Suicides among male Finnish seafarers

On analysing death registers of Finnish seafarers, 117 cases of suicide were found among active professional males in the years 1965-77. The suicide rate of the officers was similar to that of occupationally active males in the general population, while the suicide rate of the crew was 2 1/2 times higher (P less than 0.05). Many of the men who committed suicide had been at sea 5 to 10 years. Before their death they frequently changed ships.     

Sorption of fluoroacetate (compound 1080) by Colestipol, activated charcoal and anion-exchange in resins in vitro and gastrointestinal decontamination in rats

The sorption of sodium fluoroacetate (FA) by activated charcoal (AC) and 5 anion exchange resins (AERs) was tested in 2 simulated gastrointestinal (GI) fluids. Each sorbent was incubated with FA in a shaker-water-bath at 37 C for 24 h. Supernatant was removed and filtered, and the concentration of FA was determined by gas chromatographic detection of the dichloroaniline derivative. Under simulated gastric conditions (0.1 M HCl at approximately pH 1.5), the sorbents removed the following proportions of FA from solution: Carbosorb AC, 87 +/- 2%; cholestyramine, 28 +/- 7%; colestipol, 96 +/- 0%; Amberlite IRA-96, 70 +/- 2%; DEAE-Sephadex, 7 +/- 4%; Chitosan, 66 +/- 2%. Under simulated intestinal conditions (0.05 M sodium phosphate at approximately pH 7.4), binding was as follows: Carbosorb AC, 68 +/- 4%; cholestyramine, 53 +/- 5%; colestipol, 46 +/- 2%; AmberliteIRA-96, 10 +/- 20%; DEAE-Sephadex, 64 +/- 7%; Chitosan, 5 +/- 2%. All findings differed significantly from control, with the exception of Amberlite IRA-96 and Chitosan in phosphate buffer, and DEAE-Sephadex in HCI. In a second study, rats were given 5 mg FA/kg, and then gavaged with 2 g/kg Carbosorb AC, colestipol or bentonite. Over 4 h, the area under the curve of serum FA versus time (AUC) decreased by 39% in the rats treated with colestipol and 42% in those treated with bentonite. In contrast, Carbosorb AC did not affect the AUC,yet increased Tmax In another study, mortality was assessed 96 h after rats were orally dosed with 5 mg FA/kg followed by gavage with 2 g/kg Carbosorb AC, colestipol or water immediatey or 30 min after dosing. When the sorbents were given immediately, mortality was the same as control (75%). Surprisingiy, the 30-min delay resulted in lower mortality in colestipol-treated rats, (approximately 38%) compared to 100% in the group treated with Carbosorb AC. Before any recommendation can be made regarding the use of colestipol as a GI decontaminant, the latter findings require confirmation in an intensive care setting. The potential for synergistic effects with 2 or more sorbents also warrant investigating.     

Imaging oncogene expression

This review briefly outlines the importance of molecular imaging, particularly imaging of endogenous gene expression for noninvasive genetic analysis of radiographic masses. The concept of antisense imaging agents and the advantages and challenges in the development of hybridization probes for in vivo imaging are described. An overview of the investigations on oncogene expression imaging is given. Finally, the need for further improvement in antisense-based imaging agents and directions to improve oncogene mRNA targeting is stated.     

Biogeochemical toxicity and phytotoxicity of nitrogenous compounds in a variety of arctic soils

Ammonium nitrate (NH(4)NO(3)) is a common water pollutant associated with many industrial and municipal activities. One solution to reduce exposure of sensitive aquatic systems to nitrogenous compounds is to atomize (atmospherically disperse in fine particles) contaminated water over the Arctic tundra, which will reduce nitrogen loading to surface water. The toxicity of ammonium nitrate to Arctic soils, however, is poorly understood. In the present study, we characterized the biogeochemical toxicity and phytotoxicity of ammonium nitrate solutions in four different Arctic soils and in a temperate soil. Soil was exposed to a range of ammonium nitrate concentrations over a 90-d period. Dose responses of carbon mineralization, nitrification, and phytotoxicity endpoints were estimated. In addition to direct toxicity, the effect of ammonium nitrate on ecosystem resilience was investigated by dosing nitrogen-impacted soils with boric acid. Ammonium nitrate had no effect on carbon mineralization activity and only affected nitrification in one soil, a polar desert soil from Cornwallis Island, Northwest Territories, Canada. In contrast, ammonium nitrate applications (43 mmol N/L soil water) significantly impaired seedling emergence, root length, and shoot length of northern wheatgrass (Elymus lanceolatus). Concentrations of ammonium nitrate in soil water that inhibited plant parameters by 20% varied between 43 and 280 mmol N/L soil water, which corresponds to 2,100 to 15,801 mg/L of ammonium nitrate in the application water. Arctic soils were more resistant to ammonium nitrate toxicity compared with the temperate soil under these study conditions. It is not clear, however, if this represents a general trend for all polar soils, and because nitrogen is an essential macronutrient, nitrogenous toxicity likely should be considered as a special case for soil toxicity.     

Targeting Apoptosis for Optical Imaging of Infection

Purpose  

Infection is ubiquitous and a major cause of morbidity and mortality. The most reliable method for localizing infection requires radiolabeling autologous white blood cells ex vivo. A compound that can be injected directly into a patient and can selectively image infectious foci will eliminate the drawbacks. The resolution of infection is associated with neutrophil apoptosis and necrosis presenting phosphatidylserine (PS) on the neutrophil outer leaflet. Targeting PS with intravenous administration of a PS-specific, near-infrared (NIR) fluorophore will permit localization of infectious foci by optical imaging.     

Human promyelocytic leukemia HL-60 cell proliferation and c-myc protein expression are inhibited by an antisense pentadecadeoxynucleotide targeted against c-myc mRNA.

The human promyelocytic leukemia cell line HL-60 overexpresses the c-myc protooncogene. A calculated secondary structure for c-myc mRNA placed the initiation codon in a bulge of a weakly base-paired region. Treatment of HL-60 cells with 5' d(AACGTTGAGGGGCAT) 3', complementary to the initiation codon and the next four codons of c-myc mRNA, inhibited c-myc protein expression in a dose-dependent manner. However, treatment of HL-60 cells with 5' d(TTGGGATAACACTTA) 3', complementary to nucleotides 17-31 of vesicular stomatitis virus matrix protein mRNA, displayed no such effects. These results agree with analogous studies of normal human T lymphocytes [Heikkila, R., Schwab, G., Wickstrom, E., Loke, S. L., Pluznik, D. H., Watt, R. & Neckers, L. M. (1987) Nature (London) 328, 445-449], except that only one-third as much oligomer was needed for a comparable effect. Proliferation of HL-60 cells in culture was inhibited in a sequence-specific, dose-dependent manner by the c-myc-complementary oligomer, but neither the oligomer complementary to vesicular stomatitis virus matrix protein mRNA nor 5' d(CATTTCTTGCTCTCC) 3', complementary to nucleotides 5399-5413 of human immunodeficiency virus tat gene mRNA, inhibited proliferation. It thus appears that antisense oligodeoxynucleotides added to myc-transformed cells via culture medium are capable of eliciting sequence-specific, dose-dependent inhibition of c-myc protein expression and cell proliferation.     

Confidence of academic general internists and family physicians to teach ambulatory procedures

OBJECTIVE: To evaluate and compare the readiness of academic general internal medicine physicians and academic family medicine physicians to perform and teach 13 common ambulatory procedures. DESIGN: Mailed survey. SETTING: Internal medicine and family medicine residency training programs associated with 35 medical schools in 9 eastern states. PARTICIPANTS: Convenience sample of full-time teaching faculty. MEASUREMENTS AND MAIN RESULTS: A total of 331 general internists and 271 family physicians returned completed questionnaires, with response rates of 57% and 65%, respectively. Academic generalists ranked most of the ambulatory procedures as important for primary care physicians to perform; however, they infrequently performed or taught many of the procedures. Overall, compared with family physicians, general internists performed and taught fewer procedures, received less training, and were less confident in their ability to teach these procedures. Physicians’ confidence to teach a procedure was strongly associated with training to perform the procedure and performing or precepting a procedure at least 10 times per year. CONCLUSIONS: Many academic general internists do not perform or precept common adult ambulatory procedures. To ensure that residents have the opportunity to learn routine ambulatory procedures, training programs may need to recruit qualified faculty, train current faculty, or arrange for academic specialists or community physicians to teach these skills. Presented in part at the 1996 and 1998 meetings of the Society of General Internal Medicine and at the 1998 meetings of the Midwest Society of General Internal Medicine. This work was supported in part by grant 2D28PE54004 from the Bureau of Health Professions, Health Resources and Services Administration, to the Faculty, Development Program for General Internal Medicine, University of North Carolina at Chapel Hill, and by Grant 52285 from the Summa Health System, Akron, Ohio.