Prostaglandin levels in BL6 melanoma cells cultured in vitro: the effect of vitamin E succinate supplementation

Malignant murine melanoma (BL6-F10) cells convert arachidonic acid primarily to PGD2, PGF2alpha, PGE2, PGI2 in descending order of magnitude. Supplementation with 1-10 microg/ml vitamin E succinate resulted in a significant (P < or = 0.05) decrease in PGD2 levels at vitamin concentrations of 3, 5, 7 and 10 microg/ml respectively, while PGF2alpha levels were significantly decreased at 1, 3, 5 (P < or = 0.05), 7 and 10 microg/ml (P < or = 0.01) vitamin E succinate. BL6-F10 cells supplemented with 7 and 10 microg/ml vitamin E succinate showed a marked increase in PGE2 levels with a significant increase occurring at 10 microg/ml (P < or = 0.025). PGI2 levels followed a similar trend to PGE2 with a significant increase (P < or = 0.05) occurring at 10 microg/ml.

Acute auto immune haemolytic anaemia secondary to hepatitis A infection

Auto immune haemolytic anaemia has been described in association with a variety of hepatotropic viruses, in particular cytomegalovirus, Epstein-Barr virus and hepatitis B. There is a well-recognized association between chronic active hepatitis and auto immune haemolytic anaemia. We present the first reported case of acute hepatitis A which resulted in a fall in haemoglobin concentration from 14.6 to 4.5 g/dl due to an acute haemolytic anaemia with an associated rise in bilirubin from 149 to 960 mumol/l.

Indium-111-diethylenetriaminepentaacetic acid-octreotide is delivered in vivo to pancreatic, tumor cell, renal, and hepatocyte lysosomes

To better understand the factors that govern the target-to-background ratios of 111In-diethylenetriaminepentaacetic acid (DTPA) polypeptides, we studied 111In-DTPA-octreotide and a model nontargeted compound, 111In-DTPA-poly(D)lysine-biotin. We evaluated the fate of 111In-DTPA-octreotide after it localizes in somatostatin receptor-positive tissues and sought to determine why such a large fraction of these and other 111In-DTPA-polypeptides accumulate in the liver and kidneys. Biodistribution studies in rats with an implanted pancreatic adenocarcinoma demonstrated rapid accumulation of 111In-DTPA-octreotide in the pancreas and tumor. Indium-111 also accumulated in the liver and kidneys. Subcellular fractionation of the liver, kidneys, tumor, and pancreas showed that the majority of the radioactivity copurified with lysosomal enzymes. Even at 1 h, little radioactivity was found in the fractions containing a cell surface enzyme. This suggests that in each tissue, the 111In-DTPA-octreotide was rapidly shuttled from the cell surface to lysosomes. In the liver, hepatocyte lysosomes were separated from sinusoidal and Kupffer cell lysosomes by administering chloroquine prior to sacrifice. This density shift experiment indicated that 111In-DTPA-octreotide accumulated predominantly in hepatocyte lysosomes. A low molecular weight 111In-DTPA-poly(D)lysine-biotin compound was synthesized, and biodistribution studies showed substantial renal accumulation. The poly(D)lysine backbone conferred resistance to degradation, and this fact allowed determination of the distribution of this compound at the cellular level using an antibiotin antibody and immunohistochemical techniques. These experiments, as well as subcellular fractionation studies, demonstrated that the 111In-DTPA-poly(D)lysine-biotin compound accumulated in the lysosomes of proximal renal tubular cells. These results indicate that lysosomes play a critical role in the cellular physiology of radiolabeled polypeptides. Using these data, we propose a comprehensive model that summarizes the factors that govern the target to background ratios of radiolabeled polypeptides.

Results of the 1996 survey of the American Association of Academic Chief Residents in Radiology

RATIONALE AND OBJECTIVES

Diagnostic radiology chief residents were surveyed on issues related to residency training to compare features and gauge trends in training.

METHODS

Questionnaires were mailed to accredited programs in the United States. A variety of demographic and common-interest questions were asked.

RESULTS

Forty-three percent of surveys were returned. The percentage of female residents was similar to that reported in other recent surveys; however, the percentage of women among 1st-year residents had decreased. Resident salaries had increased, although the average salary for a 4th-year resident had decreased when adjusted for inflation. Most 1st-year residents started participating in overnight hospital coverage by their 12th month of residency, and the total number of call days during residency correlated inversely with the size of the residency program. Almost half of residency programs used a night-float resident to provide after-hours coverage.

CONCLUSION

The information derived from the survey should be useful for program evaluation and future planning.

Effect of vitamin E and indomethacin treatment on adenylate cyclase activity, PGE2 and cAMP levels in murine melanoma cells

Malignant murine melanoma (BL6) cells cultured in vitro were supplemented with indomethacin (0.15 microM) and varying levels (1-10 micrograms/ml) of vitamin E succinate. The effect of combined indomethacin and vitamin E succinate treatment on the growth as well as the levels of adenylate cyclase activity, prostaglandin E2 (PGE2) and cyclic adenosine monophosphate (cAMP) were determined in these cells. BL6 cells supplemented with 0.15 microM indomethacin and 1-10 micrograms/ml vitamin E succinate showed a significant (P < or = 0.05) decrease in growth at 1 microgram/ml vitamin E succinate, while at 3-10 micrograms/ml, no significant increase or decrease in growth was observed when compared to control cultures (OE). Results from studies of adenylate cyclase activity in BL6 cells showed no significant increase or decrease in enzyme activity, nor were the levels of PGE2 and cAMP affected when the cells were supplemented with 0.15 microM indomethacin and 1-10 micrograms/ml vitamin E succinate.

Implementation of a continuous-flow stirred bioreactor system in the bioremediation of heavy metals from industrial waste water

The industrial applicability of immobilized non-viable yeast biomass (Saccharomyces cerivisiae) in continuous-flow stirred bioreactors was tested with respect to metal removal from electroplating effluent solutions containing Cu, Cd, Cr, Ni and Zn in excess of the stipulated water quality criteria. Two systems, a dual bioreactor and triple bioreactor system in series, were tested and compared regarding their efficiency of metal removal. The system containing two bioreactors linked in series provided a more efficient solution to the problem. The introduction of a third bioreactor into the system had a marginal effect on the amount of metal removed. Subsequent to treatment within the bioreactors the levels of Cu, Cr and Ni in the effluent complied with the stipulated drinking water quality criteria and, although in excess of these criteria only 18% of the initial Zn and 17% of the Cd remained in solution.

Effect of alpha-tocopherol succinate on free radical and lipid peroxidation levels in BL6 melanoma cells

Numerous studies have proposed a radical or oxidant involvement in a number of degenerative diseases such as cancer. This has led to suggestions that the supplementation of antioxidants such as alpha-tocopherol (vitamin E) may function to reduce the growth of cancer. In this study, a nonmalignant Monkey kidney (LLCMK) and a malignant Murine melanoma (BL6-F10) cell line were supplemented with varying levels of alpha-Tocopherol acid succinate (vitamin E succinate) ranging from 1 to 10 microg/ml. BL6-F10 cells supplemented with 5, 7, and 10 microg/ml vitamin E succinate, showed significant decreases in cell proliferation, and this decrease was accompanied by a concomitant increase rather than a decrease in the levels of free radicals and lipid peroxidation. LLCMK cells supplemented with 1-10 microg/ml vitamin E succinate showed no significant increase or decrease in growth, while the levels of lipid peroxidation were shown to be insignificantly elevated at 5, 7, and 10 microg/ml vitamin E succinate. Free radical levels in LLCMK cells were significantly decreased at 1 microg/ml vitamin E succinate, while at 3, 5, 7, and 10 microg/ml supplementary vitamin E succinate, free radical levels increased compared to the 1 microg/ml group, but not compared to control cultures. These results suggest that the inhibitory effects of vitamin E succinate on BL6-F10 cell growth in vitro is not a consequence of its antioxidant properties, but may, in fact, be due to one or more of its other potential roles within the cells, such as the regulation of cellular enzyme activities involved in growth.

Portal branch occlusion safely facilitates in vivo retroviral vector transduction of rat liver

Hepatic gene therapy might correct the clinical manifestations of several genetic disorders in patients. Although retroviral vectors with a strong liver-specific promoter can result in stable and therapeutic levels of expression of genes from the liver, application of these techniques in humans is limited by the need to perform one or more invasive procedures to achieve ex vivo or in vivo transduction of hepatocytes. In vivo delivery involves injection of retrovirus into the portal vein during liver regeneration. Although transduction is efficient and specific for the liver, induction of hepatocyte replication requires a 70% partial hepatectomy or administration of a liver toxin. An alternative method for inducing hepatocyte replication is to occlude branches of the portal vein. This results in apoptosis of hepatocytes in the occluded lobes and compensatory replication of the hepatocytes in the nonoccluded lobes. We demonstrate here that portal branch occlusion is nearly as effective as partial hepatectomy at facilitating retroviral vector transduction in vivo and has a lower morbidity. Portal branch occlusion could be performed in larger animals by minimally invasive techniques and has been used safely to treat human patients with liver cancer. Portal branch occlusion might ultimately be used in humans to facilitate retroviral vector transduction in vivo for the treatment of genetic diseases.

The role of adenylate cyclase, cAMP and PGE2 in the in vitro growth regulation of murine melanoma cells by vitamin E

Previous studies have shown that vitamin E supplementation inhibits murine melanoma cell growth in vitro. In this study, malignant murine melanoma (BL6) and non-malignant monkey kidney (LLCMK) cells were supplemented with 1-10 micrograms/ml D-alpha-tocopherol acid succinate (vitamin E succinate). The effect of vitamin E succinate supplementation on growth as well as the levels of adenylate cyclase activity, prostaglandin E2 (PGE2) and cyclic adenosine monophosphate (cAMP) were determined in these cells. Results from these studies indicated a significant inhibition of BL6 cell growth at 5 (P < 0.025), 7 and 10 micrograms/ml (P < 0.001) vitamin E succinate supplementation, while LLCMK cells showed no significant increase or decrease in growth following vitamin E succinate supplementation. BL6 cells supplemented with 7 and 10 micrograms/ml vitamin E succinate showed a marked increase in PGE2 levels, with a significant increase (P < 0.025) occurring at 10 micrograms/ml. Adenylate cyclase activity in BL6 cells was also significantly increased at vitamin E succinate concentrations of 7 (P < 0.05) and 10 micrograms/ml (P < 0.05), respectively, and supplementation of these cells with 5 (P < 0.05), 7 and 10 micrograms/ml (P < 0.001) vitamin E succinate resulted in a significant increase in the levels of cAMP, while LLCMK cells showed no significant increase or decrease in PGE2, adenylate cyclase activity or cAMP levels over the vitamin concentrations tested.

Results of the 1994 survey of the American Association of Academic Chief Residents in Radiology

RATIONALE AND OBJECTIVES

Radiology chief residents are surveyed annually and the data are used to improve the training of diagnostic radiology residents.

METHODS

Questionnaires were mailed to accredited programs in the United States and Canada. A variety of demographic and common-interest questions were asked. For the first time, an individual resident questionnaire also was included.

RESULTS

Completed surveys from 53 programs (42%) were returned. The percentage of female residents was similar to that reported in other recent surveys. Resident salaries continued to increase. Residency selection remained highly competitive. Residents indicated that the utility of a fellowship in radiology exceeded the utility of clinical training in other fields prior to the radiology residency. Residents agreed with recommendations by the American Association of Academic Chief Residents in Radiology concerning proposed changes in the American Board of Radiology (ABR) examinations.

CONCLUSION

The information derived from the surveys on resident selection, the utility of preradiology clinical training, and the ABR examination may be useful for residents, program directors, and departmental chairs.

Identification of metabolites of 111In-diethylenetriaminepentaacetic acid-monoclonal antibodies and antibody fragments in vivo

The in vivo fate of various 111In-labeled polypeptides has been the subject of many investigations. Intracellular metabolism has been studied through the use of 111In-labeled glycoproteins that are concentrated in the lysosome by receptor-mediated endocytosis. These studies have indicated that the main lysosomal metabolite is 111In-chelate-epsilon-lysine, both in vitro and in vivo (Y. Arano et al., J. Nucl. Med., 35: 890-898, 1994; F. N. Franano et al., Nucl. Med. Biol., 21: 1023-1034, 1994). Since the vast majority of radiolabeled antibodies do not localize within the target tissue, an understanding of the metabolism of 111In-labeled antibodies in nontarget tissues is important for the rational design of future radiolabeled antibodies. We investigated the in vivo metabolism of 111In-DTPA3-conjugated antibody in female Sprague-Dawley rats using the anticolorectal carcinoma monoclonal antibody (MAb) 1A3 and MAb 1A3-F(ab')2. Livers and kidneys were harvested from rats injected with either intact MAb or MAb fragments and analyzed by gel filtration chromatography. Thirty-five % of the radioactivity from 111In-DTPA-1A3 MAb present in the liver was in the form of a low molecular weight species at 1 through 5 days. In contrast, 111In-DTPA-1A3-F(ab')2 was > 98% degraded to a low molecular weight species in the kidney after 1 day. In each case, the low molecular weight metabolites were collected and further analyzed by silica gel thin-layer chromatography, reversed phase high-performance liquid chromatography, and ion-exchange chromatography and compared to 111In-DTPA and 111In-DTPA-epsilon-lysine standards. In each system, the major metabolite co-eluted with 111In-DTPA-epsilon-lysine, similar to the results obtained with 111In-labeled glycoproteins that are delivered to lysosomes by receptor-mediated endocytosis. A minor metabolite that was more highly charged than 111In-DTPA was also observed. Analysis of urine and feces demonstrated that the main excretory product of both 111In-labeled intact 1A3 and 1A3-F(ab')2 was 111In-DTPA-epsilon-lysine. Based on this data, we propose that 111In-DTPA-antibodies are degraded within lysosomes of nontarget organs such as the liver and kidneys.

Influence of antioxidants on cadmium toxicity of mouse preimplantation embryos in vitro

To test the hypothesis that the developmental toxicity of cadmium (Cd) is due in part to oxidative damage, embryos were cultured in medium containing 0.0, 1.0, 3.0, or 6.0 microM Cd with or without various antioxidants for 72 h. Ascorbate, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and glutathione (GSH) were all effective at ameliorating 1.0 microM Cd-induced embryotoxicity. For embryos cultured in medium containing either 3.0 or 6.0 microM Cd, GSH was effective at ameliorating Cd toxicity while the other antioxidants tested were ineffective. Pretreating embryos with antioxidants for 24 h prior to exposing them to Cd and antioxidants did not significantly alter the previously observed improvement with the exception that pretreatment with GSH virtually eliminated Cd-induced embryotoxicity between 1.0 and 6.0 microM Cd. A 4-h exposure to GSH prior to culture in Cd markedly improved embryo development suggesting that GSH taken up during pretreatment can provide protection against Cd-induced embryotoxicity. This work supports the hypothesis that the developmental toxicity of Cd is in part due to oxidative damage that can be modulated by select antioxidants.

Phospholipase A2 activity in vitro cultured cells--influence of ascorbate supplementation

Non-malignant LLCMK cells and malignant B16 cells were supplemented with ascorbate, over the concentration range 0-100 micrograms/ml ascorbate. The effects of ascorbate supplementation on cell growth and phospholipase A2 activity of the membrane fractions of the respective cell lines were determined. Increasing ascorbate supplementation had a significant inhibitory effect on the growth of the B16 cells. Phospholipase A2 activity in the control B16 cells was lower than that detected in the control LLCMK cells. Phospholipase A2 activity decreased significantly in the B16 cells upon increasing ascorbate supplementation, while the supplementation of ascorbate to the LLCMK cells did not have any significant effect on phospholipase A2 activity in these cells.

Effect of a metallothionein antisense oligonucleotide on embryo development

The effect of a metallothionein (MT) antisense oligodeoxynucleotide (ODN) on mouse preimplantation embryo development was investigated. Preimplantation embryos were cultured for 72 h and examined following exposure to either an MT antisense or sense ODN. Blastocyst formation (cavitation) and embryo cell number were lower in embryos exposed to the MT antisense ODN than in controls or in embryos exposed to the MT sense ODN. In embryos cultured in medium containing free nucleotides, cavitation frequency was not affected, although mean embryo cell number was lower than in controls. Combined, this work shows that an antisense ODN against MT can significantly affect blastocyst formation of preimplantation embryos; some, but not all, of the observed effects on embryo cell number may have been due to nucleotide toxicity.

Biodistribution and metabolism of targeted and nontargeted protein-chelate-gadolinium complexes: evidence for gadolinium dissociation in vitro and in vivo

The intracellular metabolism of receptor-targeted 153Gd-DTPA-glycoproteins was studied in vitro and in vivo. These agents bound to cell surface receptors, underwent receptor mediated endocytosis, and were rapidly degraded to a metabolite which co-migrated with a 153Gd-DTPA-lysine standard on thin layer chromatography. The rates of dissociation of 153Gd and 111In from a glycoprotein-chelate conjugate were determined in vitro. Gadolinium readily dissociated, in a pH-sensitive manner, from glycoprotein-DTPA, and to a lesser degree glycoprotein-MX-DTPA. The biodistribution of targeted and blood pool 153Gd/111In labeled proteins also suggested that gadolinium dissociates from protein-DTPA and protein-MX-DTPA and their metabolites leading to an accumulation of gadolinium in bone. Metal-DTPA-glycoprotein agents targeted to cell surface receptors can still produce very high concentrations of radioactive or paramagnetic metals within the lysosome due to the high rate of accumulation afforded by receptor mediated endocytosis and the low release rate of metabolites such as metal-DTPA-lysine. However, the continued development of gadolinium based macromolecular agents will require improvements in bifunctional chelates.

Metabolism of receptor targeted 111In-DTPA-glycoproteins: identification of 111In-DTPA-epsilon-lysine as the primary metabolic and excretory product

The hepatic and renal retention of indium-111 (111In) from 111In-labeled polypeptides has been the subject of many investigations. Because the lysosome is a common intracellular destination for the degradation of polypeptides, we studied the lysosomal metabolism of 111In-DTPA-labeled glycoproteins targeted to cell surface receptors in vitro and in vivo. We found that 111In-DTPA-glycoproteins were degraded to 111In-DTPA-epsilon-lysine, which was slowly released from cells and recovered intact in urine and feces. These results suggest a mechanism for 111In retention at target and non-target sites.

Interrelationship of ascorbate, arachidonic acid and prostaglandin E2 in B16 melanoma cells

Previous studies have shown that ascorbate (Asc) supplementation affects arachidonic acid (AA) and prostaglandin E2 (PGE2) levels in B16 murine melanoma cells. In this study, non-malignant LLCMK cells and malignant B16 cells were respectively supplemented with 20 microCi 15-3H AA, to investigate whether these two cell types were able to take up AA from the media. Furthermore, these cells were also supplemented with Asc (0-100 micrograms/ml) to determine the effect of Asc supplementation on 15-3H AA uptake. Both cell types incorporated 15-3H AA, while Asc supplementation enhanced this 15-3H AA uptake. To determine the site of the AA incorporation, both cell types were supplemented with 2.5 microM AA and Asc (0-100 micrograms/ml). The % AA composition of the stroma fractions of both cell types was increased with 100 micrograms/ml Asc supplementation. Supplementation of these cells with AA (0-50 microM) resulted in an increase in PGE2 levels in the B16 cells. Since PGE2 has been shown, in turn, to stimulate adenylate cyclase (AC) activity, the LLCMK and B16 cells were supplemented with 0-100 microM PGE2. A 3-fold increase of AC activity in the B16 cells occurred as a result of this supplementation.