A unique role for p53 in the regulation of M2 macrophage polarization

P53 is critically important in preventing oncogenesis but its role in inflammation in general and in the function of inflammatory macrophages in particular is not clear. Here, we show that bone marrow-derived macrophages exhibit endogenous p53 activity, which is increased when macrophages are polarized to the M2 (alternatively activated macrophage) subtype. This leads to reduced expression of M2 genes. Nutlin-3a, which destabilizes the p53/MDM2 (mouse double minute 2 homolog) complex, promotes p53 activation and further downregulates M2 gene expression. In contrast, increased expression of M2 genes was apparent in M2-polarized macrophages from p53-deficient and p53 mutant mice. Furthermore, we show, in mice, that p53 also regulates M2 polarization in peritoneal macrophages from interleukin-4-challenged animals and that nutlin-3a retards the development of tolerance to Escherichia coli lipopolysaccharide. P53 acts via transcriptional repression of expression of c-Myc (v-myc avian myelocytomatosis viral oncogene homolog) gene by directly associating with its promoter. These data establish a role for the p53/MDM2/c-MYC axis as a physiological 'brake' to the M2 polarization process. This work reveals a hitherto unknown role for p53 in macrophages, provides further insight into the complexities of macrophage plasticity and raises the possibility that p53-activating drugs, many of which are currently being trialled clinically, may have unforeseen effects on macrophage function.

Anterior urethral valves without diverticulae: a report of two cases and a review of the literature

Two unusual cases of anterior urethral valves (AUV) without diverticulae are presented. The first case is a male child born with prenatal diagnosis of bilateral hydronephrosis. On cystoscopy, iris-like diaphragm valves were encountered about 3 mm distal to the skeletal sphincter. In the second case, an 18-month-old male child was investigated for recurrent febrile urinary tract infections and obstructed urinary symptoms. Cystoscopy confirmed the presence of slit-like valves 5 mm distal to the skeletal sphincter. Fulguration of the AUVs was performed in both cases. It may be worthwhile to review all cases of anterior urethral obstruction collectively and re-categorize them appropriately to include the unusual AUVs without diverticulum in that classification.

Giant renal angiomyolipoma: unusual cause of huge abdominal mass

We present the imaging and histopathological characteristics of a giant renal angiomyolipoma (AML) in a 49-year-old female patient, who presented with bloating sensation in the abdomen and a steadily increasing abdominal girth for about 3 years. Contrast enhanced computed tomography (CECT) scan films of abdomen revealed that a large fat containing tumor had replaced the left kidney while displacing the rest of the abdominal contents toward the other side of the midline. Intraoperatively the left kidney was completely replaced by a fat containing tumor. The recovered surgical specimen measured 39 cm × 25 cm × 9 cm and weighed 7500 g. Histopathological investigation with immuno-histochemical staining of the specimen with hydroxy beta-methylbutyric acid-45 confirmed this lesion as AML. CECT scan of the head did not show any lesion suggestive of tuberous sclerosis. The giant tumor of the present case is the heaviest AML in both syndromic and sporadic categories and largest by dimensions as sporadic AML ever reported in the literature.

Incomplete transverse vesical septum: An unusual congenital anomaly

A rare case of incomplete transverse vesical septum with urinary tract tuberculosis is being reported. A 52-year-old male presented with lower urinary tract and systemic symptoms. On investigation he had anemia, leucocytosis, and high serum creatinine. On cystopanendoscopy, there was a transverse ledge of tissue connecting the two lateral walls of the bladder approximately 4 cm proximal to the bladder neck dividing the caudal vesical cavity into anterior and posterior parts. Also, the left ureteric orifice had double barrel look. To our knowledge this is the first ever reported case of incomplete transverse vesical septum.

A rational combination of intravesical and systemic agents for the treatment of interstitial cystitis

OBJECTIVE

Interstitial cystitis is a condition with a poorly understood etiology and, consequently, various treatment options have been described in the literature, with a less than optimal outcome. The aim of this study was to examine the role of a combination of intravesical hydrocortisone and heparin, together with oral bladder sedatives and systemic triamcinolone, for the treatment of interstitial cystitis.

MATERIAL AND METHODS

A total of 26 patients who were diagnosed as having interstitial cystitis were treated with weekly intravesical hydrocortisone (200 mg) and heparin (25,000 IU) in physiological saline for 6 weeks. In addition, they were given oral bladder sedatives such as oxybutynin or tolterodine. Ulcerative, refractory and recurrent cases were treated with intramuscular triamcinolone (40 mg) weekly for 6 weeks.

RESULTS

All patients experienced an improvement in symptoms within 48 h of their first intravesical instillation. While 19 patients (73%) experienced almost complete pain relief, five of the remaining seven patients improved with intramuscular triamcinolone. Frequency reduced from a mean of 23.2 to 10.9 voids per day and was acceptable in 21 patients (80%). Six patients (23%) had a relapse of symptoms in the form of pain and were treated satisfactorily by means of intramuscular triamcinolone. The mean duration of follow-up was 18.3 months.

CONCLUSION

A combination of intravesical hydrocortisone and heparin, along with oral bladder sedatives and systemic steroids, has been used with encouraging results in a small group of patients with interstitial cystitis.

A Rational Combination Pharmacotherapy in Men with Erectile Dysfunction who Initially Failed to Oral Sildenafil Citrate Alone: A Pilot Study

INTRODUCTION

Erectile dysfunction (ED) is a complex condition wherein men with minimal organic ED may develop a variable degree of psychogenic component sufficient to reduce the efficacy of medical management. A combination of trazodone with sildenafil has been used to overcome both organic as well as psychogenic components, thus improving the results of medical management.

AIM

To evaluate the efficacy of combination of trazodone with sildenafil citrate in treatment of ED in men with initial failure to sildenafil citrate alone.

MAIN OUTCOME MEASURES

The symptoms of ED were evaluated using the Erectile Dysfunction Intensity Scale (EDIS) before and after the treatment.

METHODS

Eighteen men with ED who initially failed to respond to sildenafil citrate alone were enrolled in the study between February 2004 and December 2004. All these men were given a priming dose of trazodone for a 2-week period before giving them sildenafil citrate.

RESULTS

Of the 18 men, 12 responded favorably to the above treatment and continued to enjoy good sexual activity while on trazodone and sildenafil. The score on EDIS improved considerably in 12 (66.7%) men, marginally in two (11.1%) men, and did not improve at all in four (22.2%) men.

CONCLUSIONS

Priming the patients with trazodone appears to be a reasonably good alternative in patients who have initial failure to oral sildenafil citrate and have been found to have no organic cause of ED. However, large double-blind studies are required to potentiate this hypothesis.

Surgeon workload and motion efficiency with robot and human laparoscopic camera control

BACKGROUND

Surgeons are now being assisted by robotic systems in a wide range of laparoscopic procedures. Some reports have suggested that robot-assisted camera control (RACC) may be superior to a human driver in terms of quality of view and directional precision, as well as long-term cost savings. Therefore, we setout to investigate the impact of RACC of surgeon motion efficiency.

METHODS

Twenty pigs were randomized to undergo a standardized laparoscopic Nissen fundoplication with either a human or RACC system, the AESOP 2000. All procedures were performed by the same surgical fellow. Time was recorded for dissection and suture phases. Inertial motion sensors were used to monitor both the surgeon's hands and the camera. Digitized data were analyzed to produce summary measures related to overall motion.

RESULTS

The operative times were slightly longer with RACC (mean 80.2 +/- 20.6 vs 73.1 +/- 15.4 min, not significant). With regard to operative times and surgeon motion measures, the only statistically significant differences were for setup and breakdown times, which contributed <15% to the total time for the procedure.

CONCLUSION

In terms of impact on surgeon motion efficiency and operative time under normal surgical conditions, RACC is essentially the same as an expert human driver. However, careful planning and structuring of the surgical suite may yield some small gains in operative time.

Defective T cell activation and autoimmune disorder in Stra13-deficient mice

Stra13, a basic helix-loop-helix transcription factor, is up-regulated upon activation of CD4+ T cells. Here we show that Stra13-deficient mice exhibit defects in several phases of CD4+ T cell activation. In vivo, Stra13 deficiency results in ineffective elimination of activated T and B cells, which accumulate progressively, leading to lymphoid organ hyperplasia. Consequently, aging Stra13-/- mice develop autoimmune disease characterized by accumulation of spontaneously activated T and B cells, circulating autoantibodies, infiltration of T and B lymphocytes in several organs and immune complex deposition in glomeruli. Our studies identify Stra13 as a key regulator of lymphocyte activation that is vital for maintenance of self-tolerance and for constraint of autoimmunity.

Cross-regulatory interaction between Stra13 and USF results in functional antagonism

Transcription factors belonging to the basic helix-loop-helix (bHLH) family are critical regulators of cellular proliferation and differentiation. The functional activity of these proteins can be regulated by heterodimerization through the HLH domain, as a result of formation of functional or non-functional heterodimers. The presence of a leucine zipper in bHLH-leucine zipper (bHLHZip) proteins, however, prevents such heterodimeric interactions via the HLH domain between bHLH and bHLHZip proteins. To identify cellular proteins that directly interact with and modulate transcriptional repression mediated by the bHLH protein Stra13, we carried out a yeast two hybrid screen. The bHLHZip protein USF (Upstream Stimulatory factor) was identified as a Stra13 interacting protein. We demonstrate a direct interaction between Stra13 and USF that is dependent upon the C-terminal repression domain of Stra13 and the DNA-binding domain of USF. Stra13 and USF also colocalize and functionally interact in mammalian cells. Co-expression of USF abrogates Stra13-mediated repression of target genes and conversely, Stra13 inhibits DNA-binding and USF-mediated transactivation. Taken together, our data demonstrate that Stra13 and USF interact physically and functionally, and identify a novel mode of cross regulatory interaction between members of the bHLH and bHLHZip families that abrogates their functional activity.

Targeted drug delivery systems 6: Intracellular bioreductive activation, uptake and transport of an anticancer drug delivery system across intestinal Caco-2 cell monolayers

We demonstrate transport across, intracellular accumulation and bioreductive activation of a conformationally constrained, anticancer drug delivery system (the CH(3)-TDDS) using Caco-2 cell monolayers (CCMs) as an in vitro model of the human intestinal mucosa. Reverse-phase High Performance Liquid Chromatography (HPLC) coupled with UV detection was used to detect CH(3)-TDDS, the bioreduction product (lactone) and the released drug (melphalan methyl ester; MME). Upon incubation of the CH(3)-TDDS with the apical (AP) surface of 21-day-old CCM, we observed rapid decrease in the AP concentration of the CH(3)-TDDS (60%/hr) as a result of cellular uptake. Rapid intracellular accumulation of the CH(3)-TDDS was followed by bioreductive activation to deplete the cellular levels of CH(3)-TDDS. The drug part (MME) and lactone, as well as CH(3)-TDDS, were detected in the basolateral (BL) chamber. Intracellular Caco-2 levels of TDDS and lactone were also detectable. Bioreductive activation of the CH(3)-TDDS was additionally confirmed by formation of lactone after incubation of the CH(3)-TDDS in the presence of freshly prepared Caco-2 cell homogenates. During transport studies of melphalan or MME alone (as control), the intact drug was not detected in the intracellular compartment or in the BL chamber. These observations demonstrate that CH(3)-TDDS has potential for improving intestinal delivery of MME. TDDS could be useful in facilitating oral absorption of MME as well as the oral delivery of other agents.

Phagocytosis of Candida albicans induces apoptosis of human neutrophils

Neutrophil-mediated inflammation is terminated through the programmed cell death or apoptosis of the neutrophil, a process that can be inhibited by soluble mediators released during an inflammatory response. It has been reported, however, that the phagocytosis of intact bacteria can accelerate apoptosis. We evaluated the effects of the phagocytosis of a common nosocomial pathogen, Candida albicans, on the expression of apoptosis. Phagocytosis of killed Candida induced a dose-dependent increase in the apoptosis of normal neutrophils after 18 h of in vitro culture, from 40.7+/-9.1% to 81.7+/-4.5%, while supernatants from neutrophil:Candida co-cultures actually inhibited apoptosis. Induction of apoptosis was not dependent on phagocytosis, since opsonization of yeast with serum failed to increase apoptosis, while inhibition of phagocytosis with latrunculin B resulted in a slightly increased apoptotic rate. Increased apoptosis induced by Candida was associated with increased activity of the membrane-associated apoptotic enzyme, caspase 8, and with increased expression of the active form of the key executioner caspase, caspase 3. Increased apoptosis was associated with depletion of intracellular glutathione (GSH), and could be inhibited by the addition of exogenous GSH. These data demonstrate an important physiologic role for host-pathogen interactions in the resolution of inflammation and suggest that the response to an invading pathogen is an important stimulus to the restoration of normal immunologic homeostasis.