Antiproliferative and apoptotic potencies of glucocorticoids: nonconcordance with their antiinflammatory and immunosuppressive properties

Relative antiinflammatory and immunosuppressive potencies of glucocorticoids (GC) were previously well defined. Nonetheless, GC also regulate cell proliferation and programmed death (apoptosis). The aim of this study was to determine the relative potency of different GC on the modulation of cell survival. The GC-sensitive lymphoblast cell line CEM-c7/14 was submitted to 48 h-exposure to GC (dose-response curve from 10(-8) to 10(-5) M). Cell survival was analyzed employing the DimethylTiazol-Tetrazolium (MTT) test. For each GC at least 4 experiments were performed in quadruplicate. Responses to different GC at the same molarity were analyzed by ANOVA on Ranks. Cell responses to the same GC in different concentrations were tested by repeated measures ANOVA. The EC50 for each GC was calculated with the GraphPad Prism 3.0 software. The use of low concentrations (10(-8) and 10(-7) M) of hydrocortisone and methylprednisolone determined a similar effects on cell survival, which was less prominent than that observed with betamethasone, budesonide or momethasone. Momethasone was the most potent GC, inducing the most intense dexamethasone reduction on cell survival at the lowest concentration (10(-8) M). Momethasone and methylprednisolone were the two GC with the strongest impact on cell survival. Our findings suggest that antiproliferative and apoptotic potencies of GC are different from those previously reported antiinflammatory and immunosuppressive actions.     

Prenatal intramedullary gliofibroma

Summary A case of an unusual congenital intramedullary tumor of the spinal cord is reported. A paraplegic 11-day-old boy with hypotonia and atrophy of the abdominal and lower-extremity muscles showed a complete myelographic block between T-5 and T-8. Surgical exploration disclosed an elongated tumor mass within the spinal cord, that blended with the surrounding nervous-system tissue. Light and electron microscopy showed that the tumor was composed of intermingled well differentiated astrocytes and fibroblasts. These two cell types often were surrounded by the same basal lamina. There were no intercellular junctions. Gliofibrils were abundant, and the interstitial spaces contained abundant collagen and reticulin fibers There were no histological signs of malignancy. We conclude that this is a case of prenatally arising gliofibroma.     

Evaluation of giant cell tumor by computerized tomography

The use and value of computerized tomography in giant cell tumor is demonstrated. The usefulness of computerized tomography, in the evaluation of giant cell tumor, rests upon its ability to demonstrate the presence and extent of its soft tissue component, as well as its intraosseous extent, more accurately than conventional methods. Computerized tomography is a non-invasive procedure, and in the postoperative state can demonstrate more accurately the presence and extent of residual or recurrent disease.     

Functional asplenia in patients with chronic graft-versus-host disease: concise communication

Liver/spleen images were performed with technetium-99m sulfur colloid in 53 patients who had undergone bone-marrow transplantation. The spleen was not seen in the images in five out of the ten patients with chronic graft-versus-host disease (GVHD). None of the five had a history of splenectomy. In two of these patients, anatomical presence of the spleen had been documented earlier by scintigram. The spleen was visible in all seven patients with acute and in all 36 patients without GVHD. Neither the differences in methods of treating the patients before bone-marrow transplantation nor the time lapse between transplantation and the liver/spleen image correlated with the observed effect among these three groups of transplant patients. We conclude that there is a high association between chronic GVHD and functional asplenia.     

Effect of scorpion toxin (tityustoxin, TsTx) on the salivary gland of the rat, in vivo and in vitro

Intravenous injection of purified scorpion toxin (tityustoxin, TsTX) brings about the appearance of salivary flow and of kallikrein and amylase secretion in the saliva of rats. In experiments performed in vitro, using slices of parotid gland, a dose-response curve correlating tityustoxin concentration with kallikrein and amylase activities was obtained. The secretion of kallikrein is slower and smaller than that of amylase after up to 60 min of incubation. Experiments in which propranolol, phenoxybenzamine or atropine were injected into rats or added to parotid gland slices showed that the release of kallikrein is more dependent on cholinergic mechanisms, whereas the release of amylase is mainly related to adrenergic effects. Pre-treatment of the animals with reserpine confirms these results. The actions of tityustoxin on the kallikrein and amylase secretions, per min, are more effective than those by pilocarpine and isoproterenol, respectively.     

Mechanisms of the impaired diuretic and natriuretic responses to a sustained and moderate saline infusion in rats with experimental cirrhosis

Kidney function and tubular handling of water and sodium by superficial nephrons, packed cell volume, total plasma proteins and albumin distribution space were studied in control and cirrhotic rats before and after a moderate and sustained saline infusion (3% body weight per 30 min + reposition of urinary losses). Tubular fluid samples were obtained from late proximal, early distal and late distal convolutions of superficial nephrons using micropuncture. Protein distribution was assessed by intravenous injection of 0.5 muCi of (125I)-albumin. In basal conditions, both groups of rats showed similar glomerular filtration rate and renal plasma flow, but cirrhotic animals had lower sodium excretion (fractional excretion of sodium = 0.04 +/- 0.01% vs. 0.22 +/- 0.02%, p less than 0.05) and urinary volume (4.31 +/- 0.41 vs. 7.57 +/- 0.53 microliter per min; p less than 0.05). After saline infusion, total plasma proteins decreased more in cirrhotic than in control rats (-18.5 +/- 2.7 vs. -12.9 +/- 2.2%, p less than 0.05). The opposite was observed for albumin distribution space (34.5 +/- 6.1 vs. 22.1 +/- 3.5%, p less than 0.05). Fractional sodium excretion increased to 2.98 +/- 0.15% in control rats but only to 0.61 +/- 0.080% in cirrhotic rats. The ratio single nephron glomerular filtration rate/glomerular filtration rate increased from 19.6 +/- 0.7 to 21.2 +/- 1.0 (X10(-6), p less than 0.005) in control animals but did not change in cirrhotic rats. These animals were unable to decrease adequately fractional fluid reabsorption in the proximal tubule and the loop of Henle.(ABSTRACT TRUNCATED AT 250 WORDS)     

Preparation of bovine platelet aggregating factor (PAF)

A simple four step procedure for the preparation of bovine platelet aggregating factor (PAF)¹ is described. The final product is obtained in good yield. After reduction, the product gives one main band with polyacrylamide sodium dodecyl sulfate (SDS) disc electrophoresis that stains for protein and carbohydrate and has an approximate molecular weight of 260,000. Before reduction, electrophoresis of the product on two percent agarose in SDS shows a series of high molecular weight aggregates ranging in molecular weight from 1.15 to 12 million.