Geography of the circadian gene clock and photoperiodic response in western North American populations of the three-spined stickleback Gasterosteus aculeatus.

Controlled laboratory experiments were used to show that Oregon and Alaskan three-spined stickleback Gasterosteus aculeatus, collected from locations differing by 18° of latitude, exhibited no significant variation in length of the polyglutamine domain of the clock protein or in photoperiodic response within or between latitudes despite the fact that male and female G. aculeatus are photoperiodic at both latitudes. Hence, caution is urged when interpreting variation in the polyglutamine repeat (PolyQ) domain of the gene clock in the context of seasonal activities or in relationship to photoperiodism along geographical gradients.

Licensed nursing staff reductions and substitutions in Pennsylvania hospitals, 1991-1997.

Nurses report a decline in RN/patient and skill mix in the 1990s while quantitative studies fail to confirm this. This study examines aggregate hospital nursing staff in Pennsylvania from 1991-1997, focusing on changes in licensed nursing staff. It finds that licensed nursing staff declined while nursing assistants increased in this period. With adjustment for patient acuity, there was a slight decrease in RN/adjusted patient days of care (APDC), a 23% decrease in LPN/APDC, and a 4% decrease in licensed nurse/APDC. The RN/nurse ratio increased slightly, and licensed nurse/nurse fell slightly. Since RNs often operate in environments which make use of teams of licensed staff, nurses' perceptions of a decline in the RN/patient ratio is a result of the decline in licensed staff/APDC, and of an increase in patient acuity.

Clinical efficacy of doxycycline for pleurodesis.

To determine the efficacy of doxycycline as a pleural sclerosing agent, we examined the outcomes in 31 patients (aged 31 to 87 years) receiving doxycycline (500 to 1,000 mg) through a chest tube for malignant pleural effusions or persistent bronchopleural fistulae. Of the 27 patients with malignant pleural effusions, 21 patients had a complete short-term response (no fluid reaccumulation during the initial hospitalization); 5 of the 6 short-term nonresponders had partial control of effusions, with improvement in respiratory symptoms. Of the 23 patients who survived longer than 1 month, 15 patients did not have reaccumulation of fluid during follow-up. All four patients with persistent bronchopleural fistulae had resolution of their air leaks; one patient had recurrence with a partial pneumothorax. Pleural pain controllable with narcotic therapy was the only important complication. Thus, doxycycline is a suitable substitute for tetracycline as a pleural sclerosing agent.

Detection of carcinogen-DNA adducts in exfoliated urothelial cells of cigarette smokers: association with smoking, hemoglobin adducts, and urinary mutagenicity.

The presence of covalent modifications in DNA obtained from exfoliated urothelial cells of smokers and nonsmokers was determined using 32P postlabeling methods. Urine and blood samples were procured from 73 persons. Cells were removed from the urine by filtration. DNA was isolated using an enzyme-solvent extraction method and then coprecipitated with glycogen. Sufficient DNA to detect 1 carcinogen-DNA adduct/10(9) normal nucleotides was obtained from 40 of the 73 samples. DNA was hydrolyzed to 3'-phosphodeoxynucleotides and then 32P postlabeled under conditions of excess [32P]ATP. Carcinogen-DNA adducts were resolved using anion-exchange thin-layer chromatography and visualized by autoradiography; film exposures lasted as long as 7 days. Twelve different carcinogen-DNA adducts and a diagonal zone of radioactivity could be found, but no sample contained all adducts. At least four adducts appeared to be cigarette smoking related. These adducts were from 2 to 20 times higher in the smokers than the nonsmokers. Two carcinogen-DNA adducts were qualitatively very similar to adducts described earlier in a study of human bladder biopsies. One of these corresponded to N-(deoxyguanosin-8-yl)-4-aminobiphenyl. Adducts were correlated significantly with the levels of 4-aminobiphenyl hemoglobin adducts and number of cigarettes smoked. In addition, levels of the putative N-(deoxyguanosin-8-yl)-4-aminobiphenyl adduct and a measure of total adducts were correlated with the mutagenic activity of the individual's urine. These data suggest that noninvasive, biological monitoring techniques can be applied to the study of carcinogen-DNA adducts in humans at high risk for bladder cancer.

Comparative regioselective and stereoselective metabolism of 7-chlorobenz[a]anthracene and 7-bromobenz[a]anthracene by mouse and rat liver microsomes.

Quantitative metabolism of 7-chlorobenz[a]anthracene (7-Cl-BA) and 7-bromobenz[a]anthracene (7-Br-BA) by liver microsomes of uninduced mice and rats was studied. Both enzymatic systems metabolize 7-Cl-BA preferentially at the C-8 and C-9 aromatic double bond region, approximately 42 and approximately 56% respectively, of the total metabolites. 7-Cl-BA and 7-Br-BA were metabolized considerably at C-3 and C-4, C-5 and C-6, C-8 and C-9, and C-10 and C-11. While 7-Cl-BA trans-3,4-dihydrodiol was formed in a 7-8% yield of the total metabolites in both enzymatic systems, 7-Br-BA trans-3,4-dihydrodiol was formed 16.0 and 9.9% respectively, from the mouse and rat liver microsomal metabolism. In mutagenicity assays with the Salmonella typhimurium tester strain TA100 in the presence of S9 activation enzymes, both of these trans-3,4-dihydrodiols exhibited higher mutagenicity than 7-Cl-BA and 7-Br-BA, while the other trans-dihydrodiol metabolites were either essentially inactive or weaker than the parent compounds. These results suggest that 7-Cl-BA trans-3,4-dihydrodiol and 7-Br-BA trans-3,4-dihydrodiol are the proximate metabolites of 7-Cl-BA and 7-Br-BA. Metabolism of 7-Cl-BA and 7-Br-BA by mouse liver microsomes was also in a stereoselective manner, preferentially giving trans-dihydrodiol metabolites an R, R stereochemistry.

Separation of amino- and acetylamino-polycyclic aromatic hydrocarbons by reversed- and normal-phase high-performance liquid chromatography.

In the field of chemical carcinogenesis, amino- and acetylamino-polycyclic aromatic hydrocarbons (PAHs) are among the most studied compounds. Many of these compounds have recently been detected in the environment. Presently, knowledge permitting predictions of the high-performance liquid chromatographic (HPLC) retention order of amino- and acetylamino-PAHs, particularly among their geometric isomers is lacking. In order to obtain a better understanding of the separation of these types of compounds, we have studied the separation of a series of structurally related amino- and acetylamino-PAHs derived from naphthalene, phenanthrene, anthracene, pyrene, benz[a]anthracene, benzo[a]pyrene, and benzo[e]pyrene by using reversed-phase and normal-phase HPLC columns of different types (monomeric, polymeric, and chiral stationary phase). The results indicate: (i) Pirkle-type chiral stationary phase columns and the Zorbax SIL column can efficiently separate both the amino-PAHs and acetylamino-PAHs; (ii) in general, there was no correlation between retention time and molecular size; (iii) when acetylamino-PAHs were separated on the monomeric Zorbax ODS column, the isomer with the acetylamino group located at the carbon position of higher electron density has a shorter retention time; and (iv) separation of the parent PAHs was better than that of the amino-PAHs and acetylamino-PAHs. Our results thus may provide useful information for the analysis of amino-PAHs, particularly for distinguishing the geometric isomers of environmental samples.

Relationships among direct-acting mutagenicity, nitro group orientation and polarographic reduction potential of 6-nitrobenzo[a]pyrene, 7-nitrobenz[a]anthracene and their derivatives.

The direct-acting mutagenicity in Salmonella typhimurium strains TA98 and TA100 and the half-wave reduction potentials of 6-nitrobenzo[a]pyrene (6-nitro-BaP), 7-nitrobenz[a]anthracene (7-nitro-BA), and a series of their derivatives were compared. The common structural feature of these compounds is that their nitro substituents, in order to minimize steric hindrance, preferentially adopt an orientation perpendicular or nearly perpendicular to the aromatic rings. All of the compounds, except 7-hydroxy-6-nitro-BaP and 7-acetoxy-6-nitro-BaP, were found to exhibit very weak or no direct-acting mutagenicity. 7-Acetoxy-6-nitro-BaP and 7-hydroxy-6-nitro-BaP were also found to have the lowest reduction potentials among the tested compounds. The results suggest that a combination of the orientation of the nitro substituent and the first half-wave reduction potential of the compound may correlate with the direct-acting bacterial mutagenicity of nitro-polycyclic aromatic hydrocarbons.

Enhancement of estradiol potency by the 17 beta-hydroxysteroid dehydrogenase inhibitor, 16-methylene E2 in vivo.

The ability of 16-methylene E2, a 17 beta-hydroxysteroid dehydrogenase inhibitor, to enhance estradiol 17 beta (E2) potency was assayed by 24-hr weight gain in the immature rat uterus. Initial studies demonstrated that 16-methylene E2 (1-100 micrograms s.c.) did not produce significant uterine weight gain 24 hr after administration, whereas E2 (0.1-10 micrograms s.c.) produced a significant uterine weight gain under the same experimental conditions. A subthreshold dose of E2 (0.01 microgram s.c.) when administered in combination with 100 micrograms (s.c.) of 16-methylene E2 produced a significant uterine weight gain. When rats were predosed with 16-methylene E2 at 72, 48, 24, 6 or 0 hr before the administration of 0.01 microgram of E2, the magnitude of the 24-hr uterine weight gain increased and attained maximal values for the 6-hr pretreatment time point. A subsequent dose-response study of 16-methylene E2 (1-100 micrograms s.c.) administered 6 hr before 0.01 microgram of E2 revealed that the 10, 50 and 100 microgram 16-methylene E2 dose significantly increased uterine weight gain in a dose-dependent manner. These results indicate that 16-methylene E2 is not a direct acting estrogen but acts synergistically with E2 to produce an enhanced uterine response. In a separate set of monkey experiments: 1) A trace dose of [3H]E2 was perfused through the in situ, term rhesus monkey placenta via the umbilical arteries and samples were collected from the umbilical vein of this open system.(ABSTRACT TRUNCATED AT 250 WORDS)

Formation and identification of glutathione conjugates from 2-nitrosofluorene and N-hydroxy-2-aminofluorene.

2-Nitrosofluorene (NOF) and N-hydroxy-2-aminofluorene (N-HO-AF) are potent direct-acting mutagens, derived from metabolic activation of the carcinogen, N-acetyl-2-aminofluorene (AAF). To assess the ability of cellular glutathione (GSH) to detoxify these electrophilic derivatives, we examined the reaction of NOF and N-HO-AF with GSH in vitro. Two reaction products were isolated and identified as glutathionyl derivatives of 2-aminofluorene (AF) containing an N-S linkage. Amino acid analysis, infrared and NMR (500 MHz) spectroscopy, fast atom bombardment mass spectrometry and analysis of reaction characteristics and hydrolysis products established their structures as N-(glutathion-S-yl)-2-aminofluorene S-oxide (GS-AFI) and N-(glutathion-S-yl)-2-aminofluorene (GS-AFII). Ascorbic acid, which reduces NOF to N-HO-AF, was used to modify reaction yields. These results indicated that GS-AFI was derived from reaction with NOF and that GS-AFII could be formed from both NOF and N-HO-AF. A reaction scheme is proposed in which NOF reacts with GSH to form an intermediate addition product that can rearrange either to GS-AFI or be reduced to GS-AFII. The latter could also be formed by direct reaction with N-HO-AF.

Formation of DNA adducts by the carcinogen N-hydroxy-2-naphthylamine.

The probable ultimate urinary bladder carcinogen, N-hydroxy-2-naphthylamine (N-OH-2-NA), reacted with nucleic acids and proteins under mildly acidic conditions (pH 5) to form covalently bound derivatives. The extent of reaction was in the order: Polyguanylic acid greater than DNA approximately protein greater than rRNA greater than tRNA greater than polyadenylic acid approximately polyuridylic acid greater than polycytidylic acid. At pH 7, appreciable reaction occurred only with protein. Enzymatic hydrolyses of the DNA, which contained 1.5 naphthyl residues/1,000 nucleotides, yielded 3 nucleoside-arylamine adducts. From chemical, UV, nuclear magnetic resonance, and mass spectrometric analyses, the adducts were identified as 1-(deoxyguanosin-N2-yl)-2-NA, 1-(deoxyadenosin-N6-yl)-2-NA, and a purine ring-opened derivative of N-(deoxyguanosin-8-yl)-2-NA, tentatively identified as 1-[5-(2-6-diamino-4-oxopyrimidinyl-N6-deoxyriboside)]-2-(2-naphthyl)urea. Preliminary experiments with a dog given [3H]2-NA suggested the presence of these adducts in vivo. The properties of adducts derived from N-OH-1-NA and N-OH-2-NA and their possible roles in the initiation of carcinogenesis are discussed.

Alteration of urinary levels of the carcinogen, N-hydroxy-2-naphthylamine, and its N-glucuronide in the rat by control of urinary pH, inhibition of metabolic sulfation, and changes in biliary excretion.

The hepatic metabolism of arylamine bladder carcinogens to N-hydroxy arylamine N-glucuronides, their excretion in the urine, and their subsequent acidic hydrolysis to highly carcinogenic and reactive N-hydroxy arylamines have been proposed as essential steps in arylamine-induced urinary bladder carcinogenesis. In this study, alteration of urinary pH, inhibition of metabolic sulfation, and blockage of biliary disposition were shown to profoundly affect the urinary excretion of the probable ultimate bladder carcinogen, N-hydroxy-2-naphthylamine (N-HO-2-NA) and its N-glucuronide conjugate. The normal pH of rat urine (6.7) was altered to 5.7 or 7.7 by administration of NH4Cl or NaHCO3 in the drinking water. Subsequent treatment with either 2-naphthylamine (2-NA) or 2-nitronaphthalene (2-NN) resulted in increased urinary levels of free N-HO-2-NA (relative to its N-glucuronide) in acidic urines and decreased relative amounts of free N-HO-2-NA in alkaline urines. In addition, 2-NN yielded 5--10-fold greater levels of urinary N-HO-2-NA and its N-glucuronide than rats given 2-NA; and 2-NA was not detected as a urinary metabolite of 2-NN. Some 12 additional metabolites of 2-NA and 2-NN were also found. Of these, 2-amino-1-naphthol and its sulfate and glucuronide conjugates were quantitated. From these data, 2-NA and 2-NN appear to share common metabolic pathways which yield free N-HO-2-NA as a putative ultimate urinary bladder carcinogen. Pentachlorophenol, a known inhibitor of hepatic sulfotransferases, was shown to cause a 2--3-fold increase in the urinary levels of N-HO-2-NA N-glucuronide and N-HO-2-NA from 2-NA-treated rats. Similarly, inhibition of the biliary excretion of 2-NA by bile duct ligation resulted in a 6-fold increase in total urinary N-HO-2-NfA. Furthermore, analyses of bile revealed that substantial amounts of N-HO-2-NA N-glucuronide, but not free N-HO-2-NA, were present. The role of urinary versus biliary excretion of N-hydroxy arylamines in relation to bladder and colon carcinogenesis is discussed.

In vitro reaction of the carcinogen, N-hydroxy-2-naphthylamine, with DNA at the C-8 and N2 atoms of guanine and at the N6 atom of adenine.

The probable ultimate urinary bladder carcinogen, N-hydroxy-2-naphthylamine (N-HO-2-NA), reacted with nucleic acids and proteins under mildly acidic conditions (pH 5) to form covalently bound derivatives. The extent of reaction was in the order: polyguanylic acid > DNA > or = protein > rRNA > tRNA > polyadenylic acid, polyuridylic acid > polycytidylic acid. At pH 7, appreciable reaction occurred only with protein. Enzymatic hydrolyses of the DNA, which contained 1.5 naphthyl residues/1000 nucleotides, yielded 3 nucleoside-arylamine adducts. From chemical, u.v., n.m.r., and mass spectrometric analyses, the adducts were identified as 1-(deoxyguanosin-N2-yl)-2-naphthylamine, 1-(deoxyadenosin-N6-yl)-2-naphthylamine, and a purine ring-opened derivative of N-(deoxyguanosin-8-yl)-2-naphthylamine, tentatively identified as 1-[5-(2,6-diamino-4-oxopyrimidinyl-N6-deoxyriboside)]-3-(2-naphthyl)urea. The properties of these adducts and their possible role in the initiation of carcinogenesis are discussed.