Activation of preformed EGF receptor dimers by ligand-induced rotation of the transmembrane domain

The epidermal growth factor receptor plays crucial roles throughout the development of multicellular organisms, and inappropriate activation of the receptor is associated with neoplastic transformation of many cell types. The receptor is thought to be activated by ligand-induced homodimerisation. Here, however, we show by chemical cross-linking and sucrose density-gradient centrifugation that in the absence of bound ligand the receptor has an ability to form a dimer and exists as a preformed dimer on the cell surface. We also analysed the receptor dimerisation by inserting cysteine residues at strategic positions about the putative alpha-helix axis of the extracellular juxtamembrane region. The mutant receptors spontaneously formed disulphide bridges and transformed NIH3T3 cells in the absence of ligand, depending upon the positions of the cysteine residue inserted. Kinetic analyses of the disulphide bonding indicate that EGF binding induces flexible rotation or twist of the juxtamembrane region of the receptor in the plane parallel with the lipid bilayer. The binding of an ATP competitor to the intracellular domain also induced similar flexible rotation of the juxtamembrane region. All the disulphide-bonded dimers had flexible ligand-binding domains with the same biphasic affinities for EGF as the wild-type. These results demonstrate that ligand binding to the flexible extracellular domains of the receptor dimer induce rotation or twist of the juxtamembrane regions, hence the transmembrane domains, and dissociate the dimeric, inactive form of the intracellular domains. The flexible rotation of the intracellular domains may be necessary for the intrinsic catalytic kinase to become accessible to the multiple tyrosine residues present in the regulatory domain and various substrates, and may be a common property of many cell-surface receptors, such as the insulin receptor.

Insulin within islets is a physiologic glucagon release inhibitor

To determine if glucagon secretion is under physiological control of intra-islet insulin, pancreata from normal rats were perfused at a 100 mg/dl glucose concentration with either guinea pig antiinsulin serum or normal guinea pig serum in a nonrecirculating system. Perfusion of antiserum was followed within 3 min by a significant rise in glucagon that reached peak levels three times the base-line values and assumed a hectic pattern that returned rapidly to base-line levels upon termination of the antiserum perfusion. Nonimmune guinea pig serum had no effect. To gain insight into the probable site of insulin neutralization, 125I-labeled human gamma-globulin was added to antiserum or nonimmune serum and perfused for 3 min. More than 83% of the radioactivity was recovered in the effluent within 3 min after termination of the infusion, and only 0.05 +/- 0.015% of the radioactivity injected was present in the pancreas 10 min after the perfusion. The maximal amount of insulin that could be completely bound to insulin antibody at a dilution and under conditions simulating those of the perfusion experiments was 20 mU/min. It is concluded that insulin maintains an ongoing restraint upon alpha cell secretion and in its absence causes hectic hypersecretion of glucagon. This restraint probably occurs largely in the intravascular compartment. Loss of this release-inhibiting action of insulin may account for initiation of hyperglucagonemia in insulin-deficient states.

The TGF-beta signaling inhibitor Smad7 enhances tumorigenicity in pancreatic cancer

Transforming growth factor-beta (TGF-beta) signaling is dependent on the heterodimerization of the type II TGF-beta receptor (TbetaRII) with the type I TGF-beta receptor (TbetaRI). Activated TbetaRI then mediates TGF-beta signals by inducing the phosphorylation of Smad2 and/or Smad3, which separately hetetorodimerize with Smad4 and translocate to the nucleus. Phosphorylation of Smad2/Smad3 by activated TbetaRI is inhibited by two newly discovered members of the Smad family, Smad6 and Smad7. We now report that Smad7 mRNA levels are increased in human pancreatic cancer by comparison with the normal pancreas, and that by in situ hybridization, Smad7 is over-expressed in the cancer cells within the tumor mass. Stable transfection of COLO-357 human pancreatic cancer cells with a full-length Smad7 construct leads to complete loss of the growth inhibitory response to TGF-beta1, without altering TGF-beta1-mediated induction of PAI-I. Furthermore, Smad7 transfected COLO-357 cells display enhanced anchorage-independent growth and accelerated growth in nude mice. These findings point to a previously unrecognized mechanism for selective suppression of TGF-beta-mediated growth inhibition in cancer cells that allows for continued activation of the PAI-I promoter by TGF-beta1, which may act to enhance the tumorigenicity of certain cancer cells.

Molecular features of the CAG repeats and clinical manifestation of Machado-Joseph disease

Machado--Joseph disease (MJD) is an autosomal dominant spinocerebellar degeneration mapped to chromosome 14q32.1. The CAG expansions of the MJD1 gene was identified as the cause of the disease. We have analyzed 90 MJD individuals from 62 independent MJD families and found that the MJD1 repeat length is inversely correlated with the age of onset (r = -0.87). The MJD chromosomes contained 61-84 repeat units, whereas normal chromosomes displayed 14-34 repeats. In the normal chromosomes, 14 repeat units were the most common and the shortest. In association with the clinical anticipation of the disease, a parent--child analysis showed the unidirectional expansion of CAG repeats and no case of diminution in the affected family. The differences in CAG repeat length between parent and child and between siblings are greater in paternal transmission than in maternal transmission. Detailed analysis revealed that a large degree of expansion was associated with a shorter length of MJD1 gene in paternal transmission. On the other hand, the increments of increase were similar for shorter and longer expansion in maternal transmission. Among the three clinical subtypes, type I of MJD, with dystonia, showed a larger degree of expansion in CAG repeats of the gene and younger ages of onset than the other types.

Bone morphogenetic protein 2 exerts diverse effects on cell growth in vitro and is expressed in human pancreatic cancer in vivo

BACKGROUND & AIMS

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor beta superfamily of signaling molecules. We characterized the expression of BMP-2 and its receptors in human pancreatic tissues and pancreatic cancer cell lines and examined the effects of BMP-2 on mitogenesis.

METHODS

Expression of BMP-2 and its receptors was determined by Northern blot analysis using specific complementary DNA probes. Distribution of BMP-2 in pancreatic cancers was examined by immunohistochemistry and in situ hybridization. Effects of BMP-2 on mitogenesis were assessed by monitoring cell proliferation and activation of mitogen-activated protein kinase (MAPK).

RESULTS

Compared with the normal pancreas, pancreatic cancers showed a 12.5-fold (P < 0.01), 2-fold (P < 0.01), and 8-fold (P < 0.01) increase of BMP-2, BMP receptor (R)-IA, and BMPR-II messenger RNA levels, respectively. By immunohistochemistry and in situ hybridization, BMP-2 was expressed in the cancer cells within the tumor mass. There was a significant correlation between the presence of BMP-2 immunostaining in the tumors and shorter postoperative survival. Pancreatic cancer cell lines expressed variable levels of messenger RNA encoding BMP-2 and its receptors. BMP-2 stimulated the growth of two pancreatic cancer cell lines (ASPC-1 and CAPAN-1). This mitogenic effect was associated with MAPK activation and blocked by the MAPK inhibitor PD98059 in CAPAN-1 but not in ASPC-1 cells. In both cell lines, expression of wild-type Smad4 abolished the BMP-2-mediated growth stimulation. BMP-2 inhibited the growth of COLO-357 cells, an effect that was blocked by expressing a dominant negative Smad4. BMP-2 had no effect in three cell lines that underexpressed either the BMP receptors or Smad1.

CONCLUSIONS

These findings indicate that BMP-2 has the capacity to act as a mitogen when Smad4 is mutated and suggest that it might play a role in the pathobiology of human pancreatic cancer.

Detection and localization of Mip-3alpha/LARC/Exodus, a macrophage proinflammatory chemokine, and its CCR6 receptor in human pancreatic cancer

Macrophage Proinflammatory Human Chemokine-3alpha (Mip-3alpha/LARC/Exodus) belongs to a large family of chemotactic cytokines, which participate in directing inflammatory cell migration and in modulating angiogenesis. Mip-3alpha signals through a recently identified G-protein linked 7-transmembrane receptor, CCR6. In this study, we have characterized the expression of Mip-3alpha and CCR6 in 12 normal and 16 cancerous human pancreatic tissues and in 4 cultured pancreatic cancer cell lines, and assessed the effects of Mip-3alpha on growth and invasion of these cell lines. Pancreatic cancer tissues markedly overexpressed Mip-3alpha in comparison with normal pancreatic samples. By in situ hybridization Mip-3alpha and CCR6 mRNA moieties were present in cancer cells within the tumors. In addition, Mip-3alpha was abundant in the macrophages infiltrating the tumor mass. Mip-3alpha and its receptor CCR6 were expressed in all 4 tested pancreatic cancer cell lines. Mip-3alpha stimulated the growth of one cell line, enhanced the migration of another cell line, and was without effect in the other 2 cell lines. Together, our findings suggest that Mip-3alpha has the potential to act via autocrine and paracrine mechanisms to contribute to the pathobiology of human pancreatic cancer.

Lack of an association of estrogen receptor alpha gene polymorphisms and transcriptional activity with Alzheimer disease

BACKGROUND

Long-term cognitive decline in postmenopausal women is associated with aging and Alzheimer disease (AD). Estrogen replacement therapy has been reported to reduce the risk of developing AD. The distribution of estrogen receptors (ERs) in neurons overlaps that of the brain neurons known to develop AD. Estrogen increases the secretion and metabolism of amyloid precursor protein, may help synapse formation, and is reported to protect neurons from toxins. Restriction fragment length polymorphisms (RFLPs) of the ERalpha gene at intron 1 and exon 2 were associated with a low bone mineral density in postmenopausal women and also with AD in a Japanese population.

OBJECTIVE

To determine whether ERalpha gene polymorphisms are associated with transcriptional activity and AD.

METHODS

A luciferase reporter assay analyzed enhancer activity of the ERalpha gene at intron 1 and exon 2. This activity was evaluated according to the RFLPs. The RFLPs of the ERalpha gene were determined in Japanese patients clinically diagnosed as having AD, white patients diagnosed as having AD at autopsy, and corresponding healthy control subjects. The RFLPs were also evaluated for the contribution of the ERalpha gene RFLPs to AD.

RESULTS

We found weak (about 2-fold) enhancer activity of the ERalpha gene, which differed among RFLPs. Although there were racial differences in these polymorphisms, we could not confirm the previously reported association between ERalpha gene polymorphisms and AD.

CONCLUSION

Regulatory element of the ERalpha gene was found in intron 1, but we found no association between ERalpha gene polymorphisms and AD.

Id-1 and Id-2 are overexpressed in pancreatic cancer and in dysplastic lesions in chronic pancreatitis

Id proteins antagonize basic helix-loop-helix proteins, inhibit differentiation, and enhance cell proliferation. In this study we compared the expression of Id-1, Id-2, and Id-3 in the normal pancreas, in pancreatic cancer, and in chronic pancreatitis (CP). Northern blot analysis demonstrated that all three Id mRNA species were expressed at high levels in pancreatic cancer samples by comparison with normal or CP samples. Pancreatic cancer cell lines frequently coexpressed all three Ids, exhibiting a good correlation between Id mRNA and protein levels, as determined by immunoblotting with highly specific anti-Id antibodies. Immunohistochemistry using these antibodies demonstrated the presence of faint Id-1 and Id-2 immunostaining in pancreatic ductal cells in the normal pancreas, whereas Id-3 immunoreactivity ranged from weak to strong. In the cancer tissues, many of the cancer cells exhibited abundant Id-1, Id-2, and Id-3 immunoreactivity. Scoring on the basis of percentage of positive cells and intensity of immunostaining indicated that Id-1 and Id-2 were increased significantly in the cancer cells by comparison with the respective controls. Mild to moderate Id immunoreactivity was also seen in the ductal cells in the CP-like areas adjacent to these cells and in the ductal cells of small and interlobular ducts in CP. In contrast, in dysplastic and atypical papillary ducts in CP, Id-1 and Id-2 immunoreactivity was as significantly elevated as in the cancer cells. These findings suggest that increased Id expression may be associated with enhanced proliferative potential of pancreatic cancer cells and of proliferating or dysplastic ductal cells in CP.

CTLA4 gene polymorphism confers susceptibility to Graves' disease in Japanese

Susceptibility to Graves' disease (GD) is determined by environmental and genetic factors. The genetic susceptibility to GD is conferred by genes in the human leukocyte antigen (HLA), and several other genes unlinked to HLA are thought to contribute to the development of GD. Three recent papers described the association of GD with the CTLA-4 gene. CTLA-4 is a candidate gene for T-cell mediated autoimmune diseases because it is a negative regulator of T-cell proliferation. As CTLA-4 association with GD may be influenced by the racial composition of the population, it is important to study it in other ethnic groups. We investigated the distribution of CTLA-4 gene polymorphism in 153 Japanese patients with GD (35 males and 118 females) and 200 controls (96 males and 104 females). An A/G transition at position 49 of exon 1 was analyzed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The distribution of genotype frequencies differs between GD and controls (chi2 = 9.46, 2 degrees of freedom, p < 0.01). The presence of at least one G allele (GG or AG) conferred an odds ratio of 2.64 (95% CI = 1.92-3.36). The present study supported the association of the CTLA-4 gene with GD in Japanese and showed that the CTLA4 gene could be one of the non-HLA linked susceptibility genes for GD.

Indispensability of pelvic and paraaortic lymphadenectomy in endometrial cancers

The purposes of this study were to analyze the relationship between retroperitoneal lymph node (RLN) metastasis and clinical and pathologic risk factors in endometrial cancers, and to clarify the correlation between RLN metastasis and survival of patients with the disease. This analysis included 63 patients with endometrial cancer who underwent simultaneous pelvic lymph node (PLN) and paraaortic lymph node (PAN) dissection between April 1988 and December 1995. Patients with stage Ia grade 1 and stage IV disease were excluded from this analysis. Both PLN and PAN metastases were found in 10.0% (4/40) of patients with stage I (FIGO, 1988) disease. Of 14 cases with PLN metastases, 8 (57.1%) had PAN metastases simultaneously, whereas 4 (8.2%) of 49 cases without PLN metastases had PAN metastases. There was no significant relationship between the sites or numbers of positive PLN and PAN metastases. Multivariate analysis revealed that poor grade and deep myometrial invasion had an independent relationship with PAN metastases, whereas vascular space invasion and cervical invasion were independently associated with PLN metastases. When divided into the groups of stage I-II and stage III, the prognosis of patients with RLN metastases was significantly poorer than that of patients without RLN metastases in each stage. Furthermore, survival of patients with PAN metastases was significantly worse compared with that of patients with only PLN metastases (44.4 and 80.0%, respectively, P < 0.05). These results reveal that PLN and PAN metastases occur frequently even in early-stage endometrial cancer, and that RLN metastases, especially PAN metastases, have a serious impact on patient survival. In conclusion, systemically simultaneous pelvic and paraaortic lymphadenectomy is essential for all the patients with endometrial cancer except those with stage Ia grade 1 and stage IV to provide prognostic information and select suitable postoperative treatment as well as to perform accurate FIGO staging, provided the condition of the patient permits.

Treatment of 37 patients with anaplastic carcinoma of the thyroid

BACKGROUND

Most patients with anaplastic carcinoma of the thyroid die within several months of diagnosis, and aggressive treatment is uncommon. We evaluated the effect of active multimodal treatment (surgery, radiotherapy, and chemotherapy) on this disease, including one patient treated with autologous bone marrow transplantation and high-dose chemotherapy.

METHODS

The outcome was assessed in 37 patients with anaplastic thyroid carcinoma treated between 1971 and 1993. Patients without distant metastasis when initially seen underwent surgery followed by radiotherapy. From 1984, conventional radiotherapy was replaced by hyperfractionated radiotherapy.

RESULTS

All but three patients died within 1 year of diagnosis. Patients with primary lesions less than 5 cm in diameter who had complete resection and radiotherapy survived significantly longer than the other patients, and hyperfractionated radiotherapy was effective for local control.

CONCLUSION

Active multimodal therapy is indicated for early-stage anaplastic carcinoma of the thyroid.

High-level expression of naked DNA delivered to rat liver via tail vein injection

BACKGROUND

High levels of foreign gene expression in mouse hepatocytes can be achieved by rapid tail vein injection of a large volume of a naked DNA solution, the 'hydrodynamics-based procedure'. Rats are more tolerant of the frequent phlebotomies required for monitoring blood parameters than mice, and thus are better for some biomedical research.

METHODS

We tested this technique for the delivery of a therapeutic protein in normal rats, using a rat erythropoietin (Epo) expression plasmid vector, pCAGGS-Epo.

RESULTS

We obtained maximal Epo expression when the DNA solution was injected in a volume of 25 ml (approximately 100 ml/kg body weight) within 15 s. We observed a dose-response relationship between serum Epo levels and the amount of injected DNA up to 800 microg. Using quantitative real-time PCR, the vector-derived Epo mRNA expression was mainly detected in the liver. When a lacZ expression plasmid was injected similarly, beta-galactosidase was exclusively detected in the liver, mainly in hepatocytes. Toxicity attributable to the technique was mild and transient, as assessed by histochemical analysis. Epo gene expression and erythropoiesis occurred with Epo gene transfer in a dose-dependent manner, and persisted for at least 12 weeks, the last time point examined. Repeated administration of the plasmid DNA also effectively led to erythropoiesis.

CONCLUSIONS

These results demonstrate that gene transfer into the liver via rapid tail vein injection can easily be achieved in the rat, which is more than 10 times larger than the mouse, and has significant value for gene function analysis in rats.

Molecular features of the CAG repeats of spinocerebellar ataxia 6 (SCA6)

Spinocerebellar ataxia 6 (SCA6) is an autosomal dominant spinocerebellar degeneration caused by the expansion of the polymorphic CAG repeat in the human alpha1A voltage-dependent calcium channel subunit gene (CACNL1A4 gene). We have analyzed 60 SCA6 individuals from 39 independent SCA6 Japanese families and found that the CAG repeat length is inversely correlated with the age of onset (n = 58, r = -0.51, P < 0.0001). SCA6 chromosomes contained 21-30 repeat units, whereas normal chromosomes displayed 6-17 repeats. There was no overlap between the normal and affected CAG repeat number. The anticipation of the disease was observed clinically in all eight parent-child pairs that we examined; the mean age of onset was significantly lower (P = 0.0042) in children than in parents. However, a parent-child analysis showed the increase in the expansion of CAG repeats only in one pair and no diminution in any affected cases. This result suggests that factors other than CAG repeats may produce the clinical anticipation. A homozygotic case could not demonstrate an unequivocal gene dosage effect on the age of onset.

Smad6 suppresses TGF-beta-induced growth inhibition in COLO-357 pancreatic cancer cells and is overexpressed in pancreatic cancer

Transforming growth factor (TGF)-beta signaling is initiated by heterodimerization of TGF-beta receptor type I (TbetaRI) and type II (TbetaRII). Subsequently, the signal is transduced via Smad proteins, which upon phosphorylation and heterodimerization translocate to the nucleus and regulate gene transcription. Smad6 functions as an intracellular antagonist of TGF-beta signaling. In the present study we demonstrate that Smad6 is overexpressed in vivo in human pancreatic cancer cells. We also show that stable transfection of a full-length Smad6 construct into COLO-357 pancreatic cancer cells abrogates TGF-beta1 induced growth inhibition, and leads to enhanced anchorage-independent growth. Thus, enhanced expression of the TGF-beta signaling inhibitor Smad6 in pancreatic cancer may present a novel mechanism of TGF-beta resistance, which might have the potential to enhance the transformed phenotype of human cancer cells.

Characteristic magnetic resonance imaging findings in Machado-Joseph disease

OBJECTIVE

To clarify the characteristic magnetic resonance imaging (MRI) findings in patients with Machado-Joseph disease (MJD) diagnosed by genetic analysis.

PATIENTS AND METHODS

Using MRI, we examined 31 patients genetically diagnosed as having MJD, 20 patients with sporadic olivopontocerebellar atrophy, and 26 control subjects.

RESULTS

The MRIs of patients with MJD disclosed remarkably reduced width of the superior cerebellar peduncles, atrophy in the frontal and temporal lobes, diminished transverse diameter of the globus pallidus, and decreased anteroposterior and transverse diameters of the pons, which correlated with the width of the middle cerebellar peduncle. The width of the superior cerebellar peduncles also correlated with the diameter of the dentate or red nucleus in patients with MJD, but not in controls or in patients with sporadic olivopontocerebellar atrophy. On T2- and/or proton-weighted axial MR imaging, a high signal intensity in the transverse pontine fibers was observed in 14 (45.2%) of 31 patients with MJD and in all patients with sporadic olivopontocerebellar atrophy, but not in any controls.

CONCLUSION

Affected afferent and efferent cerebellar tracts and atrophy of the frontal and temporal lobes and globus pallidus are characteristics of MRI of patients with MJD.

Results of revascularization in patients with severe left ventricular dysfunction

BACKGROUND

In patients with coronary artery disease and poor ventricular function (ejection fraction, < 20%), bypass grafting remains a surgical challenge. This study evaluates experience with isolated revascularization in such patients.

METHODS AND RESULTS

In 79 consecutive patients (69 men, 10 women; average age, 59 +/- 9 years), preoperative ejection fraction was 18 +/- 5%. Indications for surgery were congestive heart failure (CHF) in 5 of 79 patients (6%), CHF and angina in 19 (24%), angina in 41 (52%), ventricular arrhythmias (VAs) in 8 (10%), and critical anatomy in 6 (8%). Some patients had prior VAs (23 of 79; 29%) or mitral regurgitation (18; 23%) and required emergent surgery (25; 32%). At surgery, temperature mapping ensured adequate distribution of antegrade cold cardioplegia, with 3.6 +/- 0.7 grafts per patient, including left internal mammary artery graft in 60 of 79 (76%) and endarterectomy in 14 (18%). Hospital mortality was 3.8%. Perioperative support included intra-aortic balloon pump in 18 of 79 (23%) and drugs for VAs in 28 (35%). Morbidity included myocardial infarction in 2 of 79 (2.5%) and stroke in 2 (2.5%). During follow-up, there were 19 late deaths. Actuarial survival was 94%, 82%, and 68% at 1, 2, and 5 years, respectively, and was similar in patients with severe angina, CHF, mitral regurgitation, or VAs. Freedom from sudden death was 100%, 98%, and 91% at 1, 2, and 5 years, respectively. Among survivors, angina improved in 84% and heart failure improved in 26%.

CONCLUSIONS

These data support bypass graft surgery in patients with severe LV dysfunction. With careful cardioplegic techniques, hospital mortality was low (3.8%). Long-term survival is encouraging, with good relief of symptoms in most patients. Perioperative VAs are frequent but respond to medical treatment, with only 23% of patients discharged on antiarrhythmic drugs. Five-year freedom from sudden death is 91%, with only 3 late sudden deaths in this series.

Overexpression of activin A in stage IV colorectal cancer

BACKGROUND AND AIMS

Activins and inhibins are dimeric polypeptides that belong to the transforming growth factor beta (TGF-beta) superfamily and that bind to transmembrane receptors with serine/threonine kinase activity. The aim of this study was to characterise, in colon cancer cell lines and in normal and malignant human colon tissues, levels of expression of inhibin subunits that are involved in activin/inhibin dimer formation, and of the type I and II activin receptors (actRI and actRII).

METHODS

Expression of inhibin subunits and activin receptors was analysed by northern blot analysis. Inhibin betaA and activin receptor expression were also assessed by use of polymerase chain reaction (PCR). In addition, activin A/inhibin betaA localisation in human colon samples was assessed by immunohistochemistry and in situ hybridisation.

RESULTS

Inhibin betaA mRNA was expressed in CaCo2 cells but not in SW 837 or SW 1463 cells whereas inhibin betaB and inhibin alpha were below the level of detection. In contrast, all four activin receptors were present in the three cell lines. Colon cancers overexpressed inhibin betaA mRNA in comparison with normal colon, and this overexpression was greatest in stage IV tumours. ActRIb mRNA levels were slightly higher in the normal colon than in cancer tissues. By immunohistochemistry and in situ hybridisation, activin A and inhibin betaA mRNA were present in the mucosal epithelial cells in normal tissues from patients with stage I disease but were either absent or weakly present in normal tissues from patients with stage IV disease. Conversely, they were present at weak to moderate levels in stage I cancers but at high levels in stage IV cancers.

CONCLUSIONS

Our findings indicate that activin A is overexpressed in human colorectal tumours, especially in stage IV disease, raising the possibility that activin A may have a role in advanced colorectal cancer.

Effect of dietary seaweed preparations on 1,2-dimethylhydrazine-induced intestinal carcinogenesis in rats

Nineteen preparations from 8 species of edible seaweeds, sodium alginate and cellulose powder were incorporated into a basic diet in proportions ranging from 0.05% to 2.0%, and used as experimental diets. Experimental rats were fed these diets and controls were fed the basic diet for 12 weeks. All rats also received the carcinogen, 1,2-dimethylhydrazine, during above period. After 20 weeks, all rats were autopsied and the incidence of intestinal tumors induced were examined. There was a significant decrease in incidence in rats fed 6 preparations from Eisenia bicyclis, Laminaria angustata, L. angustata var. longissima and Porphyra tenera (P less than 0.05).

Skin-targeted gene transfer using in vivo electroporation

The skin is an important target for gene transfer because of its easy accessibility. Using plasmid DNA expressing rat erythropoietin (pCAGGS-Epo) as the vector, we previously demonstrated long-term Epo delivery in rats by muscle-targeted gene transfer using in vivo electroporation. Here we examined whether this electroporation approach could be applied to gene delivery in rat skin. To optimize gene transfer, we tested the efficiency of skin-targeted Epo gene transfer with three types of electrodes at three different electrode voltages. Each rat was injected intradermally with a total of 800 microg of pCAGGS-Epo, in the abdominal area. Plate-and-fork-type electrodes were effective for Epo delivery by skin-targeted gene transfer at low voltages (12 approximately 24 V). The vector-derived Epo mRNA was expressed only at the DNA injection site. The Epo gene was expressed in a dose-dependent manner, the expression persisted for 7 weeks, and hematocrit levels were increased for 11 weeks. Skin injection with pCAGGS-lacZ showed lacZ gene expression in the epidermis on day 1 after injection and in the subcutaneous muscle layer on day 7. Slight skin damage due to the gene transfer procedure was evident on day 1, but absent by day 7. These results demonstrate that skin-targeted pCAGGS-Epo transfer by in vivo electroporation at low voltage is a useful procedure for the short-term delivery of Epo.

Serum glutathione-S-transferase-pi as a tumor marker for gastrointestinal malignancies

A glutathione-S-transferase-pi (GST-pi) immunoradiometric assay was devised as a potential marker for serodiagnosis of malignant disease. Elevated serum GST-pi levels were observed in patients with various gastrointestinal malignancies including gastric, esophageal, colonic, pancreatic, hepatocellular, and biliary tract cancers. Patients with benign gastrointestinal diseases had normal GST-pi, but some patients with chronic hepatitis and cirrhosis had slightly elevated levels. Over 80% of patients with Stage III or IV gastric cancer and even about 50% of those with Stage I and II had elevated serum GST-pi. After surgery serum GST-pi levels returned to normal. Resected stomach cancers were immunohistochemically positive for GST-pi. During chemotherapy of colonic, gastric, and hepatocellular cancers with a series of different drugs, GST-pi changed in a biphasic manner; increases during initial phases of therapy may reflect acquisition of drug resistance by the tumor. In general, serum GST-pi assays provide a sensitive and reliable marker for gastrointestinal malignancies.

Walking patterns and finger rhythm of older adults

Walking patterns and rhythmic movement of the fingers were examined in a total of 1,134 male and female community residents 65 years of age and over. Walking patterns were characterized according to the ratio of step length divided by step rate (cadence), called the Walk Ratio, during level walking at preferred and maximum speeds. The walking pattern tended to change according to age; older subjects walked with shorter steps (smaller Walk Ratio). Rhythmic movement was examined using the finger-tapping test in time to the sound of a 4-Hz metronome. Hastened tapping or finger festination, in which the subject tapped faster than requested (constant error of 3 msec. and over in the intertap interval), was characteristic of aging; 16.8% of the subjects exhibited finger festination and the occurrence increased with age, especially among those in their eighties (29.3%). Finger festination was accompanied by walking patterns with an increased step rate, or a smaller Walk Ratio. These characteristics of aging were discussed as similar to extrapyramidal symptoms of walking and rhythm production in patients with Parkinson's disease.

The effect of dietary seaweeds on 7,12-dimethyl-benz[a]anthracene-induced mammary tumorigenesis in rats

Six groups of female rats were fed diets containing 2% of one of six powdered seaweeds for 152 days and a basic diet for 59 or 60 successive days, and controls were fed the basic diet for the whole experimental period. The 7,12-dimethylbenz[a]anthracene was given to all rats intragastrically (20 mg/kg X 1), 27 days after the start of feeding. Diets with 3 weeds, Porphyra tenera (PT), Laminaria religiosa (LR) and L. japonica var. ochotensis (LO), showed an inhibitory effect on mammary tumorigenesis. Tumor incidences were 35% (7/20), 35% (7/20) and 50% (9/18), respectively, whereas that in the control group was 69% (20/29). There was a significant delay in the time to first palpable tumor in LR-fed and PT-fed rats (P less than 0.01). As for the tumor weight per rat in each group, it was significantly lower in the LR-fed group with a weight of 1.6 g, as compared with that of 16.3 g in the control group (P less than 0.02).

Continuous erythropoietin delivery by muscle-targeted gene transfer using in vivo electroporation

It has been demonstrated that gene transfer by in vivo electroporation of mouse muscle increases the level of gene expression by more than 100-fold over simple plasmid DNA injection. We tested continuous rat erythropoietin (Epo) delivery by this method in normal rats, using plasmid DNA expressing rat Epo (pCAGGS-Epo) as the vector. A pair of electrodes was inserted into the thigh muscles of rat hind limbs and 100 microg of pCAGGS-Epo was injected between the electrodes. Eight 100-V, 50-msec electric pulses were delivered through the electrodes. Each rat was injected with a total of 400 microg of pCAGGS-Epo, which was delivered to the medial and lateral sides of each thigh. The presence of vector-derived Epo mRNA at the DNA injection site was confirmed by RT-PCR. The serum Epo levels peaked at 122.2 +/- 33.0 mU/ml on day 7 and gradually decreased to 35.9 +/- 18.2 mU/ml on day 32. The hematocrit levels increased continuously, from the preinjection level of 49.5 +/- 1.1 to 67.8 +/- 2.2% on day 32 (p < 0.001). In pCAGGS-Epo treated rats, endogenous Epo secretion was downregulated on day 32. In a control experiment, intramuscular injection of pCAGGS-Epo without subsequent electroporation did not significantly enhance the serum Epo levels. These results demonstrate that muscle-targeted pCAGGS-Epo transfer by in vivo electroporation is a useful procedure for the continuous delivery of Epo.

Expression of multiple UNC-13 proteins in the Caenorhabditis elegans nervous system

The Caenorhabditis elegans UNC-13 protein and its mammalian homologues are important for normal neurotransmitter release. We have identified a set of transcripts from the unc-13 locus in C. elegans resulting from alternative splicing and apparent alternative promoters. These transcripts encode proteins that are identical in their C-terminal regions but that vary in their N-terminal regions. The most abundant protein form is localized to most or all synapses. We have analyzed the sequence alterations, immunostaining patterns, and behavioral phenotypes of 31 independent unc-13 alleles. Many of these mutations are transcript-specific; their phenotypes suggest that the different UNC-13 forms have different cellular functions. We have also isolated a deletion allele that is predicted to disrupt all UNC-13 protein products; animals homozygous for this null allele are able to complete embryogenesis and hatch, but they die as paralyzed first-stage larvae. Transgenic expression of the entire gene rescues the behavior of mutants fully; transgenic overexpression of one of the transcripts can partially compensate for the genetic loss of another. This finding suggests some degree of functional overlap of the different protein products.

Protection against autoimmune myocarditis by gene transfer of interleukin-10 by electroporation

BACKGROUND

Although immunosuppressive therapy for myocarditis has attracted a great deal of attention, its effectiveness is controversial. Interleukin (IL)-10 has a variety of immunomodulatory properties. Among the nonviral techniques for gene transfer in vivo, the direct injection of plasmid DNA into muscle is simple, inexpensive, and safe.

METHODS AND RESULTS

We examined the applicability of murine IL-10 (mIL-10) gene transfer to the treatment of rats with experimental autoimmune myocarditis. Nine-week-old Lewis rats were inoculated with pig myosin (day 0). A plasmid vector expressing mIL-10 cDNA (800 microgram per rat) was transferred into the tibialis anterior muscles by electroporation 3 times (5 days before immunization and at days 4 and 13); control rats received empty plasmid. Electroporation increased the serum mIL-10 levels to >250 pg/mL. The 21-day survival rate in rats treated with mIL-10 cDNA was higher (15 of 15; 100%) than that of the control group (9 of 15; 60%). Furthermore, mIL-10 treatment significantly attenuated myocardial lesions and improved hemodynamic parameters.

CONCLUSIONS

These findings showed that gene transfer into muscle by electroporation in vivo is an effective means of delivery of IL-10 for the treatment of autoimmune myocarditis.