Yellow-Gold Polarized Light Microscopy May Improve Accuracy of Pathological Staging of Colorectal Adenocarcinoma

Introduction Polarized light (PL) has been used in pathology for multiple reasons, including the demonstration of foreign bodies, the evaluation of crystals, and the demonstration of fibrosis. We incidentally found that yellow-gold polarization routinely occurs surrounding desmoplastic scar tissue abutting the invasive glands of colonic adenocarcinoma. We hypothesized that evaluating the use of polarized light over a series of invasive adenocarcinomas of the large intestine might produce evidence of its utility. Methods Large intestinal resections with invasive adenocarcinoma were reviewed with yellow-gold polarized light microscopy by two surgical pathologists postoperatively between January 2017 and March 2019. Specimens were examined under yellow-gold polarized light to evaluate invasion from the submucosa into the muscularis propria, from the muscularis propria into pericolic fat, and to the serosa. The diagnosed location, T stage, history of radiotherapy, mucinous features, and grade were recorded. Photographs were taken when images were deemed to be of value. The two-tailed Fisher's exact test was used to compare the invasion detection of the tumor into fat in scar tissue in colorectal cancer. Results A total of 75 large intestinal resections with invasive adenocarcinoma from 75 patients were accessioned. Concerning the initial stage, three (4%) were T1, nine (12%) were T2, 46 (61%) were T3, and 17 (22%) were T4. A history of previous radiation treatment was seen in 10 (13%). Two (2%) were poorly differentiated. Nine (12%) were mucinous carcinomas; mucinous areas were seen to pose difficulty in 12 (16%). Overall, one out of nine, initially staged as T2, was upstaged to T3 (11%), with the addition of yellow-gold polarized light microscopy. One tumor was downstaged from T2 to T1 (11%). For many T2 and T3 tumors, invasion into the muscularis propria was better defined by yellow-gold polarized light. Conclusion Yellow-gold polarized light microscopy may be a useful adjunct to conventional microscopy in more precisely staged pathological colorectal cancer specimens.

Chronic exposure to excess iron promotes EMT and cancer via p53 loss in pancreatic cancer

Based on the evidence that hemochromatosis, an iron-overload disease, drives hepatocellular carcinoma, we hypothesized that chronic exposure to excess iron, either due to genetic or environmental causes, predisposes an individual to cancer. Using pancreatic cancer as our primary focus, we employed cell culture studies to interrogate the connection between excess iron and cancer, and combined in vitro and in vivo studies to explore the connection further. Ferric ammonium citrate was used as an exogenous iron source. Chronic exposure to excess iron induced epithelial-mesenchymal transition (EMT) in normal and cancer cell lines, loss of p53, and suppression of p53 transcriptional activity evidenced from decreased expression of p53 target genes (p21, cyclin D1, Bax, SLC7A11). To further extrapolate our cell culture data, we generated EL-Kras^G12D (EL-Kras) mouse (pancreatic neoplastic mouse model) expressing Hfe^+/+and Hfe^−/− genetic background. p53 target gene expression decreased in EL-Kras/Hfe^−/− mouse pancreas compared to EL-Kras/Hfe^+/+ mouse pancreas. Interestingly, the incidence of acinar-to-ductal metaplasia and cystic pancreatic neoplasms (CPN) decreased in EL-Kras/Hfe^−/− mice, but the CPNs that did develop were larger in these mice than in EL-Kras/Hfe^+/+ mice. In conclusion, these in vitro and in vivo studies support a potential role for chronic exposure to excess iron as a promoter of more aggressive disease via p53 loss and SLC7A11 upregulation within pancreatic epithelial cells.

A glucocorticoid receptor agonist improves post-weaning growth performance in segregated early-weaned pigs

While beneficial for sow reproductive efficiency and biosecurity, segregated early weaning (SEW) leads to a systemic immune response that adversely affects the digestive physiology and post-weaning growth of pigs. Two experiments were conducted to evaluate the effects of a glucocorticoid receptor agonist (GA) on growth performance, measures of immune function and intestinal integrity of SEW pigs. In both experiments, pigs were fed corn-soybean meal-based starter diets. In the first experiment, 48 pigs (initial BW 4.8 ± 0.7 kg) were weaned at 21 ± 1 days and randomly assigned to three GA treatment groups: 0, 0.2 and 0.6 mg GA/kg of BW injected intramuscularly. Treatments were administered one day before weaning. Pigs in the 0 mg GA group received sterile saline in place of GA. Body weight was measured daily from one day before to 7 days post-weaning, and then weekly until 28 days post-weaning. Piglets treated with 0.2 mg GA had a higher BW than piglets in other treatment groups during the 28-day course of the study (P <0.02). To further explore the mechanisms behind this result, a second experiment was performed in which a total of 18 gilts (BW 5.6 ± 0.85 kg) were randomly assigned into three treatment groups: suckling plus saline (UWS), weaned treated with GA (WGA; 0.2 mg GA/kg BW) and weaned plus saline (CON). Treatments were administered one day before and 3 days post-weaning. The WGA and CON groups were weaned at 23 ± 2 days, while the UWS group remained with sow for the duration of the study. Body weight was measured daily and blood plasma was collected at 0, 1, 4 and 5 days post-weaning. All gilts were euthanized 5 days after weaning and jejunum samples were collected for mucosal scrapings, histomorphological analysis and gene expression analysis. Plasma levels of interleukin-1β (IL-1β) and haptoglobin were lower in WGA pigs compared with CON (P <0.02), while plasma total antioxidant capacity was higher in WGA pigs compared with both CON and UWS groups (P <0.01). Relative to CON, GA downregulated IL-18 gene expression in the jejunum, as assessed by both tissue homogenate and mucosal scrapings, but it upregulated claudin-IV gene expression only in the tissue homogenate (P <0.01). These results suggest that GA treatment improves the growth performance of SEW pigs in part by mitigating the negative effects of systemic inflammation. However, the effect of GA on barrier integrity requires further investigation.

Abstract 1889: Chronic exposure to excess iron promotes EMT and cancer via p53 loss in pancreatic cancer

Pancreatic cancer especially the pancreatic ductal adenocarcinoma (PDAC) is by far the most lethal of all cancers with a five year survival rate of less than 5%. Gemcitabine is currently used as a first line therapy for locally advanced and metastatic PDAC but with a very low success rate. Hence, there is an urgent need to better understand what actually drives this cancer so as to come up with a better diagnostic and therapeutic strategies. Excess heme and iron are known to be pro-tumorigenic. When present in excess, these molecules become toxic. Fe2+ in free form is a potent oxidant; it catalyzes the Fenton reaction to generate hydroxyl radicals (Fe2++ H2O2 → Fe3+ + HO• + OH-), a potent reactive oxygen species. Free heme is also toxic as it catalyzes free radical reaction and induces oxidative damage. Accumulation of iron and heme to toxic levels occurs in genetic diseases (hemochromatosis, sickle cell disease), pathological conditions (hemolytic anemia, ischemia reperfusion), infections, and clinical/therapeutic conditions (repeated blood transfusion). Excess intake of iron and heme from dietary sources could also lead to iron/heme overload, particularly in the colon. In this regard, red meat with its ~10-fold higher heme content than white meat is specifically relevant. Among these conditions however, hemochromatosis deserves special mention. Based on the evidence that hemochromatosis, an iron-overload disease, drives hepatocellular carcinoma, we hypothesized that chronic exposure to excess iron, either due to genetic or epigenetic causes, predisposes an individual to cancer. We employed cell culture studies to interrogate the connection between excess iron and cancer in multiple tissues and combined in vitro and in vivo studies to explore the connection in pancreas further. Ferric ammonium citrate was used as an exogenous iron source. Chronic exposure to excess iron induced epithelial-mesenchymal transition (EMT) in normal and cancer cell lines, loss of p53, and suppression of p53 transcriptional activity. In order to further extrapolate our cell culture data, we generated EL-KRASG12D or EL-Kras mouse (pancreatic neoplastic mouse model) expressing Hfe+/+ and Hfe-/- genetic background. p53 target gene expression decreased in EL-Kras/Hfe-/- mouse pancreas compared to EL-Kras/Hfe+/+ mouse pancreas. Interestingly, the incidence of acinar-to-ductal metaplasia and cystic pancreatic neoplasms (CPN) decreased in EL-Kras/Hfe-/- mice, but the CPNs that did develop were larger in these mice than in EL-Kras/Hfe+/+ mice. In conclusion, these in vitro and in vivo studies support a potential role for chronic exposure to excess iron as a promoter of more aggressive disease via p53 loss within pancreatic epithelial cells.

Citation Format: Devaraja Rajasekaran, Jiro Ogura, Mitchell Wachtel, Sabarish Ramachandran, Ellappan Babu, Sathish Sivaprakasam, Paul J. Grippo, Carolina Torres, Thangaraju Muthusamy, Jaya P. Gnana-Prakasam, Yangzom D. Bhutia. Chronic exposure to excess iron promotes EMT and cancer via p53 loss in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1889.

Osteoclastic giant cell tumor of the pancreas

INTRODUCTION

Pancreatic giant cell tumors are rare, with an incidence of less than 1% of all pancreatic tumors. Osteoclastic giant cell tumor (OGCT) of the pancreas is one of the three types of PGCT, which are now classified as undifferentiated carcinoma with osteoclast-like giant cells.

PRESENTATION OF CASE

The patient is a 57 year old woman who presented with a 3 week history of epigastric pain and a palpable abdominal mass. Imaging studies revealed an 18 cm × 15 cm soft tissue mass with cystic components which involved the pancreas, stomach and spleen. Exploratory laparotomy with distal pancreatectomy, partial gastrectomy and splenectomy was performed. Histology revealed undifferentiated pancreatic carcinoma with osteoclast-like giant cells with production of osteoid and glandular elements.

DISCUSSION

OGCT of the pancreas resembles benign-appearing giant cell tumors of bone, and contain osteoclastic-like multinucleated cells and mononuclear cells. OGCTs display a less aggressive course with slow metastasis and lymph node spread compared to pancreatic adenocarcinoma. Due to the rarity of the cancer, there is a lack of prospective studies on treatment options. Surgical en-bloc resection is currently considered first line treatment. The role of adjuvant therapy with radiotherapy or chemotherapy has not been established.

CONCLUSION

Pancreatic giant cell tumors are rare pancreatic neoplasms with unique clinical and pathological characteristics. Osteoclastic giant cell tumors are the most favorable sub-type. Surgical en bloc resection is the first line treatment. Long-term follow-up of patients with these tumors is essential to compile a body of literature to help guide treatment.

Acute effect of sildenafil on central hemodynamics in mechanically ventilated patients with WHO group III pulmonary hypertension and right ventricular failure necessitating administration of dobutamine

BACKGROUND/OBJECTIVES

Sildenafil decreases pulmonary vascular resistance index (PVRI), in patients with pulmonary hypertension (PH). We investigated sildenafil's effects on central hemodynamics of mechanically ventilated patients with WHO group-III PH and RV failure necessitating dobutamine administration.

METHODS

Prospective non-controlled study involving 12 (9 males, 59 ± 4 years old), patients with the above characteristics. All patients in phase-1 (days 1-2) received dobutamine (5 μg/kg/min IV). During phase-2 (days 3-6), sildenafil was started via nasogastric tube (80 mg/day) and dobutamine discontinuation was attempted. Patients were designated responders or non-responders based on whether dobutamine could be stopped or not. Phase-3 lasted from day 7 to day of weaning from mechanical ventilation; or if weaning failed, until day 20 following admission (end-of-study). Invasive and echocardiographic parameters were repeatedly recorded throughout the study.

RESULTS

Significantly changed parameters (P<0.025) from baseline to phase-1, -2 and -3 (%change of mean ratios), in responders (n=7) included among others PVRI (-40%, -51%, -42%), RV stroke work index (RVSWI: 43%, 79%, 41%) and cardiac index (49%, 54%, 48%), which also differed significantly from non-responders (N=5). In phases-1 and -3 non-responders had not significant changes, in phase-2 PVRI (27%) and RVSWI (-22%) changed significantly. In contrast to non-responders, all responders were weaned from mechanical ventilation until the end-of-study (P<0.025).

CONCLUSIONS

Sildenafil may improve central hemodynamics and RV function indices in ventilated patients with WHO group-III PH and RV failure requiring dobutamine infusion, when they respond favorably to the latter. Accordingly, an adequate RV systolic reserve may be mandatory for sildenafil to exert its actions.

Sonographic lobe localization of alveolar-interstitial syndrome in the critically ill

Introduction. Fast and accurate diagnosis of alveolar-interstitial syndrome is of major importance in the critically ill. We evaluated the utility of lung ultrasound (US) in detecting and localizing alveolar-interstitial syndrome in respective pulmonary lobes as compared to computed tomography scans (CT). Methods. One hundred and seven critically ill patients participated in the study. The presence of diffuse comet-tail artifacts was considered a sign of alveolar-interstitial syndrome. We designated lobar reflections along intercostal spaces and surface lines by means of sonoanatomy in an effort to accurately localize lung pathology. Each sonographic finding was thereafter grouped into the respective lobe. Results. From 107 patients, 77 were finally included in the analysis (42 males with mean age = 61 ± 17 years, APACHE II score = 17.6 ± 6.4, and lung injury score = 1.0 ± 0.7). US exhibited high sensitivity and specificity values (ranging from over 80% for the lower lung fields up to over 90% for the upper lung fields) and considerable consistency in the diagnosis and localization of alveolar-interstitial syndrome. Conclusions. US is a reliable, bedside method for accurate detection and localization of alveolar-interstitial syndrome in the critically ill.

Serum albumin alters the expression of iron-controlled genes in Pseudomonas aeruginosa

Pseudomonas aeruginosa, which causes serious infections in immunocompromised patients, produces numerous virulence factors, including exotoxin A and the siderophore pyoverdine. As production of these virulence factors is influenced by the host environment, we examined the effect serum has on global transcription within P. aeruginosa strain PAO1 at different phases of growth in an iron-deficient medium. At early exponential phase, serum significantly enhanced expression of 138 genes, most of which are repressed by iron, including pvdS, regA and the pyoverdine synthesis genes. However, serum did not interfere with the repression of these genes by iron. Serum enhanced regA expression in a fur mutant of PAO1 but not in a pvdS mutant. The serum iron-binding protein apotransferrin, but not ferritin, enhanced regA and pvdS expression. However, in PAO1 grown in a chemically defined medium that contains no iron, serum but not apotransferrin enhanced pvdS and regA expression. While complement inactivation failed to eliminate this effect, albumin absorption reduced the effect of serum on pvdS and regA expression in the iron-deficient medium chelexed tryptic soy broth dialysate. Additionally, albumin absorption eliminated the effect of serum on pvdS and regA expression in the chemically defined medium. These results suggest that serum enhances the expression of P. aeruginosa iron-controlled genes by two mechanisms: one through apotransferrin and another one through albumin.

Incidental rectal carcinoid discovered after stapled hemorrhoidopexy: importance of histopathologic examination

AIM

Haemorrhoids are the most common surgically-treated gastrointestinal disorder. Complications of this surgery are generally non-neoplastic. Because rectal tumours usually present demonstratively during endoscopic examination, it is perhaps tempting to omit histopathologic examination after haemorrhoidectomy, especially in younger patients.

METHODS

The AA present a case of an early rectal carcinoid discovered after surgical treatment of haemorrhoids in a 27 years old man as an example of why it is essential to send all such specimens in the pathologist.

RESULTS

The detection of early lesions permits the adequate follow-up necessary to preclude more extensive surgery and eventually to prevent recurrence of tumour.

CONCLUSION

All tissue resected by haemorrhoidopexy must be sent to the pathology laboratory to protect the life and health of the patient .

The value of transcranial Doppler sonography with a transorbital approach in the confirmation of cerebral circulatory arrest

OBJECTIVE

Transcranial Doppler sonography (TCD) provides accurate confirmation of cerebral circulatory arrest (CCA) in brain death (BD), but is not feasible in patients with absent temporal bone windows. We added the transorbital approach in the TCD protocol for the diagnosis of CCA and compared findings with angiography. Furthermore, we evaluated whether reporting the angiographic and sonographic confirmation of CCA to relatives of brain-dead patients improves their comprehension and satisfaction with the medical information.

PATIENTS AND METHODS

Eighty-two clinically brain-dead patients underwent 4-vessel angiography, TCD of the basilar and middle cerebral arteries, and transorbital Doppler sonography (TOD) of the internal carotid arteries. Relatives were randomly allocated to 41 in whom BD was presented as a clinical diagnosis (group A) and to 41 in whom BD was presented as a clinical diagnosis confirmed by TCD and angiography (group B). Comprehension and satisfaction of the relatives were assessed using an interview and a questionnaire.

RESULTS

Both angiography and TCD verified CCA in all cases (k = 1). In 11 patients with failure of the transtemporal approach, CCA was confirmed by the transorbital recordings. The addition of TOD enabled 15.5% more cases of CCA to be diagnosed by TCD. Group B exhibited improved comprehension and satisfaction rates (P < .05).

CONCLUSIONS

The addition of TOD increases the efficacy of TCD in confirming CCA in BD. Reporting confirmation of CCA to families of brain-dead patients may improve their comprehension and satisfaction with the provided medical information.

Acute stress affects the physiology and behavior of allergic mice

Physical and psychological stressors have been implicated in acute asthma exacerbation. The objective of the current study was to determine the effects of forced swimming stress (FST) on allergic pulmonary inflammation in BALB/c mice. Eighty female mice were allocated to one of four treatments arranged in a 2 x 2 factorial consisting of two levels of allergy and two levels of stress. The effects of stress and allergy were assessed by examination of cytokines and leukocyte differentials in the bronchoalveolar lavage fluid, corticosterone and immunoglobulin (Ig) E in the plasma, leukocyte differentials in the peripheral blood, natural killer cytotoxicity, and histopathology of the lungs. Behavior was recorded during the FST. Stress and allergy increased plasma corticosterone in mice. Allergy increased IgE concentrations and pulmonary inflammation. Interleukin-4 was greater among allergic stressed and non-stressed mice and stressed, non-allergic mice compared with non-stressed, non-allergic mice. Interleukin-5 (IL-5) and 6 (IL-6) were greater among allergic stressed and non-stressed mice compared with non-allergic mice. Interleukin-5 and 6 were reduced among stressed-allergic mice compared with non-stressed, allergic mice. Stress and allergy shifted mice towards a T-helper 2 response as shown by increased interleukin-4. Stress reduced IL-5 and IL-6 in allergic mice but not non-allergic mice. Pulmonary inflammation was not reduced among allergic stressed mice in spite of elevated glucocorticoids. Mice induced to be allergic responded to FST differently than non-allergic mice. Our findings suggest that stress induces a differential response among allergic and non-allergic mice.

Prognostic utility of impedance cardiography measurements in elderly hemodialysis patients with coronary artery disease

AIM

We evaluated the utility of impedance cardiography (IC) in elderly hemodialysis (HD) patients with coronary artery disease (CAD).

PATIENTS AND METHODS

Seventy-five HD patients (30 with CAD) participated. IC cardiac output (ICCO), systemic vascular resistance and pulse pressure (PP) were calculated at baseline, and 30 and 180 days after study entry. ICCO was compared to echocardiography cardiac output (ECO). Relationships of IC measurements and cardiovascular mortality were assessed. Patients were followed up for 6 years after study entry or until death due to cardiovascular events.

RESULTS

ICCO and ECO were strongly correlated (r = 0.94, p < 0.001). ICCO correlated inversely with PP (r = -0.61; p < 0.001). Thirty fatal cardiovascular events were recorded. Using the bayesian' information criterion, multivariate Cox regression models revealed that increased PP and New York Heart Association (NYHA) class as well as decreased diastolic blood pressure (DBP) were predictors of cardiovascular mortality. Having a DBP <60 mm Hg (adjusted for NYHA) yielded a hazard ratio of 2.8 (95% confidence interval = 1.2-6.7).

CONCLUSION

IC accurately estimates the hemodynamic status in HD patients with CAD. Deterioration of cardiovascular performance expressed by decreased DBP values, adjusted for NYHA, may help to predict outcome.

Comparative expression profiling identifies an in vivo target gene signature with TFAP2B as a mediator of the survival function of PAX3/FKHR

The chromosomal translocation t(2;13), characteristic for the aggressive childhood cancer alveolar rhabdomyosarcoma (aRMS), generates the chimeric transcription factor PAX3/FKHR with a well known oncogenic role. However, the molecular mechanisms mediating essential pathophysiological functions remain poorly defined. Here, we used comparative expression profiling of PAX3/FKHR silencing in vitro and PAX3/FKHR-specific gene signatures in vivo to identify physiologically important target genes. Hereby, 51 activated genes, both novel and known, were identified. We also found repression of skeletal muscle-specific genes suggesting that PAX3/FKHR blocks further differentiation of aRMS cells. Importantly, TFAP2B was validated as direct target gene mediating the anti-apoptotic function of PAX3/FKHR. Hence, we developed a pathophysiologically relevant transcriptional profile of PAX3/FKHR and identified a critical target gene for aRMS development.

A comparison of anterior and posterior approaches for the surgical treatment of pancreatic pseudocyst using laparoscopic cystogastrostomy

BACKGROUND

Laparoscopic treatment of pancreatic pseudocyst allows for definitive drainage with faster recovery. Although many groups have reported their experience with an anterior approach, only a few have done so with a posterior approach. This paper compares the approaches, analyzing their potential benefits and pitfalls.

MATERIALS AND METHODS

Seven females and one male underwent laparoscopic cystgastrostomy to treat pancreatic pseudocysts. The anterior approach was performed by opening the stomach anteriorly, localizing the pseudocyst ultrasonographically, draining the cyst with a needle and, via the same opening, using a stapler to form a cystgastrostomy. The posterior approach was performed by directly visualizing the posterior gastric wall and the pseudocyst, opening and draining the cyst with a needle, and using a stapler and running sutures for closure.

RESULTS

All patients had gallstone pancreatitis. Cystgastrostomy via the anterior approach was used in 4 patients and via the posterior approach in 4 patients. Dense adhesions required one attempted posterior cystgastrostomy to be converted to an anterior approach. The mean age of the anterior group was 38 years (range, 18-58 years) and hospital stay was 6 days (range, 4-8 days): for the posterior group, mean age was 42 years (range, 40-44 years) and length of stay was 3 days (range, 2-4 days).

CONCLUSION

Although both approaches had good results with no complications and short hospital stays, the posterior approach is safer, with a more precise cyst visualization and dissection that permits more tissue to be sent for histopathologic examination. Furthermore, the posterior approach?s larger anastomosis would seem to yield fewer occlusions, which are commonly seen with the anterior approach. The anterior approach is easier to learn, but it requires the opening of the anterior stomach and the use of ultrasound.

The incidence of lower mid-trunk hyperpigmentation (linea nigra) is affected by sex hormone levels

The incidence of linea nigra was studied in 1,550 Nigerians of both sexes and of different age groups and among pregnant women and men with benign and malignant prostatic diseases over a nine-month period. From the study, it would appear that linea nigra increases in incidence from the age group 0-15 years (31.4%) to the age group 16-30 years (47.3%) before starting to fall in clinically normal individuals >30 years to 19.2%. For age groups 0-5 years, 6-10 years and 16-30 years, females more often than males have a linea nigra. For age group 11-15, males are equally as likely as females to have a linea nigra. The results suggest that women over 30 are more likely to have a linea nigra than men, but there are too few patients to make a definite statement, given the number of statistical tests performed. Pregnant women far more often have a linea nigra than nonpregnant women of the same age. The findings suggest that the likelihood of having a linea nigra depends on the level of sex hormones. This means that changes in the levels of hormones, either due to disease or drugs, may be reflected in changes in the incidence of a linea nigra. If this finding is confirmed, the linea nigra may serve as a convenient, noninvasive, free marker of alterations in sex hormones.

Molecular and cellular permeability control at the blood-brain barrier

The blood-brain barrier (BBB) is formed by brain capillary endothelial cells. These cells have at least three properties which distinguish them from their peripheral counterparts: (1) tight junctions (TJs) of extremely low permeability; (2) low rates of fluid-phase endocytosis; (3) specific transport and carrier molecules. In combination, these features restrict the nonspecific flux of ions, proteins, and other substances into the central nervous system (CNS) environment. The restriction protects neurons from harmful compositional fluctuations occurring in the blood and allows uptake of essential molecules. Breakdown of the BBB is associated with a variety of CNS disorders and results in aggravation of the condition. Restoration of the BBB is thus one strategy during therapy of CNS diseases. Its success depends on a precise knowledge of the structural and functional principles underlying BBB functionality. In this review we have tried to summarise the current knowledge of TJs, including information gained from non-neuronal systems, and describe selected mechanisms involved in permeability regulation.

Down-regulation of occludin expression in astrocytes by tumour necrosis factor (TNF) is mediated via TNF type-1 receptor and nuclear factor-kappaB activation

Tight junctions form the diffusion barrier of brain microcapillary endothelial cells and support cell polarity. Also astrocytes express tight junction components such as occludin, claudin-1, ZO-1 and ZO-2, but do not establish a permeability barrier. However, little is known about the function and regulation of these molecules in astrocytes. We studied the impact of tumour necrosis factor (TNF) on occludin and ZO-1 expression in astrocytes. TNF decreased occludin, but not ZO-1 expression. In brain microcapillary endothelial cells, as well as in epithelial cells, occludin expression was not influenced by TNF. Removal of TNF from astrocytes restored the basal level of occludin. Down-regulation was inhibited by caffeic acid phenethyl ester, a specific inhibitor of nuclear factor-kappaB (NF-kappaB) activation. Exposure of astrocytes isolated from mice deficient in either TNF type-1 receptor (TNFR1), TNF type-2 receptor (TNFR2), or both, respectively, revealed that down-regulation was mediated entirely by TNFR1. ZO-1, which can interact with occludin, was found to co-precipitate connexin43, but not occludin. These findings demonstrate that TNF selectively down-regulates occludin in astrocytes, but not in cells forming established tight junctions, through TNFR1 and suggest that NF-kappaB is involved as a negative regulator.

Occludin proteolysis and increased permeability in endothelial cells through tyrosine phosphatase inhibition

Regulation of epithelial and endothelial permeability is essential for proper function of compartmentalized organisms, and tyrosine phosphorylation plays an important role in this process. We analyzed the impact of protein tyrosine phosphatase (PTP) inhibition on the structure of endothelial junctional proteins. In human umbilical vein endothelial cells (HUVECs) the PTP inhibitors phenylarsine oxide (PAO) and pervanadate induced proteolysis of the tight junction protein occludin. Occludin proteolysis was inhibited by the metalloproteinase inhibitor 1,10-phenanthroline (PHEN), but not by inhibitors against other types of proteases. The junctional proteins ZO-1, cadherin and beta-catenin were not cleaved. Under conditions of occludin proteolysis, PAO treatment elevated permeability for FITC-dextran. Simultaneous incubation of HUVECs with PAO and PHEN inhibited the rise in permeability by more than 60%. PAO treatment lead to progressive disappearance of occludin from the cell periphery. In contrast, ZO-1, cadherin and beta-catenin retained their positions at the sites of intercellular contact. Simultaneous administration of PAO and PHEN greatly prevented the redistribution of occludin. These results demonstrate a selective cleavage of occludin by a metalloproteinase and suggest that this process can contribute to the control of paracellular permeability in endothelial cells.

Use of the "triple test" for palpable breast lesions yields high diagnostic accuracy and cost savings

BACKGROUND

The "triple test" for palpable breast lesions consists of physical examination, mammography, and fine-needle aspiration.

METHODS

Forty-six lesions in 43 patients were subjected to all three components of the triple test, followed by confirmatory open biopsy.

RESULTS

In all 21 cases where the triple test was concordant (elements had either all malignant or all benign results), pathologic analysis of open biopsy samples was confirmatory (predictive value and sensitivity 100%). Fine-needle aspiration was the most reliable element of the triple test in cases where the elements of the test were nonconcordant (negative predictive value and sensitivity of 95% and 96%, respectively).

CONCLUSIONS

The triple test was 100% accurate in the diagnosis of palpable breast lesions when all three elements were concordant. Cost analysis revealed that elimination of confirmatory open biopsy in such cases and also in cases in which the fine-needle aspiration and one other element of the test had a suspicious or malignant result, could yield an average per-case cost savings of up to $1,412 compared to triple test followed by routine confirmatory open biopsy.

Clusters of chromosome 9 aberrations are associated with clinico-pathologic subsets of non-Hodgkin's lymphoma

In this study we analyzed nonrandom aberrations affecting chromosome 9 in a series of 426 consecutively ascertained, karyotypically abnormal non-Hodgkin's lymphoma (NHL) tumors derived from 407 patients. Cytogenetic abnormalities were correlated with clinical, histologic, and immunologic features. Structural abnormalities of chromosome 9 were identified in 60 specimens derived from 59 patients. The recurring abnormalities among these were associated with 4 clinico-pathologic subsets. The first comprised 7 cases of t(9;14)(p13;q32), 6 of which had small lymphocytic lymphoma, plasmacytoid subtype, and an indolent clinical course. The second group included 12 cases with breaks at 9q11-13 and diffuse lymphomas with a large-cell component and a typical response to combination chemotherapy. The third group was comprised of 7 cases with 9q deletions, with a common deleted region encompassing 9q31-32. These cases were characterized by diffuse B-cell histology, young age, and poor clinical outcome. The fourth subset included 5 intermediate- to high-grade T-cell tumors with breaks at 9q34. This analysis of chromosome 9 aberrations in NHL comprises the first such effort based on a large series of tumors. We identify and report here new clinico-pathologic subsets with shared abnormalities of chromosome 9, which should facilitate new approaches to the analysis of the etiology and clinical behavior of NHL.