice. CMP was administered to mice in groups of 50 male and 50 female mice by the inhalation route 5 days per week for 104 weeks at doses of 0, 50, 100 or 200 ppm. Male and female mice in the CMP-exposed groups had decreased body weight but no noticeable clinical signs when compared with the control group. Dose-related increases in the incidences of gastric mucosal hyperplasia and squamous cell papilloma were observed in both sexes, and squamous cell carcinoma was observed in only one male mouse in the 100 ppm group. An increased incidence of Harderian gland adenoma in female mice was also recognized. In the nasal cavity, eosinophilic exudate associated with atrophy of olfactory epithelia, respiratory metaplasia of olfactory epithelia and olfactory gland, and eosinophilic changes in respiratory and olfactory epithelia were increased in both sexes.

Histopathological analysis of non-malignant and malignant epithelium in achalasia of the esophagus

We studied the premalignant nature of achalasia using anti-Ki-67 and anti-p53 monoclonal antibodies immunohistochemically. In this study, four patients with esophageal carcinoma and achalasia were investigated. Three tumors were pT4 (UICC pTNM) and one tumor was pT1. The majority of non-malignant esophageal epithelium showed esophagitis and/or dysplasia histologically. Esophageal epithelial cells in the lesions of esophagitis and/or dysplasia had a higher number of Ki-67-positive cells than normal epithelial cells. p53 protein was expressed in two tumors and it was not expressed in non-malignant epithelium. From these results, we found that esophageal epithelium in achalasia lesions is changed to varying degrees of esophagitis and/or dysplasia by stagnation of intake foods, and these abnormal epithelial cells showed a high proliferative state compared with the normal cells without the p53 gene mutation. We suggest that the distinct proliferative status is a cause of carcinogenesis.

CDw108 expression during T-cell development

We recently reported a gene encoding the human CDw108, a glycosylphosphatidylinositol (GPI)-anchored membrane glycoprotein that is preferentially expressed on activated T lymphocytes and erythrocytes. The present study investigated the expression of CDw108 on various tissues and cells, particularly on T cells during development. The murine CDw108 cDNA was cloned initially, and it was highly homologous to the human CDw108 (88.0% or 89.3% similarity at the nucleotide or amino acid level, respectively) or identical to the murine semaphorin K1/Sema7A. The CDw108 mRNA was demonstrated in a few tissues including thymus and brain with the highest expression coming on day 7 in whole embryo followed by relatively consistent expression during development. Cell-surface expression of the CDw108 during T-cell development was further examined by flow cytometry in the human umbilical cord blood and thymus. It was preferentially expressed on a CD34+ stem cell population of umbilical cord blood, and CD3dull CD34+/- CD117 (c-kit)+ CD4bright CDbright cells in the thymus that are involved in the stage of positive selection. These results suggest the contribution of CDw108 in T-cell development, especially in the stage of positive selection in the thymus.

Innervation of nociceptors in the menisci of the knee joint: an immunohistochemical study

Using histology, we studied the innervation of nociceptors in the medial and lateral menisci of the knee joint. Specimens examined were taken from 16 patients during arthroplasty. The patients were 6 men and 10 women, with ages ranging from 14 to 76 years (mean 56 years). Immunohistochemistry with the unlabeled antibody biotin-streptavidin method was employed to detect protein gene product 9.5 (PGP 9.5) or substance P (SP) in the specimen. The antibody for PGP 9.5 detected nerve tissues in the menisci. Most but not all of the nerve fibers were associated with blood vessels. Nerve fibers and sensory receptors were found mainly in the peripheral, vascular zone, representing the outer one-third of the meniscus, and the innervated area was wider in the anterior and posterior horns. Pacinian and Ruffini corpuscles as well as free nerve endings were identified in these areas. Larger fibers coursed circumferentially in the peripheral zone, with smaller branches of nerve fibers running radially into the meniscus. Nerve fibers positive for SP were also detected in the menisci, but were fewer in number. Their branches also were fewer, oriented radially and paralleling blood vessels. This study showed that some of the pain in cases of meniscal tear could originate in the meniscus itself, especially with peripheral tears that may be accompanied by bleeding.

The effects of water extracts of CagA positive or negative Helicobacter pylori on proliferation, apoptosis and connexin formation in acetic acid-induced gastric ulcer of rats

AIM

To investigate the influence of water extracts of CagA-positive or -negative Helicobacter pylori on healing of chronic gastric ulcers and on connexin formation, proliferation and apoptosis, in acetic acid-induced chronic gastric ulcers in rats.

METHODS

Acetic acid was used to induce chronic gastric ulcers in rats, and a water extract of H. pylori was given by mouth every day. Connexin 32 formation was assessed using Western blotting as previously described. The frequencies of proliferating cell nuclear antigen staining and of TdT-mediated dUTP-biotin nick end labelling were examined.

RESULTS

In untreated rats, acetic acid-induced gastric ulcers healed after 14 days and the electrophoretic band corresponding to connexin 32 appeared 4 days after ulcer induction. Treatment with a water extract of H. pylori delayed ulcer healing, with the ulcers remaining unhealed even on the 14th day; healing was delayed more when treatment was with an extract of CagA-positive rather than CagA-negative H. pylori. Connexin 32 appeared earlier when treatment was with a CagA-negative rather than a CagA-positive extract, but in both cases later than in the untreated control group. Proliferating cell nuclear antigen labelling on the fourth day was seen in 14.5% +/- 1.6% of mucosal cells of control group, but in 35.9% +/- 1.4% and 36.5% +/- 1.4% of mucosal cells treated with either VacA(+)CagA(-) and VacA(+)CagA(+) H. pylori extract, respectively. Furthermore, extracts of both H. pylori strains, especially VacA(+)Cag(+) H. pylori promoted apoptosis.

CONCLUSIONS

A water extract of H. pylori increased both proliferation and apoptosis, which are related to exacerbation and healing of ulcer as well as appearance of connexin 32.

Changes in autonomic nervous activity prior to spontaneous coronary spasm in patients with variant angina

Although the autonomic nervous system has been implicated in the genesis of coronary spasm, the precise mechanism by which it serves as the trigger of coronary spasm remains unclear. The aim of this study was to investigate changes in autonomic nervous activity associated with ischemic episodes in patients with variant angina (VA). Heart rate variability (HRV) on Holter monitoring was analyzed during 17 ischemic episodes in 11 patients with VA. The parameters of HRV were measured during a 2-min period at various time intervals prior to the onset of ST-segment elevation. The low frequency (LF) and high frequency (HF) components of the HRV, LF/HF ratio, mean RR interval, and the coefficient of the RR interval variation (CV) were calculated for each time interval. Both the HF and the CV increased significantly in the 2 min prior to the onset of ST-segment elevation, suggesting heightened vagal activity. The LF/HF ratio, a measure of cardiac sympatho-vagal balance, did not change. The LF, a measure of sympathetic activity with vagal modulation, also did not change. The RR interval decreased significantly in the 2 min prior to the onset of ST-segment elevation. These results suggest that enhancement of both the vagal and the sympathetic nervous activity plays an important role in the initiation of coronary spasm.

Establishment and epitope analysis of allo-specific cytotoxic T lymphocytes at a tumor site recognizing a spouse's HLA-A0206 molecule

PROBLEM

The molecular basis of allo-reactivity in reproductive immunity has not been fully clarified.

METHOD OF STUDY

Cytotoxic T lymphocytes (CTLs) were established from tumor-infiltrating lymphocytes (TILs). The allo-reactivity of the CTLs against various tumor cell lines or human leukocyte antigen (HLA)-A allele-transfected COS-7 cells was measured by 51Cr-release or interferon-gamma production assay.

RESULTS AND CONCLUSIONS

We have established CTLs reacting to an HLA-A0206 molecule that matched a spouse's HLA-A allele from the TILs of a 68-year-old multiparous patient with gastric cancer. The amino acids at positions 66 and 88 in the alpha1 domain of HLA-A0206, both of which were common in the other HLA-A2 subtypes, were involved in the recognition by the CTLs. Endogenous peptides in the groove were not involved in the recognition. These results suggest the presence of long-lasting memory CTLs raised by the reproduction process, and may facilitate a better understanding of the molecular basis of allo-recognition during reproduction.

Mouse homologue of the human SART3 gene encoding tumor-rejection antigen

We recently isolated a human SART3 (hSART3) gene encoding a tumor-rejection antigen recognized by HLA-A2402-restricted cytotoxic T lymphocytes (CTLs). The hSART3 was also found to exist as an RNA-binding nuclear protein of unknown biological function. In this study, we cloned and analyzed the homologous mouse SART3 (mSART3) gene in order to understand better the function of hSART3, and to aid in establishing animal models of specific immunotherapy. The cloned 3586-bp cDNA encoded a 962-amino acid polypeptide with high homology to hSART3 (80% or 86% identity at the nucleotide or protein level, respectively). Nonapeptides recognized by the HLA-A2402-restricted CTLs and all of the RNA-binding motifs were conserved between hSART3 and mSART3. The mSART3 mRNA was ubiquitously expressed in normal tissues, with low level expression in the liver, heart, and skeletal muscle. It was widely expressed in various organs from as early as day 7 of gestation. mSART3 was mapped to chromosome 5, a syntenic region for human chromosome 12q23-24, and its genomic DNA extended over 28-kb and consisted of 19 exons. This information should be important for studies of the biological functions of the SART3 protein and for the establishment of animal models of specific cancer immunotherapy.

Rare incidence of interspousal transmission of Helicobacter pylori in asymptomatic individuals in Japan

PCR-restriction fragment length polymorphism electrophoretic patterns of amplified ureB and ureC of Helicobacter pylori were compared between spouses after digestion with restriction endonucleases. Twenty of 21 couples, both members of which were positive for H. pylori, showed ureB and ureC patterns that differed between spouses. We concluded that in Japan, interspousal transmission of H. pylori occurs rarely.

Distribution of adrenomedullin (AM), proadrenomedullin N-terminal 20 peptide, and AM mRNA in the rat gastric mucosa by immunocytochemistry and in situ hybridization

Adrenomedullin (AM) is a novel vasorelaxant peptide isolated from pheochromocytoma. Proadrenomedullin N-terminal 20 peptide (PAMP) is a hypotensive peptide generated by posttranslational enzymatic processing of a 185-amino acid pro-AM molecule, the same precursor as AM. In this study, we investigated localizations of these peptides by immunocytochemistry and AM mRNA by non-radioisotopic in situ hybridization followed by the streptavidin and biotin complex (ABC) method and catalyzed signal amplification (CSA) in the rat adrenal medulla and gastric mucosa. In the gastric mucosa, both AM- and PAMP-like immunoreactivities were found in the neuroendocrine cells, but PAMP-positive cells were more abundant than AM-positive ones. By immunoelectron microscopy, AM and PAMP were localized exclusively in the secretory granules. The distribution pattern of AM mRNA-positive cells, only a limited portion of which had AM and/or PAMP, was also similar to that of the two peptides. But AM mRNA was detected also in a few epithelial cells as well as neuroendocrine cells. The two peptides might play an important role in the control of local circulation in the rat stomach.

Expression of tetraspans transmembrane family in the epithelium of the gastrointestinal tract

Tetraspans transmembrane family (TSTF) members, also known as tetraspanin superfamily, have various effects on cell proliferation, motility, and adhesion not only in hematopoietic cells, but also in other type of cells. However, little is known about their expression in the human gastrointestinal (GI) tract. The authors characterized immunohistologically the localization of six members of TSTF (CD9, CD37, CD53, CD63, CD81, and CD82) in the normal epithelium from esophagus to colon. CD9 and CD82 molecules were strongly expressed in all epithelial surface membranes, from esophagus to colon, and their staining pattern was quite similar. Expression of CD37 was not detectable throughout the GI tract. Expression of CD53 was barely detectable. Expression of CD63 was clearly detected distal to the stomach, including the duodenum, small intestine, and colon. On the contrary, expression of CD81 was detected only in the esophagus--confined to a few layers from the basal layer. From these data it seems likely that the expression of TSTF molecules might be regulated differentially depending on the site of the GI tract.

Total esophagectomy versus proximal esophagectomy for esophageal cancer at the cervicothoracic junction

To investigate the adequate extent of esophagectomy and lymphadenectomy for an esophageal cancer localized at the cervicothoracic junction, the mortality and morbidity rates, survival rates, and patterns of recurrence were retrospectively analyzed in two groups-14 patients who underwent total esophagectomy with or without laryngectomy and 15 patients who underwent proximal esophagectomy with or without laryngectomy-at Kurume University Hospital from 1981 to 1996. Proximal esophagectomy with or without laryngectomy resulted in a lower hospital mortality rate and better overall survival for patients who underwent curative esophagectomy compared with total esophagectomy with or without laryngectomy. Multivariate analysis indicated that the extent of esophagectomy (total esophagectomy versus proximal esophagectomy) was not a prognostic factor. The incidence of recurrence was not different between the two groups. Lymph node metastasis or recurrence from such esophageal cancers was localized to the neck and upper mediastinum. For an esophageal cancer localized at the cervicothoracic junction, therefore, proximal esophagectomy with or without laryngectomy and with cervical and upper mediastinal lymphadenectomy could be better indicated for preselected patients.

Involvement of Rab4 in regulated exocytosis of rat pancreatic acini

BACKGROUND & AIMS

Rab4, a Ras-related small guanosine triphosphate (GTP)-binding protein, has been suggested to participate in exocytosis. The function of Rab4 in regulated exocytosis of pancreatic acini was examined in this study.

METHODS

Subcellular localization of Rab4 was determined by Western blotting and immunohistochemistry. The Rab4 function in regulated exocytosis was examined by introducing Rab4 hypervariable carboxy-terminal domain peptide (Rab4 peptide) and anti-Rab4 antibody into streptolysin O-permeabilized acini. The regulation of Rab4 by cholecystokinin (CCK) and 12-O-tetradecanoyl-phorbol 13-acetate (TPA) was investigated by examining their effects on [32P]GTP binding rate into the Rab4 immunoprecipitates. The participation of protein kinase C in the Rab4 regulation by CCK was confirmed by calphostin C pretreatment of acini.

RESULTS

Rab4 was localized on zymogen granule membranes. Both Rab4 peptide and anti-Rab4 antibody enhanced calcium-stimulated amylase release from streptolysin O-permeabilized acini, suggesting the inhibitory role of Rab4 in exocytosis. CCK and TPA increased GTP binding to Rab4. Calphostin C attenuated the stimulatory effect of CCK on GTP binding to Rab4.

CONCLUSIONS

Rab4 negatively modulates regulated exocytosis of pancreatic acini and is controlled by CCK through a protein kinase C pathway.

Molecular cloning of a glycosylphosphatidylinositol-anchored molecule CDw108

CDw108, also known as the John-Milton-Hagen human blood group Ag, is an 80-kDa glycosylphosphatidylinositol (GPI)-anchored membrane glycoprotein that is preferentially expressed on activated lymphocytes and E. The molecular characteristics and biological function of the CDw108 were not clarified previously. In this manuscript, we identify the cDNA clone containing the entire coding sequence of the CDw108 gene and report its molecular characteristics. The 1998-base pairs of the open reading frame of the cloned cDNA encoded a protein of 666 amino acids (aa), including the 46 aa of the signal peptide and the 19 aa of the GPI-anchor motif. Thus, the membrane-anchoring form of CDw108 was the 602 aa, and the estimated molecular mass of the unglycosylated form was 68 kDa. The RGD (Arg-Gly-Asp) cell attachment sequence and the five potential N-linked glycosylation sites were located on the membrane-anchoring form. Flow cytometric and immunoprecipitation analyses of the CDw108 cDNA transfectants confirmed that the cloned cDNA encoded the native form of CDw108. The CDw108 mRNA was expressed in activated PBMCs as well as in the spleen, thymus, testis, placenta, and brain, but was not expressed in any other tissues tested. Radiation hybrid mapping indicated that the CDw108 gene was located in the middle of the long arm of chromosome 15 (15q23-24). This molecular information will be critical for understanding the biological function of the CDw108 Ag.

Inhibition of stimulated amylase secretion by adrenomedullin in rat pancreatic acini

Adrenomedullin is a novel hypotensive peptide originally isolated from human pheochromocytoma and recently localized to PP cells of the pancreatic islets of Langerhans. Based on the pancreatic islet-acinar axis model, we investigated the effect of adrenomedullin on regulated exocytosis of exocrine pancreas. Using rat [125I]-adrenomedullin, specific binding sites were localized to rat pancreatic acini. We next examined the effect of adrenomedullin on 100 pM cholecystokinin (CCK)-stimulated amylase release from pancreatic acini. Adrenomedullin inhibited amylase secretion in a dose-dependent manner by approximately 50% at maximum, and the IC50 was 1.1 pM. However, adrenomedullin did not affect rat [125I]CCK binding to isolated acini or reduce the intracellular free Ca2+ concentration increased by CCK. Adrenomedullin also inhibited amylase secretion induced by 1 microM calcium ionophore A23187, suggesting that adrenomedullin inhibits stimulated amylase secretion by functioning at a step(s) distal to the ligand-receptor binding system and intracellular calcium mobilizing mechanism. In streptolysin-O permeabilized acini, 10 nM adrenomedullin shifted the calcium dose-response curve to the right, indicating that adrenomedullin inhibits calcium-induced amylase secretion by reducing calcium sensitivity of the pancreatic exocytotic machinery. In addition, pretreatment of pancreatic acini with pertussis toxin abolished the inhibitory effect of adrenomedullin on CCK-stimulated amylase secretion. These results indicate that adrenomedullin inhibits stimulated amylase secretion by reducing the calcium sensitivity of the exocytotic machinery of the pancreatic acini. A pertussis toxin-sensitive GTP-binding protein(s) is also involved in this mechanism.

Expression in Escherichia coli of a new multidrug efflux pump, MexXY, from Pseudomonas aeruginosa

Two new genes (mexXY) similar to mexAB, mexCD, and mexEF and mediating multidrug resistance were cloned from the chromosome of Pseudomonas aeruginosa. Elevated ethidium extrusion was observed with Escherichia coli cells harboring the plasmid carrying mexXY. This MexXY system confers higher resistance to fluoroquinolones than the MexAB and MexCD systems, and E. coli ToIC or P. aeruginosa OprM is necessary for the function of the MexXY system.

Relationship between the eradication of Helicobacter pylori and the healing pattern of peptic ulcer

We investigated the relationship between the eradication of Helicobacter pylori and the stage after the eradication of this bacterium. Eighty-six patients with H. pylori who had gastric ulcer (n=45) or duodenal ulcer (n=41) were enrolled in the study. As eradication therapy, patients received 1,500 mg amoxicillin, 400 mg clarithromycin, and 30 mg lansoprazole for 2 weeks, followed by 30 mg lansoprazole for 6 weeks in patients with gastric ulcer or for 4 weeks in those with duodenal ulcer. The ulcer stages were evaluated using the indigocarmine method at the third and sixth month after entry. The overall eradication rate of H. pylori was 85% in this study. In the gastric ulcer group, 62% of H. pylori-eradicated patients and 37.5% of H. pylori-uneradicated patients showed the S2 stage (white scar) at the sixth month. In the duodenal ulcer group, 61% of H. pylori-eradicated patients showed the S2 stage and none of the H. pylori-uneradicated patients showed the S2 stage (p < 0.05). We concluded that H. pylori eradication might promote not ulcer healing but maturity of the ulcer scar, especially in duodenal ulcer patients, and that this might also be related to the reduction of ulcer relapse.

Zonal differences in effects of HGF/SF and EGF on DNA synthesis in hepatocytes under fed or starved conditions

Zonal differences of DNA synthesis in hepatocytes induced by hepatocyte growth factor and/or scatter factor (HGF/SF) and epidermal growth factor (EGF) were investigated using male Wistar rats under fed or starved conditions. Overall, DNA synthesis was greater in fed rats than in starved rats. The predominance of EGF in periportal hepatocytes (PPH) on zonal DNA synthesis was reversed by starved conditions, but the predominance of HGF/SF on zonal DNA synthesis in perivenous hepatocytes (PVH) was not influenced by nutritional conditions. 125I-labeled EGF and 125I-labeled HGF/SF-receptor binding studies revealed no significant difference between PPH and PVH in starved or fed rats. To investigate the mechanism of the signal transduction pathway, we used genistein, an inhibitor of tyrosine kinase. Genistein had different effects on zonal difference in EGF and HGF/SF. In EGF, 1 microgram/ml genistein abolished zonal differences, but in HGF/SF 1 microgram/ml genistein did not abolish zonal differences. These data suggest that, in contrast to HGF/SF, zonal difference of DNA synthesis by EGF was dependent on nutritional conditions and DNA synthesis induced by HGF/SF and EGF might be related to tyrosine kinase, but the influence of tyrosine kinase on DNA synthesis was different between HGF/SF and EGF.

NorM, a putative multidrug efflux protein, of Vibrio parahaemolyticus and its homolog in Escherichia coli

We found that cells of Vibrio parahaemolyticus possess an energy-dependent efflux system for norfloxacin. We cloned a gene for a putative norfloxacin efflux protein from the chromosomal DNA of V. parahaemolyticus by using an Escherichia coli mutant lacking the major multidrug efflux system AcrAB as the host and sequenced the gene (norM). Cells of E. coli transformed with a plasmid carrying the norM gene showed elevated energy-dependent efflux of norfloxacin. The transformants showed elevated resistance not only to norfloxacin and ciprofloxacin but also to the structurally unrelated compounds ethidium, kanamycin, and streptomycin. These results suggest that this is a multidrug efflux system. The hydropathy pattern of the deduced amino acid sequence of NorM suggested the presence of 12 transmembrane domains. The deduced primary structure of NorM showed 57% identity and 88% similarity with that of a hypothetical E. coli membrane protein, YdhE. No reported drug efflux protein in the sequence databases showed significant sequence similarity with NorM. Thus, NorM seems to be a novel type of multidrug efflux protein. We cloned the ydhE gene from E. coli. Cells of E. coli transformed with the cloned ydhE gene showed elevated resistance to norfloxacin, ciprofloxacin, acriflavine, and tetraphenylphosphonium ion, but not to ethidium, when MICs were measured. Thus, it seems that NorM and YdhE differ somehow in substrate specificity.

Evidence for chloramphenicol/H+ antiport in Cmr (MdfA) system of Escherichia coli and properties of the antiporter

We detected chloramphenicol/H+ antiport activity in membrane vesicles of Escherichia coli and cloned a gene for the antiporter from chromosomal DNA of E. coli. Introduction of the gene into E. coli cells conferred resistance to chloramphenicol and ethidium. A slight increase in resistance to acridine orange was also observed. Elevated chloramphenicol efflux and ethidium efflux were observed in cells harboring a plasmid carrying the gene. Addition of chloramphenicol to the assay mixture reduced the efflux of ethidium. Elevated chloramphenicol/H+ antiport activity was observed in membrane vesicles prepared from cells harboring the plasmid. The pH optimum for the activity was 6.5. We sequenced the gene and deduced the amino acid sequence of its product. A sequence homology search revealed that it was same as that of Cmr (or MdfA). Thus, it became clear that Cmr (MdfA) is the chloramphenicol(and ethidium)/H+ antiporter.

Assessment of a new triple agent regimen for the eradication of Helicobacter pylori and the nature of H. pylori resistance to this therapy in Japan

BACKGROUND

Multiple regimens for the eradication of Helicobacter pylori have been tested, but the best therapy has not been determined yet. To determine the efficacy of a new triple agent regimen using a combination of lansoprazole, amoxicillin, and clarithromycin against Helicobacter pylori (H. pylori), and to examine H. pylori resistance to this therapy in ineffective cases.

METHODS

We studied a total of 71 patients infected with H. pylori who had gastric ulcer (n = 37) or duodenal ulcer (n = 34) as confirmed by endoscopy. Patients received 1500 mg amoxicillin, 400 mg clarithromycin and 30 mg lansoprazole for 2 weeks followed by 30 mg lansoprazole for 6 weeks in patients with gastric ulcer or for 4 weeks in those with duodenal ulcer. Endoscopic examination was performed before treatment and at 1 month, 2 months, and 5 months after initiating treatment to check the status of ulceration and H. pylori infection.

RESULTS

The eradication rate of H. pylori was 92% (CI, 83-100%) in the gastric ulcer group and 94% (CI, 86-100%) in the duodenal ulcer group at 5 months, as determined by per-protocol analysis. Resistance to clarithromycin was present in 1 of 71 (1%) patients before treatment and in 2 of 5 (40%) patients after treatment. No resistance to amoxicillin and lansoprazole was found in patients before or after treatment. The resistance to clarithromycin changed during the observation period.

CONCLUSIONS

The new triple agent regimen was effective against H. pylori. Resistance to clarithromycin may not be permanent and it might be one of the risk factors which affect the efficacy of a clarithromycin-based therapy.

[Urease-negative Helicobacter pylori isolates from gastrointestinal mucosa of patients with peptic ulcer]

It is well known that Helicobacter pylori produced a large amount of urease which plays an important role in the maintenance of infection and adhesion. Two thousand three hundred and thirty-one specimens of the gastrointestinal mucosa were obtained from patients with peptic ulcer to isolate H. pylori strains. Of these specimens, 1602 strains of H. pylori were isolated and 7 urease-negative H. pylori strains were found. Biological characteristics (except urease production) of urease-negative H. pylori were in accord with urease-positive reference strains (ATCC strains). Furthermore, these urease-negative strains were confirmed to be H. pylori strains by PCR. These results suggest that the emergence of urease-negative strains pose a new problem for H. pylori infection in patients with peptic ulcer.

Relationship between healing of acetic acid-induced chronic gastric ulcer and connexin

This study examined the relationship between healing of acetic acid-induced chronic gastric ulcer and connexin formation. In addition, the effect of anti-ulcer drugs on ulcer healing and the presence of connexin was investigated. In a rat model, acetic acid-induced gastric ulcers were healed without administration of drugs after 14 days. Appearance of an electrophoretic connexin 32 band was observed 7 days after ulcer induction. Administration of cimetidine (3 mg/day) promoted ulcer healing, i.e., ulcers were healed 12 days after ulcer induction, 2 days earlier than the control. The appearance of a connexin 32 band in electrophoresis was observed on the fourth day after ulcer induction. Administration of cimetidine at a higher dose further promoted ulcer healing and the connexin 32 band was more strongly visible. After administration of i.p. 2 nM EGF, acetic acid-induced gastric ulcers were healed 12 days after ulcer induction and the appearance of connexin 32 was observed on the fourth day after induction. These results indicate that connexin 32 is related to the healing of acetic acid-induced gastric ulcers.

Formation of insulin-producing cells from pancreatic acinar AR42J cells by hepatocyte growth factor

Pancreatic AR42J cells are derived from acinar cells and express both exocrine and neuroendocrine properties. We have recently shown that these cells convert into insulin-producing cells in vitro after treatment with activin A and betacellulin. Here, we investigated the effect of hepatocyte growth factor (HGF) in those cells. When AR42J cells were incubated with HGF, DNA synthesis was attenuated, and the amylase content was reduced in a concentration-dependent manner. HGF-treated cells extended processes, but bundle formation was not observed using an antibody against tubulin. Reverse both insulin and pancreatic polypeptide (PP) were expressed in HGF-treated, but not naive, AR42J cells. Immunocytochemical analysis indicated that approximately 3% of the HGF-treated cells were stained with antiinsulin antibody, and some were also stained with anti-PP antibody. When AR42J cells were exposed to a combination of activin A and HGF, cells extended longer processes, and over 10% of them were stained with antiinsulin antibody. In these cells, messenger RNAs for insulin, PP, glucose transporter 2, and glucokinase, but not those for glucagon or somatostatin, were expressed. A subclone of AR42J cells, AR42J-B13, was obtained. Most of the AR42J-B13 cells converted to insulin-producing cells after the incubation with activin A and HGF. Insulin secretion was augmented by tolbutamide, depolarizing concentrations of potassium, carbachol, and glucagon-like peptide-1 in these cells. These results indicate that HGF reduces the acinar cell-like property of AR42J cells and converts them into insulin-producing cells. The effect of HGF was markedly enhanced by activin A.

Effects of inhibin on activin A-Induced glucose metabolism in rat hepatocytes

This study was conducted to investigate the effects of inhibin on hepatic glucose metabolism. We have previously reported that activin A induced a dose-dependent glycogenolytic action on hepatocytes, and that 10(-9) M activin A induced a maximum glycogenolytic effect. Inhibin itself induced no increase or decrease in glucose output at any dose tested. At a concentration of 10(-10) M, inhibin was seen to inhibit 10(-9) M activin A-induced glucose output by 30% as compared to the control. In contrast to its inhibitory effect on the action of activin A, 10(-10) M and higher concentrations of inhibin did not inhibit angiotensin II-or vasopressin-induced glycogenolysis. We further investigated the mechanism of the inhibitory effect of inhibin on activin A-induced glycogenolysis, and found that 10(-10) M inhibin did inhibit the increase in cytoplasmic-free calcium concentration that was seen with 10(-9) M activin A.We also investigated the effects of inhibin on the activin A-induced production of inositol trisphosphates, and the results showed that 10(-10) M inhibin inhibited the activin A-induced production of inositol trisphosphates by 30% compared to the control. Furthermore, it was demonstrated that inhibin did not affect the binding of activin A to isolated hepatocytes. These data demonstrated that inhibin inhibited the activin A-induced glycogenolysis by inhibiting the increases of inositol trisphosphates and cytoplasmic free calcium concentrations.

Characterization of the activin receptor in cultured rat hepatocytes

Activin A is an autocrine inhibitor of initiation of DNA synthesis in rat hepatocytes. The present study was conducted to characterize the cell-surface receptors for activin A in cultured rat hepatocytes by measuring 125I-activin A binding. Scatchard analysis of 125I-activin A binding indicated the existence of two classes of binding sites with apparent Kd values of 3 x 10(-10) mol/L and 3.5 x 10(-9) mol/L. Pretreatment of the cells with heparitinase reduced the number of low-affinity binding sites, whereas pretreatment with excess exogenous follistatin increased the number of low-affinity binding sites. Affinity cross-linking of 125I-activin A to hepatocytes revealed distinct protein complexes with molecular weights of approximately 48, 65, and 85 kd, which may represent cross-linked cell-bound follistatin, type I and type II activin receptors, respectively. Another band with a molecular weight of 180 kd was also found, which may represent the type III activin receptor. When hepatocytes were cultured with epidermal growth factor (EGF), both high- and low-affinity binding sites increased at 12 hours without altering their affinities. At 60 hours of the incubation with EGF, the high-affinity binding sites decreased while the number of low-affinity binding sites increased slightly. These results indicate that two classes of 125I-activin A binding sites exist in cultured hepatocytes: the high-affinity binding site may represent oligomeric complex of the type I and type II receptors, and at least part of the low-affinity binding site may represent cell-bound follistatin. The number of activin receptors in hepatocytes is increased after the stimulation with EGF.

Intravenous administration of follistatin: delivery to the liver and effect on liver regeneration after partial hepatectomy

When 1 microgram 125I-follistatin was administered into a rat intravenously, radioactivity levels in serum decreased rapidly. Analysis with a biexponential equation showed that the initial half-life and the terminal half-life were 4.0 and 130.8 minutes, respectively. After 2 hours of infusion, approximately 9% of the follistatin infused remained in the liver, which was much more than that in kidney, spleen, pancreas, intestine, or lung. Autoradiography of the liver obtained at 24 hours of infusion revealed that numerous grains were located in parenchymal cells. Radioactivity of 125I-follistatin in the liver remained elevated until 72 hours and declined markedly thereafter. When a booster shot of 125I-follistatin was administered at 72 hours, radioactivity in the liver at 120 hours was markedly increased compared with that in rats that received a single shot of 125I-follistatin. We then examined the effect of intravenous infusion of follistatin on liver regeneration after hepatectomy of 70%. Immediately after the hepatectomy, either 1 microgram follistatin or saline was infused intravenously. In some rats, a booster shot was infused at 72 hours. After 120 hours of hepatectomy of 70%, remnant liver weight, liver regeneration rate, and DNA content were significantly (P < .05) higher in rats that received a booster shot of follistatin at 72 hours than those in control rats. These results indicate that follistatin administered intravenously accumulates in the liver and promotes liver regeneration after partial hepatectomy.

Betacellulin and activin A coordinately convert amylase-secreting pancreatic AR42J cells into insulin-secreting cells

Rat pancreatic AR42J cells possess exocrine and neuroendocrine properties. Activin A induces morphological changes and converts them into neuron-like cells. In activin-treated cells, mRNA for pancreatic polypeptide (PP) but not that for either insulin or glucagon was detected by reverse transcription-PCR. About 25% of the cells were stained by anti-PP antibody. When AR42J cells were incubated with betacellulin, a small portion of the cells were stained positively with antiinsulin and anti-PP antibodies. The effect of betacellulin was dose dependent, being maximal at 2 nM. Approximately 4% of the cells became insulin positive at this concentration, and mRNAs for insulin and PP were detected. When AR42J cells were incubated with a combination of betacellulin and activin A, approximately 10% of the cells became insulin positive. Morphologically, the insulin-positive cells were composed of two types of cells: neuron-like and round-shaped cells. Immunoreactive PP was found in the latter type of cells. The mRNAs for insulin, PP, glucose transporter 2, and glucokinase, but not glucagon, were detected. Depolarizing concentration of potassium, tolbutamide, carbachol, and glucagon-like peptide-1 stimulated the release of immunoreactive insulin. These results indicate that betacellulin and activin A convert amylase-secreting AR42J cells into cells secreting insulin. AR42J cells provide a model system to study the formation of pancreatic endocrine cells.

A detoxication route for acetaldehyde: metabolism of diacetyl, acetoin, and 2,3-butanediol in liver homogenate and perfused liver of rats

The metabolism of diacetyl (2,3-butanedione), acetoin (3-hydroxy-2-butanone), and 2,3-butanediol, which are metabolites of acetaldehyde was quantitatively investigated using rat liver homogenate, liver perfusion, and in vivo experiments. Diacetyl and acetoin were reduced to 2,3-butanediol in these experiments, but acetoin and 2,3-butanediol were scarcely oxidized to diacetyl, indicating that the reduction reaction to 2,3-butanediol from diacetyl occurs actively in rat liver. The formation of acetoin from diacetyl required either NADH or NADPH as a reductant, while the reduction of acetoin to 2,3-butanediol required NADH. Acetoin and 2,3-butanediol were more readily accumulated than diacetyl in brain tissue.

Norepinephrine reverses the effects of activin A on DNA synthesis and apoptosis in cultured rat hepatocytes

Activin A, an autocrine factor produced by hepatocytes, inhibits mitogen-stimulated DNA synthesis and induces apoptotic death of cultured rat hepatocytes. Several lines of evidence indicate that norepinephrine (NE), as a comitogenic growth factor, alters the balance between growth stimulation and inhibition and acts as a trigger for the initiation of hepatocyte proliferation. In the present study, we examined whether NE modulated the effects of activin A on rat hepatocytes in primary culture. Activin A, at a concentration of 10(-9) mol/L, blocked the effect of epidermal growth factor (EGF) on DNA synthesis, that was assessed by measuring [3H] thymidine incorporation and nuclear labeling, almost completely, and NE reversed the inhibitory effect of activin A on DNA synthesis. This effect of NE was dose-dependent, being significant at concentrations of 10(-6) mol/L and above, but was overcome by higher concentrations of activin A, and was attenuated by prazosin, but not by yohimbine or propranolol. NE exerted its effect during the first 24 hours of culture, but was ineffective when added after 24 hours. EGF augmented the release of follistatin, an activin-binding protein known to block the action of activin A, by hepatocytes and NE did not affect the amount of follistatin they released. In addition to inhibiting DNA synthesis by hepatocytes cultured with EGF, activin A induced death of hepatocytes cultured in the absence of EGF. The nuclear morphology of cells cultured with activin A alone was strikingly changed compared with untreated control cells and marked identation of the nuclear membranes and moderate chromatin condensation were observed. Fragmentation of DNA was also observed, suggesting that activin A induced apoptosis, and activin-mediated cell death was prevented significantly by NE. These results indicate that NE, acting on alpha 1-adrenergic receptors, attenuates the effects of activin A on DNA synthesis by and apoptosis of cultured rat hepatocytes.

Attenuation of glycogenolytic action of activin A in intact rat liver

Activin A stimulates glucose production by causing glycogenolysis in isolated hepatocytes. To determine the physiological significance of this effect, we examined the effect of activin A on glucose production in the perfused liver. Unlike the effect in isolated cells, activin A did not enhance glucose production nor did it cause radiocalcium efflux in the perfused liver. There was no effect of activin A in the liver perfused in the opposite direction. Although activin A did not promote glucose production, it was recovered from the hepatic vein in a bioactive form. When liver perfusion was performed in partially hepatectomized rats, activin A increased radiocalcium efflux. In isolated hepatocytes, activin A increased inositol phosphates, and the effect of activin A was attenuated by the plasma membrane fraction of hepatocytes. The inhibitory effect of the plasma membrane was abolished by digestion of the membrane with trypsin. These results indicate that the effect of activin A on glucose production is attenuated in the intact liver and that a protein factor(s) in plasma membrane may be involved in the inhibition.

External radiotherapy for biliary decompression of hilar cholangiocarcinoma

Obstructive jaundice due to hilar cholangiocarcinoma is difficult to decompress because of the location of the tumor. We used external radiation alone for biliary decompression and reviewed its efficacy in this study. Subjects comprised 14 patients diagnosed as having inoperable hilar cholangiocarcinoma by ultrasonography, percutaneous transhepatic cholangiography, and CT scanning. The total bilirubin level on admission ranged from 0.4 to 34.6 mg/dl (mean: 11.0 mg/dl). These patients were irradiated with a 4MeV linear accelerator using parallel opposing fields measuring from 7 x 7 cm to 8 x 10 cm. The total radiation dose ranged from 50 Gy to 60 Gy and in fractions of 1.8-2.0 Gy per day. No patient underwent further biliary decompression after percutaneous transhepatic cholangiography, and irradiation was performed immediately after diagnosis. Eleven of the 14 patients received the full dose of external radiation. Three patients discontinued radiotherapy because of severe vomiting and nausea, pneumonia, and a hemorrhagic gastric ulcer. In 10 of the 11 patients, the serum total bilirubin level returned to normal (p < 0.005) and no cholangitis occurred. Obstructive jaundice recurred in one patient, and serum total bilirubin returned to normal again after further irradiation. Eight of the 11 patients could be discharged from hospital and returned to society. The survival time of the 11 patients ranged from 3 to 25 months and the 12-month survival rate was 50% (Kaplan-Meier method). This study suggests that external radiation therapy is an effective treatment for biliary decompression in patients with unresectable hilar cholangiocarcinoma.

Conversion of amylase-secreting rat pancreatic AR42J cells to neuronlike cells by activin A

When AR42J cells, an amylase-secreting pancreatic exocrine cell line, were treated with activin A, cells extended neuritelike processes, and, concomitantly, amylase-containing vesicles disappeared. Immunofluorescence and immunoelectron microscopy revealed that these processes had neurite-specific cytoskeletal architectures: neurofilaments and microtubule bundles with cross-bridges of microtubule-associated protein 2. In addition to such morphological changes, activin-treated cells exhibited a marked increase in cytoplasmic free calcium concentration in response to depolarizing concentration of potassium. Moreover, activin-treated AR42J cells expressed mRNA for alpha 1 subunit of the neuroendocrine/beta cell-type voltage-dependent calcium channel. In naive AR42J cells, a sulfonylurea compound, tolbutamide, did not affect free calcium concentration, while it induced a marked elevation of free calcium in activin-treated cells. Single channel recording of the membrane patch revealed the existence of ATP-sensitive potassium channel in activin-treated cells. These results indicate that activin A converts amylase-secreting AR42J cells to neuronlike cells. Given that pancreatic endocrine cells possess neuronlike properties and express ATP-sensitive potassium channel as well as neuroendocrine/beta cell-type voltage-dependent calcium channel, activin treatment of AR42J cells may provide an in vitro model system to study the conversion of pancreatic exocrine cells to endocrine cells in islets.

A single intraportal administration of follistatin accelerates liver regeneration in partially hepatectomized rats

BACKGROUND/AIMS

Activin A is an autocrine negative regulator of DNA synthesis in rat hepatocytes and is expressed in remnant liver after partial hepatectomy. To determine the role of activin A in liver regeneration, the effects of exogenous follistatin, which blocks the action of activin A, were examined.

METHODS

Human recombinant follistatin was infused into the portal vein immediately after 70% hepatectomy. Changes in body weight, remnant liver weight, liver regeneration rate, and nuclear bromodeoxyuridine labeling were measured.

RESULTS

In control rats, nuclear labeling was observed at 24 hours and peaked at 36 hours after the hepatectomy. In follistatin-treated rats, nuclear labeling was first observed after 18 hours and was significantly (P < 0.05) greater than that in control rats at 24 hours. In follistatin-treated rats, both remnant liver weight and liver regeneration rate were significantly greater at 120 hours. Serum concentrations of albumin and glucose remained reduced for up to 120 hours in control rats but recovered in follistatin-treated rats.

CONCLUSIONS

A single administration of follistatin accelerates the initial round of DNA synthesis after partial hepatectomy. Activin A produced in remnant liver may exert tonic inhibitory effect on liver regeneration. Follistatin may be useful as a potential therapeutic agent to promote liver regeneration.

Derangements in the activin-follistatin system in hepatoma cells

BACKGROUND/AIMS

The growth of normal hepatocytes is regulated by the activin-follistatin system. The aim of this study was to investigate the activin-follistatin system in hepatoma cells.

METHODS

The production and action of activin and follistatin in human hepatoma cell lines were examined. Activin A and follistatin were measured by bioassay and protein-binding assay, respectively.

RESULTS

Activin A inhibited cell growth in HepG2 cells but not in either PLC/PRF/5 or HLE cells. However, the effect of activin A in HepG2 cells was attenuated at high cell density. In HepG2 cells, two classes of activin-binding sites were expressed, and affinity cross-linking showed that 125I-activin A bound specifically to three proteins with molecular weights of 48, 67, and 94 kilodaltons. In PLC/PRF/5 cells, a single class of binding site was observed, and the binding capacity was approximately 60% of the capacity in HepG2 cells. Virtually no 125I-activin A binding was detected in HLE cells. Bioactivity and messenger RNA for activin A were undetectable in three cell lines. In contrast, follistatin was released from three cell lines.

CONCLUSIONS

Multiple alterations in the activin-follistatin system were found in three hepatoma cell lines. The accelerated growth observed in hepatoma cells may be caused, at least partly, by the attenuation of the action of activin A.

Ultrastructural observations on the ossification of the supraspinous ligament

STUDY DESIGN

This study analyzed the process of ossification of spinal ligaments. Supraspinous ligaments excised during surgery were studied by light and scanning electron microscopy.

OBJECTIVES

The results were correlated to determine the mechanism of ossification of spinal ligaments.

SUMMARY OF BACKGROUND DATA

Ossification of the ligamentum flavum has been described in detail by Hiraoka, Yamaguchi, and others. However, the pathogenesis of ossification of the spinal ligaments remains unclear. Some studies have been performed by light and transmission electron microscopy, but no detailed investigation of the ossification of the spinal ligaments by scanning electron microscopy has been performed.

METHODS

Specimens of supraspinous ligament were taken from 41 patients during spinal surgery. Ossification was diagnosed macroscopically and radiologically for 20 patients. The specimens were examined using light and scanning electron microscopy.

RESULTS

Collagen fibrils were 700-2000 A in diameter and were arranged in parallel. The ligament insertion divided into four zones and seemed to fit the description of Enthesis histologically. Close to the ossification region, there were a region in which some fibrils were thinner and branchings became slightly stronger, tending to form bridges of minute fibrils between other fibrils. Closer to the region of actual ossification, there was a region in which extra-fibrillar substances completely deposited. In the region of actual ossification, there were medullary spaces of varying sizes, and the surrounding collagen fibers were dense and arranged in a lamellar fashion. Osteocyte lacunae had formed and the cells regarded to be the osteocytes were present on the inside.

CONCLUSION

Ossification of the supraspinous ligament possibly occurs as follows. Fibroblasts or chondrocyte-like cells respond to some external stimulus, form an irregular network of fine fibrils, and produce acid mucopolysaccharide. These undergo calcification and capillary invasion. Undifferentiated mesenchymal cells invaded and are transformed into osteoblasts. Then osteogenesis ensues with progressive calcification.