Squamous epithelial dysplasia associated with squamous cell carcinoma of the esophagus

To investigate the relationship between dysplasia and carcinoma of the esophagus, 159 cases of esophageal carcinoma without any preoperative treatment were reviewed retrospectively. There were 75 dysplastic lesions in 32 cases (20.1%). The incidence of co-existence of dysplastic lesions was 0, 58.3, 31.3, 20.8 and 11.4% in intra-epithelial, mucosal and submucosal cancers and those invading the proper muscular layer and adventitia, respectively. Thus, excluding the cases of intra-epithelial carcinoma, the less advanced the lesion, the higher the incidence of dysplasia. Epithelial dysplastic lesions were classified as 12 with mild, 33 with moderate and 30 with severe degrees of dysplasia. Although the continuity of dysplastic lesions to the areas of carcinoma was not so frequent (48.0%), it was more often encountered in severe dysplasia rather than in moderate or mild dysplasia, which suggested some relationship between the severity of dysplasia and carcinoma. In the cases with a dysplastic lesion the multiplicity of squamous cell carcinoma and the intra-epithelial spread of the main lesion were more frequently seen (P < 0.001), suggesting a multicentric occurrence of dysplastic lesions and carcinomas.

Mediastinal drainage prevents fatal pyothorax from anastomotic leakage after intrathoracic anastomosis in reconstruction for carcinoma of the esophagus

In our experience, anastomotic leakage occurred in five of 69 patients with intrathoracic anastomosis after resection of carcinoma of the esophagus. In the early period, only an ordinary right thoracic drain was put in place, and when leakage occurred, two patients died because of pyothorax, while one patient was saved by surgical drainage. However, in the recent period, in addition to the ordinary right thoracic drain, another drain has also been placed just distal to the anastomosis through the esophageal hiatus through the abdominal cavity, exiting the abdominal wall. After such procedure, drainage has been adequate without any occurrence of pyothorax, even when anastomotic leakage occurred, as in the two most recent instances. Therefore, unless drainage is inadequate and surgical drainage is indicated, as in instances of necrosis of substitutes, mediastinoabdominal drainage seems to be effective in the treatment of intrathoracic anastomotic leakage.

[Multidisciplinary treatment of esophageal cancer]

Hyperthermia combined with irradiation and chemotherapy was prescribed for patients with resectable squamous cell carcinoma of the esophagus. The long-term results were compared between two groups of patients, one treated with chemotherapy, radiotherapy and hyperthermia (HCR), the other with chemotherapy and radiotherapy, but not hyperthermia (GR). The five-year survival rates of patients with resectable carcinoma, given preoperative HCR or CR, were 22.3 and 13.7 per cent, respectively. In particular, for the patients classified as Stages III and IV, a longer survival period was obtained with HCR (p < 0.05). Since 1990, we applied a protocol of prospective randomized study for neoadjuvant chemotherapy. We presented the results of comparison between two groups, one of which was treated by chemotherapy alone and the other by chemotherapy combined with hyperthermia, for both resectable and non-resectable cases. Data on 21 patients with a primary squamous cell carcinoma of the thoracic esophagus were included in the present study. Among these 21 cases, 10 received only chemotherapy (Group A), and 11 were treated by hyperthermo-chemotherapy (Group B). In each group, 6 and 9 patients each were surgically treated. According to our regimen, in Group A, 30 mg of oil bleomycin (BLM) orally six times, and 50mg div. of cisplatin (CDDP) triplicate, were administered during three weeks, respectively. Besides chemotherapy, RF intraluminal hyperthermia was performed six times just after administration of BLM in Group B. There was no significant difference of prognostic factors between groups, and all the patients tolerated well the treatment modalities. The overall efficacy (% CR+PR+MR) of Group A and B was 30.0% and 63.6%, respectively. Histopathological evaluation of the effectiveness was 16.7% and 33.3% in Groups A and B, respectively. Thus, as severe side effects in patients given hyperthermia were nil, this treatment deserves serious consideration when treating patients with a malignant lesion of the esophagus. Moreover, postoperative adjuvant therapies were also important, and choice of the treatment according to the status of carcinoma and the patient's condition is essential.

The evaluation of submucosal carcinoma of the esophagus as a more advanced carcinoma

Of 75 patients with superficial esophageal carcinoma, there were 16 cases with epithelial or mucosal, and 59 cases with submucosal, lesions. The incidence of nodal metastasis in patients with epithelial or mucosal carcinoma was zero, and the 5-year survival rate was 100%. However, 13 out of 59 cases (22.0%) with submucosal carcinoma were accompanied by nodal involvement, and the rate of vessel invasion was 27.1% (16/59). Even in 46 cases of submucosal carcinoma without nodal involvement, there were 13 cases (22.1%) with vessel invasion. The 5-year survival rate of the 26 submucosal cases with either nodal metastasis or vessel invasion was 37.6%, and even that of the 33 cases with neither lymph node metastasis nor vessel invasion was 60.0%. On the other hand, of the 74 patients with carcinoma invading the muscularis propria, there were 35 cases (47.3%) without nodal metastasis and 27 cases (36.5%) which were also free of vessel invasion. The 5-year survival rate of the former was 32.6%, and of the latter 33.1%. On the basis of these findings, we wish to emphasize that submucosal carcinoma should be classified as an advanced carcinoma.

Long-term results of esophagectomy for early esophageal carcinoma

In this paper we report on the long-term results achieved in 75 patients with superficial carcinoma of the thoracic esophagus who have been treated since 1965 with esophagectomy at our institute. In three of these patients, the carcinoma was limited to the epithelium (intra-epithelial carcinoma), while in 13 cases it was confined to the mucosa, and in 59 cases to the submucosa. There was no lymph node metastasis in patients with intra-epithelial or mucosal carcinoma, but lymph node involvement was found in 13 (22.0%) of the 59 cases of submucosal carcinoma. The five-year survival rate of patients with intra-epithelial carcinoma and mucosal carcinoma was 100%, which was significantly better than that for carcinoma invading the submucosa (49%). The five-year survival rate for patients with lymph node involvement was only 46%, which was significantly worse than that for patients without lymph node involvement (60%). No recurrence occurred in patients with intra-epithelial carcinoma or mucosal carcinoma, while recurrent disease occurred in 19 (32.2%) of the 59 patients with submucosal carcinoma. Lymph node recurrence and hematogenic recurrence such as lung and bone metastasis were the most frequent developments in patients with submucosal carcinoma of the esophagus.

Endoscopic ultrasonography in the diagnosis of an early esophageal carcinoma

Patients with epithelial or mucosal carcinoma of the esophagus are considered to have a much better prognosis than those with submucosal carcinoma, although both lesions are classified as superficial carcinomas of the esophagus. With this in mind, we evaluated the usefulness of endoscopic ultrasonography for pre-operatively distinguishing either epithelial or mucosal carcinoma from submucosal carcinoma by comparing the results of endoscopic ultrasonography with the histological findings established in resected specimens. Between 1987 and 1991, 26 patients with no pre-operative treatment were confirmed histologically to have epithelial (2 cases), mucosal (11 cases) or submucosal (13 cases) carcinomas of the esophagus. In 13 patients with epithelial or mucosal carcinoma, 10 were correctly diagnosed with endoscopic ultrasonography (76.9%), while the remaining 3 were overdiagnosed as being submucosal. In 13 patients with submucosal carcinoma, 12 were correctly diagnosed by endoscopic ultrasonography (92.3%), although another case was overestimated. Including one patient with an advanced carcinoma who was underdiagnosed by endoscopic ultrasonography as having a submucosal lesion, the overall accuracy of endoscopic ultrasonography was 81.5% for diagnosing the depth of invasion of a superficial esophageal carcinoma. The above results show that endoscopic ultrasonography can provide surgeons with important information in the pre-operative assessment of a superficial esophageal carcinoma.

Photoaffinity labelling of smooth-muscle myosin by methylanthraniloyl-8-azido-ATP

Methylanthraniloyl-8-azido-ATP (Mant-8-N3-ATP), which binds to the 20 kDa C-terminal tryptic fragment of skeletal-muscle myosin subfragment-1 [Maruta, Miyanishi and Matsuda (1989) Eur. J. Biochem. 184, 213-221], was synthesized and used as a probe of the conformational change of smooth-muscle myosin. Mant-8-N3-ATP, like ATP, induced the formation of the 10 S conformation at low ionic strength. In the presence of vanadate, smooth-muscle myosin formed a stable complex with Mant-8-N3-ADP, and this complex showed the 10 S-->6 S transition of myosin. ATP-binding sites for 6 S (extended state) and 10 S (folded state) myosin were studied by photolabelling of myosin with Mant-8-N3-ADP. For both 6 S and 10 S myosin, Mant-8-N3-ATP was incorporated into the 29 kDa N-terminal tryptic fragment of myosin heavy chain. This is unlike the labelling of skeletal-muscle myosin, in which the 20 kDa C-terminal fragment is labelled. The labelling of 29 kDa fragment was diminished significantly by addition of ATP. These results suggest that the conformation of the ATP-binding site of smooth-muscle myosin is different from that of skeletal-muscle myosin. To examine further the possible differences in the labelling site between 6 S and 10 S myosin, the affinity-labelled 29 kDa fragment was subjected to complete proteolysis by lysylendo-peptidase. The fluorescent-labelled-peptide map suggested that the Mant-8-N3-ADP-binding sites for 6 S and 10 S myosin were identical.

Dephosphorylation of microtubule-binding sites at the neurofilament-H tail domain by alkaline, acid, and protein phosphatases

The dephosphorylation-induced interaction of neurofilaments (NFs) with microtubules (MTs) was investigated by using several phosphatases. Escherichia coli alkaline and wheat germ acid phosphatases increased the electrophoretic mobility of NF-H and NF-M by dephosphorylation, and induced the binding of NF-H to MTs. The binding of NFs to MTs was observed only after the electrophoretic mobility of NF-H approached the exhaustively dephosphorylated level when alkaline phosphatase was used. The number of phosphate remaining when NF-H began to bind to MTs was estimated by measuring phosphate bound to NF-H. NF-H did not bind to MTs even when about 40 phosphates from the total of 51 had been removed by alkaline phosphatase. The removal of 6 further phosphates finally resulted in the association of NF-H with MTs. A similar finding, that the restricted phosphorylation sites in the NF-H tail domain, but not the total amount of phosphates, were important for binding to MTs, was also obtained with acid phosphatases. In contrast to alkaline and acid phosphatases, four classes of protein phosphatases (protein phosphatases 1, 2A, 2B, and 2C) were ineffective for shifting the electrophoretic mobility of NF proteins and for inducing the association of NFs to MTs.

DNA ploidy as a prognostic factor in early esophageal carcinoma

Cell nuclear DNA content was cytophotometrically determined in biopsy specimens obtained from thirty-five patients with superficial esophageal carcinoma. The relationship between the DNA distribution pattern and histopathological features, prognosis and postoperative survival time was then investigated. Patients with a low ploidy pattern had a more favorable postoperative course, with 62% attaining a 5-year survival rate, than those with high ploidy, of whom 34% attained a 5-year survival rate (p < 0.01). The recurrence rate was higher for the high ploidy pattern (64.3%) than for the low ploidy pattern (35.3%). Moreover, the rate of recurrence within 2 years was 50% in high ploidy, which was higher than the 5.9% rate in the case of low ploidy (p < 0.05). Although there was no clearly established relationship between the DNA distribution pattern and clinicopathological features, a multivariate analysis revealed that the DNA distribution pattern was one of the independent and significant prognostic factors of superficial esophageal carcinoma. These results thus suggest the usefulness of a preoperative DNA analysis of biopsy specimens in predicting the prognosis and determining perioperative therapeutic strategy for both superficial esophageal carcinoma and for advanced cases.

Histopathology of early esophageal carcinoma and squamous epithelial dysplasia

To examine the histogenesis of esophageal cancer and the pathological relationship between dysplasia and carcinoma of the esophagus, 44 cases of superficial esophageal carcinoma (restricted to within the submucosal layer) who received no pre-operative treatment were reviewed retrospectively. There were 40 dysplastic lesions in 17 cases (38.6%) and epithelial dysplastic lesions were classified into 6 with mild, 17 with moderate and 17 with severe, degrees of dysplasia. Although the continuity of dysplastic lesions with the carcinomatous areas was not frequent (35.0%), it was more often encountered in severe dysplasia than in moderate or mild dysplasia, suggesting some relationship between the severity of dysplasia and carcinoma. In the cases with a dysplastic lesion, multiplicity of squamous cell carcinoma was more frequently seen (p < 0.01), suggesting a multicentric occurrence of dysplastic lesions and carcinomas.

Formation of the stable myosin-ADP-aluminum fluoride and myosin-ADP-beryllium fluoride complexes and their analysis using 19F NMR

The effects of aluminum fluoride and beryllium fluoride on smooth muscle myosin and its subfragments were studied. Mg(2+)-ATPase activity was inhibited in the presence of aluminum fluoride (beryllium fluoride). [3H]ADP bound to heavy meromyosin (HMM) in the presence of aluminum fluoride (beryllium fluoride) and was not dissociated after 3 days of dialysis demonstrating that [3H]ADP was trapped in HMM. These results suggest the formation of a stable HMM-ADP-fluoroaluminate (fluoroberyllate) complex. The intrinsic tryptophane fluorescence intensity was increased in the presence of ADP and aluminum fluoride (beryllium fluoride). Acto-S1 was dissociated upon the formation of S1-ADP-fluoroberyllate and actin destabilized S1-ADP-fluoroberyllate complex, while S1-ADP-fluoroaluminate failed to bind to actin. Furthermore, when S1 formed the complex with actin, nucleotide trapping did not occur in the presence of fluoraluminate. These results indicated that the myosin-ADP-fluoroberyllate complex resembles a weak binding state while myosin-ADP-fluoroaluminate complex is a distinct conformation although the binding to actin was also weak. The structure of the ternary complex was investigated using 19F NMR. The 19F NMR spectrum of the S1-ADP-fluoroaluminate complex showed a peak at -66.7 ppm which is due to the binding of fluoraluminate to S1. The peak was not observed when 5'-adenylylimidodiphosphate was substituted for ADP suggesting that aluminum fluoride plays a role as a phosphate analogue. The stoichiometry of the bound fluoride was determined to be 3.8 mol/mol S1 suggesting that the bound species is AlF-4.

[Clinical study of hyperthermia combined with chemotherapy in the treatment of carcinoma]

From November 1990 to July 1991, data on 21 patients with primary squamous cell carcinoma of the thoracic esophagus were used for the present study. Among these 21 cases, 10 received only chemotherapy (Group A) and 11 were given hyperthermo-chemotherapy (Group B). Six and nine cases were surgically treated after preoperative chemotherapy or hyperthermo-chemotherapy in Group A and B, respectively. After treatment of Group A or B, 5/10 patients in Group A (50%) mentioned improvement in swallowing capability, as did 9/11 patients (81.8%) in Group B. In the upper GI series, done after treatment, a complete response was seen in one case in Group B, while a partial response was obtained in 3 patients (30%) and in 3 patients (27.3%) with minimal response in Group A and B, respectively. A histopathologic examination of the resected specimen revealed marked effectiveness in 0 and one (11.1%) patients, and moderate effectiveness in 1 (16.7%) and 2 (22.2%) patients in Group A and B, respectively. Consequently, this intensive treatment should be expected to greatly improve local control without causing either any severe side effects or complications.

Expression of Sialyl-Tn antigens in normal squamous epithelium, dysplasia, and squamous cell carcinoma in the esophagus

Two monoclonal antibodies, TKH2 and B72.3, directed toward the Sialyl-Tn antigen (SA 2, 6GalNAc alpha-O-Ser/Thr), were examined immunohistochemically to analyze the expression of these antigens in 20 areas of normal squamous epithelium, 12 lesions of dysplasia, and 86 cases of squamous cell carcinoma including 32 with superficial carcinoma in the esophagus. No expression of TKH2 or B72.3 was found in the normal squamous epithelium. Among the 12 lesions of dysplasia only one expressed TKH2. In carcinoma the expression of TKH2 and B72.3 was found in 40 (47%) and 21 (24%) of the 86 carcinomas, respectively; however, the number of positive malignant cells with TKH2 and B72.3 totaled less than half that in the tissue, and no relationship was found between either prognosis or lymph node metastasis and the expression of Sialyl-Tn antigen. These results indicate that Sialyl-Tn antigen appears in the process of malignant transformation or tumor progression in esophageal squamous cell carcinoma; however, the positive expression of Sialyl-Tn antigen was not directly connected to either prognosis or lymph node metastasis.

The control of protein phosphatase-1 by targetting subunits. The major myosin phosphatase in avian smooth muscle is a novel form of protein phosphatase-1

The major protein phosphatase that dephosphorylates smooth-muscle myosin was purified from chicken gizzard myofibrils and shown to be composed of three subunits with apparent molecular masses of 130, 37 and 20 kDa, the most likely structure being a heterotrimer. The 37-kDa component was the catalytic subunit, while the 130-kDa and 20-kDa components formed a regulatory complex that enhanced catalytic subunit activity towards heavy meromyosin or the isolated myosin P light chain from smooth muscle and suppressed its activity towards phosphorylase, phosphorylase kinase and glycogen synthase. The catalytic subunit was identified as the beta isoform of protein phosphatase-1 (PP1) and the 130-kDa subunit as the PP1-binding component. The distinctive properties of smooth and skeletal muscle myosin phosphatases are explained by interaction of PP1 beta with different proteins and (in conjunction with earlier analysis of the glycogen-associated phosphatase) establish that the specificity and subcellular location of PP1 is determined by its interaction with a number of specific targetting subunits.

Molecular cloning of the chicken gizzard telokin gene and cDNA

Telokin is a protein which consiste of the C-terminal portion of smooth muscle myosin light chain kinase (MLCK) (M. Ito, R. Dabrowska, V. Guerriero, Jr., and D. J. Hartshone (1989) J. Biol. Chem. 264, 13971-13974). In this study, the chicken gizzard telokin cDNA and gene were cloned and analyzed. The telokin cDNA coded 157 amino acid residues which were completely identical to the C-terminal portion of the amino acid sequence of chicken gizzard MLCK. The telokin gene was coded in a 6.3-kb EcoRI genomic fragment and it consisted of three exons. The 5'-leader sequence of the telokin cDNA and genomic sequence revealed that the telokin gene was included in the MLCK gene and the transcription started in the intronic sequence of the MLCK gene. The analysis of the telokin gene suggests that the telokin expression was under the control of an independent promotor. Northern blotting and the reverse transcriptase-polymerase chain reaction methods revealed that telokin was expressed not only in chicken gizzard but also in chicken heart, lung, intestine, and skeletal muscle although the levels of the expression in the latter were much less than that in the gizzard.

Primary structure required for the inhibition of smooth muscle myosin light chain kinase

Myosin light chain kinase (MLCK) contains the autoinhibitor sequence right next to the N-terminus side of the calmodulin binding region. In this paper, the structural requirement of the inhibition of MLCK activity was studied using synthetic peptide analogs. Peptides Ala-783-Lys-799 and Ala-783-Arg-798 inhibited calmodulin independent MLCK at the same potency as the peptide Ala-783-Gly-804. Deletion of Arg-797-Lys-799 or substitution of these residues to Ala markedly increased the Ki while the substitution of Lys-792 and Lys-793 to Ala and the deletion of Lys-784-Lys-785 did not affect the inhibitory activity of the peptides. The results suggest that Arg-797-Arg-798 are especially important for the inhibitory activity among other basic residues in the autoinhibitory region.

Endoscopic diagnosis of early carcinoma of the esophagus using Lugol's solution

Small esophageal lesions, particularly intraepithelial cancers, are extremely difficult to detect. We used Lugol's iodine solution with panendoscopic examination to detect the presence and spread of small squamous cell carcinomas of the esophagus. Serial histologic specimens of the surgically removed esophagus from 32 patients with Lugol's combined endoscopic diagnosis of early esophageal carcinoma were examined to determine the correlation between endoscopic and histologic findings. All of the early staged carcinomas clearly remained unstained by Lugol's solution. We believe that the application of Lugol's solution will greatly aid in instances when a suspicious mucosal lesion is noted, when the margin of the lesion is unclear, or when there is suspicion that a mucosal lesion may have been overlooked.

Peptide analogs of the pseudosubstrate domain of smooth muscle myosin light chain kinase inhibit actomyosin ATPase activity at concentrations that do not inhibit superprecipitation

The inhibitory effect of calmodulin antagonists, synthetic peptide analogs of the pseudosubstrate domain of smooth muscle MLC kinase, and an inhibitor based on the sequence of MLC were examined using bovine aortic actomyosin and isolated chicken gizzard MLC. Much lower concentrations of the peptides were necessary to inhibit actomyosin ATPase activity than to inhibit superprecipitation. In contrast, calmodulin antagonists inhibited both ATPase activity and superprecipitation at similar concentrations. The peptide analogs were competitive with isolated MLC, but not calmodulin, for inhibition of MLC kinase. These results suggest that in addition to the calmodulin dependence of MLC phosphorylation, a second calmodulin-like protein may be important in actin-myosin interactions. The data also suggest that the pseudosubstrate hypothesis may not completely account for regulation of MLC kinase activity.

[Mode of origin of esophageal squamous cell carcinoma--serial histopathologic and immunohistochemical studies]

I. Serial histopathologic study of esophageal squamous cell carcinoma. A review of 335 cases of squamous cell carcinoma disclosed 55 cases (16.4%) with glandular components in addition to the ordinary component of squamous cell carcinoma, suggesting that this type of esophageal tumor had originated not only from the covering squamous epithelium but from esophageal gland or ductal epithelium. Intra-epithelial carcinoma concomitant with squamous cell carcinoma was seen in 95 cases (28.4%). The incidences of coexistence in such lesion were higher in the groups of early stage esophageal cancer. These observations support the concept of field carcinogenesis of esophageal cancer. II. Histopathologic study of squamous epithelial dysplasia. Among 91 cases without preoperative treatment, there were 40 dysplastic lesions in 23 cases (25.3%). The continuity of dysplasia to the carcinoma was 48.3% and it was often encountered in severe dysplasia rather than in moderate or mild dysplasia, suggesting some relationship between the severity of dysplasia and carcinoma. III. Immunohistochemical study of EGF and c-myc. Among 27 cases, EGF was positive in 10 (37.0%). c-myc was positive in 18 (66.7%) not only cancer but normal epithelium suggesting that some change of products of oncogene occurred also in the normal epithelium of the patients of esophageal cancer.

Purification and characterization of smooth muscle myosin-associated phosphatase from chicken gizzards

Myosin light chain phosphatase associated with smooth muscle myosin (MAPP) was isolated from chicken gizzard. The MAPP was tightly associated with myosin and was not dissociated from myosin under the physiological ionic conditions. The phosphatase was dissociated from myosin in the presence of high MgCl2, i.e. 80 mM MgCl2. The binding site of the enzyme on the myosin molecule was the subfragment-2 region, since the enzyme did bind to the myosin rod and heavy meromyosin but not to the subfragment-1 affinity column. MAPP was purified with a heparin-Sepharose 6B column, and two activity peaks were obtained, i.e. MAPP I and MAPP II. The major activity peak, MAPP I, was further purified to homogeneity by thiophosphorylated myosin light chain-Sepharose 4B column chromatography. MAPP I was a tetramer composed of four 34-kDa subunits. The enzyme preferentially dephosphorylated the beta-subunit of phosphorylase kinase and was strongly inhibited by the heat- and acid-stable protein phosphatase inhibitor-1, whereas it was partially inhibited by the inhibitor-2. The IC50 (concentration of inhibitor giving 50% inhibition) value for the inhibition of the enzyme by okadaic acid was 70 nM which was about eight times higher than skeletal muscle type-1 and 390 times higher than type-2 protein phosphatase. These results demonstrate that the MAPP I is a type-1-like protein phosphatase, although the properties are not the same as type-I phosphatase. The properties of the myosin-associated phosphatase were distinct from the phosphatases reported previously, although some properties were similar to smooth muscle phosphatase-IV. Therefore, it is concluded that MAPP I is a novel smooth muscle protein phosphatase. Since it strongly associated with smooth muscle myosin, it is likely that MAPP I is responsible for the dephosphorylation of smooth muscle myosin in situ.

The inhibitory effects of okadaic acid on platelet function

Okadaic acid (OA), a potent inhibitor of protein phosphatases type 1 and type 2A, inhibited thrombin-induced platelet aggregation (IC50 = 0.8 microM), [14C]serotonin release and increase in intracellular Ca2+ ([Ca2+]i) in the same dose dependence. In the absence of thrombin OA increased the phosphorylation of 50-kDa protein and 20-kDa myosin light chain (MLC20). The 50-kDa protein phosphorylation was accomplished within a shorter time period and at a lower concentration than was the MLC20. OA decreased the thrombin-induced phosphorylation of 47-kDa protein and MLC20, although phosphorylation of MLC20 reincreased at higher concentrations of OA (5-10 microM). Since type 2A phosphatase is more sensitive to OA than type 1, these results suggest that type 2A phosphatases are involved in the regulation of Ca2+ signaling in thrombin-induced platelet activation.

Myosin light chain phosphatase activities and the effects of phosphatase inhibitors in tonic and phasic smooth muscle

Phosphatase inhibitors microcystin-LR, tautomycin, and okadaic acid caused contraction and increased 20-kDa myosin light chain (MLC20) phosphorylation in Ca(2+)-free solutions in both phasic and tonic smooth muscle permeabilized with beta-escin, and inhibited the heavy meromyosin (HMM) phosphatase activity of smooth muscle homogenates with the same potency sequence: microcystin-LR greater than tautomycin greater than okadaic acid. The sensitivity to all three inhibitors was significantly higher, the half-times of relaxation and dephosphorylation were 4-6 times longer, and the HMM phosphatase and MLC20 kinase activity/smooth muscle cell wet weight was 2.0- and 1.9-fold lower in the tonic, femoral artery, than in the phasic, ileum or portal vein, smooth muscle. Preincubation with 0.2 microM inhibitor-2 decreased the HMM phosphatase activity by 35% in the ileum and by 60% in the femoral artery. The results suggest that the HMM phosphatases of smooth muscle have properties common to type 1 protein phosphatases, but are inhibited only partially by high concentrations of inhibitor-2, and that the lower HMM phosphatase activity of tonic smooth muscle may contribute to its greater sensitivity to phosphatase inhibitors and its slower rate of relaxation.

A complete response of an advanced oesophageal carcinoma treated with hyperthermic chemotherapy: a case report

A 56-year-old Japanese man with an advanced squamous cell carcinoma in the middle oesophagus was treated with a combination of hyperthermia, intravenous infusion of cisplatin (CDDP) and oral administration of oily bleomycin(BLM)-polyacrylate paste. After performing six sessions of hyperthermia treatment conducted at 42-45 degrees C for 30 min with 150 mg of CDDP and 180 mg of BLM, a subtotal oesophagectomy and lymph node dissection were performed. A histopathological study of the resected specimen showed no residual viable cancer cells either in the oesophagus or in the dissected lymph nodes. There were no side effects or perioperative complications and the patient is now healthy and leading a normal life 10 months after operation without undergoing any further treatment, at the time of writing. The effect of small amounts of CDDP and the oral application of oily BLM were thought to be strongly enhanced by hyperthermia in the treatment of oesophageal squamous carcinoma, and this regimen is therefore recommended as a safe and effective strategy, especially for preoperative treatment.