Cell-cell interactions in the endocrine pancreas

Cell-cell communication within any given tissue is an important aspect of correct organ function. The islets of Langerhans forming the endocrine pancreas are composed of alpha-, beta-, delta-, epsilon- and PP-cells, and interactions between these cells are required for fine-tuning glucose homeostasis of the body. The endocrine cells communicate through homotypic or heterotypic cell-cell adhesion, or in a paracrine fashion, and this communication is involved in the regulated secretion of islet hormones. This review discusses how islet hormones, secreted molecules and ions influence the endocrine cells and how cell adhesion molecules such as neural cell adhesion molecule, cadherins, connexin-36, Eph receptors and ephrin ligands, as well as extracellular matrix proteins, modulate pancreatic islet function.

Macrophage activation syndrome in an inadequately treated patient with systemic onset juvenile idiopathic arthritis

Macrophage activation syndrome is a rare and potentially life threatening complication of childhood rheumatic disorders. It is described most commonly with systemic onset juvenile idiopathic arthritis (soJIA). The major clinical manifestations are non-remitting fever, hepatosplenomegaly, lymphadenopathy, bleeding diathesis, altered mental status and rash and may mimic a fl are of soJIA. The characteristic laboratory findings are leucopenia, thrombocytopenia and dramatic elevation of urinary beta2 microglobulin. Corticosteroids and cyclosporine are the drugs commonly used in its management. Early diagnosis and prompt treatment can be life saving. We report a case of 12 year old female child with inadequately treated systemic onset juvenile idiopathic arthritis who developed fatal macrophage activation syndrome. The diagnosis and management of macrophage activation syndrome are discussed.

Real-time sonography of orbital tumours, Colour Doppler characterization: initial experience

Fifty-seven patients with orbital tumours were examined with 3.5 MHz and 5 MHz real-time sector sonography. The lesions were evaluated for their echomorphology, relationship to anatomical structures of the orbit, and extra-orbital extension. Twenty-two patients were further evaluated by Colour Doppler Flow Imaging (CDFI). The lesions were located to four compartments, namely intraocular, intraconal, extraconal and extraorbital. An attempt was made to provide a histological diagnosis on the basis of clinical features and sonographic morphology. Colour Doppler flow patterns in 22 patients were correlated with the presumed or proven histological diagnosis in an attempt to detect and classify any specific patterns. Real-time US is an excellent screening procedure in the evaluation of orbital mass lesions. CT/MRI should be added in selected cases where extra-orbital extension requires evaluation. CDFI of tumours still being in its infancy it seems promising and may help in providing a more precise pre-operative histological diagnosis non-invasively.

Dose-response relationships in phase I trials: Are patients treated at lower doses at a disadvantage?

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Background: A major goal of phase I trials is to determine a drug's maximally tolerated dose (MTD). However, it has been argued that low-dose patient cohorts are at a disadvantage given the clear dose/response relationships seen with cytotoxics. Since an increasing number of targeted/biologic agents are entering the clinic, and the dose/response relationship of these drugs is less clear, we analyzed response versus benefit for patients on phase I trials. Methods: We evaluated 71 consecutive trials treating 1,420 patients with solid tumors or lymphoma from August 2004 to August 2008 in the Department of Investigational Cancer Therapeutics at M.D. Anderson for inclusion in our analysis. Twenty-four trials treating 687 patients met criteria (systemic therapy that has reached an MTD or a maximum test dose). 97.7% of these patients received a targeted/biologic drug. Patients were assigned to low (≤25%), medium (25–75%), or high dose (≥75%), where dose range = maxium - minimum dose for each study (for ≤ MTD analysis, max dose = MTD if it was achieved). Time on treatment (TOT), progression free survival (PFS), overall survival (OS), and response (complete response = CR, partial response = PR, stable disease = SD, progressive disease = PD) were assessed. Results: Of all comers (n = 683), the low-dose group stayed on treatment significantly longer than the high-dose group, primarily due to increased toxicity at higher doses. In ≤ MTD subgroup analysis (n = 588), there was also a trend for the low-dose group to stay on treatment longer (p = 0.06). PFS and OS were similar among groups. Favorable responses (CR/PR/SD) were as common for low dose as other dose groups. Conclusions: In a large cohort of pts treated on phase I studies that predominantly included one or more targeted/biologic agent, there was no downside to being on low versus medium or high doses. These data should alleviate concerns about relative lack of benefit for low-dose patient cohorts on phase I trials, and support the notion that dose/response relationships for targeted agents may be less clear than for cytotoxics.

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No significant financial relationships to disclose.

Seroprevalence and risk factors for hepatitis B virus infection among general population in Northern India

BACKGROUND

Infection with hepatitis-B virus has been a significant cause of morbidity claiming more than a million lives every year. Epidemiological data reveals that there are 360 million carriers of hepatitis-B virus throughout the globe and 78% of the world populations' hail from Asia. Though several studies from Indian sub-continent have provided an estimate of the prevalence of this viral infection, there exist only few studies, which reflect the status in the general population.

AIM

The present study was designed to investigate the prevalence of hepatitis-B infection in North Indian general population.

METHODS

The study population comprised of 20,000 healthy blood donors who were screened for hepatitis-B surface antigen (HBsAg) status using third generation ELISA kit. Seroprevalence rate of seropositive donors was calculated and stratified by age, sex and blood groups. Statistical analysis was performed using tests of proportions, chi-square and confidence interval.

RESULTS

The study showed that out of 20,000 donors, 450 (2.25%) were HBsAg positive (95% confidence interval (CI), 2.0445-2.4554). Higher prevalence of HbsAg was found among males (440/19235) than females (10/765). The age specific prevalence rose from 1.78% (108/6058) in donors aged 19-25 years to a maximum of 3.03% (96/3161) in donors aged 35-45 years and decreased in older age groups. The peaks were detected in male donors aged 35-45 years and in females aged 25-35 years. Rh-negative blood group donors (21/873) and Rh-positive group donors (429/19127) had almost equivalent prevalence rates of HBsAg. HBsAg was more prevalent in blood group B donors (174/7426) and less prevalent in AB blood group donors (38/2032).

CONCLUSION

It was found that variables including gender and age were significantly associated with HBsAg positivity. HBsAg positivity in our population was statistically not associated with ABO blood groups.

Composite intestinal-type adenocarcinoma and small cell carcinoma of sinonasal tract

BACKGROUND AND AIMS

Sinonasal intestinal-type adenocarcinomas (ITACs) are rare neoplasms resembling intestinal adenocarcinomas. Although several studies have documented neuroendocrine differentiation in ITACs, the combination of ITAC and small cell carcinoma has not been previously described in detail. The aim of this report is to detail the histopathological and immunohistochemical characteristics of two cases of composite ITAC with small cell carcinoma.

METHODS

Two cases of composite ITAC with small cell carcinoma were routinely processed, and representative sections were stained with CAM5.2, AE1:AE3, keratin 7, keratin 20, keratin 19, CDX-2, p63, villin, chromogranin, synaptophysin and CD56.

RESULTS

One tumour consisted of a mixed-type ITAC showing colonic-type and poorly differentiated adenocarcinoma with foci of "signet-ring" cells combined with small cell carcinoma. Both components stained positively with CAM5.2, AE1:AE3, CK7, CK20 and CK19, whereas only the small cell carcinoma expressed synaptophysin and CD56. Both components stained negatively with CDX-2, villin, CD99 and p63. The "signet-ring" cells stained positively with chromogranin and synaptophysin. The second tumour showed a papillary-type ITAC combined with a small cell carcinoma. The adenocarcinoma and small cell carcinoma stained positively with CAM5.2, AE1:AE3, CK7, CK19 and CK20. Only the adenocarcinoma was CDX-2 positive, whereas the small cell carcinoma expressed CD56 and synaptophysin.

CONCLUSIONS

The two components of the combined ITACs and neuroendocrine small cell carcinoma show significant immunohistochemical overlap, supporting a common origin. The occurrence of a distinct neuroendocrine carcinoma combined with ITACs expands the histopathological spectrum of these tumours.

Tolosa-Hunt syndrome: MRI appearances

A review of MRI findings in seven patients with Tolosa-Hunt syndrome was carried out. Seven patients presented with unilateral painful ophthalmoplegia. Magnetic resonance imaging studies were carried out to evaluate the cavernous sinuses and orbits. Coronal fast spin-echo T2-weighted images and fat-saturated T1-weighted coronal and transverse images with and without contrast enhancement were obtained for the cavernous sinuses and orbits. All patients showed focal-enhancing masses expanding the ipsilateral cavernous sinus. In one patient the mass was extending to the orbital apex and intraorbitally. All patients recovered on corticosteroid therapy and resolution of the masses was documented on follow-up MRI studies in five patients. One patient had a relapse of symptoms after discontinuing therapy. Magnetic resonance imaging studies of the cavernous sinus and orbital apex show high sensitivity for the detection and follow up of inflammatory mass lesions in Tolosa-Hunt syndrome. Magnetic resonance imaging should be the initial screening study in these patients.

Artificial neural network-based glaucoma diagnosis using retinal nerve fiber layer analysis

PURPOSE

To develop, train, and test an artificial neural network (ANN) for differentiating among normal subjects, primary open angle glaucoma (POAG) suspects, and persons with POAG in Asian-Indian eyes using inputs from clinical parameters, optical coherence tomography (OCT), visual fields, and GDx nerve fiber analyzer.

METHODS

One hundred eyes were classified using optic disc examination and perimetry into normal (n=35), POAG suspects (n=30), and POAG (n=35). EasyNN-plus simulator was used to develop an ANN model with inputs including age, sex, myopia, intraocular pressure (IOP), optic nerve head, and retinal nerve fiber layer (RNFL) parameters on OCT, Octopus 30-2 full threshold visual field, and GDx parameters.

RESULTS

With two outputs (POAG or normal), specificity was 80% and sensitivity was 93.3%. Ninety percent of POAG suspects were labeled as abnormal in this analysis. ANN assigned the highest importance to Smax/Imax RNFL on OCT followed by cup-area (OCT) and other RNFL parameters (OCT) for two outputs. With three outputs (normal, POAG, and POAG suspect), ANN gave an overall classification rate of 65%, specificity of 60%, and sensitivity of 71.4% with a target error rate of the training set at 1%. The parameters for three outputs, in decreasing order of relative importance, were Savg, vertical cup-disc ratio, cup-volume, and cup-area on OCT.

CONCLUSIONS

An ANN taking varied diagnostic imaging inputs was able to separate POAG eyes from normal subjects and POAG suspects. The network had reasonable sensitivity with three outputs; however, it had a tendency to mislabel POAG suspects as POAG.

Exenatide and acute pancreatitis

For a female, type 2 diabetic patient, with 4 years duration of diabetes, Exenatide (Byetta) was prescribed as glycaemic control was not satisfactory along with Glimepiride and Metformin. She had gastrointestinal disturbances, since the first day of the injection. From the eighth day she developed signs of acute pancreatitis which was confirmed with CT-Scan and biochemical investigations. Byetta was withdrawn, the patient was treated for acute pancreatitis and the symptoms subsided.

Efficacy, safety and patterns of response and recurrence in patients with recurrent high-grade gliomas treated with bevacizumab plus irinotecan

Our objective is to assess treatment efficacy, safety and pattern of response and recurrence in patients with recurrent high-grade glioma treated with bevacizumab and irinotecan. We reviewed retrospectively 51 patients with recurrent high-grade glioma treated with this combination at the Henry Ford Hermelin Brain Tumor Center from 11/15/2005 to 04/01/2008. The 6-month progression-free survival (PFS) for anaplastic gliomas (AGs) was 78.6 and 63.7% for glioblastoma. The median PFS was 13.4 months for AG and 7.6 months for those with glioblastoma. The overall survival rate (OS) at 6 months was 85.7% for AG and 78.0% for glioblastoma. The 12-month OS was 77.9% for AG and 42.6% for glioblastoma. The median OS time for AGs was not reached and was 11.5 months for those with glioblastoma. Thirty-six out of 51 (70.59%) patients demonstrated partial (32/51) or complete (4/51) radiographic response to treatment and 8/51 (15.69%) remained stable. Of the 38 who demonstrated progression on post-gadolinium studies, 23 showed distant progression with or without local recurrence. Seven patients showed progression on FLAIR without concordant findings on post-Gd sequences. Six patients (11.76%) discontinued treatment due to a treatment-emergent adverse event, including one with end-stage renal failure and another with gastric perforation. No symptomatic intracranial hemorrhages were reported. Patients with recurrent high-grade glioma treated with bevacizumab plus irinotecan demonstrate an excellent radiographic response rate and improved clinical outcome when compared to historical data. The high rate of distant tumor progression suggests that tumors may adapt to inhibition of angiogenesis by increased infiltration and vascular co-option.

Delayed maturation of an IL-12-producing dendritic cell subset explains the early Th2 bias in neonatal immunity

Primary neonatal T cell responses comprise both T helper (Th) cell subsets, but Th1 cells express high levels of interleukin 13 receptor α1 (IL-13Rα1), which heterodimerizes with IL-4Rα. During secondary antigen challenge, Th2-produced IL-4 triggers the apoptosis of Th1 cells via IL-4Rα/IL-13Rα1, thus explaining the Th2 bias in neonates. We show that neonates acquire the ability to overcome the Th2 bias and generate Th1 responses starting 6 d after birth. This transition was caused by the developmental maturation of CD8α⁺CD4⁻ dendritic cells (DCs), which were minimal in number during the first few days of birth and produced low levels of IL-12. This lack of IL-12 sustained the expression of IL-13Rα1 on Th1 cells. By day 6 after birth, however, a significant number of CD8α⁺CD4⁻ DCs accumulated in the spleen and produced IL-12, which triggered the down-regulation of IL-13Rα1 expression on Th1 cells, thus protecting them against IL-4–driven apoptosis.

Fetal exposure to high-avidity TCR ligand enhances expansion of peripheral T regulatory cells

Lately, it has become clear that regulatory T cells (Tregs) play a major role in the maintenance of peripheral tolerance and control of autoimmunity. Despite these critical functions, the process underlying the development of Tregs remains largely undefined. Herein, altered peptide ligand (APL) variants derived from the proteolipid protein-1 (PLP1) epitope were expressed on immunoglobulins (Igs) and the resulting Ig-APLs were used to deliver the APLs from mother to fetus through the maternal placenta to influence thymic T cell selection. This delivery system was then adapted to the SJL/J mouse, a strain that expresses only the DM20 form of PLP, which lacks the dominant PLP1 epitope in the thymus during fetal and neonatal development. This model, which restores thymic T cell selection for PLP1, was then used to determine whether affinity plays a role in the development of Tregs. The findings show that fetal exposure to low-affinity peptide ligand was unable to drive development of Tregs while variants with higher affinity to the TCR resulted in significant seeding of the periphery with mature, naive Tregs. Thus, contrary to pathogenic T cells, Tregs require avid TCR-ligand interaction to undergo thymic development and maturation.