Neuroepithelial stem cells differentiate into neuronal phenotypes and improve intestinal motility recovery after transplantation in the aganglionic colon of the rat

The purpose of this study was to elucidate the possibility and the biological significance of intracolonic grafting of neuroepithelial stem cells (NESCs) as a therapeutic strategy for neuronal replacement in disorders of the enteric nervous system (ENS) such as aganglionosis. The enteric plexus of rat colon were eliminated by serosal application of the cationic surfactant benzalkonium chloride. NESCs were harvested from the neural tube of embryonic rat, labelled with bromodeoxyuridine (BrdU), and transplanted into the denervated colon. After 2, 4 and 8 weeks, grafted cells were visualized in colon sections by fluorescent double-staining for BrdU and neuronal, astrocytic, neurochemical or stem cell markers. Eight weeks post-transplantation, the intestinal motility was assessed by measuring the changes of intraluminal pressure responding to inflating stimulation and the responses to electrical field stimulation (EFS). Our results indicate that when transplanted into the denervated gut, NESCs survived and could differentiate into neurons and glial cells in vivo. Furthermore, inflation stimulated contraction and EFS-induced response were observed in NESCs grafted group compared with no reaction in denervated group. Therefore, NESCs can survive and function in the denervated rat colon in vivo, which indicates that NESCs provide a promising cellular replacement candidate for ENS.

Distinct phosphorylation sites in the SST2A somatostatin receptor control internalization, desensitization, and arrestin binding

The somatostatin subtype 2A (sst2A) receptor, a member of the G protein-coupled receptor superfamily, mediates many of the neuroendocrine and neuromodulatory actions of somatostatin, and it represents the primary target for somatostatin analogs used in cancer therapy and tumor localization. Agonist stimulation leads to the rapid phosphorylation, endocytosis, and desensitization of the sst2A receptor; however, little is known about the role of phosphorylation in sst2A regulation. sst2A phosphorylation occurs on serine and threonine residues in the third intracellular loop and carboxyl terminus. Therefore, we generated mutant receptors in which serine (Ser-), threonine (Thr-), or both (Ser-/Thr-) residues in these regions were mutated to alanine. In contrast to the wild-type receptor, somatostatin treatment did not stimulate the phosphorylation of the Ser-/Thr- mutant, and it did not produce desensitization. Furthermore, internalization of the Ser-/Thr- mutant occurred 5 times more slowly than with the wild-type receptor. Mutating only the Ser residues did not inhibit either internalization or desensitization. In contrast, mutating only the Thr residues inhibited receptor endocytosis to the same extent as in the full mutant, but it did not affect receptor desensitization. In both the wild-type and Ser- receptors, agonist binding produced a stable arrestin-receptor complex that was maintained during receptor trafficking, whereas arrestin was not recruited to either the Thr- or the Ser-/Thr- receptors. These results demonstrate that agonist-stimulated receptor phosphorylation is necessary for both desensitization and rapid internalization of the sst2A receptor. However, sst2A receptor internalization and uncoupling can occur independently, involve different receptor phosphorylation sites, and exhibit different requirements for stable arrestin association.

Renal pathological change in patients with type 2 diabetes is not always diabetic nephropathy: a report of 52 cases

AIMS

The present study examined the relationship between clinical features and renal histological changes in the Type 2-diabetic patients and evaluated the usefulness of renal biopsy in the diagnosis of diabetic versus non-diabetic kidney disease.

METHODS

52 patients with Type 2-diabetic mellitus were retrospectively analyzed for differential clinical, laboratory features and pathological characteristics including overt proteinuria (> 0.5 g/day), elevated serum creatinine and/or the development of hematuria.

RESULTS

Of 52 patients, 20 cases (38.5%) showed no detectable diabetic lesions and, thus, were diagnosed as non-diabetic renal disease (NDRD), while 32 patients (61.5%) exhibited diabetic nephropathy. Interestingly, while 29 patients showed diabetic nephropathy (DN) alone, NDRD was also found in 3 patients with DN. Clinically, 24 out of 52 patients (46.16%) had a diagnosis consistent with the pathological findings, while 10 (19.23%) were diagnosed incorrectly. Compared to NDRD patients, patients with DN had prolonged diabetic history with or without retinopathy, while 25% of patients with NDRD exhibited mesangial proliferative glomerulonephritis.

CONCLUSIONS

NDRD was a common feature in Type 2-diabetic patients with renal involvement. The absence of retinopathy and short periods of diabetic history may be useful indicators for diagnosis of NDRD clinically.

A comparison of the mechanical and structural properties of fibrin fibers with other protein fibers

In the past few years a great deal of progress has been made in studying the mechanical and structural properties of biological protein fibers. Here, we compare and review the stiffness (Young's modulus, E) and breaking strain (also called rupture strain or extensibility, epsilon(max)) of numerous biological protein fibers in light of the recently reported mechanical properties of fibrin fibers. Emphasis is also placed on the structural features and molecular mechanisms that endow biological protein fibers with their respective mechanical properties. Generally, stiff biological protein fibers have a Young's modulus on the order of a few Gigapascal and are not very extensible (epsilon(max) < 20%). They also display a very regular arrangement of their monomeric units. Soft biological protein fibers have a Young's modulus on the order of a few Megapascal and are very extensible (epsilon(max) > 100%). These soft, extensible fibers employ a variety of molecular mechanisms, such as extending amorphous regions or unfolding protein domains, to accommodate large strains. We conclude our review by proposing a novel model of how fibrin fibers might achieve their extremely large extensibility, despite the regular arrangement of the monomeric fibrin units within a fiber. We propose that fibrin fibers accommodate large strains by two major mechanisms: (1) an alpha-helix to beta-strand conversion of the coiled coils; (2) a partial unfolding of the globular C-terminal domain of the gamma-chain.

Apolipoprotein A-I stimulates AMP-activated protein kinase and improves glucose metabolism

AIMS/HYPOTHESIS

In humans, one of the hallmarks of type 2 diabetes is a reduced plasma concentration of HDL and its major protein component, apolipoprotein A-I (APOA-I). However, it is unknown whether APOA-I directly protects against diabetes. The aim of this study was to characterise the functional role of APOA-I in glucose homeostasis.

METHODS

The effects of APOA-I on phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase (ACC), glucose uptake and endocytosis were analysed in C2C12 myocytes. Glucose metabolism was investigated in Apoa-I knockout (Apoa-I (-/-)) mice.

RESULTS

APOA-I was able to stimulate the phosphorylation of AMPK and ACC, and elevated glucose uptake in C2C12 myocytes. APOA-I could be endocytosed into C2C12 myotubes through a clathrin-dependent endocytotic process. Inhibition of endocytosis abrogated APOA-I-stimulated AMPK phosphorylation. In Apoa-I (-/-) mice, AMPK phosphorylation was reduced in skeletal muscle and liver, and expression of gluconeogenic enzymes was increased in liver. In addition, the Apoa-I (-/-) mice had increased fat content and compromised glucose tolerance.

CONCLUSIONS/INTERPRETATION

Our data indicate that APOA-I has a protective effect against diabetes via activation of AMPK. ApoA-I deletion in the mouse led to increased fat mass and impaired glucose tolerance.

Laparoscopic excision of extraprostatic ejaculatory duct cyst

Our experiences with laparoscopic excisions of symptomatic extraprostatic ejaculatory duct cysts (EDCs) are reported. Three laparoscopic excisions of extraprostatic EDCs performed by one urologist in 2003 and 2004 were retrospectively reviewed. Investigations included history, physical examination, image analysis, semen analysis, operation time, estimated blood loss, time of post-operative hospital stay, recovery time for regular activities, sexual function and complications. The laparoscopic excisions of EDCs were successful. The mean operation time was 105 min, and the mean estimated blood loss was 65 ml. The average post-operative hospital stay was 3.0 days. All patients exhibited normal erection and normal ejaculation. Improvement in semen quality was observed in two patients. All patients remained free of symptoms, and recurrence of EDCs was not detected on transrectal ultrasonography over a mean 32-month follow-up period. It is concluded that laparoscopic excision of an EDC is feasible and effective. Due to minimal invasiveness, short post-operative hospitalisation and rapid recovery, laparoscopic surgery is an attractive approach to managing symptomatic EDCs, especially for sizeable cysts or those including calculus.

Magnetic studies of a syn-anti triatomic carboxylate-bridging chainlike copper(II) complex exhibiting ferromagnetic exchange

The magnetic properties of triatomic syn-anti carboxylate bridging copper(II) complex, {[Cu(2,2'-bipydine)(maleate)].2H2O}infinity (complex 1), were investigated experimentally and theoretically, suggesting weak ferromagnetic intrachain interaction. The magnetic data were analyzed and interpreted in terms of Heisenberg chain model corrected by a mean molecular field. Fitting parameters obtained for J, g, and zJ' are 3.14 cm(-1), 2.08, and -0.13, respectively. Density functional theory with generalized gradient approximation was applied to calculate the electronic structure and spin distribution of the present complex. The structural and electronic factors controlling the magnetic interactions were also determined. Ferromagnetic intrachain interactions through triatomic syn-anti carboxylate bridge result from nonplanarity of the bridging network, the exchange pathway involving both the sigma and pi orbitals of the carboxylate bridge and the spin delocalization of each magnetic orbital on the atoms of the carboxylate bridge from the copper(II) centers.

Genome scan implicates adhesion biological pathways in secondary leukemia

The genetic risk factors for etoposide-induced leukemia with MLL translocations remain largely unknown. To identify genetic risk factors for and novel characteristics of secondary leukemia, we profiled 116,204 single nucleotide polymorphisms (SNPs) in germline and paired leukemic cell DNA from 13 secondary leukemia/myelodysplasia cases and germline DNA from 13 matched and 156 unmatched controls, all with acute lymphoblastic leukemia treated with etoposide. We analyzed global gene expression from a partially overlapping cohort. No single locus was altered in most cases. We discovered 81 regions of loss of heterozygosity (LOH) in leukemic blasts and 309 SNPs whose allele frequencies differed in cases vs controls. Candidate genes were prioritized on the basis of genes whose SNPs or expression differentiated cases from controls or showed LOH or copy number change in germline vs paired blast DNA from the 13 cases. Three biological pathways were altered: adhesion, Wnt signaling and regulation of actin. Validation experiments using a genome scan for etoposide-induced leukemogenic MLL chimeric fusions in 15 HapMap cell lines also implicated genes involved in adhesion, a process linked to de novo leukemogenesis. Independent clinical epidemiologic and in vitro genome-wide approaches converged to identify novel pathways that may contribute to therapy-induced leukemia.

Expression of hGC-1 is correlated with differentiation of gastric carcinoma

AIMS

The human G-CSF-stimulated clone-1 (hGC-1) gene encodes a 510-amino acid olfactomedin-related glycoprotein whose exact in vivo localization and function still remain elusive. The aim of this study was to demonstrate hGC-1 protein localization in the normal human gastrointestinal tract and to explore further a potential relationship between hGC-1 expression and gastric carcinoma.

METHODS AND RESULTS

A specific hGC-1 polyclonal antibody raised against purified hGC-1 protein was developed and characterized. Using immunohistochemistry, it was demonstrated that hGC-1 is expressed in the oesophagus, stomach, small intestine and colon. The expression pattern of hGC-1 protein in 173 cases of gastric carcinoma was investigated and a striking correlation was demonstrated between hGC-1 expression and histological type and differentiation of gastric carcinoma. Enhanced hGC-1 expression was more frequently seen in intestinal-type adenocarcinoma, whereas loss of expression tended to occur in the diffuse type. hGC-1 was highly expressed in well or moderately differentiated cancers and was remarkably reduced or lost in poorly differentiated or undifferentiated tumours.

CONCLUSIONS

These investigations have defined for the first time the expression pattern of hGC-1 in the normal human gastrointestinal tract and provide a novel and sensitive marker for the differentiation of gastric carcinoma.

[Cerebrotendinous xanthomatosis]

HISTORY AND CLINICAL FINDINGS

A 43-year-old woman had since childhood suffered from progressive dementia. Gait ataxia and mild polyneuropathy were noted in the neurological examination. She also had painful xanthomas of the achilles tendons. A bilateral cataract operation had been performed during adolescence.

INVESTIGATIONS

An elevated concentration of cholestanol and a normal cholesterol level were found in the blood samples. The cerebral computed tomography revealed slight cerebral atrophy, predominantly affecting the cerebellum. Neurophysiological tests detected a sensory polyneuropathy in the legs. In addition the electroencephalogram showed a generalized slowing of electrical activity.

DIAGNOSIS, TREATMENT AND COURSE

Clinical findings and laboratory values indicated the diagnosis of a cerebrotendinous xanthomatosis. After initiation of a drug therapy, based on a combination of an HMG-CoA-reductase inhibitor (simvastatin 20 mg/day) and a bile acid, chenodeoxycholic acid (15 mg/kg/day), further progression of the disease was prevented.

CONCLUSION

The diagnosis of cerebrotendinous xanthomatosis is easily made in patients presenting all clinical symptoms expected in the disease. However, up to 30% of the patients do not show severe xanthomas. Especially in early stages of the disease the diagnosis may be difficult. Treatment can be efficacious and should be started as early as possible to prevent irreversible damage, particularly in the nervous system.

Pooling batches in drug stability study by using constant-width simultaneous confidence bands

One important study objective in drug stability studies is to estimate the shelf-life of a drug. A key statistical problem involved in this is how to assess the practical equivalence of different batches of the same drug so that different batches can be subgrouped to produce a single shelf-life for the drug. In this paper constant-width simultaneous confidence bands are proposed to quantify the magnitude of difference between different batches, with a particular view to establish the practical equivalence of different batches. This approach is suitable for the situation that the intercepts and slopes of the regression lines for the batches cannot be assumed to be equal. It is shown how constant-width simultaneous confidence bands can be easily constructed for the multiple comparison of several general linear regression models. In particular, it is shown that constant-width simultaneous confidence bands have a better chance to establish the equivalence than, and so are preferable to, the hyperbola-shaped simultaneous confidence bands considered.

Novel functional proteomics approach to defining ovarian cancer molecular heterogeneity

5502

Background: A number of clinicopathologic risk factors are used for survival prediction and clinical decision-making in epithelial ovarian cancer (EOC). Information from novel technologies such as gene arrays has not had an impact on patient management. We studied EOC protein signaling profiles to determine if their addition to accepted clinicopathologic factors improves their accuracy in predicting individual patient outcomes. Methods: We applied a novel functional proteomics technology, reverse phase protein array (RPPA), to quantify expression and activation of 42 steroid and kinase signaling pathway proteins in 106 high-grade EOCs from patients with stages 1–4 tumors managed with surgery and platinum-based chemotherapy. Cox regression analysis and a novel committee modeling approach were used to study the impact of functional proteomics on patient outcomes. Results: In a Cox model using only clinical variables, stage and residual disease were significantly related to overall survival. By adding the proteins to the clinical Cox model, two proteins that were significantly associated with overall survival on univariate analysis (phosphorylated-MAPK (p-MAPK; log rank p = 0.0047) and progesterone receptor (PR; log rank p = 0.027)) remained significant at the alpha=0.10 level (z-test p-values 0.074 and 0.034, respectively, when treated as binary variables according to martingale residual plots); as a result, these two proteins added to the predictive accuracy of the clinical survival model. However, using the novel committee modeling approach in test and validation EOC sets, a closest neighbor metric was applied to successfully define distinct proteins groups, each composed of nine proteins, that are predictive of specific survival times in patients with EOC. This granular approach to modeling is particularly suited to defining the molecular heterogeneity of EOC. Conclusions: EOC is a complex process with significant individual variability. Using novel approaches to functional proteomic study and statistical modeling, our striking finding is that distinct combinations of steroid and kinase signaling proteins are predictive markers of specific survival times in EOC.

No significant financial relationships to disclose.

Ultrastaging of sentinel lymph nodes (SLNs) compared to non-SLNs in colorectal (CRca) cancer: Do we need both?

4055

Background: SLN mapping (M) accurately stages many solid tumors including CRca. SLNs are 3–5 times more likely to have metastases (mets) when ultrastaged by microsections and IHC as compared to non-SLNs examined by standard pathological methods. It is unknown whether ultrastaging of initially -ve non-SLNs would lead to higher incidence of +ve nodes. Hence, we retrospectively analyzed all initially -ve non-SLNs by microsections and IHC similar to SLNs in CRca patients (pts) undergoing SLNM to determine its impact on final nodal staging. Methods: All CRca pts underwent SLNM by circumferential subserosal injection of 1% lymphazurin. First 1–4 blue nodes were marked as SLNs and ultrastaged by 4 section with H&E and 1 with IHC. All non-SLNs were initially examined by single H& E section and initial staging was made as per AJCC criteria. We re-examined all initially -ve non-SLNs similar to the SLNs by a senior pathologist blinded to prior results. Results: There were 156 pts with Cca and 44 pts with Rca. SLNM was successful in 100% pts with 94% accuracy rate. A total of 2,755 nodes (13.78/pt) were identified, of which 494 were SLNs and 2,261 were non-SLNs. Nodal positivity was 46% and 16% for Cca and Rca pts respectively. Mets were detected in 20.9% of SLNs vs. 8.6% of non-SLNs (p< 0.0001). The exclusive site of nodal mets was detected in 6.5% of SLNs vs.0.8% of non-SLNs (p< 0.0001). Skip mets were found in 6% of pts. After ultrastaging all initially -ve non-SLNs (n=2,065), only 0.58% (12/2065) nonSLNs became +ve in 12 pts. Of these, 10 pts already had +ve SLNs, hence no change of staging occurred. Only 2/200 pts (1%) with initially -ve non-SLNs were found to have a cluster of tumor cells. Thus, ultrastaging of 2065 initially -ve non-SLNs in 200 pts changed the staging from II to III only in 1% of pts. Conclusions: SLNM is highly accurate in staging CRca. The chance of finding additional mets by ultrastaging of all non-SLNs is extremely low (< 1%), hence of little benefit. Therefore, ultrastaging restricted to SLNs alone will assure accurate staging of CRca.

[Table: see text]

No significant financial relationships to disclose.

Pharmacodynamic analysis of receptor tyrosine kinase (RTK) activity reveals differential target inhibition in skin and tumor in a phase I study of advanced colorectal cancer patients treated with AEE788

3601

Background: AEE788 (AEE) is an oral inhibitor against tyrosine kinases and has an IC50 of < 100 nM against EGFR and VEGFR-2. This PD study investigated the effects of AEE on its targets in vitro and in biopsies from advanced colorectal cancer patients. Methods: HUVECs and HT-29 cells were incubated with AEE for 4h at 0–1 mM. 22 pts were treated at doses of 25 (n=4), 50 (n=3), 100 (n=4), 250 (n=1), 300 (n=4), and 400 mg (n=6) mg/day in 28-day cycles. No major clinical respones were observed. Wound-induced paired skin biopsies were performed on days -8, -1, 22, 29. Tumor biopsies were obtained before and 28 days post-treatment. Evaluable paired skin and tumor samples were available in 18 and 14 patients respectively. The effects of AEE on pKDR, pEGFR, AKT, Ki67, and apoptosis were analyzed by laser scanning cytometry (LSC). Wilcoxon signed rank test and Spearman correlation were used to compare biomarker changes post-treatment and correlation with dose, respectively. Results: In vitro, AEE treatment resulted in a dose-dependent inhibition of pKDR and pEGFR with inhibition of 65% and 63% at 1 mM in HUVECs and HT-29 cells, respectively. pKDR levels increased in response to AEE treatment in HT-29 cells. In skin, AEE increased basal levels of pKDR (p=0.03) post-treatment. AEE increased AKT (p=0.02) and EGFR (p=0.01) in a dose-dependent manner. In wound-induced skin pairs, AEE significantly inhibited endothelial cell pKDR/KDR (ratio) in a dose-dependent manner (p=0.02). In tumors, AEE increased pKDR expression (p=0.05) and was dose-dependent (p=0.06). Tumor endothelial cell pKDR levels decreased (avg. 47%) after AEE treatment (p=0.08). Furthermore, levels of Ki67 increased (p=0.08) and no significant effects were observed on pEGFR or apoptosis at any dose level in post-treatment samples. Conclusions: LSC quantitative analysis confirmed the target inhibition of AEE in vitro and in wound-induced skin pairs. The lack of significant target inhibition in tumors is consistent with the lack of clinical activity of AEE in this cohort of patients. Quantifying pKDR/KDR in wound-induced skin pairs may serve as a surrogate for assessing the activity of an angiogenesis inhibitor such as AEE.

[Table: see text]

Impact of Drug‐Exposure Intensity and Duration of Therapy on the Emergence ofStaphylococcus aureusResistance to a Quinolone Antimicrobial

We have shown previously in animal model and in vitro systems that antimicrobial therapy intensity has a profound influence on subpopulations of resistant organisms. Little attention has been paid to the effect of therapy duration on resistant subpopulations. We examined the influence of therapy intensity (area under the concentration/time curve for 24 h:minimum inhibitory concentration [AUC24:MIC] ratio) and therapy duration on resistance emergence using an in vitro model of Staphylococcus aureus infection. AUC24:MIC ratios of>or=100 were necessary to kill a substantial portion of the total population. Importantly, we demonstrated that therapy duration is a critical parameter. As the duration increased beyond 5 days, the intensity needed to suppress the antibiotic-resistant subpopulations increased, even when the initial bacterial kill was>4 log10 (cfu/mL). These findings were prospectively validated in an independent experiment in which exposures were calculated from the results of fitting a large mathematical model to all data simultaneously. All of the prospectively determined predictions were fulfilled in this validation experiment.