Pneumothorax and other lung diseases: effect of altered resolution and edge enhancement on diagnosis with digitized radiographs

Prior studies have shown that pneumothorax is one of the more difficult entities to diagnose with digitized radiography. This study was designed to test whether increasing resolution from 1.25 to 2.5 line pairs per millimeter (lp/mm) and image processing (edge enhancement from unsharp masking) would increase accuracy and confidence in the diagnosis of pneumothorax, as well as normal cases and other forms of lung disease. Conventional radiographs were digitized with use of a laser reader and then reformatted as film hard copy. Eleven observers read 35 cases reformatted in three different ways (1.25 lp/mm, 2.5 lp/mm, 1.25 lp/mm unsharp mask). The images with finer resolution (2.5 lp/mm) and unsharp mask images were superior to those with coarser resolution (1.25 lp/mm) for the diagnosis of pneumothorax. There was no difference in diagnostic accuracy for normal patients. For abnormalities other than pneumothorax, the unsharp mask images were significantly worse. Confidence in the diagnosis of pneumothorax and other abnormalities was highest with the finest resolution (2.5 lp/mm).     

Chronology of cellular events leading to derangements in function of pancreatic islets in chronic renal failure.

In chronic renal failure (CRF), a multitude of metabolic derangements occur in the pancreatic islets, resulting in impaired glucose-induced insulin secretion. These abnormalities include a rise in the basal level of cytosolic calcium ([Ca2+]i) in the islet, a decrease in their basal and stimulated ATP and ATP/ADP ratio, a reduction in the Vmax of Ca2+ATPase and Na(+)-K+ATPase, and an impaired glucose-induced calcium signal. The sequence of events that lead to these derangements and to the impairment in insulin secretion during the evolution of CRF are not defined. The study presented here examined this issue by measuring the metabolic profile of pancreatic islets weekly during the evolution of CRF over a period of 6 wk. The results show that serum levels of parathyroid hormone (PTH) begin to rise during the first week of CRF. The Vmax of Ca2+ATPase and Na(+)-K+ATPase increased during weeks 1 to 3 of CRF but fell to low levels thereafter. At week 3 of CRF, the basal level of [Ca2+]i began to rise, whereas basal and the stimulated ATP content and ATP/ADP ratio started to fall. Glucose-induced calcium signal, delta[Ca2+]i/basal [Ca2+]i, and insulin secretion became abnormally low between weeks 3 and 6 of CRF. The data allow the following formulation: as serum levels of PTH begins to rise, calcium entry into islets is augmented; this in turn will stimulate the activity of Ca2+ATPase and the Na(+)-Ca2+ exchanger, and hence, calcium extrusion out of the islets is increased. As a result, [Ca2+] remains normal during the first 2 wk of CRF.(ABSTRACT TRUNCATED AT 250 WORDS)     

A monoclonal antibody (IID510g52) for the determination of functional domains within integrin cell surface receptors.

Monoclonal antibodies against cell surface receptors can be useful for the study of structural and biochemical features involved in protein interactions underlying platelet adhesion and aggregation. We report here the characterization of a monoclonal antibody, IID510g52 (hereafter referred to as IID5), which has been selected based on its specific binding properties against the platelet membrane glycoprotein IIIa. Characterization of the reactive epitope, including evolutionary conservation and identification of related IID5 target antigens in tumor cells, suggest that the IID5 epitope is implicated in the ligand-binding function of integrin receptors. Indeed, we show that this MoAb acts as a potent inhibitor of platelet aggregation and cell adhesion. Taken together, these results indicate that such a monoclonal may be a strategic tool for better understanding multiple integrin-mediated adhesive reactions, as well as the determination of interacting recognition sites.     

The Role of Donor Bone Marrow Infusions in Withdrawal of Immunosuppression in Adult Liver Allotransplantation

We investigated the role of donor bone marrow cell (DBMC) infusions in immunosuppression withdrawal in adult liver transplantation. Patients enrolled were at least 3 years post-transplantation, with stable graft function. Forty-five (study group: G1) received DBMC, and 59 (control group: G2) did not. Immunosuppression was reduced by one third upon enrollment, by another third the second year of the study and was completely withdrawn the third year. Patient and graft survival were similar between the two groups. Although rejection episodes were significantly less in G1 the first 2 years of the study (35% vs. 57%, p = 0.016), there was no significant difference overall (74% vs. 81%, p = 0.14). Until February 2004, 20 patients, 10 in each group, were immunosuppression free for 1-3 years. Approximately 20% of long-term survivors of liver transplantation can successfully discontinue their immunosuppression. DBMC infusions, do not increase this likelihood.     

Experimental investigation on histocompatibility of bovine collagen in rat tongue.

Authors injected a 1.5-2 cc Gax-Collagen into the tongue of 13 rats in order to examine the reactivity of the tissues around the graft and its attitude and duration. The research had practical purposes as the material is mainly used in E.N.T. for reconstructing the vocal cords. The animals have been sacrificed from 1 day to 9 months and the tongue subjected to the ordinary histologic methods. Our conclusions are as follows: a) a moderate inflammatory reaction following the introduction of the foreign body, then it attenuates and disappears at the third month; b) the implant is well tolerated, does not cause structural alterations in the surrounding tissues, in particular in the musculature where it is placed; c) a neovascularization appears, it lessens over the time, keeping itself only at the edge of the graft; d) in the formed fissures, fibroblasts, traces of collagen and neocollagen are present. All these conditions allow for taking root and the persistence of the implant. It is remarkable that the spherical form of the Gax-Collagen does not modify even if it has been implanted into a muscular organ and therefore subjected to severe and continuous mechanical stress.     

Inhibition of angiotensin converting enzyme by ramipril in serum and tissue of man.

Studies in animal models have indicated that ramipril is a potent inhibitor of angiotensin converting enzyme (ACE) in serum and tissue. In our study, the normal range of ACE activity and the inhibitory effect of short-term oral administration of ramipril on ACE activity in human serum and tissue samples of renal cortex, heart and blood vessels were determined. ACE activity in the renal cortex (125.2 +/- 11.5 nmol/mg per min) was greater than 600 times that of the heart (0.20 +/- 0.01 nmol/mg per min), greater than 500 times that of the veins (0.23 +/- 0.09 nmol/mg per min) and greater than 150 times that of the arteries (0.80 +/- 0.23 nmol/mg per min). ACE activity in the renal cortex and arteries 2 h after last dosing was almost completely inhibited by ramipril whereas ACE activity in the veins and heart was inhibited to a lesser extent. Our results demonstrate in man, for the first time, an inhibition of tissue ACE following short-term oral treatment with an ACE inhibitor.     

The imprecision of stereopsis

In comparison to lateral judgments of distance, stereoscopic judgments are not precise. Although stereoacuity thresholds for targets presented in the fixation plane can equal the best thresholds for the monocular hyperacuities, i.e. a few sec arc, the increment thresholds for disparity are substantially larger than the increment thresholds for lateral separation (width). We measured the minimum detectable change in the three-dimensional distance separating two features, one presented in the fixation plane, and the other some distance in front of it, i.e. with a significant standing disparity between the two features. For briefly-presented targets (150 msec), the Weber fraction for disparity was 10-20% over the range from 1 to 20 min arc, while the Weber fraction for width was only 2-3% under comparable conditions. The disparity thresholds were substantially improved for a longer duration target (1000 msec), but they were still a factor of two worse than the monocular width thresholds. In a related experiment, the vernier acuity for a standard vernier target was profoundly degraded by pairing the offset upper line presented to one eye with a disparate line in the other eye; the vernier threshold was elevated for disparities ranging from 3 to 30 min arc. This finding shows that the more precise monocular signals are actively suppressed in fused or partially-fused stereoscopic images.     

Corticosteroids reduce regenerative repair of epithelium in experimental gastric ulcers.

The association between corticosteroid treatment and gastric ulcer healing is controversial. The effects of corticosteroids on experimental ulcer healing in the rat were studied and the effect of coadministration of a prostaglandin E1 analogue was determined. Forty male adult rats were divided into five groups and pretreated for 10 days as follows: (a) control, (b) prednisolone (10 mg/kg), (c) prednisolone and misoprostol (300 micrograms/kg), (d) misoprostol, and (e) indomethacin (2 mg/kg) Gastric ulcer was induced by applying a cryoprobe to the serosal surface of the stomach. Healing was assessed by determining the ulcer size at three and six days. Mucosal regenerative activity at the ulcer edge was assessed by quantitating DNA synthesis in cells by immunohistochemical techniques using monoclonal antibodies to detect expression of proliferating cell nuclear antigen (PCNA) and incorporated 5-bromo-5-iododeoxyuridine (BrdU). Compared with control rats, the rate of healing and the mucosal regenerative activity were significantly reduced in rats treated with prednisolone and indomethacin (p < 0.05). Coadministration of misoprostol and corticosteroids reversed the delay in healing and the reduction in mucosal regeneration induced by corticosteroids alone. With misoprostol alone, the ulcer size and the number of epithelial cells that actively synthesised DNA did not differ from control animals. A comparison between the two immunohistochemical markers of cell proliferation showed a highly significant correlation between the two techniques (r = 0.64, p < 0.005), indicating that the simpler PCNA technique should prove valuable in assessing regeneration in experimental ulcer disease.