The stimulation of capillary endothelial cell migration by aqueous humor

We have developed a quantitative in vitro assay of aqueous humor based on capillary endothelial cell migration. Bovine adrenal capillary endothelial cells are plated onto glass coverslips that have previously been coated with colloidal gold and incubated for 18 hr. During this time, cells that migrate sweep up the gold and leave a bare track that serves as a record of their movement. When the coverslips are projected by phase microscopy onto a television screen, the tracks can be traced and their areas are measured by a Zeiss MOP-3 digital image analyzer. V-2 carcinoma was implanted onto the iris of each eye of 15 NZ white rabbits and 200 μl of aqueous humor was aspirated from the anterior chamber. The aqueous humor was added to nonconditioned culture medium (DME with 10% calf serum) in concentrations of 6.25, 25, 50, and 100 μl. The tracks of 100 cells were traced for each concentration. The aqueous humor from these tumor-bearing animals stimulated capillary endothelial cell migration in a statistically significant, dose-dependent fashion. Aqueous humor from the eyes of 10 control rabbits (5 sham operated and 5 with heat killed, washed tumor implants) did not stimulate capillary endothelial cell migration at any concentration. This in vitro quantitative capillary endothelial cell migration assay of aqueous humor might improve the clinical diagnosis of intraocular tumors, guide subsequent treatment regimens, and identify those patients at a high risk of developing malignant eye tumors.     

A new look at irritable bowel syndrome [IBS]: a neuroenteric disorder

Irritable bowel syndrome is difficult to treat because of poorly defined pathophysiology, lack of diagnostic marker, and until recently, limited pharmacotherapy. After diagnosis, treatment includes diet and behavior modifications, along with pharmacologic treatment for mild disease and severe cases. The author has stated that she is a consultant and speaker for Astra-Zeneca, Biocodex, GlaxoSmithKline, Novartis, and Wyeth.     

Nuances in treating irritable bowel syndrome

Irritable bowel syndrome (IBS) is a difficult disease to treat because of its ill-defined triggers, variable clinical course, and unpredictable myriad of symptoms of varying severity. Both doctors and patients are frustrated by the insidious nature of IBS--a nonlethal disorder that destroys lives, relationships, and careers. Traditional therapies are sometimes effective in mild disease but are often self-limiting because they focus primarily on individual symptoms. A combination of lifestyle and diet modifications, pharmacologic agents, and therapeutic interventions is usually necessary to address the multiple symptoms characteristic of IBS. One of the major advancements in the treatment of patients with IBS has been the development of US Food and Drug Administration--approved serotonergic therapeutics that specifically target the underlying causes of IBS and provide multisymptom relief by improving gastrointestinal function. Although they are controversial, alternative treatment approaches that target normalization of intestinal bacterial microflora may be helpful for some patients in whom intestinal bacterial overgrowth is present. Patients who have co-existing pelvic floor dysfunction may benefit from physical therapy. Overall, treatment approaches for IBS should address multisymptom relief and improvement of overall patient well-being.     

Clinical trial: dextofisopam in the treatment of patients with diarrhoea-predominant or alternating irritable bowel syndrome

Background  Dextofisopam modulates stimulated activity in animal models of stress, altered bowel motility, and visceral hypersensitivity.
Aim  To evaluate the effects of dextofisopam in men and women with diarrhoea-predominant or alternating irritable bowel syndrome (IBS) (d-IBS or a-IBS).
Methods  In this double-blind, placebo-controlled study, patients were randomly assigned to receive dextofisopam 200 mg b.d. or placebo for 12 weeks. The prospectively defined primary endpoint was number of months of adequate overall relief of IBS symptoms. Bowel function was assessed primarily via stool frequency and consistency.
Results  Of 140 enrolled patients, 66 received dextofisopam and 74 placebo; 73% of the patients were women, and 78% had d-IBS. Dextofisopam was superior to placebo on the primary endpoint ( P  = 0.033). In d-IBS patients treated with dextofisopam, both men and women had improved stool consistency, but stool frequency was reduced only in women. Benefit diminished over time on the primary endpoint, but persisted on frequency and consistency. Dextofisopam and placebo had similar rates and types of adverse events, with more events of worsening abdominal pain with dextofisopam (12% vs. 4%) and more headaches with placebo (12% vs. 5%). Constipation was rare.
Conclusion  Dextofisopam should be further evaluated as a new treatment for men and women with d-IBS and a-IBS.     

The pharmacology and clinical relevance of proton pump inhibitors

Gastroesophageal reflux disease is a complex, multifaceted disorder affecting a large proportion of the US population. Its management is based on the principle of optimal antisecretory therapy, mainly with proton pump inhibitors (PPIs). The optimal treatment outcome is complete symptom relief, which can be achieved with optimal use of PPIs. PPI treatment requires an understanding of the pharmacology of these agents as well as their clinical efficacy, strengths, and weaknesses. This paper reviews the pharmacology of PPIs, the principles of optimal dosing, nocturnal gastric acid breakthrough and its clinical importance, and a treatment approach to gastroesophageal reflux disease using these agents.     

The role of gender and biological sex in irritable bowel syndrome

Irritable bowel syndrome (IBS), which is characterized by abdominal pain or discomfort that is associated with altered bowel function (diarrhea, constipation, or alteration between the two), is one of several gastrointestinal motility disorders. IBS affects up to one in five North Americans, mostly women. The reason(s) this disorder is reported more often by women than men, and the role of gender and biological sex in the prevalence, pathophysiology, symptom presentation, impact on quality of life, diagnosis, and response to treatment, are poorly understood. The purpose of this article is to review the evidence surrounding the roles of gender and biological sex in IBS.     

Symptom overlap and comorbidity of irritable bowel syndrome with other conditions

Irritable bowel syndrome (IBS) is one of several highly prevalent, multi-symptom gastrointestinal motility disorders that have a wide clinical spectrum and are associated with symptoms of gastrointestinal dysmotility and visceral hypersensitivity. Symptom overlap and comorbidity between IBS and other gastrointestinal motility disorders (eg, chronic constipation, functional dyspepsia, gastroesophageal reflux disease), with gastrointestinal disorders that are not related to motility (eg, celiac disease, lactose intolerance), and with somatic conditions (eg, fibromyalgia, chronic fatigue syndrome), are frequent. The clinical associations and pathophysiologic links between IBS and these disorders continue to be explored. This review discusses overlapping symptoms and comorbidity of IBS with select gastrointestinal and non-gastrointestinal disorders and attempts to identify commonalities among these conditions.     

FTY720 demonstrates promising preclinical activity for chronic lymphocytic leukemia and lymphoblastic leukemia/lymphoma

FTY720 is an immunosuppressant developed to prevent organ transplant rejection. Recent studies indicate an additional role for FTY720 in inducing cell apoptosis. We demonstrate here that FTY720 mediates toxic effects in cell lines representing different B-cell malignancies and primary B cells from patients with chronic lymphocytic leukemia (CLL). In contrast to previous reports in T-cell lines, FTY720-induced toxicity in the Raji cell line and primary CLL B cells is independent of activation of caspases or poly(ADP-ribose) polymerase processing. Further, pancaspase inhibitor Z-VAD-fmk failed to rescue these cells from apoptosis mediated by FTY720. FTY720 induced down-regulation of Mcl-1 but not Bcl-2 in CLL B cells. Overexpression of Bcl-2 failed to protect transformed B cells from FTY720-induced apoptosis, suggesting a Bcl-2-independent mechanism. Interestingly, FTY720 induced protein phosphatase 2a (PP2a) activation and downstream dephosphorylation of ERK1/2, whereas okadaic acid at concentrations that inhibited the FTY720-induced PP2a activation also resulted in inhibition of FTY720-mediated apoptosis and restoration of baseline ERK1/2 phosphorylation in primary CLL cells, indicating a role for PP2a activation in FTY720-induced cytotoxicity. Further, FTY720 treatment resulted in significant prolonged survival in a xenograft severe combined immunodeficiency (SCID) mouse model of disseminated B-cell lymphoma/leukemia. These results provide the first evidence for the potential use of FTY720 as a therapeutic agent in a variety of B-cell malignancies, including CLL.     

OSU-DY7, a novel D-tyrosinol derivative, mediates cytotoxicity in chronic lymphocytic leukaemia and Burkitt lymphoma through p38 mitogen-activated protein kinase pathway

Drug resistance and associated immune deregulation limit use of current therapies in chronic lymphocytic leukaemia (CLL), thus warranting alternative therapy development. Herein we demonstrate that OSU-DY7, a novel D-tyrosinol derivative targeting p38 mitogen-activated protein kinase (MAPK), mediates cytotoxicity in lymphocytic cell lines representing CLL (MEC-1), acute lymphoblastic leukaemia (697 cells), Burkitt lymphoma (Raji and Ramos) and primary B cells from CLL patients in a dose- and time-dependent manner. The OSU-DY7-induced cytotoxicity is dependent on caspase activation, as evidenced by induction of caspase-3 activation and poly (ADP-ribose) polymerase (PARP) cleavage and rescue of cytotoxicity by Z-VAD-FMK. Interestingly, OSU-DY7-induced cytotoxicity is mediated through activation of p38 MAPK, as evidenced by increased phosphorylation of p38 MAPK and downstream target protein MAPKAPK2. Pretreatment of B-CLL cells with SB202190, a specific p38 MAPK inhibitor, results in decreased MAPKAPK2 protein level with concomitant rescue of the cells from OSU-DY7-mediated cytotoxicity. Furthermore, OSU-DY7-induced cytotoxicity is associated with down regulation of p38 MAPK target BIRC5, that is rescued at protein and mRNA levels by SB202190. This study provides evidence for a role of OSU-DY7 in p38 MAPK activation and BIRC5 down regulation associated with apoptosis in B lymphocytic cells, thus warranting development of this alternative therapy for lymphoid malignancies.