Transepithelial paracellular leakiness induced by chronic phorbol ester exposure correlates with polyp-like foci and redistribution of protein kinase C-alpha

Although exposure of LLC-PK1 epithelial cell sheets to phorbol esters (TPA) causes a near immediate and total decrease of transepithelial electrical resistance (TER), continuation of exposure for 3 to 4 days results in a tachyphylactic response as TER begins to return to control levels. Recovery of TER is maximal by 5 to 6 days, but reaches only 70 to 80% of control level. A reciprocal change in the transepithelial flux of D-mannitol indicates that the TER decrease is indicative of an increase in tight junction permeability. Exposure of cell sheets to TPA for several days also results in the appearance of multilayered polyp- like foci (PLFs) across the otherwise one cell layer thick cell sheets. The pattern of penetration of the electron dense dye, ruthenium red, from the apical surface, across the tight junction and into the lateral intercellular space indicates that the tight junctions of the cell sheet become uniformly leaky after acute exposure to TPA. However, when exposure is continued for several days, only the junctions of cells in the PLFs manifest leakiness. The decrease in TER following acute TPA exposure correlates with the translocation of protein kinase C-alpha (PKC alpha) into a membrane-associated compartment. With exposure of several days, only a trace of PKC alpha is visible by Western immunoblot, and this is in the membrane-associated compartment. Immunofluorescent microscopy indicates that the trace of PKC alpha seen in the Western immunoblots is ascribable distinctly to cells of the PLFs. Monolayer areas between PLFs show no discernible immunofluorescent signal. The data therefore indicate that tight junction barrier function may be restored in certain areas by the down regulation of PKC alpha from the membrane-associated compartment. Failure to down regulate may result in the paracellular leakiness and abnormal cell architecture of the PLFs. Possible implications of this model for in vivo epithelial tumor promotion are discussed.      

Sputum tumour necrosis factor-alpha and leukotriene concentrations in cystic fibrosis

It is postulated that a vigorous host inflammatory response in the cystic fibrosis lung contributes to lung injury. Tumour necrosis factor-alpha (TNF-alpha) may play a part in that process and in the generation of leukotrienes. Therefore, the relationships between sputum TNF-alpha, leukotriene concentration, and lung function abnormalities in 16 children with cystic fibrosis were investigated. Each subject provided sputum samples and performed spirometry. TNF-alpha was measured by enzyme linked immunosorbent assay; individual leukotrienes were separated using high performance liquid chromatography and quantified by radioimmunoassay. The geometric mean concentration of TNF-alpha was 129.7 pg/ml and 95% confidence interval 48.2 to 348.3. Mean (SEM) leukotriene B4 (LTB4) was 97.8 (22.9) pmol/g and total cysteinyl leukotrienes were 60.9 (14.8) pmol/g. Mean (SD) forced expiratory volume in one second (FEV1) of the group was 53 (15)% of predicted and forced vital capacity (FVC) was 65 (14)% of predicted. There was a significant positive correlation between TNF-alpha and both LTB4 and the total cysteinyl leukotriene sputum content. An inverse relationship existed between TNF-alpha and FEV1 and FVC. Moreover, a negative correlation was observed between sputum LTB4 and FEV1 and FVC. These results suggest that TNF-alpha and the leukotrienes may participate in the airways inflammation and airflow obstruction observed in cystic fibrosis subjects and support the hypothesis that TNF-alpha upregulates the 5-lipoxygenase pathway in vivo.     

A new amino acid mixture permits new approaches to the treatment of phenylketonuria

A new amino acid mixture for incorporation into medical foods for the treatment of hyperphenylalaninemia has been tested in a regular clinic. The mix is designed to be as unobtrusive as possible, consistent with good nutrition. After more than 1 year of trial as a beverage, we have shown that it is safe and well tolerated but that plasma phenylalanine is no better controlled than with some other products. The mix can be incorporated into a large number of different foods without affecting the taste. Occult monitoring of the quantity of medical foods purchased compared with the amounts reported to be consumed in diet histories provides an excellent way to monitor dietary compliance.     

Bovine seminal ribonuclease is cytotoxic for both malignant and normal telomerase-positive cells

Bovine seminal-ribonuclease (BS-RNase) is a member of the 'ribonucleases with special biological actions' family since it possesses specific anti-tumour, anti-spermatogenic and embryotoxic activities and exerts an immunosuppressive effect on T lymphocytes. In previous studies it was demonstrated that BS-RNase induced apoptosis in proliferating, malignant and normal cells and that telomerase activity loss also caused apoptotic death in neoplastic cells. Since an obvious relationship between cell proliferation and telomerase activity exists, the aim of this work was to study if the pro-apoptotic cytotoxic action exerted by BS-RNase on proliferating malignant cells (HT29) and proliferating normal cells (PHA-stimulated lymphocytes) could be linked to a possible BS-RNase effect on telomerase activity. In BS-RNase-treated HT29 cells (Na-butyrate-differentiated or not) and human lymphocytes (proliferating or not), we investigated cell vitality (MTT method) and morphology (SEM), BS-RNase localization (immunofluorescence), telomerase activity (TRAP-ELISA method), hTR mRNA expression (RT-PCR), and hTERT levels (western blot). While no BS-RNase effect was detectable on not proliferating cells, a clear relationship was noticed between the diminished number of vital elements of both proliferating cell populations after treatment (48 h and 72 h for HT29 and PHA-stimulated lymphocytes, respectively) with 50 microg/ml BS-RNase and the decrease of their telomerase activity. At the same time, we found that hTR levels, the RNA subunit of telomerase, in proliferation-inhibited BS-RNase-treated cells were diminished. Moreover, by immunofluorescence technique, we detected BS-RNase in the HT29 cell nucleolus after 3-h treatment. Therefore, as hTR has been recently proven to co-fractionate with nucleoli, we hypothesize that a BS-RNase direct action on the telomerase hTR subunit could be a possible mechanism of action by which BS-RNase exerts its pro-apoptotic effects only on proliferating cells.     

Liver transplantation in children weighting less than 6 kg: the Bergamo experience

Liver transplantation (OLT) remains a major medical and surgical challenge in small patients. From October 1997 through July 2004, 17 babies less than 6 kg underwent 18 OLTs. Median age and weight were 3 months (range = 1 to 9) and 4.7 kg (range = 2.2 to 5.8). Two whole, one reduced, and 15 split-liver grafts (left lateral segments) were obtained from donors of median age and weight of 11.6 years (range = 0.5 to 62) and 50 kg (range = 7 to 63). Donor-to-recipient median weight ratio (D/R) was 9.1 kg (range = 1.3 to 17.6) and median graft-to-recipient weight ratio (GRWR) was 5% (range = 3.1 to 10). The incidence of biliary complications was 23%. The only vascular complication was a portal vein thrombosis (6%). Fourteen patients (79%) are alive with good graft function at a median follow-up of 39 months (range = 0.5 to 74). Three patients (all status 1) died on postoperative day 285 (brain death), 17 (multiorgan failure), and 229 (cardiovascular failure during retransplantation). Actuarial patient survivals at 6 months and 6 years are 94% and 78% while graft survivals are 89% and 74%, respectively. Currently all the patients listed as UNOS status 2 and 3 (73%) at the time of transplant are alive. During the same period one premature neonate (1.8 kg) who presented with fulminant hepatic failure died on the waiting list after 12 days. Our data confirm that the extensive use of a split-liver technique from small adult or pediatric cadaveric donors can offer the benefits of liver transplantation to small pediatric candidates with excellent results.     

Acceptance of marginal liver donors increases the volume of liver transplant: early results of a single-center experience

To expand the donor pool, clinicians are continually modifying criteria to accept organs, particularly those in the so-called expanded or marginal donor pool. The concept and definition of a marginal donors continues to evolve. The impact of their use is the result of a combination of donor and recipient factors. Most clinicians accept steatosis above 30%, donor age over 60 years, prolonged ischemia time, prolonged intensive care unit stay, hypernatremia, previous cardiac arrest, prolonged episodes of hypotension, large use of inotrope drugs, and elevated liver function tests as criteria for designation of a marginal organ. In June 2003, we started to use marginal donors each year tripling the number of transplants per year at our center.     

Gastric Cancer Precursor Lesions and Helicobacter pylori Infection in Patients with Partial Gastrectomy for Peptic Ulcer

The mucosa of the gastric stump is considered at greater risk of dysplastic and neoplastic changes than that of the intact stomach. The combination of enteric reflux and Helicobacter pylori infection may have a synergistic damaging effect on the mucosa of the gastric remnant, both producing and increasing mucosal proliferation. The aim of this study was to assess whether the occurrence of H. pylori infection in the remnant mucosa of partially gastrectomized subjects for peptic ulcer disease is associated with an increase of the mucosal precursor lesions of malignancy. A series of 151 subjects who underwent partial gastrectomy for peptic ulcer disease were submitted to upper digestive endoscopy for long-term surveillance. Biopsy specimens of the gastric stump were tested for the occurrence of H. pylori infection and for the presence of precancerous mucosal lesions. The prevalence of H. pylori colonization in the remnant stomach was less than 30% and similar in subjects with different time intervals between gastrectomy and endoscopy. Age at surgery (χ²: p = 0.03) and H. pylori infection (χ²: p = 0.002) were significantly associated with the grading of mucosal lesions. The prevalence of normal mucosa was 10 times higher in H. pylori-negative patients as in H. pylori-positive ones (22.0% vs. 2.4%), and the prevalence of intestinal metaplasia was four times higher in H. pylori-positive patients than in H. pylori-negative ones (19.6% vs. 4.6%). We concluded that H. pylori infection may play a causal role in the development of gastric lesions in the operated stomach.     

Iloprost infusion in diabetic patients with peripheral arterial occlusive disease and foot ulcers

The aim of the study was to evaluate iloprost infusion as an alternative to open surgical revascularisation in diabetic patients with foot ulcers, also as a support measure in conjunction with endovascular procedures. We studied 244 patients with critical ischaemia of the lower limbs, 146 of whom (59.8%) affected by diabetes. A femoro-distal bypass was performed in 175 patients. In the 69 nonsurgical diabetic patients (47.3% of the diabetics) an iloprost infusion was started. These diabetics presented foot ulcers, a palpable or slightly hypo-sphygmic popliteal pulse and high distal arterial flow at the ankle. In 55 of these patients (79.7% of those not operated on and 37.6% of the diabetics) who were non-responders to medical therapy, an endovascular procedure was also performed. The results of the iloprost infusion (69 pts.) were evaluated after one week. In 14 responders treated only with iloprost infusion, complete healing of the lesions occurred during the 3 weeks following the end of the 4-week course of therapy. No severe ischaemia recurrences were reported in the follow-up of these 69 patients. In the 47.3% of subjects with diabetic arteriopathy presenting foot ulcers and high distal flow, it proved possible to avoid an open surgical revascularisation procedure and to resort to medical therapy with iloprost, completed in 79.7% of cases with endovascular procedures. Iloprost infusion improves limb perfusion and, in selected cases may be an important therapeutic tool for the care of ulcerative lesions of the diabetic foot, also as a support measure in conjunction with endovascular procedures.