Tumour-suppressor activity of H19 RNA

Loss of heterozygosity in certain human embryonal tumours implicates a tumour-suppressor gene at chromosome 11p15.5 and selective loss of maternal alleles suggests that this gene is paternally imprinted. The human H19 gene maps to 11p15.5, is expressed in differentiating fetal cells and is paternally imprinted. We report here that two embryonal tumour cell lines, RD and G401, showed growth retardation and morphological changes when transfected with an H19 expression construct. More importantly, clonogenicity in soft agar and tumorigenicity in nude mice were abrogated in the G401-H19 transfectants. In addition to demonstrating its tumour-suppressor potential, this transfection system should help structural and functional studies of the enigmatic H19 gene.

Identification of antiangiogenic and antiinflammatory proteins in human amniotic membrane

PURPOSE

To identify the potential antiangiogenic and antiinflammatory proteins expressed in human amniotic membrane tissue.

METHODS

Human amniotic epithelial and mesenchymal cells were isolated from human amniotic membranes by sequential trypsin and collagenase digestion. Total RNAs were harvested from freshly obtained human amniotic epithelial and mesenchymal cells. Antiangiogenic and antiinflammatory proteins were detected by the reverse transcriptase-polymerase chain reaction (RT-PCR) technique and further confirmed by DNA sequencing of PCR-amplified transcripts. The distribution of tissue inhibitors of metalloproteinase (TIMPs) were studied further by immunohistochemistry performed on paraffin-embedded amniotic membrane tissue.

RESULTS

RT-PCR results showed that both human amniotic epithelial and mesenchymal cells express interleukin-1 receptor antagonist, all four TIMPs, collagen XVIII, and interleukin-10. Thrombospondin-1 was expressed in all of the epithelial cell specimens and in one out of five mesenchymal cell specimens. Furthermore, immunohistochemistry studies performed on freshly prepared amniotic membrane confirmed that all members of the TIMP family were present in epithelial and mesenchymal cells as well as in the compact layer of the amniotic stroma. In cryopreserved amniotic membranes, positive staining was seen in residual amniotic cells and stroma.

CONCLUSIONS

Human amniotic membrane epithelial and mesenchymal cells express various antiangiogenic and antiinflammatory proteins. Some of those proteins also were found in amniotic membrane stroma. These findings may explain in part the antiangiogenic and antiinflammatory effects of amniotic membrane transplantation.

Apoptosis: final common pathway of photoreceptor death in rd, rds, and rhodopsin mutant mice

Mutations in the retinal degeneration, retinal degeneration slow(/peripherin) and rhodopsin genes cause photoreceptor degeneration in humans and mice. Although the phenotypes arising from these mutations are different, suggesting different mechanisms of pathogenesis, we present evidence that apoptosis may be the final common pathway of the disease process linking genotype to phenotype. We observed internucleosomal cleavage of retinal DNA by gel electrophoresis and fragmented DNA at the single cell level by labeling the nicked DNA ends with biotinylated poly(dU). In retinal degeneration mice, DNA fragmentation occurred during the period of photoreceptor degeneration. In retinal degeneration slow mice and in transgenic mice expressing a mutant (Pro347Ser) rhodopsin gene, DNA fragmentation occurred after normal histogenetic cell death (also apoptosis) had ceased. Since DNA fragmentation by internucleosomal cleavage is a cardinal feature of apoptosis, our data suggest that all three of these genetic mutations lead to apoptosis.

Epigenetic lesions at the H19 locus in Wilms' tumour patients

To test the potential role of H19 as a tumour suppressor gene we have examined its expression and DNA methylation in Wilms' tumours (WTs). In most WTs (18/25), H19 RNA was reduced at least 20-fold from fetal kidney levels. Of the expression-negative tumours ten retained 11p15.5 heterozygosity: in nine of these, H19 DNA was biallelically hypermethylated and in two cases hypermethylation locally restricted to H19 sequences was also present in the non-neoplastic kidney parenchyma. IGF2 mRNA was expressed in most but not all WTs and expression patterns were consistent with IGF2/H19 enhancer competition without obligate inverse coupling. These observations implicate genetic and epigenetic inactivation of H19 in Wilms' tumorigenesis.

Outcome and prognosis in retroperitoneal soft tissue sarcoma

PURPOSE

To retrospectively evaluate the outcome of treatment and identify factors prognostic for survival and locoregional and distant disease control for patients with retroperitoneal soft tissue sarcoma.

METHODS AND MATERIALS

The records of 104 patients with retroperitoneal soft tissue sarcoma (RSTS) managed with surgery and irradiation at Princess Margaret Hospital between 1975 and 1988 were retrospectively reviewed. Univariate log-rank analysis was used to evaluate potential prognostic factors.

RESULTS

Presentation was new primary disease, 74; primary recurrence, 20; metastases, 10. Pathology was liposarcoma for 42, leiomyosarcoma for 22, malignant fibrous histiocytoma for 19, and 21 with other histologies. Grade was low for 36, high for 35, and 33 were not graded. Median tumor size was 17 cm. Grossly complete surgical excision was achieved for 45 (43%), of whom 6 (6%) also had clear surgical margins. Adjuvant postoperative irradiation was administered to 36 patients to a median dose of 40 Gy/20 fractions/4 weeks and 16 received adjuvant chemotherapy. Nine patients received no adjuvant postoperative radiotherapy. Gross residual tumor was present postoperatively in 57 patients. The overall 5- and 10-year survival rates were 36% and 14%, respectively. The locoregional relapse free rate (RFR) was 28% at 5 years and 9% at 10 years, and the distant RFR was 76% at 5 years and 60% at 10 years. For the 45 patients treated with complete excision, survival was 55% and 22% at 5 and 10 years, and locoregional RFR was 50% and 18% at 5 and 10 years. Univariate analysis demonstrated that complete surgical removal was the only factor significant for improved survival, locoregional RFR, and distant RFR. Liposarcoma histology predicted for improved survival (p = 0.02), and leiomyosarcoma histology for a lower distant RFR, compared to other histologies (p = 0.003). Patients under 62 years had an improved survival (p = 0.002) and local RFR (p = 0.02), and patients presenting with recurrent disease had improved survival (p = 0.03). Sex, tumor size, or grade, or the use of adjuvant chemotherapy were not predictive for any of the endpoints tested. Those who received adjuvant irradiation following gross surgical clearance experienced a prolonged median locoregional RFR over those who did not, and this approached statistical significance for those receiving radiation doses > 35 Gy. (103 months vs. 30 months, p = 0.06). Statistical significance was reached (p = 0.02) if only the infield RFR was considered.

CONCLUSIONS

This study demonstrates that failure to achieve local control is the primary cause of treatment failure for patients with RSTS, and that postoperative irradiation in doses > 35 Gy after complete surgery delayed, but did not prevent local recurrence. Improvements in outcome for patients with RSTS will require alternate treatment strategies, and preoperative irradiation with an aggressive surgical attempt at complete excision is currently under investigation.

Genetically engineered large animal model for studying cone photoreceptor survival and degeneration in retinitis pigmentosa

Patients with retinitis pigmentosa (RP) typically develop night blindness early in life due to loss of rod photoreceptors. The remaining cone photoreceptors are the mainstay of their vision; however, over years or decades, these cones slowly degenerate, leading to blindness. We created transgenic pigs that express a mutated rhodopsin gene (Pro347Leu). Like RP patients with the same mutation, these pigs have early and severe rod loss; initially their cones are relatively spared, but these surviving cones slowly degenerate. By age 20 months, there is only a single layer of morphologically abnormal cones and the cone electroretinogram is markedly reduced. Given the strong similarities in phenotype to that of RP patients, these transgenic pigs will provide a large animal model for study of the protracted phase of cone degeneration found in RP and for preclinical treatment trials.

Gadolinium(III) texaphyrin: a tumor selective radiation sensitizer that is detectable by MRI

Gadolinium(III) texaphyrin (Gd-tex2+) is representative of a new class of radiation sensitizers detectable by magnetic resonance imaging (MRI). This porphyrin-like complex has a high electron affinity [E1/2 (red.) approximately = -0.08 V versus normal hydrogen electrode] and forms a long-lived pi-radical cation upon exposure to hydrated electrons, reducing ketyl radicals, or superoxide ions. Consistent with these chemical findings, Gd-tex2+ was found to be an efficient radiation sensitizer in studies carried out with HT29 cells in in vitro as well as in in vivo single and multifraction irradiation studies with a murine mammary carcinoma model. Selective localization of Gd-tex2+ in tumors was confirmed by MRI scanning.

Evolutionary relationship between K(+) channels and symporters

The hypothesis is presented that at least four families of putative K(+) symporter proteins, Trk and KtrAB from prokaryotes, Trk1,2 from fungi, and HKT1 from wheat, evolved from bacterial K(+) channel proteins. Details of this hypothesis are organized around the recently determined crystal structure of a bacterial K(+) channel: i. e., KcsA from Streptomyces lividans. Each of the four identical subunits of this channel has two fully transmembrane helices (designated M1 and M2), plus an intervening hairpin segment that determines the ion selectivity (designated P). The symporter sequences appear to contain four sequential M1-P-M2 motifs (MPM), which are likely to have arisen from gene duplication and fusion of the single MPM motif of a bacterial K(+) channel subunit. The homology of MPM motifs is supported by a statistical comparison of the numerical profiles derived from multiple sequence alignments formed for each protein family. Furthermore, these quantitative results indicate that the KtrAB family of symporters has remained closest to the single-MPM ancestor protein. Strong sequence evidence is also found for homology between the cytoplasmic C-terminus of numerous bacterial K(+) channels and the cytoplasm-resident TrkA and KtrA subunits of the Trk and KtrAB symporters, which in turn are homologous to known dinucleotide-binding domains of other proteins. The case for homology between bacterial K(+) channels and the four families of K(+) symporters is further supported by the accompanying manuscript, in which the patterns of residue conservation are demonstrated to be similar to each other and consistent with the known 3D structure of the KcsA K(+) channel.

Outcome and prognostic factors in soft tissue sarcoma in the adult

PURPOSE

To evaluate the outcome, patterns of failure and prognostic factors in this rare disease in adult patients treated at a single institution in the modern era.

METHODS AND MATERIALS

The records of all patients (389 cases) with soft tissue sarcoma in the extremities, torso (excluding retroperitoneum), and head and neck managed between 1980 and 1988 were reviewed. A curative (radical) approach was used in 321 patients of whom 10% were recurrent lesions. The local management consisted of surgery alone in 54 cases, surgery and radiotherapy in 250 and radiotherapy alone in 17. Adjuvant chemotherapy was used as a policy for high grade lesions in the initial five years of the study (98 cases), but was omitted subsequently.

RESULTS

Extremity lesions fared more favourably compared to head and neck and torso lesions (p = 0.02) with respect to survival. Extremity and torso lesions had significantly better local control (p < 0.0001) than in the head and neck where local failure was a common cause of death. A multiple Cox regression analysis revealed that resection margins, local extension of tumor, age at diagnosis, and grade correlated with local relapse and distant relapse was also associated with local extension, high grade and in addition, large lesions. Size appeared especially predictive for distant failure, the most common cause of death. Distant failure was not influenced by the use of adjuvant chemotherapy. Patients treated for recurrence in this series had significantly worse survival due to increased distant failure despite similar local control to primary cases.

CONCLUSION

This series highlights the overall problem of distant failure in this disease. It also reaffirms the importance of obtaining local control both in the head and neck, where uncontrolled local disease is the major cause of death, and in general since local relapse appears to increase the risk of distant failure. It appears that the current staging systems should be reviewed in the light of the apparent effect of different prognostic factors.

Serotonin released from intestinal enterochromaffin cells mediates luminal non-cholecystokinin-stimulated pancreatic secretion in rats

BACKGROUND & AIMS

Similar to cholecystokinin (CCK), non-CCK-dependent duodenal factors stimulate vagal mucosal afferent fibers to mediate pancreatic enzyme secretion via a common cholinergic pathway. We tested the hypothesis that 5-hydroxytryptamine (5-HT) released from enterochromaffin (EC) cells plays an important role in the transduction of luminal information to the central nervous system via vagal afferent fibers to mediate pancreatic secretion.

METHODS

Pancreatic secretions were examined in conscious rats after intragastric administration of chopped rodent chow in the presence and absence of CCK or 5-HT(3) and 5-HT(2) antagonists. Pancreatic responses to intraduodenal administration of maltose, hyperosmolar NaCl, and light mucosal stroking were examined in rats pretreated with various pharmacological antagonists or after surgical or chemical ablation of vagal and 5-HT neural pathways.

RESULTS

Administration of L364, 718 inhibited 54% of pancreatic protein secretion evoked by intragastric administration of rodent chow. L364,714 and ICS 205-930, a 5-HT(3) antagonist, combined produced a 94% inhibition. Vagal afferent rootlet section eliminated pancreatic secretions evoked by intraduodenal stimuli. p-Chlorophenylalanine, a 5-HT synthesis inhibitor, but not 5,7-hydroxytryptamine, a 5-HT neurotoxin, also eliminated the pancreatic response to these luminal stimuli. The 5-HT(3) antagonist markedly inhibited pancreatic secretion induced by maltose and hyperosmolar NaCl. 5-HT(2) and 5-HT(3) antagonists combined inhibited the pancreatic response to light stroking of the mucosa.

CONCLUSIONS

Luminal factors such as osmolality, disaccharides, and mechanical stimulation stimulated pancreatic secretion via intestinal vagal mucosal afferent fibers. It is likely that 5-HT originating from intestinal EC cells activated 5-HT(3) and 5-HT(2) receptors on vagal afferent fibers to mediate luminal factor-stimulated pancreatic secretion.

Cellular interactions implicated in the mechanism of photoreceptor degeneration in transgenic mice expressing a mutant rhodopsin gene

Photoreceptors of transgenic mice expressing a mutant rhodopsin gene (Pro347-->Ser) slowly degenerate. The mechanism of degeneration was studied by aggregation of embryos of normal and transgenic mice to form chimeras. In these chimeras, mosaicism was observed in the coat color, retinal pigment epithelium, and retina. In the retina, the genotype of adjacent patches of normal and transgenic photoreceptors was determined by in situ hybridization with a transgene-specific RNA probe. Photoreceptors in the chimeric retina degenerated uniformly, independent of the genotype and similar to the photoreceptors in transgenic mice. However, the chimeric retinas showed varying proportions of normal and transgenic cells. The chimeric retina with a nearly even proportion of normal and transgenic photoreceptors displayed uniform but slower degeneration than that observed in a transgenic mouse of the same age. Our results demonstrate non-autonomy of gene action for the mutated rhodopsin gene and imply that cellular interactions between photoreceptors in the retina probably play a role in degeneration.

Ectopic synaptogenesis in the mammalian retina caused by rod photoreceptor-specific mutations

In addition to rod photoreceptor loss, many mutations in rod photoreceptor-specific genes cause degeneration of other neuronal types. Identifying mechanisms of cell-cell interactions initiated by rod-specific mutations and affecting other retinal cells is important for understanding the pathogenesis and progression of retinal degeneration. Here we show in animals with rod and cone degeneration due to mutations in the genes encoding rhodopsin and cGMP phosphodiesterase beta-subunit (PDE-beta) respectively, that rod bipolar cells received ectopic synapses from cones in the absence of rods. Thus, synaptic plasticity links certain rod-specific mutations to retina-wide structural alterations that involve different types of neurons.

Human BAG-1/RAP46 protein is generated as four isoforms by alternative translation initiation and overexpressed in cancer cells

Previously, a Bcl-2-interacting protein, BAG-1, was cloned from mouse cells and was shown to interact with several other proteins and to be important for inhibition of apoptosis. Human BAG-1 (hBAG-1) cDNA, recently isolated by us and two other groups, has been shown to be identical to a hormone receptor-binding protein, RAP46. However, different molecular masses of hBAG-1 protein products were noted by these three groups. Here we demonstrated that hBAG-1 protein was expressed as four isoforms, designated p50, p46, p33 and p29, with apparent molecular masses of 50 kDa, 46 kDa, 33 kDa and 29 kDa, respectively. Deletion, site-directed mutagenesis and in vitro transcription/translation analysis showed that the four protein products of hBAG-1 were expressed by alternative initiation from four different start codons through a leaky scanning mechanism. Furthermore, we demonstrated that the distinct forms of hBAG-1 have different subcellular localizations, suggesting that they may have distinct functions in the cells. Characterization of hBAG-1 RNA and protein also showed that hBAG-1 was overexpressed in human cervical, breast and lung cancer cell lines. Taken together, these data clarify the conflicting observations reported in the literature and suggest that hBAG-1 is expressed as four forms of protein products, which may play a differential role in apoptosis and oncogenesis of human cells.

Quality of life following bone marrow transplantation: a comparison of patient reports with population norms

All surviving patients who had received an allogeneic bone marrow transplant at the Princess Margaret Hospital were asked to participate in a health-related quality of life (HQL) study using the Medical Outcomes Survey-Short Form 36 (MOS SF-36), the Satisfaction with Life Domains Scale-Bone Marrow Transplantation (SLDS-BMT) and a current symptoms checklist. The main objective was to compare the health status of BMT survivors with age-adjusted population norms. Of the 251 patients contacted, 93% returned questionnaires. The median follow-up after BMT was 40 months, ranging from 1-253 months. On average, survivors had some diminished HQL relative to the health status of the population in general. Time since transplant had a significant influence on HQL; those less than 3 years from transplant experienced considerable impairment while those who had survived beyond this point were indistinguishable from the normal population in most domains and significantly better in certain psychosocial aspects of health. Many patients still reported symptoms months after BMT; some were mildly affected while others experienced more troublesome symptoms. However, 81% of patients were satisfied with the HQL outcome that they had achieved and 94% would recommend a transplant for someone in similar circumstances.

Clinicopathological study of distant metastases of salivary adenoid cystic carcinoma

Most studies of the clinicopathological characteristics and prognosis of patients with distant metastasis of salivary adenoid cystic carcinoma (SACC) have used small patient samples. To further explore this issue, a descriptive and prognostic study of 467 patients with SACC who were treated from 1963 to 2009 was conducted at a single institution. One hundred and forty-five patients (31.0%) had distant metastases. At least 20% of patients who presented with the early-stage disease and no recurrence developed distant metastasis. The overall 5-, 10-, and 20-year survival rates were 85.6%, 67.4%, and 50.4%, respectively, for patients without distant metastasis, and 69.1%, 45.7%, and 14.3%, respectively, for patients with distant metastasis. The median survival time after distant metastasis was 36 months (range 1-112 months). The prognosis was similar between patients who received treatment for metastasis and those who did not. Patients who were diagnosed with early-stage disease and without local recurrence of the primary tumours could also develop distant metastases. The biological characteristics of adenoid cystic carcinoma were different from those of squamous cell carcinoma. At present, the effectiveness of treatment for distant metastases is not ideal and further research is needed.

The extracellular signal-regulated kinase pathway contributes to the control of behavioral excitement

The extracellular signal-regulated kinase (ERK) pathway mediates neuronal plasticity in the CNS. The mood stabilizers lithium and valproate activate the ERK pathway in prefrontal cortex and hippocampus and potentiate ERK pathway-mediated neurite growth, neuronal survival and hippocampal neurogenesis. Here, we examined the role of the ERK pathway in behavioral plasticity related to facets of bipolar disorder. Mice with ERK1 ablation acquired reduced phosphorylation of RSK1, an ERK substrate, in prefrontal cortex and striatum, but not in hippocampus or cerebellum, indicating the ablation-induced brain region-specific ERK signaling deficits. ERK1 ablation produced a behavioral excitement profile similar to that induced by psychostimulants. The profile is characterized by hyperactivity, enhanced goal-directed activity and increased pleasure-related activity with potential harmful consequence. ERK1-ablated mice were hyperactive in multiple tests and resistant to behavioral despair in the forced swim test. These mice displayed more home-cage voluntary wheel running activities, rearings in a large arena and open-arm visits in an elevated plus maze. Treatments with valproate and olanzapine, but not lithium reduced baseline activities in ERK1-ablated mice. All three treatments attenuated amphetamine-induced hyperactivity in ablated mice. These data indicate a profound involvement of ERK1 signaling in behavioral excitement and in the behavioral action of antimanic agents. The extent to which ERK pathway perturbation contributes to the susceptibility, mood switch mechanism(s) and symptom pathophysiology of bipolar disorder requires further investigation. Whether there is a shared mechanism through which mood stabilizers produce their clinical actions on mood, thought and behavioral symptoms of mania also requires further investigation.

Dysfunction of the WT1-MEG3 signaling promotes AML leukemogenesis via p53-dependent and -independent pathways

Long non-coding RNAs (lncRNAs) play a pivotal role in tumorigenesis, exemplified by the recent finding that lncRNA maternally expressed gene 3 (MEG3) inhibits tumor growth in a p53-dependent manner. Acute myeloid leukemia (AML) is the most common malignant myeloid disorder in adults, and TP53 mutations or loss are frequently detected in patients with therapy-related AML or AML with complex karyotype. Here, we reveal that MEG3 is significantly downregulated in AML and suppresses leukemogenesis not only in a p53-dependent, but also a p53-independent manner. In addition, MEG3 is proven to be transcriptionally activated by Wilms’ tumor 1 (WT1), dysregulation of which by epigenetic silencing or mutations is causally involved in AML. Therefore MEG3 is identified as a novel target of the WT1 molecule. Ten–eleven translocation-2 (TET2) mutations frequently occur in AML and significantly promote leukemogenesis of this disorder. In our study, TET2, acting as a cofactor of WT1, increases MEG3 expression. Taken together, our work demonstrates that TET2 dysregulated WT1-MEG3 axis significantly promotes AML leukemogenesis, paving a new avenue for diagnosis and treatment of AML patients.

Envelopment of varicella-zoster virus: targeting of viral glycoproteins to the trans-Golgi network

Previous studies suggested that varicella-zoster virus derives its final envelope from the trans-Golgi network (TGN) and that envelope glycoproteins (gps) are transported to the TGN independently of nucleocapsids. We tested the hypothesis that gpI is targeted to the TGN as a result of a signal sequence or patch encoded in its cytosolic domain. cDNAs encoding gpI wild type (wt) and a truncated mutant gpI(trc) lacking transmembrane and cytosolic domains were cloned by using the PCR. Cells transfected with cDNA encoding gpI(wt) or gpI(trc) synthesized and N glycosylated the proteins. gpI(wt) accumulated in the TGN, some reached the plasmalemma, but none was secreted. In contrast, gpI(trc) was retained and probably degraded in the endoplasmic reticulum; none was found on cell surfaces, but some was secreted. The distribution of gpI(trc) was not affected by deletion of potential glycosylation sites. To locate a potential gpI-targeting sequence, cells were transfected with cDNA encoding chimeric proteins in which the ectodomain of a plasmalemmal marker, the interleukin-2 receptor (tac), was fused to different domains of gpI. A chimeric protein in which tac was fused with the transmembrane and cytoplasmic domains of gpI was targeted to the TGN. In contrast, a chimeric protein in which tac was fused only with the gpI transmembrane domain passed through the TGN and concentrated in endosomes. We conclude that gpI is targeted to the TGN as a result of a targeting sequence or patch in its cytosolic domain.

Targeting of glycoprotein I (gE) of varicella-zoster virus to the trans-Golgi network by an AYRV sequence and an acidic amino acid-rich patch in the cytosolic domain of the molecule

Previous studies suggested that varicella-zoster virus (VZV) envelope glycoproteins (gps) are selectively transported to the trans-Golgi network (TGN) and that the cytosolic domain of gpI (gE) targets it to the TGN. To identify targeting signals in the gpI cytosolic domain, intracellular protein trafficking was studied in transfected cells expressing chimeric proteins in which a full-length or mutated gpI cytosolic domain was fused to the gpI transmembrane domain and interleukin-2 receptor (tac) ectodomain. Expressed protein was visualized with antibodies to tac. A targeting sequence (AYRV) and a second, acidic amino acid-rich region of the gpI cytosolic domain (putative signal patch) were each sufficient to cause expressed protein to colocalize with TGN markers. This targeting was lost when the tyrosine of the AYRV sequence was replaced with glycine or lysine, when arginine was replaced with glutamic acid, or when valine was substituted with lysine. In contrast, tyrosine could be replaced by phenylalanine and valine could be substituted with leucine. Mutation of alanine to aspartic acid or deletion of alanine abolished TGN targeting. Exposure of transfected cells to antibodies to the tac ectodomain revealed that the TCN targeting of expressed tac-gpI chimeric proteins occurred as a result of selective retrieval from the plasmalemma. These data suggest that the AYRV sequence and a second signaling patch in the cytosolic domain of gpI are responsible for its targeting to the TGN. The observations also support the hypothesis that the TGN plays a critical role in the envelopment of VZV.

Treatment of locally recurrent rectal carcinoma--results and prognostic factors

PURPOSE

To assess the local control and survival in patients who received pelvic irradiation for locally recurrent rectal carcinoma.

METHODS AND MATERIALS

The records of 519 patients with locally recurrent rectal carcinoma treated principally with external-beam radiation therapy between 1975 to 1985 at a single institute were retrospectively reviewed. These included 326 patients who relapsed locally following previous abdominoperineal resection, 151 after previous low anterior resection, and 42 after previous local excision or electrocoagulation for the primary. No patients had received adjuvant radiation therapy or chemotherapy for the primary disease. Concurrent extrapelvic distant metastases were found in 164 (32%) patients at local recurrence and, in the remaining 355, the relapse was confined to the pelvis. There were 290 men and 229 women whose age ranged from 23 to 91 years (median = 65). Median time from initial surgery to radiation therapy for local recurrence was 18 months (3-138 months). Radiation therapy was given with varying dose-fractionation schedules, total doses ranging from 4.4 to 65.0 Gy (median = 30 Gy) over 1 to 92 days (median = 22 days). For 214 patients who received a total dose > or = 35 Gy, radiation therapy was given in 1.8 to 2.5 Gy daily fractions.

RESULTS

The median survival was 14 months and the median time to local disease progression was 5 months from date of pelvic irradiation. The 5-year survival was 5%, and the pelvic disease progression-free rate was 7%. Twelve patients remained alive and free of disease at 5 years after pelvic irradiation. Upon multivariate analysis, overall survival was positively correlated with ECOG performance status (p = 0.0001), absence of extrapelvic metastases (p = 0.0001), long intervals from initial surgery to radiation therapy for local recurrence (p = 0.0001), total radiation dose (p = 0.0001), and absence of obstructive uropathy (p = 0.0013). Pelvic disease progression-free rates were positively correlated with ECOG performance status (p = 0.0001), total radiation dose (p = 0.0001), and previous conservative surgery for the primary (p = 0.02).

CONCLUSIONS

Survival is poor for patients who develop local recurrence following previous surgery for rectal carcinoma. Pelvic radiation therapy provides only short-term palliation, and future efforts should be directed to the use of effective adjuvant therapy for patients with rectal carcinoma who are at high risk of local recurrence.

Structural models of the transmembrane region of voltage-gated and other K+ channels in open, closed, and inactivated conformations

A large collaborative, multidisciplinary effort involving many research laboratories continues which uses indirect methods of molecular biology and membrane biophysics to analyze the three-dimensional structures and functional mechanisms of K+ channels. This work also extends to the distant relatives of these channels, including the voltage-gated Na+ and Ca2+ channels. The role that our group plays in this process is to combine the information gained from experimental studies with molecular modeling techniques to generate atomic-scale structural models of these proteins. The modeling process involves three stages which are summarized as: (I) prediction of the channel sequence transmembrane topology, including the functionality and secondary structure of the segments; (II) prediction of the relative positions of the transmembrane segments, and (III) filling in all atoms of the amino acid residues, with conformations for energetically stabilized interactions. Both physiochemical and evolutionary principles (including sequence homology analysis) are used to guide the development. In addition to testing the steric and energetic feasibilities of different structural hypotheses, the models provide guidance for the design of new experiments. Structural modeling also serves to "fill in the gaps" of experimental data, such as predicting additional residue interactions and conformational changes responsible for functional processes. The modeling process is currently at the stage that experimental studies have definitely confirmed most of our earlier predictions about the transmembrane topology and functionality of different segments. Additionally, this report describes the detailed, three-dimensional models we have developed for the entire transmembrane region and important functional sites of the voltage-gated Shaker K+ channel in the open, closed, and inactivated conformations (including the ion-selective pore and voltage-sensor regions). As part of this effort, we also describe how our development of structural models for many of the other major K+ channel families aids in determining common structural motifs. As an example, we also present a detailed model of the smaller, bacterial K+ channel from Streptomyces lividans. Finally, we discuss strategies for using newly developed experimental methods for determining the structures and analyzing the functions of these channel proteins.

The first multicenter and randomized clinical trial of herbal Fufang for treatment of postmenopausal osteoporosis

This multicenter and randomized clinical trial showed that daily oral herbal formula Xian Ling Gu Bao (XLGB) was safe in postmenopausal women over a 1-year treatment. Those patients (n ∼ 50) treated with XLGB at the conventional dose demonstrated a statistically significant increase in dual-energy X-ray absorptiometry (DXA) bone mineral density (BMD) at lumbar spine at 6 months and a numerically increased BMD at 12 months.

INTRODUCTION

The aim of this study was to examine the safety and efficacy of a herbal formula XLGB in postmenopausal women (ChiCTR-TRC-00000347).

METHODS

One hundred eighty healthy postmenopausal women (≥60 years old) with BMD T-score ≤ -2.0 (lumbar spine or femoral neck) were recruited from four clinical centers to receive low-dose (conventional dose) XLGB (L-XLGB group, 3 g/day, n = 61) or high-dose XLGB (H-XLGB group, 6 g/day, n = 58) or placebo (CON group, n = 61). Women received daily calcium (500 mg) and vitamin D (200 IU) supplementation. Primary endpoints were lumbar spine BMD and safety; secondary endpoints were femoral neck BMD and bone turnover markers measured at baseline and at 6 and 12 months.

RESULTS

Of 180 women recruited, 148 completed the study. The compliance in each group was comparable. Prominent adverse events were not observed in either group. In the L-XLGB group at 6 months, lumbar spine BMD by DXA increased significantly from baseline (+2.11% versus CON +0.58%, p < 0.05), but femoral neck BMD did not; at 12 months, BMD in the L-XLGB group decreased from 6-month levels yet remained higher than baseline, but without difference from the CON group. There was no dose-dependent response. Bone turnover marker levels declined during the first 6 months after XLGB treatment. There was no significant difference in the overall incidence of side effects among treatment and control groups.

CONCLUSION

XLGB over 1-year treatment at the conventional dose demonstrated safe and only a statistically significant increase in BMD at lumbar spine at 6 months in postmenopausal women.