Validation of the

The cluster structure of the neutron-rich isotope ^{10}Be has been probed via the (p,pα) reaction at 150 MeV/nucleon in inverse kinematics and in quasifree conditions. The populated states of ^{6}He residues were investigated through missing mass spectroscopy. The triple differential cross section for the ground-state transition was extracted for quasifree angle pairs (θ_{p},θ_{α}) and compared to distorted-wave impulse approximation reaction calculations performed in a microscopic framework using successively the Tohsaki-Horiuchi-Schuck-Röpke product wave function and the wave function deduced from antisymmetrized molecular dynamics calculations. The remarkable agreement between calculated and measured cross sections in both shape and magnitude validates the molecular structure description of the ^{10}Be ground-state, configured as an α-α core with two valence neutrons occupying π-type molecular orbitals.

Predictors of the response to treatment in acute lupus hemophagocytic syndrome.

OBJECTIVE: The objective of this paper is to identify predictors for the response to treatment of acute lupus hemophagocytic syndrome (ALHS). METHODS: We reviewed seven cases with ALHS admitted to our hospital and published ALHS cases identified in the 2001-2014 Medline database, and then conducted univariate and multivariate analyses to identify predictors for the response to treatment. RESULTS: Review of our cases showed a significant and negative correlation between serum ferritin and anti-DNA antibody (p = 0.0025). All three patients treated with cyclosporine A (CsA) were considered responders despite high serum ferritin and corticosteroid resistance. We also reviewed 93 patients with ALHS identified in 46 articles. Multiple logistic regression analysis identified C-reactive protein (CRP) (OR 0.83, p = 0.042) and hemoglobin (OR 1.53, p = 0.026) measured at diagnosis of ALHS as significant predictors of the response to corticosteroid monotherapy. Moreover, among 32 patients treated with CsA, serum ferritin was significantly higher in CsA responders (12163 ± 16864 µg/l, n = 22) than in non-responders (3456 ± 6267/µg/l, p = 0.020, n = 10). Leukocyte count was significantly lower in the CsA responders (1940.0 ± 972.3/µl) than in the non-responders (3253 ± 2198/µl, p = 0.034). CONCLUSION: Low CRP and high hemoglobin can predict a positive response to corticosteroid monotherapy while high serum ferritin and low leukocyte count can predict a positive response to CsA in patients with ALHS and therefore, when corticosteroid monotherapy is not effective in such cases, CsA could be the first choice of an additional immunosuppressive agent.

Novel Soybean Variety Lacking Raffinose Synthase 2 Activity.

Variation in the raffinose family oligosaccharide (RFO) content in soybean is advantageous for livestock farming and health science. In this study, a soybean variety (GmJMC172) with a significantly low stachyose content in its seeds was identified in the NARO Genebank core collection. The results of the single-nucleotide polymorphism (SNP) analysis suggested that this phenomenon was related to a single-base deletion, inducing a frameshift mutation in raffinose synthase 2 (RS2), rather than the polymorphisms in the RS3, RS4, and stachyose synthase (STS) sequences. Differences in the enzymatic properties between the native RS2 and truncated RS2 were examined by using a three-dimensional model predicted using Alphafold2. In addition to revealing the missing active pocket in truncated RS2, the modeled structure explained the catalytic role of W331* and suggested a sufficient space to bind both sucrose and raffinose in the ligand-binding pocket. The soybean line, with seeds available from the NARO Genebank, could serve as breeding materials for manipulating the RFO content.

Three-dimensional structure database of natural metabolites (3DMET): a novel database of curated 3D structures.

A database of 3D structures of natural metabolites has been developed called 3DMET. During the process of structure conversion from 2D to 3D, we found many structures were misconverted at chiral atoms and bonds. Several popular converters were tested in regard to their conversion accuracy. For verification, three canonical strings were also tested. No procedure could satisfactorily cover all the structures of the natural products. The misconverted structures had to be corrected manually. However, a nonnegligible number of mistakes were also observed even after manual curation, so a self-checking system was developed and introduced to our work flow. Thus, the 3D structures in our 3DMET database were evaluated in two steps: automatically and manually. The current version includes most of the natural products of the KEGG COMPOUND collection [ http://www.genome.jp/kegg/compound/ ] and is searchable by string, value range, and substructure. 3DMET can be accessed via http://www.3dmet.dna.affrc.go.jp/ , which also has detailed manuals.

WIP regulates N-WASP-mediated actin polymerization and filopodium formation.

Induction of filopodia is dependent on activation of the small GTPase Cdc42 and on neural Wiskott-Aldrich-syndrome protein (N-WASP). Here we show that WASP-interacting protein (WIP) interacts directly with N-WASP and actin. WIP retards N-WASP/Cdc42-activated actin polymerization mediated by the Arp2/3 complex, and stabilizes actin filaments. Microinjection of WIP into NIH 3T3 fibroblasts induces filopodia; this is inhibited by microinjection of anti-N-WASP antibody. Microinjection of anti-WIP antibody inhibits induction of filopodia by bradykinin, by an active Cdc42 mutant (Cdc42(V12)) and by N-WASP. Our results indicate that WIP and N-WASP may act as a functional unit in filopodium formation, which is consistent with their role in actin-tail formation in cells infected with vaccinia virus or Shigella.

Rho family GTPase Cdc42 is essential for the actin-based motility of Shigella in mammalian cells.

Shigella, the causative agent of bacillary dysentery, is capable of directing its movement within host cells by exploiting actin dynamics. The VirG protein expressed at one pole of the bacterium can recruit neural Wiskott-Aldrich syndrome protein (N-WASP), a downstream effector of Cdc42. Here, we show that Cdc42 is required for the actin-based motility of Shigella. Microinjection of a dominant active mutant Cdc42, but not Rac1 or RhoA, into Swiss 3T3 cells accelerated Shigella motility. In add-back experiments in Xenopus egg extracts, addition of a guanine nucleotide dissociation inhibitor for the Rho family, RhoGDI, greatly diminished the bacterial motility or actin assembly, which was restored by adding activated Cdc42. In N-WASP-depleted extracts, the bacterial movement almost arrested was restored by adding exogenous N-WASP but not H208D, an N-WASP mutant defective in binding to Cdc42. In pyrene actin assay, Cdc42 enhanced VirG-stimulating actin polymerization by N-WASP-actin-related protein (Arp)2/3 complex. Actually, Cdc42 stimulated actin cloud formation on the surface of bacteria expressing VirG in a solution containing N-WASP, Arp2/3 complex, and G-actin. Immunohistological study of Shigella-infected cells expressing green fluorescent protein-tagged Cdc42 revealed that Cdc42 accumulated by being colocalized with actin cloud at one pole of intracellular bacterium. Furthermore, overexpression of H208D mutant in cells interfered with the actin assembly of infected Shigella and diminished the intra- and intercellular spreading. These results suggest that Cdc42 activity is involved in initiating actin nucleation mediated by VirG-N-WASP-Arp2/3 complex formed on intracellular Shigella.

Control of protein function through oxidation and reduction of persulfidated states.

Irreversible oxidation of Cys residues to sulfinic/sulfonic forms typically impairs protein function. We found that persulfidation (CysSSH) protects Cys from irreversible oxidative loss of function by the formation of CysSSO1-3H derivatives that can subsequently be reduced back to native thiols. Reductive reactivation of oxidized persulfides by the thioredoxin system was demonstrated in albumin, Prx2, and PTP1B. In cells, this mechanism protects and regulates key proteins of signaling pathways, including Prx2, PTEN, PTP1B, HSP90, and KEAP1. Using quantitative mass spectrometry, we show that (i) CysSSH and CysSSO3H species are abundant in mouse liver and enzymatically regulated by the glutathione and thioredoxin systems and (ii) deletion of the thioredoxin-related protein TRP14 in mice altered CysSSH levels on a subset of proteins, predicting a role for TRP14 in persulfide signaling. Furthermore, selenium supplementation, polysulfide treatment, or knockdown of TRP14 mediated cellular responses to EGF, suggesting a role for TrxR1/TRP14-regulated oxidative persulfidation in growth factor responsiveness.

A novel neural Wiskott-Aldrich syndrome protein (N-WASP) binding protein, WISH, induces Arp2/3 complex activation independent of Cdc42.

We identified a novel adaptor protein that contains a Src homology (SH)3 domain, SH3 binding proline-rich sequences, and a leucine zipper-like motif and termed this protein WASP interacting SH3 protein (WISH). WISH is expressed predominantly in neural tissues and testis. It bound Ash/Grb2 through its proline-rich regions and neural Wiskott-Aldrich syndrome protein (N-WASP) through its SH3 domain. WISH strongly enhanced N-WASP-induced Arp2/3 complex activation independent of Cdc42 in vitro, resulting in rapid actin polymerization. Furthermore, coexpression of WISH and N-WASP induced marked formation of microspikes in Cos7 cells, even in the absence of stimuli. An N-WASP mutant (H208D) that cannot bind Cdc42 still induced microspike formation when coexpressed with WISH. We also examined the contribution of WISH to a rapid actin polymerization induced by brain extract in vitro. Arp2/3 complex was essential for brain extract-induced rapid actin polymerization. Addition of WISH to extracts increased actin polymerization as Cdc42 did. However, WISH unexpectedly could activate actin polymerization even in N-WASP-depleted extracts. These findings suggest that WISH activates Arp2/3 complex through N-WASP-dependent and -independent pathways without Cdc42, resulting in the rapid actin polymerization required for microspike formation.

Profilin enhances Cdc42-induced nucleation of actin polymerization.

We find that profilin contributes in several ways to Cdc42-induced nucleation of actin filaments in high speed supernatant of lysed neutrophils. Depletion of profilin inhibited Cdc42-induced nucleation; re-addition of profilin restored much of the activity. Mutant profilins with a decreased affinity for either actin or poly-l-proline were less effective at restoring activity. Whereas Cdc42 must activate Wiskott-Aldrich Syndrome protein (WASP) to stimulate nucleation by the Arp2/3 complex, VCA (verpolin homology, cofilin, and acidic domain contained in the COOH-terminal fragment of N-WASP) constitutively activates the Arp2/3 complex. Nucleation by VCA was not inhibited by profilin depletion. With purified N-WASP and Arp2/3 complex, Cdc42-induced nucleation did not require profilin but was enhanced by profilin, wild-type profilin being more effective than mutant profilin with reduced affinity for poly-l-proline. Nucleation by the Arp2/3 complex is a function of the free G-actin concentration. Thus, when profilin addition decreased the free G-actin concentration, it inhibited Cdc42- and VCA-induced nucleation. However, when profilin was added with G-actin in a ratio that maintained the initial free G-actin concentration, it increased the rate of both Cdc42- and VCA-induced nucleation. This enhancement, also seen with purified proteins, was greatest when the free G-actin concentration was low. These data suggest that under conditions present in intact cells, profilin enhances nucleation by activated Arp2/3 complex.

Choledochal cyst associated with duodenal atresia: case report and review of the literature.

We report a rare case of choledochal cyst (CC) associated with congenital duodenal atresia (DA) and annular pancreas (AP). A girl was born at 37 weeks of gestation weighing 2,974 g with a prenatal diagnosis of DA. She underwent a duodenoduodenostomy for type III DA with an AP 1 day after birth. At 4 years of age, she was admitted for evaluation of cholangitis and pancreatitis. Radiological studies demonstrated a fusiform-type CC with pancreaticobiliary maljunction (PBMJ). Excision of the CC and hepaticojejunostomy were performed. The patient was discharged without complications. Despite the fact that CC, DA, and AP are embryologically closely related entities, to the best of our knowledge, only eight such cases have been documented. We must be aware of the possible combination of CC in the follow-up of the patients with DA associated with AP.

Ultrastructure of placental hyperplasia in mice: comparison of placental phenotypes with three different etiologies.

Hyperplastic placentas have been reported in several experimental mouse models, including animals produced by somatic cell nuclear transfer, by inter(sub)species hybridization, and by somatic cytoplasm introduction to oocytes followed by intracytoplasmic sperm injection. Of great interest are the gross and histological features common to these placental phenotypes--despite their quite different etiologies--such as the enlargement of the spongiotrophoblast layers. To find morphological clues to the pathways leading to these similar placental phenotypes, we analyzed the ultrastructure of the three different types of hyperplastic placenta. Most cells affected were of trophoblast origin and their subcellular ultrastructural lesions were common to the three groups, e.g., a heavy accumulation of cytoplasmic vacuoles in the trophoblastic cells composing the labyrinthine wall and an increased volume of spongiotrophoblastic cells with extraordinarily dilatated rough endoplasmic reticulum. Although the numbers of trophoblastic glycogen cells were greatly increased, they maintained their normal ultrastructural morphology, including a heavy glycogen deposition throughout the cytoplasm. The fetal endothelium and small vessels were nearly intact. Our ultrastructural study suggests that these three types of placental hyperplasias, with different etiologies, may have common pathological pathways, which probably exclusively affect the development of certain cell types of the trophoblastic lineage during mouse placentation.

Chemical curation to improve data accuracy: recent development of the 3DMET database.

We have developed a three-dimensional structure database of natural metabolites (3DMET). Early development of the 3DMET database relied on content auto-generated from 2D-structures of other chemical databases. From 2009, we began manual curation, obtaining new compounds from published works. In the process of curation, problems of digitizing 3D-structures from structure drawings of documents were accumulated. As the same as auto-generation, structure drawings should be also payed attention about stereochemistry. Our experiences in manual curation of 3DMET, as described herein, may be useful to others in this field of research and for the development of supporting systems of a chemical structure database. Manual curation is still necessary for proper database entry of the 3D-configurations of chiral atoms, a problem encountered frequently among natural products.

Prostaglandin E1 abrogates early reductive stress and zone-specific paradoxical oxidative injury in hypoperfused rat liver.

This study was designed to investigate the effects of prostaglandin E1 on reductive stress and the subsequent oxidative cell injury in hypoperfused rat liver. The intralobular heterogeneity of hepatocellular redox state, mitochondrial dysfunction, and intracellular hydroperoxide formation were visually monitored by digital microfluorography of pyridine nucleotide autofluorescence, rhodamine 123, and dichlorofluorescein fluorescence, respectively. Under the 25% low flow perfusion, pyridine nucleotide autofluorescence increased time-dependently and reached a steady state at 10 min among the entire lobules. The decrease in mitochondrial membrane potential was > 20 mV in all portions of the lobules at 60 min. The onset of hydroperoxide formation was observed at 40 min in the marginally oxygenated proximal portion of anoxic pericentral regions and the oxidative impact reached a maximum level at 60 min. Sodium (-)-8-(3-methoxy-4-phenylsulfinylphenyl) pyrazo [1,5-a]-1,3,5-triazine-4-olate monohydrate (BOF 4272), a novel xanthine oxidase inhibitor, suppressed the zone-specific oxidative changes without attenuating the increase in pyridine nucleotide autofluorescence and mitochondrial dysfunction. Pretreatment with prostaglandin E1 not only abrogated an early increase in pyridine nucleotide fluorescence and mitochondrial dysfunction induced by hypoperfusion but also diminished the subsequent midzonal oxidative injury. Since prostaglandin E1 has no oxyradical-scavenging action, the preventive effect of this reagent on the hypoxia-induced oxidative cell injury is attributable to the attenuation of mitochondrial dysfunction. These results suggest that, in low flow hypoxia, early reductive stress plays a key role in the initiation of xanthine oxidase-mediated midzonal oxidative changes, which may lead to subsequent centrilobular necrosis.

Inhibition of RXR and PPARgamma ameliorates diet-induced obesity and type 2 diabetes.

PPARgamma is a ligand-activated transcription factor and functions as a heterodimer with a retinoid X receptor (RXR). Supraphysiological activation of PPARgamma by thiazolidinediones can reduce insulin resistance and hyperglycemia in type 2 diabetes, but these drugs can also cause weight gain. Quite unexpectedly, a moderate reduction of PPARgamma activity observed in heterozygous PPARgamma-deficient mice or the Pro12Ala polymorphism in human PPARgamma, has been shown to prevent insulin resistance and obesity induced by a high-fat diet. In this study, we investigated whether functional antagonism toward PPARgamma/RXR could be used to treat obesity and type 2 diabetes. We show herein that an RXR antagonist and a PPARgamma antagonist decrease triglyceride (TG) content in white adipose tissue, skeletal muscle, and liver. These inhibitors potentiated leptin's effects and increased fatty acid combustion and energy dissipation, thereby ameliorating HF diet-induced obesity and insulin resistance. Paradoxically, treatment of heterozygous PPARgamma-deficient mice with an RXR antagonist or a PPARgamma antagonist depletes white adipose tissue and markedly decreases leptin levels and energy dissipation, which increases TG content in skeletal muscle and the liver, thereby leading to the re-emergence of insulin resistance. Our data suggested that appropriate functional antagonism of PPARgamma/RXR may be a logical approach to protection against obesity and related diseases such as type 2 diabetes.

Essential role of insulin receptor substrate 1 (IRS-1) and IRS-2 in adipocyte differentiation.

To investigate the role of insulin receptor substrate 1 (IRS-1) and IRS-2, the two ubiquitously expressed IRS proteins, in adipocyte differentiation, we established embryonic fibroblast cells with four different genotypes, i.e., wild-type, IRS-1 deficient (IRS-1(-/-)), IRS-2 deficient (IRS-2(-/-)), and IRS-1 IRS-2 double deficient (IRS-1(-/-) IRS-2(-/-)), from mouse embryos of the corresponding genotypes. The abilities of IRS-1(-/-) cells and IRS-2(-/-) cells to differentiate into adipocytes are approximately 60 and 15%, respectively, lower than that of wild-type cells, at day 8 after induction and, surprisingly, IRS-1(-/-) IRS-2(-/-) cells have no ability to differentiate into adipocytes. The expression of CCAAT/enhancer binding protein alpha (C/EBPalpha) and peroxisome proliferator-activated receptor gamma (PPARgamma) is severely decreased in IRS-1(-/-) IRS-2(-/-) cells at both the mRNA and the protein level, and the mRNAs of lipoprotein lipase and adipocyte fatty acid binding protein are severely decreased in IRS-1(-/-) IRS-2(-/-) cells. Phosphatidylinositol 3-kinase (PI 3-kinase) activity that increases during adipocyte differentiation is almost completely abolished in IRS-1(-/-) IRS-2(-/-) cells. Treatment of wild-type cells with a PI 3-kinase inhibitor, LY294002, markedly decreases the expression of C/EBPalpha and PPARgamma, a result which is associated with a complete block of adipocyte differentiation. Moreover, histologic analysis of IRS-1(-/-) IRS-2(-/-) double-knockout mice 8 h after birth reveals severe reduction in white adipose tissue mass. Our results suggest that IRS-1 and IRS-2 play a crucial role in the upregulation of the C/EBPalpha and PPARgamma expression and adipocyte differentiation.

Mid-term results of cementless total hip replacement using a ceramic-on-ceramic bearing with and without computer navigation.

We have developed a CT-based navigation system using infrared light-emitting diode markers and an optical camera. We used this system to perform cementless total hip replacement using a ceramic-on-ceramic bearing couple in 53 patients (60 hips) between 1998 and 2001. We reviewed 52 patients (59 hips) at a mean of six years (5 to 8) postoperatively. The mid-term results of total hip replacement using navigation were compared with those of 91 patients (111 hips) who underwent this procedure using the same implants, during the same period, without navigation. There were no significant differences in age, gender, diagnosis, height, weight, body mass index, or pre-operative clinical score between the two groups. The operation time was significantly longer where navigation was used, but there was no significant difference in blood loss or navigation-related complications. With navigation, the acetabular components were placed within the safe zone defined by Lewinnek, while without, 31 of the 111 components were placed outside this zone. There was no significant difference in the Merle d'Aubigne and Postel hip score at the final follow-up. However, hips treated without navigation had a higher rate of dislocation. Revision was performed in two cases undertaken without navigation, one for aseptic acetabular loosening and one for fracture of a ceramic liner, both of which showed evidence of neck impingement on the liner. A further five cases undertaken without navigation showed erosion of the posterior aspect of the neck of the femoral component on the lateral radiographs. These seven impingement-related mechanical problems correlated with malorientation of the acetabular component. There were no such mechanical problems in the navigated group. We conclude that CT-based navigation increased the precision of orientation of the acetabular component and control of limb length in total hip replacement, without navigation-related complications. It also reduced the rate of dislocation and mechanical problems related to impingement.

Colorectal resection by a minilaparotomy approach vs. conventional operation for colon cancer. Results of a prospective randomized trial.

BACKGROUND/AIMS: The aim of this study was to evaluate the outcome of patients undergoing colorectal resection for colon cancer using a minilaparotomy approach or conventional surgical procedure. METHODOLOGY: In a prospective randomized trial, twenty consecutive patients undergoing colon resection by minilaparotomy and 26 patients undergoing conventional open colorectal resection were evaluated. Immunologic, metabolic and hemodynamic studies were performed in all patients. Cell surface markers were used to characterize Th1/2 balance, using flow cytometry. Indirect calorimetry to measure energy expenditure, and pulse dye densitometry for a hemodynamic study were performed in patients until 14 POD. RESULTS: The lengths of laparotomy incisions were 7.5+/-1.5 cm and 20.5+/-2.5 cm in the minilaparotomy and conventional group, respectively. Mean operative time, morbidity and postoperative hospital stay of the two groups was not significantly different. However, mean operative blood loss, days to p.o. liquids and walking, and amount of analgesic usage were significantly less in the minilaparotomy group. The postoperative ratio of Th1/2 in CD4+T cells was decreased in both groups, but no significant difference was seen between the groups. Significant increase of resting energy expenditure and cardiac index was seen until day 3 in the conventional group, whereas those values increased until day 1 in the minilaparotomy group. CONCLUSIONS: Compared with conventional colorectal resection for colon cancer, colorectal resection by minilaparotomy results in a more rapid return of bowel function, less pain and host response. However, the alternations of the host response for surgical stress between the two groups are similar in the early postoperative stage (days 1-2).

Postoperative metabolic and circulatory responses in patients that express SIRS after major digestive surgery.

BACKGROUND/AIMS: Systemic inflammatory response syndrome (SIRS) includes a number of pathologic states because of its loose definition. This study assessed differences in metabolic and circulatory host responses in various patients with SIRS perioperatively. METHODOLOGY: Fifty-four patients who underwent abdominal surgeries [gastric resection (n=20), colorectal resection (n=24), hepatic resection (n=8)] were divided into two groups: Group A; SIRS (+) on 1 postoperative day (POD), (n=29), B; SIRS (-) on 1 POD, (n=25). The other eight non-operated patients with SIRS caused by infection were enrolled in Group C, as common SIRS. Indirect calorimetry, body impedance measurement to assess water compartments and pulse dye-densitometry for hemodynamic examination were performed in subjects until 14 POD. RESULTS: The ratio of energy expenditure to basal energy expenditure (%REE) was significantly increased postoperatively, and there were significant differences on %REE from 3 POD to 14 POD between groups A and B. However, %REE in group C was 162+/-23%, which was significantly increased compared with that at 1 POD of groups A (130 +/- 17%) and B (125+/-18%). Cardiac output in group A showed a significant increase until 3 POD compared with that in group B but was significantly lower than that in group C. CONCLUSIONS: Subjects with common SIRS caused by infection were significantly more hypermetabolic than subjects with postoperative SIRS. Adequate energy intake and circulatory management should be cautiously determined according to the severity of SIRS.

Postoperative host responses in elderly patients after gastrointestinal surgery.

BACKGROUND/AIMS: The age-associated dysregulation of hemodynamic, metabolic and immune responses contributes to the high incidence of complications after major abdominal surgery. METHODOLOGY: Ninety-five patients who underwent gastric resection (n=51) and colorectal resection (n=44) were divided according to age into Groups A (n=45, less than 70 years old), B (n=30, 70-79 years) and C (n=20, over 80 years). Flow cytometric analysis of CD4+ lymphocytes for interferon (IFN)-gamma and interleukin (IL)-4 production determined the Th1/2 balance. Energy expenditure was measured by indirect calorimetry, and hemodynamics were studied using pulse dye densitometry. RESULTS: Surgical procedures, operating time, blood loss and morbidity did not significantly differ among the three groups. The cardiac index (CI) in group A and B increased significantly over preoperative levels until POD 3, but there were no significant perioperative changes in the CI levels of group C. Resting energy expenditure levels changed similarly to those of CI. The postoperative Th1/2 ratio decreased from young to elderly to very elderly patients, although no differences were significant before surgery. The postoperative percentage of CD4+IFN-gamma +T cells (Th1) in group C decreased significantly despite of no significant changes in that of group A and B. In contrast, the ratio of CD4+IL-4+T cells (Th2) in the all groups significantly increased after surgery. CONCLUSIONS: Host responses in elderly patients after major abdominal surgery were more hyperdynamic and hypermetabolic than those of young patients. Postoperative dysregulation of the Th1/2 balance was also associated with aging. However, host responses appear to significantly differ between elderly and very elderly patients.

Effect of 12-O-tetradecanoylphorbol-13-acetate on intercellular communication in various clones of mouse epidermal JB6 cells.

We studied gap junctional intercellular communication (IC) in various clones of mouse epidermal JB6 cells and the effect of the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA) on such communication. JB6 clones used included nonpromotable, promotable, and transformed clones, representing a spectrum in susceptibility to transformation from nontransformed, to initiated (postinitiated), to transformed cells. We used the dye transfer assay and the radioisotope transfer assay, and quantified IC both in homologous pairings, where IC among cells of a single clone was examined, and heterologous pairings, where cells of initiated or transformed clones were paired with cells of a nonpromotable clone. Both pairings showed good IC in the absence of TPA and poor IC in the presence of TPA. However, suppression of IC by TPA was more effective when cells had advanced in promotability. IC was more suppressed by TPA in heterologous pairing than in homologous pairing. These results implied that in advanced stages of promotion, the capability to retain IC with each other (homologous IC) and especially with their nontransformed counterpart (heterologous IC) is progressively lost. Thus we conclude that the interaction of initiated cells and transformed cells with nontransformed cells decreases progressively in this model system for tumor promotion and progression.