ING1 inhibits Twist1 expression to block EMT and is antagonized by the HDAC inhibitor vorinostat

ING1 is a chromatin targeting subunit of the Sin3a histone deacetylase (HDAC) complex that alters chromatin structure to subsequently regulate gene expression. We find that ING1 knockdown increases expression of Twist1, Zeb 1&2, Snai1, Bmi1 and TSHZ1 drivers of EMT, promoting EMT and cell motility. ING1 expression had the opposite effect, promoting epithelial cell morphology and inhibiting basal and TGF-β-induced motility in 3D organoid cultures. ING1 binds the Twist1 promoter and Twist1 was largely responsible for the ability of ING1 to reduce cell migration. Consistent with ING1 inhibiting Twist1 expression in vivo, an inverse relationship between ING1 and Twist1 levels was seen in breast cancer samples from The Cancer Genome Atlas (TCGA). The HDAC inhibitor vorinostat is approved for treatment of multiple myeloma and cutaneous T cell lymphoma and is in clinical trials for solid tumours as adjuvant therapy. One molecular target of vorinostat is INhibitor of Growth 2 (ING2), that together with ING1 serve as targeting subunits of the Sin3a HDAC complex. Treatment with sublethal (LD25-LD50) levels of vorinostat promoted breast cancer cell migration several-fold, which increased further upon ING1 knockout. These observations indicate that correct targeting of the Sin3a HDAC complex, and HDAC activity in general decreases luminal and basal breast cancer cell motility, suggesting that use of HDAC inhibitors as adjuvant therapies in breast cancers that are prone to metastasize may not be optimal and requires further investigation.

Spatial transcriptomics reveals distinct and conserved tumor core and edge architectures that predict survival and targeted therapy response

The spatial organization of the tumor microenvironment has a profound impact on biology and therapy response. Here, we perform an integrative single-cell and spatial transcriptomic analysis on HPV-negative oral squamous cell carcinoma (OSCC) to comprehensively characterize malignant cells in tumor core (TC) and leading edge (LE) transcriptional architectures. We show that the TC and LE are characterized by unique transcriptional profiles, neighboring cellular compositions, and ligand-receptor interactions. We demonstrate that the gene expression profile associated with the LE is conserved across different cancers while the TC is tissue specific, highlighting common mechanisms underlying tumor progression and invasion. Additionally, we find our LE gene signature is associated with worse clinical outcomes while TC gene signature is associated with improved prognosis across multiple cancer types. Finally, using an in silico modeling approach, we describe spatially-regulated patterns of cell development in OSCC that are predictably associated with drug response. Our work provides pan-cancer insights into TC and LE biology and interactive spatial atlases ( http://www.pboselab.ca/spatial_OSCC/ ; http://www.pboselab.ca/dynamo_OSCC/ ) that can be foundational for developing novel targeted therapies.

Sumoylated SnoN interacts with HDAC1 and p300/CBP to regulate EMT-associated phenotypes in mammary organoids

Protein post-translational modification by the small ubiquitin-like modifier (SUMO) regulates the stability, subcellular localization, and interactions of protein substrates with consequences on cellular responses including epithelial-mesenchymal transition (EMT). Transforming growth factor beta (TGFβ) is a potent inducer of EMT with implications for cancer invasion and metastasis. The transcriptional coregulator SnoN suppresses TGFβ-induced EMT-associated responses in a sumoylation-dependent manner, but the underlying mechanisms have remained largely unknown. Here, we find that sumoylation promotes the interaction of SnoN with the epigenetic regulators histone deacetylase 1 (HDAC1) and histone acetylase p300 in epithelial cells. In gain and loss of function studies, HDAC1 suppresses, whereas p300 promotes, TGFβ-induced morphogenetic changes associated with EMT-related events in three-dimensional multicellular organoids derived from mammary epithelial cells or carcinomas. These findings suggest that sumoylated SnoN acts via the regulation of histone acetylation to modulate EMT-related effects in breast cell organoids. Our study may facilitate the discovery of new biomarkers and therapeutics in breast cancer and other epithelial cell-derived cancers.

NCBP2 and TFRC are novel prognostic biomarkers in oral squamous cell carcinoma

There are few prognostic biomarkers and targeted therapeutics currently in use for the clinical management of oral squamous cell carcinoma (OSCC) and patient outcomes remain poor in this disease. A majority of mutations in OSCC are loss-of-function events in tumour suppressor genes that are refractory to conventional modes of targeting. Interestingly, the chromosomal segment 3q22-3q29 is amplified in many epithelial cancers, including OSCC. We hypothesized that some of the 468 genes located on 3q22-3q29 might be drivers of oral carcinogenesis and could be exploited as potential prognostic biomarkers and therapeutic targets. Our integrative analysis of copy number variation (CNV), gene expression and clinical data from The Cancer Genome Atlas (TCGA), identified two candidate genes: NCBP2, TFRC, whose expression positively correlates with worse overall survival (OS) in HPV-negative OSCC patients. Expression of NCBP2 and TFRC is significantly higher in tumour cells compared to most normal human tissues. High NCBP2 and TFRC protein abundance is associated with worse overall, disease-specific survival, and progression-free interval in an in-house cohort of HPV-negative OSCC patients. Finally, due to a lack of evidence for the role of NCBP2 in carcinogenesis, we tested if modulating NCBP2 levels in human OSCC cell lines affected their carcinogenic behaviour. We found that NCBP2 depletion reduced OSCC cell proliferation, migration, and invasion. Differential expression analysis revealed the upregulation of several tumour-promoting genes in patients with high NCBP2 expression. We thus propose both NCBP2 and TFRC as novel prognostic and potentially therapeutic biomarkers for HPV-negative OSCC.

O-199 Couples presenting to Infertility clinics - Are they really infertile?

Study question

Are couples presenting to infertility clinics actually infertile, or is there an undiagnosed underlying sexual dysfunction whose treatment can lead to natural conception avoiding the need for assisted reproductive techniques?

Summary answer

All couples presenting with infertility should be asked about sexual function. If sexual dysfunction is diagnosed, a signicant proportion can achieve pregnancy without assisted reproduction

What is known already

Infertility is defined as the inability to conceive after one year of frequent and regular unprotected sexual intercourse (SI). Although sexual histories are a key part of primary care screening guidelines for infertility, they are often overlooked during the infertility work-up. It is postulated that a large proportion of couples presenting to infertility clinics have underlying sexual dysfunction. Treatment through specialist counselling for couples with sexual dysfunction can help achieve pregnancy, negating the need for complex assisted reproductive techniques such as intravaginal insemination (IVI) and intrauterine insemination (IUl).

Study design, size, duration

108 couples were recruited from a national fertility clinic. The duration of the study was 3.5 years, from January 2016 to August 2019. The study was based primarily on surveys, where diagnostic work-up for infertility included tools for measuring sexual dysfunction, such as the IIEF-15 questionnaire. Our objectives were to find the extent of improvement of SI before and after specialist referral, and the time to conceive (TTC) in those with and without sexual dysfunction.

Participants/materials, setting, methods

Couples who never had successful completion of SI (despite producing an ejaculate sample) prior to clinic attendance were included. Treatment via specialist referral was then offered to these patients.

Data were analysed to compare outcomes between those who subsequently had successful SI (“Group A”) and those who had not had successful SI (“Group B”). Both groups were counselled for fertility treatments, such as IVI and IUI. TTC between the groups was analysed using Kaplan-Meier analysis

Main results and the role of chance

Out of 2057 couples presenting to the Infertility Clinic, 128 (5.98%) had never had successful SI. From this, 108 couples were included in the study. Two-thirds of couples revealed sexual difficulties at the beginning of the initial consultation. In men, erectile dysfunction was the predominant cause (70.4%, n = 76). In women, dyspareunia was the leading problem (18.2%, N = 20). Fertility investigations, which included hormone profiles, revealed normal results in most cases.

Treatment via referral to specialist sexual counselling was offered to all couples. Only 33 couples reported successful SI during subsequent visits (Group A). 13 of these 33 couples went on to conceive (11 naturally, 1 by IUI and 1 by IVI). The rest (n = 75), who had no improvement (Group B), had a significantly longer duration of sexual dysfunction, which was also more severe. Out of these 75 couples, 8 conceived (0 naturally, 6 by IVI, and 2 by IUI).The IIEF-15 scores (index for sexual dysfunction) between groups A and B were 10.72 ± 4.28 vs. 8 ± 4.73, P-value 0.0142. Group A couples (less severe sexual dysfunction) conceived earlier than Group B (mean duration 27.2 weeks vs. 48.8 weeks log-rank P value <0.001).

Limitations, reasons for caution

The main limitations of this study include a small sample size and a small minority of couples refusing to undergo specialist counselling despite having sexual difficulties as they were only interested in assisted reproductive interventions such as IUl and IVI. These limitations hinder the internal/external validity of the study.

Wider implications of the findings

All couples presenting with infertility should be asked about sexual function. If sexual dysfunction is diagnosed, a signicant proportion can be helped to achieve pregnancy without assisted reproduction. In the cases of couples with persistent sexual difficulty, assisted reproductive techniques like IUI and IVI give a reasonable pregnancy rate.

Trial registration number

Not applicable

P-118 Timed Intercourse exacerbates the risk of sexual dysfunction in men & women without an improvement in time to pregnancy

Study question

Investigate the differences in sexual dysfunction and time to pregnancy between infertile couples pursuing timed intercourse and Regular Intercourse (RI at least twice a week).

Summary answer

TI significantly increased the risk of SD compared to RI for both males and females after adjusting all other contributing factors.

What is known already

Timed Intercourse (TI) involves aligning sexual intercourse to the time around ovulation to increase the chance of conception in couples trying to conceive. Whilst TI is often advocated to increase conception rates and potentially accelerate the time to pregnancy (TTP) for infertile couples, the stressful nature of this approach may be associated with adverse effects such as sexual dysfunction (SD) within the couple.

Study design, size, duration

This prospective cohort study recruited 371 infertile couples who had been trying to conceive for more than a year, presenting to three regional infertility clinics between January 2016 and December 2018. 283 couples pursued TI and 88 couples pursued RI for a year, with all couples having no pre-existing sexual or psychiatric illness, and no medical contraindications to frequent intercourse.

Participants/materials, setting, methods

The SD score of both partners was assessed at the first visit using the validated Arizona Sexual Experiences Scale (ASEX) and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V). TTP was determined using Kaplan Meier Analysis in couples for whom natural conception was possible and no reversible fertility pathology was identified.

Main results and the role of chance

Timed Intercourse (TI) involves aligning sexual intercourse to the time around ovulation to increase the chance of conception in couples trying to conceive. Whilst TI is often advocated to increase conception rates and potentially accelerate the time to pregnancy (TTP) for infertile couples, the stressful nature of this approach may be associated with adverse effects such as sexual dysfunction (SD) within the couple.

TI significantly increased the risk of SD compared to RI for both males (Odds ratio [OR] 15.24, 95% confidence interval [CI] 7.96-29.15) and females (OR 5.52, 95% CI 2.38- 12.78), after adjusting for age, medical disorders, obesity, smoking, cause of infertility, and previous assisted reproductive techniques. TI carried a higher risk of developing erectile dysfunction, premature ejaculation, male hypoactive sexual dysfunction, female sexual interest-arousal disorder, and female orgasmic disorder. The TTP for natural conception was similar between TI and RI (p = 0.1365).

Limitations, reasons for caution

TI, a well-known strategy for increasing conception rates, did not improve time to natural conception compared to regular sexual intercourse. In contrast, the risk of sexual dysfunction in both men and women was significantly higher in TI, compared with RI.

Wider implications of the findings

This large study raises the question of effectiveness of the long-held belief that TI (intercourse limited around the ovulation-time, based on different methods of ovulation-prediction) improves pregnancy outcomes.

Trial registration number

N/A

Spatial transcriptomics unravels novel signaling patterns at the leading edge of oral squamous cell carcinoma

e18043

Background: Head and neck cancer is the 6th most common cancer worldwide. Oral squamous cell carcinoma (OSCC) is the most prevalent head and neck cancer that is characterized by aggressive local invasion and metastasis. Despite the leading edge (invasive front) of the tumor being a driver of OSCC pathophysiology, its biology and clinical relevance have not been fully characterized. We used spatial transcriptomics to explore signaling patterns within the leading edge and tumor core. Methods: Fresh-frozen, surgically resected OSCC samples from three HPV-negative OSCC patients were profiled using the 10x Genomics Visium Spatial Gene Expression platform. Leading edge and tumor core regions were defined by pathologist annotations and expression of previously identified edge and core gene signatures from the literature. Spatial differential gene expression (DGE) analysis and pathway analysis was performed using the Seurat package and Ingenuity Pathway Analysis (IPA), respectively. Cell-cell interaction networks were reconstructed using the CellChat package. Results: The leading edge and tumor core displayed unique transcriptional and signaling profiles that were conserved across all three OSCC patient samples. DEG analysis revealed 31 genes enriched in the leading edge and 62 genes enriched in the tumor core with a log2FC > 0.58 and adjusted p-value < 0.01. The top genes upregulated in the leading edge were FN1, COL1A1, COL1A2, IFITM3, and SPARC. Top tumor-core genes included CRCT1, LCE3D, DEFB4A, SPRR2A, and CNFN. IPA analysis of upregulated DEGs in the leading edge and tumor core predicted the activation of wound healing and GP6 signaling pathways, and activation of intrinsic prothrombin activation and MSP-RON signaling pathways, respectively. Cell communication analysis revealed that the leading edge had higher intercellular signaling than the tumor core. Upregulated leading edge cell signaling modules included collagen, CD99, CSPG4, and non-canonical WNT pathways, which have been linked to tumor invasion, metastasis, and adhesion. COL1A1 and COL1A2 ligands and CD44 and SDC1 receptors were upregulated in leading edge signaling. The tumor core was enriched for ANGPTL and PERIOSTIN cell signaling modules. Conclusions: This is the first study to characterize the tumor core and leading edge of OSCC tumors using spatial transcriptomics. Further investigation of the therapeutic potential of identified signaling pathways may improve OSCC outcomes.

TGF-β Mediated Immune Evasion in Cancer-Spotlight on Cancer-Associated Fibroblasts

Various components of the tumor microenvironment (TME) play a critical role in promoting tumorigenesis, progression, and metastasis. One of the primary functions of the TME is to stimulate an immunosuppressive environment around the tumor through multiple mechanisms including the activation of the transforming growth factor-beta (TGF-β) signaling pathway. Cancer-associated fibroblasts (CAFs) are key cells in the TME that regulate the secretion of extracellular matrix (ECM) components under the influence of TGF-β. Recent reports from our group and others have described an ECM-related and CAF-associated novel gene signature that can predict resistance to immune checkpoint blockade (ICB). Importantly, studies have begun to test whether targeting some of these CAF-associated components can be used as a combinatorial approach with ICB. This perspective summarizes recent advances in our understanding of CAF and TGF-β-regulated immunosuppressive mechanisms and ways to target such signaling in cancer.

Microwave magnetoimpedance and ferromagnetic resonance in Pr0.6Sr0.4MnO3

We report the magnetic field dependence of electrical impedance (magnetoimpedance) of a ferromagnetic Pr0.6Sr0.4MnO3 sample carrying alternating current (ac) of frequency f = 1 MHz to 3 GHz measured using an impedance analyzer and broad band ferromagnetic resonance (f = 2 to 18 GHz) measured using a coplanar wave guide based spectrometer. Ac magnetoresistance is much larger than dc magnetoresistance and its sign at low magnetic fields changes from negative to positive with increasing frequency of the ac current. The field dependence of ac magnetoresistance shows a peak around H dc = 0 for low frequencies but a double peak feature emerges at H dc = ±H p at higher frequencies and it shifts to higher magnetic field as the frequency of ac current increases. The field derivative of microwave power absorption measured by the broad band spectrometer shows features of ferromagnetic resonance and the resonance field increases with increasing frequency of microwave radiation following Kittel's equation for ferromagnetic resonance. A close correlation is found between the ferromagnetic resonance line shape and the positive peak in the ac magnetoresistance, which suggests the possibility of electrical detection of ferromagnetic resonance using high frequency current injected into a conducting magnetic sample.

Recombinant human PRG4 (rhPRG4) suppresses breast cancer cell invasion by inhibiting TGFβ-Hyaluronan-CD44 signalling pathway

Metastasis is the major cause of cancer-related morbidity and mortality. The ability of cancer cells to become invasive and migratory contribute significantly to metastatic growth, which necessitates the identification of novel anti-migratory and anti-invasive therapeutic approaches. Proteoglycan 4 (PRG4), a mucin-like glycoprotein, contributes to joint synovial homeostasis through its friction-reducing and anti-adhesive properties. Adhesion to surrounding extracellular matrix (ECM) components is critical for cancer cells to invade the ECM and eventually become metastatic, raising the question whether PRG4 has an anti-invasive effect on cancer cells. Here, we report that a full-length recombinant human PRG4 (rhPRG4) suppresses the ability of the secreted protein transforming growth factor beta (TGFβ) to induce phenotypic disruption of three-dimensional human breast cancer cell-derived organoids by reducing ligand-induced cell invasion. In mechanistic studies, we find that rhPRG4 suppresses TGFβ-induced invasiveness of cancer cells by inhibiting the downstream hyaluronan (HA)-cell surface cluster of differentiation 44 (CD44) signalling axis. Furthermore, we find that rhPRG4 represses TGFβ-dependent increase in the protein abundance of CD44 and of the enzyme HAS2, which is involved in HA biosynthesis. It is widely accepted that TGFβ has both tumor suppressing and tumor promoting roles in cancer. The novel finding that rhPRG4 opposes HAS2 and CD44 induction by TGFβ has implications for downregulating the tumor promoting roles, while maintaining the tumor suppressive aspects of TGFβ actions. Finally, these findings point to rhPRG4's potential clinical utility as a therapeutic treatment for invasive and metastatic breast cancer.

The SUMO System and TGFβ Signaling Interplay in Regulation of Epithelial-Mesenchymal Transition: Implications for Cancer Progression

Protein post-translational modification by the small ubiquitin-like modifier (SUMO), or SUMOylation, can regulate the stability, subcellular localization or interactome of a protein substrate with key consequences for cellular processes including the Epithelial-Mesenchymal Transition (EMT). The secreted protein Transforming Growth Factor beta (TGFβ) is a potent inducer of EMT in development and homeostasis. Importantly, the ability of TGFβ to induce EMT has been implicated in promoting cancer invasion and metastasis, resistance to chemo/radio therapy, and maintenance of cancer stem cells. Interestingly, TGFβ-induced EMT and the SUMO system intersect with important implications for cancer formation and progression, and novel therapeutics identification.

The PIAS3-Smurf2 sumoylation pathway suppresses breast cancer organoid invasiveness

Tumor metastasis profoundly reduces the survival of breast cancer patients, but the mechanisms underlying breast cancer invasiveness and metastasis are incompletely understood. Here, we report that the E3 ubiquitin ligase Smurf2 acts in a sumoylation-dependent manner to suppress the invasive behavior of MDA-MB-231 human breast cancer cell-derived organoids. We also find that the SUMO E3 ligase PIAS3 inhibits the invasive growth of breast cancer cell-derived organoids. In mechanistic studies, PIAS3 maintains breast cancer organoids in a non-invasive state via sumoylation of Smurf2. Importantly, the E3 ubiquitin ligase activity is required for sumoylated Smurf2 to suppress the invasive growth of breast cancer-cell derived organoids. Collectively, our findings define a novel role for the PIAS3-Smurf2 sumoylation pathway in the suppression of breast cancer cell invasiveness. These findings lay the foundation for the development of novel biomarkers and targeted therapeutic approaches in breast cancer.

Identification of the SUMO E3 ligase PIAS1 as a potential survival biomarker in breast cancer

Metastasis is the ultimate cause of breast cancer related mortality. Epithelial-mesenchymal transition (EMT) is thought to play a crucial role in the metastatic potential of breast cancer. Growing evidence has implicated the SUMO E3 ligase PIAS1 in the regulation of EMT in mammary epithelial cells and breast cancer metastasis. However, the relevance of PIAS1 in human cancer and mechanisms by which PIAS1 might regulate breast cancer metastasis remain to be elucidated. Using tissue-microarray analysis (TMA), we report that the protein abundance and subcellular localization of PIAS1 correlate with disease specific overall survival of a cohort of breast cancer patients. In mechanistic studies, we find that PIAS1 acts via sumoylation of the transcriptional regulator SnoN to suppress invasive growth of MDA-MB-231 human breast cancer cell-derived organoids. Our studies thus identify the SUMO E3 ligase PIAS1 as a prognostic biomarker in breast cancer, and suggest a potential role for the PIAS1-SnoN sumoylation pathway in controlling breast cancer metastasis.

Evaluation of Phytochemical Screening and Anti Inflammatory Activity of Leaves and Stem of Mikania scandens (L.) Wild

Background:

The greatest disadvantage in the presently available potent synthetic anti-inflammatory drugs lies in their toxicity and reappearance of symptoms after discontinuation. Hence, people are returning to the natural products with the hope of safety and security. Several species of Mikania have been reported to have anti-inflammatory properties.

Aim:

The present study aims to assess the anti-inflammatory activity of the ethanolic extract of the leaves and stem of Mikania scandensin vivo and in vitro.

Materials and Methods:

The in vitro bioassay consisted of assaying the effect of the extracts against denaturation of protein (egg albumin) and measuring the absorbance. In vivo anti-inflammatory activity was checked by measuring the percentage inhibition of carrageenan-induced rat paw edema after oral administration of the extracts to male Wistar rats.

Results:

The plant extracts revealed the presence of tannins, alkaloids, steroids and flavonoids in both the leaf and stem extracts. The in vitro study of leaf extracts of M. scandens demonstrated that at 16000 μg/ml concentration a better anti-inflammatory activity was exhibited which is more than the stem extracts. Similarly in the in vivo study, carrageenan induced inflammation was significantly antagonized by M. scandens leaf extract, with inhibition of 50% at 1000 mg/kg.

Conclusion:

The ethanolic extract of both leaf and stem of M. scandens showed potent anti-inflammatory activity. In comparison the leaf extract found to be more potent in both the conditions in vivo and in vitro, comparing with the standard drug diclofenac sodium and traditional control rumalaya perhaps due to the presence of phytochemicals like alkaloids and flavonoids in the plant.

Sliding wear behavior of submicron-grained alumina in biological environment

Sliding wear behavior of sintered alumina with grain sizes between 0.45 and 4 microm was studied in bovine serum environment with unidirectional pin-on-disc wear testing machine. Submicron grained alumina of average grain size of G=0.45 microm exhibits lowest wear factor among the others. It was found that grain pull out or localized grain dislodgement caused by coalescence of grain boundary microcracks is the basic wear mechanism of submicron grained alumina though the extent of cracking and pull-out was substantially less than that with higher grained material. However, in few cases, some areas where substantial volume of material was removed following pull-out of cluster of grains have also been observed.

Radiation-induced brain disorders in patients with pituitary tumours

Radiation-induced brain disorders (RIBD) are uncommon and they are grave sequelae of conventional radiotherapy. In the present report, we describe the clinical spectrum of RIBD in 11 patients who received post-surgery conventional megavoltage irradiation for residual pituitary tumours. Of these 11 patients (nine men, two women), seven had been treated for non-functioning pituitary tumours and four for somatotropinomas. At the time of irradiation the age of these patients ranged from 30 to 59 years (mean, 39.4 +/- 8.3; median, 36) with a follow-up period of 6-96 months (mean, 18.3 +/- 26.4; median, 11). The dose of radiation ranged from 45 to 90 Gy (mean, 51.3 +/- 13.4; median, 45), which was given in 15-30 fractions (mean, 18.6 +/- 5.0; median, 15) with 2.8 +/- 0.3 Gy (median, 3) per fraction. The biological effective dose calculated for late complications in these patients ranged from 78.7 to 180 Gy (mean, 99.1 +/- 27.5; median, 90). The lag time between tumour irradiation and the onset of symptoms ranged from 6 to 168 months (mean, 46.3 +/- 57.0; median, 57). The clinical spectrum of RIBD included new-onset visual abnormalities in five, cerebral radionecrosis in the form of altered sensorium in four, generalized seizures in four, cognitive dysfunction in five, dementia in three and motor deficits in two patients. Magnetic resonance imaging (MRI)/CT of the brain was suggestive of radionecrosis in eight, cerebral oedema in three, cerebral atrophy in two and second neoplasia in one patient. Associated hormone deficiencies at presentation were hypogonadism in eight, hypoadrenalism in six, hypothyroidism in four and diabetes insipidus in one patient. Autopsy in two patients showed primitive neuroectodermal tumour (PNET) and brainstem radionecrosis in one, and a cystic lesion in the left frontal lobe following radionecrosis in the other. We conclude that RIBD have distinctive but varying clinical and radiological presentations. Diabetes insipidus and PNET as a second neoplastic disorder in adults following pituitary irradiation have not been reported previously.

Real-time volume haptic rendering of non-linear viscoelastic behavior of soft tissue through dynamic atomic unit approach

The aim of computer haptics is to enable the user to touch, feel and maneuver virtual objects using a haptic interface. As the user "feels" the virtual object by applying force through the interface, complex calculations have to be done in real-time to generate a feedback force appropriate to the material properties of the object being "touched". In this paper we propose a method for modeling soft bodies, which incorporate non-linear, viscoelastic, anisotropic behavior that will enable real-time user interaction and still satisfy the high force-feedback frequency requirements. In this paper, we restrict the user interaction with virtual objects to palpation.

Chordomas and chondrosarcomas of the skull base: results and complications of surgical management

Object

Chordomas and chondrosarcomas are rare and difficult to treat tumors for which the optimum treatment modality remains controversial. The aim of this study was to evaluate the surgery-related results and complications in a series of patients in whom radical resection was the treatment of choice.

Methods

The authors conducted a retrospective analysis of the surgery-related results and complications associated with chordoma and chondrosarcoma in 64 patients of whom 33 (52%) had previously undergone some form of treatment. Total or near-total excision was achieved in 56% and this rate increased to 68% in patients without prior treatment. The main complications were postoperative cerebrospinal fluid leakage, intraoperative arterial injury, and new-onset cranial nerve deficits. Arterial injury occurred only and perioperative death occurred more often in patients who had undergone previous treatment.

Conclusions

Analysis of the results provides support for a policy of radical excision of chordomas and chondrosarcomas at the time of first presentation. A higher incidence of procedure-related complications is found in patients who have already undergone surgery and radiotherapy.