Fate and toxic effects of inhaled ultrafine cadmium oxide particles in the rat lung

Female Fischer 344 rats were exposed to ultrafine cadmium oxide particles, generated by spark discharging, for 6 h at a concentration of 70 microg Cd/m(3) (1 x 10(6)/cm(3)) (40 nm modal diameter). Lung morphology and quantification of Cd content/concentration by inductively coupled plasma (ICP)-mass spectrometry were performed on days 0, 1, 4, and 7 after exposure. Cd content in the lung on day 0 was 0.53 +/- 0.12 microg/lung, corresponding to 19% of the estimated total inhaled cumulative dose, and the amount remained constant throughout the study. In the liver no significant increase of Cd content was found up to 4 days. A slight but statistically significant increase was observed in the liver on day 7. We found neither exposure-related morphological changes of lungs nor inflammatory responses in lavaged cells. Another group of rats were exposed to a higher concentration of ultrafine CdO particles (550 microg Cd/m(3) for 6 h, 51 nm modal diameter). The rats were sacrificed immediately and 1 day after exposure. The lavage study performed on day 0 showed an increase in the percentage of neutrophils. Multifocal alveolar inflammation was seen histologically on day 0 and day 1. Although the Cd content in the lung was comparable between day 0 and day 1 (3.9 microg/lung), significant elevation of Cd levels in the liver and kidneys was observed on both days. Two of 4 rats examined on day 0 showed elevation of blood cadmium, indicating systemic translocation of a fraction of deposited Cd from the lung in this group. These results and comparison with reported data using fine CdO particles indicate that inhalation of ultrafine CdO particles results in efficient deposition in the rat lung. With regard to the deposition dose, adverse health effects of ultrafine CdO and fine CdO appear to be comparable. Apparent systemic translocation of Cd took place only in animals exposed to a high concentration that induced lung injury.

Fluorescence microscopic visualization of a DNA-cationic fullerene complex

Cationic fullerene derivative 1, which is soluble in aqueous medium, bound to double stranded DNA. Observation of Coliphage T4 DNA in the absence and presence of 1 by fluorescence microscopy suggested that 1 bound to DNA along its groove. Upon irradiation of visible light on the DNA complex of 1, DNA was cleaved dramatically. The process of DNA photo-cleavage could be monitored continuously by fluorescence microscopy.

Novel synthesis of a tetra-acridinyl peptide as a new DNA polyintercalator

Tetra-acridinyl peptide 2 was synthesized from Fmoc-Lys(Boc)-OH and Fmoc-Lys(Acr)-OH (1) with the peptide synthesizer. The CD measurement suggested that 2 forms a special organized structure by itself in buffered solution. Peptide 2 binds to double stranded DNA with a very large affinity constant, which is 10(3)-times larger than that of quinacrine. Spectrophotometric and hydrodynamic studies suggested that all of the acridinyl parts of 2 contribute to the intercalating interaction for the DNA binding. Our finding in this experiment demonstrates that polyintercalators such as 2 can be assembled quickly by the automated synthesizer.

Ferroceneacetyl naphthalene diimide as a new electrochemical ligand for DNA sensing

New electrochemically active DNA ligand 1 was synthesized by the connection of ferroceneacetic acid at the terminal amino moieties of two imide substituents of naphthalene diimide. Electrochemical experiments in aqueous solution containing DMSO showed that the selectivity for double stranded DNA of 1 has increased from that of ligand 2 previously reported. The peak current of 1 shifted toward the negative side from that of 2, thereby shortening the time required for gene detection.

Linker chain effect of ferrocenyl naphthalene diimide on a double stranded DNA preference

Naphthalene diimide derivative 1 carrying two 3-(ferrocenyl-methylamino)-propyl substituents was synthesized as a new hybrid indicator for electrochemical gene sensing. Ligand 1 showed a preference for double stranded DNA four-times larger than 2 previously described. The peak potential of 1 shifted 30 mV toward the negative side from that of 2, thereby shortening the time required for gene detection.

Detection of DNA hybridization by use of a lanthanide fluorescent intercalator that specifically binds to double stranded DNA

Toward development of a DNA microarray system in which neither labeling nor amplification of the nucleic acids from living cell is required, we have developed a new method for the detection and quantification of target DNA hybridized with probe DNA fixed on a solid surface. This method utilizes a fluorescent intercalator: naphthalene diimide derivative carrying two fluorescent tetradentate beta-diketone-Eu3+ chelates. This compound selectively binds to double stranded DNA (dsDNA) fixed on a plastic assay plate. The amount of the compound bound to single stranded DNA (ssDNA) is negligible. The fluorescent intensity of Eu3+ was in proportion to the amount of the fixed DNA, showing that the compound quantitatively binds to dsDNA. Therefore, this method can be used not only to detect dsDNA, but also to measure the amount of DNA on a solid surface.

DNA binding behavior of peptides carrying acridinyl units: First example of effective poly-intercalation

Bis-, tris-, tetrakis-, and pentakis-acridinyl (Acr) peptides 2-5 were synthesized from Fomc-Lys(Acr)-OH and Fmoc-Lys(Boc)-OH with the peptide synthesizer. The molar absorptivity of these peptides saturated with an increase in the number of the acridinyl unit in the peptide, suggesting intramolecular stacking of the acridinyl units. It was found from Scatchard analysis by means of spectrophotometry that all the peptides can bind to double stranded DNA with very high affinity even under high salt conditions (0.4 M NaCl) and the logarithmic binding constant increased in proportion to the number of the acridinyl unit in the peptide. This result suggested effective poly-intercalation of all the acridinyl units into double stranded DNA.

Effects of inhaled CdO particles on the sphingolipid synthesis of rat lungs

Surfactant lipids of the alveolar space protect the lung from various environmental stimuli. We investigated the influence of ultrafine (UF) CdO particles inhalation on two key enzymes involved in lung sphingolipid metabolism, serine palmitoyltransferase (SPT), and sphingomyelinase (SMase). Rats inhaled either 0.63 mg UF-CdO/m(3) for 6 h (group 1), or 1.08 mg UF-CdO/m(3) 12 h/day for 10 days (group 2). Two corresponding control groups inhaled filtered clean air. Additional rats intratracheally instilled with lipopolysaccharide (LPS) were used as positive controls. Semiquantitative reverse-transcription polymerase chain reaction (RT-PCR) of lung tissue showed a significant increase in the level of SPT mRNA (LCB2 subunit) expression in group 2 compared to the corresponding controls (p <.01). Group 1 and LPS were not statistically different from control. No alteration in the mRNA level of SMase was detected in any exposure group. The immunohistochemical analysis showed that SPT (LCB2 subunit) localization was stronger in the alveolar type II cells of group 2 lungs compared to the corresponding controls. These results were correlated with alterations in BALF cellular and biochemical parameters and lung morphology. Since SPT is the key enzyme for de novo sphingolipid synthesis in lung surfactant and SMase is responsible for sphingomyelin catabolism, we can postulate that high-dose UF-CdO exposure for 10 days induces an increase in sphingolipid synthesis in the type II cells of rat lungs that would not be promptly followed by its degradation.

Translocation of ultrafine insoluble iridium particles from lung epithelium to extrapulmonary organs is size dependent but very low

Recently it was speculated that ultrafine particles may translocate from deposition sites in the lungs to systemic circulation. This could lead to accumulation and potentially adverse reactions in critical organs such as liver, heart, and even brain, consistent with the hypothesis that ultrafine insoluble particles may play a role in the onset of cardiovascular diseases, as growing evidence from epidemiological studies suggests. Ultrafine (192)Ir radio-labeled iridium particles (15 and 80 nm count median diameter) generated by spark discharging were inhaled by young adult, healthy, male WKY rats ventilated for 1 h via an endotracheal tube. After exposure, excreta were collected quantitatively. At time points ranging from 6 h to 7 d, rats were sacrificed, and a complete balance of (192)Ir activity retained in the body and cleared by excretion was determined gamma spectroscopically. Thoracic deposition fractions of inhaled 15- and 80-nm (192)Ir particles were 0.49 and 0.28, respectively. Both batches of ultrafine iridium particles proved to be insoluble (<1% in 7 d). During wk 1 after inhalation particles were predominantly cleared via airways into the gastrointestinal tract and feces. This cleared fraction includes particles deposited in the alveolar region. Additionally, minute particle translocation of <1% of the deposited particles into secondary organs such as liver, spleen, heart, and brain was measured after systemic uptake from the lungs. The translocated fraction of the 80-nm particles was about an order of magnitude less than that of 15-nm particles. In additional studies, the biokinetics of ultrafine particles and soluble (192)Ir was studied after administration by either gavage or intratracheal instillation or intravenous injection. They confirmed the low solubility of the particles and proved that (1) particles were neither dissolved nor absorbed from the gut, (2) systemically circulating particles were rapidly and quantitatively accumulated in the liver and spleen and retained there, and (3) soluble (192)Ir instilled in the lungs was rapidly excreted via urine with little retention in the lungs and other organs. This study indicates that only a rather small fraction of ultrafine#10; iridium particles has access from peripheral lungs to systemic circulation and extrapulmonary organs. Therefore, the hypothesis that systemic access of ultrafine insoluble particles may generally induce adverse reactions in the cardiovascular system and liver leading to the onset of cardiovascular diseases needs additional detailed and differentiated consideration.

Comparison of amplitudes of surface macro motor unit potentials recorded from various muscle sites

Peak-to-peak amplitudes and total areas of surface macro motor unit potentials (S-MMUPs) were measured in 19 healthy volunteers. While participants maintained minimal isometric muscle contraction of the left biceps brachii, motor unit potentials (MUPs) were recorded from a needle and surface electrodes. The largest MUP recorded by the needle electrode was designated the trigger source. Electrical activities from the surface electrodes, which emerged synchronously with the trigger-potential, were averaged by the spike-triggered averaging (STA) technique. When the surface electrodes were placed over the muscle belly at a right angle to the muscle fibers, the S-MMUP amplitude and area decreased gradually with the distance of the electrodes from the point of insertion of the needle electrode. In contrast, when the surface electrodes were arranged parallel to the muscle fibers, the S-MMUP amplitude and area did not always decrease. In addition, negative peak positions in individual S-MMUPs showed a time delay along the muscle fibers. The placement and size of the surface electrodes, as well as the depth of the needle electrode, must be carefully considered when MUPs are analyzed by the STA technique. Muscle fiber conduction velocity (MFCV) is measurable by the STA technique combined with surface electrodes.

Isolation of a benzoate-utilizing Pseudomonas strain from soil and production of catechol from benzoate by transpositional mutants

Pseudomonas sp. Ba-0511 was isolated from soil by enrichment cultivation on a medium containing 6 mg/ml of sodium benzoate. The bacterium could grow on a medium containing 20 mg/ml of sodium benzoate by a successive enrichment culture. One hundred and twelve transpositional mutants of the bacterium produced catechol from benzoate and accumulated it outside of the cells. Among the mutants, strain BA+63 produced a maximal amount of catechol (2.3 mg/ml) from 6 mg/ml of sodium benzoate after growing for 10.5 h. The conversion rate of benzoate to catechol was 50% on a molar basis. The catechol production by the resting cells increased in the presence of glycerol, and the maximal amount of catechol produced from 6 mg/ml of sodium benzoate reached 3.3 mg/ml at the conversion rate of 72% after 5 h of incubation. The resting cells converted m-methylbenzoic acid to 3- and 4-methylcatechol and m-chlorobenzoic acid to 3- and 4-chlorocatechol.

Cobalamin deficiency results in severe metabolic disorder of serine and threonine in rats

Dietary cobalamin (vitamin B12; Cbl) deficiency caused significant increases in plasma serine, threonine, glycine, alanine, tyrosine, lysine and histidine levels in rats. In particular, the serine and threonine levels were over five and eight times, respectively, higher in the Cbl-deficient rats than those in the sufficient controls. In addition, some amino acids, including serine and threonine, were excreted into urine at significantly higher levels in the deficient rats. When Cbl was supplemented into the deficient rats for 2 weeks, in coincidence with the disappearance of the urinary excretion of methylmalonic acid (an index of Cbl deficiency), the plasma serine and threonine levels were normalized. These results indicate that Cbl deficiency results in metabolic disorder of certain amino acids, including serine and threonine. The expression level of hepatic serine dehydratase (SDH), which catalyzes the conversion of serine and threonine to pyruvate and 2-oxobutyrate, respectively, was significantly lowered by Cbl deficiency, even though Cbl does not participate directly in the enzyme reaction. The SDH activity in the deficient rats was less than 20% of that in the sufficient controls, and was normalized 2 weeks after the Cbl supplementation. It is thus suggested that the decrease of the SDH expression relates closely with the abnormalities in the plasma and urinary levels of serine and threonine in the Cbl-deficient rats.

Urinary bile alcohol profiles in healthy and cholestatic children

BACKGROUND

Bile alcohols are normal constituents of urine.

METHODS

To better understand bile alcohol profile in childhood, urinary specimens from 41 healthy children and 10 children with cholestasis, and 3 healthy adults, were analyzed by GLC and GC-MS.

RESULTS

Five bile alcohols, 27-nor-5beta-cholestane-3alpha,7alpha,12alpha,24S,25R-pentol, 5beta-cholestane-3alpha,7alpha,12alpha,24S, 25-pentol, 5beta-cholestane-3alpha,7alpha,12alpha,24S,26-pentol, 5beta-cholestane-3alpha,7alpha, 12alpha,25,26-pentol, and 5beta-cholestane-3alpha,7alpha,12alpha,26,27-pentol were identified in all specimens. C(26)-Pentol was the most abundant constituent, constituting 29.5 to 65% of bile alcohols. Among healthy children (n=41), no significant relationship was seen between proportions of the C(26)-pentol and age, but older children (n=15, 6 to 14 years) showed a significantly greater mean percentage of the C(26)-pentol than young children (n=26, 0 to 5 years; 58.1+/-4.23% vs. 46.0+/-9.24%, p<0.001). In children with cholestatic liver diseases, the percentage of C(26)-pentol in urinary bile alcohols was significantly lower than age-matched controls.

CONCLUSIONS

There is an increased composition of C(26)-pentol in older children and relatively decreased composition of C(26)-pentol in children with cholestatic liver diseases.

Calorie restriction reduced blood pressure in obesity hypertensives by improvement of autonomic nerve activity and insulin sensitivity

Association between obesity and hypertension has been well recognized. A reduction in the body weight of over-weight hypertensive patients is a recommended lifestyle modification. The purpose of our study is to examine the relationship of insulin sensitivity and autonomic nervous activity with reduction of blood pressure by the calorie restriction. We evaluated the heart rate variability, nocturnal change of blood pressure and insulin resistance before and after a short-term low-calorie diet in 12 overweight essential hypertensives. After a week of standard diet (2000 kcal), 2 weeks of low-calorie diet (800 kcal) with normal sodium content induced a significant reduction in body mass index, triglyceride, fasting immunoreactive protein, homeostasis model assessment as an index of insulin resistance, and urinary excretion of sodium and potassium. Systolic blood pressure was significantly reduced both in daytime and night-time after the low-calorie diet (daytime, 134.5+/-6.0 to 122.0+/-4.1 mmHg; night-time, 126.8+/-5.2 to 113.4+/-7.2 mmHg). In daytime, diastolic blood pressure was also reduced (90.3+/-2.1 to 88.1+/-4.8 mmHg). Although heart rate was not significantly reduced, a rise of high frequency in night-time (346+/-82 to 572+/-108 ms2) and a fall of low frequency/high frequency in day-time (3.5+/-0.4 to 2.6+/-0.1) was significant after a low-calorie diet. In conclusion, weight loss by low-calorie diet with a constant intake of sodium, reduced blood pressure in obese hypertensives by improvement of vagal nervous activity and insulin resistance.

Regulation by two CatR proteins that differ in binding affinity to catB promoters expressing two cat gene clusters

We isolated the two LysR-type regulatory proteins CatR1 and CatR2, which regulate the expression of cat1 and cat2 gene clusters, respectively, required for catechol degradation in the bacterium Frateuria sp. ANA-18. In a gel mobility shift assay using CatR1 and the DNA fragment containing the catB1 promoter region, the formation of two complexes, complex 1-1 (C1-1) and complex 1-2 (C1-2), was observed in the presence of cis,cis-muconate. On the other hand, CatR2 and the DNA fragment containing the catB2 promoter region formed only complex 2-2 (C2-2) at a lower concentration of cis,cis-muconate than that at which C1-1 and C1-2 were formed. As the concentration of cis,cis-muconate decreased, the production of the muconate cycloisomerase isozyme MC II encoded by catB2 decreased as well as that of MC I encoded by catB1. However, the amount of MC II synthesized was larger than that of MC I at low concentrations. On the basis of these results, we concluded that the catB2 promoter was activated at low concentrations of cis,cis-muconate.

Isomerization of DNA-bound distilbazolium ligand induced by electron transfer from photoexcited tris(1,10-phenanthroline)Ru(II)

The ability of the DNA duplex to behave as an efficient organized medium for cis-trans isomerization induced by electron transfer (ET) has been explored. Isomerization studies, luminescence quenching and DNA photocleavage assays show that photoexcited Ru(1,10-phenanthroline [phen])3(2+) transfers an electron to E,Z1,4-bis[2-(1-methylpyridinium-4-yl)vinyl]benzene (E,Z pMPVB), which subsequently undergoes one-way isomerization to E,E pMPVB. The unusual feature of the system is manifested by the lack of friction that is usually imposed on the photoisomerizable ligand by highly organized media. The apparent rate of ET in DNA increases when compared with the homogeneous solution. However, after correction for the local concentration of the reagents onto the biopolymer, the rate constant becomes independent of the DNA concentration and is at least 4 x 10(2) times smaller than that in the homogeneous aqueous solution. Using the photoinduced isomerization system, a large enhancement in the efficiency of single-strand break formation was found in plasmid DNA over that for Ru(phen)3(+2) alone using irradiation at lambda > 480 nm.

Survival of testicular cancer patients in Osaka, Japan

BACKGROUND

Testicular cancer is one of those cancers for which the prognosis has improved remarkably since the introduction of effective chemotherapy.

METHODS

Study subjects were 709 testicular cancer patients who were registered to the population-based Osaka Cancer Registry (OCR) as diagnosed between 1975 and 1992. The testicular cancer patients diagnosed/treated in the Osaka Medical Center for Cancer and Cardiovascular Diseases (OMCC) were also analyzed for comparison.

RESULTS

The 5-year relative survival was 75.2% for the total of 709 patients and 77.9% for those diagnosed during 1990-92. These figures were much lower than those for patients in the USA and in Europe. In contrast, the 5-year survival of the 113 patients diagnosed in the OMCC during 1975-93 was 91.5% and similar to those in the USA and in Europe.

CONCLUSIONS

The present study suggests that there are problems in the speed and extent of diffusion of effective chemotherapy for testicular cancer in Osaka.

Production of catechol from benzoate by the wild strain Ralstonia species Ba-0323 and characterization of its catechol 1,2-dioxygenase

Ralstonia sp. Ba-0323, a wild strain isolated from soil, produced catechol from benzoate and accumulated it outside the cells. The bacterium produced a maximal amount of catechol (1.6 mg/ml) from 3 mg/ml of sodium benzoate in a 20-h growing culture. The conversion rate of benzoate to catechol was 70% on a molar basis. The catechol production by the resting cells increased in the presence of glycerol, and the maximal amount of catechol produced from 3 mg/ml of sodium benzoate reached 1.9 mg/ml at the conversion rate of 83% after 8 h of incubation. Catechol 1,2-dioxygenase, which catalyzed the ring cleavage of catechol, was purified to homogeneity from a cell extract of Ralstonia sp. Ba-0323 growing on benzoate and characterized. The specific activity of the purified enzyme was much lower than those of the dioxygenases from other microorganisms reported. The Km for catechol of the purified enzyme was much higher than those of other dioxygenases. In addition, the NH2-terminal amino acid sequence of the enzyme was less similar to the other catechol 1,2-dioxygenases than they are to each other.

Pulmonary and systemic distribution of inhaled ultrafine silver particles in rats

The cardiovascular system is currently considered a target for particulate matter, especially for ultrafine particles. In addition to autonomic or cytokine mediated effects, the direct interaction of inhaled materials with the target tissue must be examined to understand the underlying mechanisms. In the first approach, pulmonary and systemic distribution of inhaled ultrafine elemental silver (EAg) particles was investigated on the basis of morphology and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Rats were exposed for 6 hr at a concentration of 133 microg EAg m(3) (3 x 10(6) cm(3), 15 nm modal diameter) and were sacrificed on days 0, 1, 4, and 7. ICP-MS analysis showed that 1.7 microg Ag was found in the lungs immediately after the end of exposure. Amounts of Ag in the lungs decreased rapidly with time, and by day 7 only 4% of the initial burden remained. In the blood, significant amounts of Ag were detected on day 0 and thereafter decreased rapidly. In the liver, kidney, spleen, brain, and heart, low concentrations of Ag were observed. Nasal cavities, especially the posterior portion, and lung-associated lymph nodes showed relatively high concentrations of Ag. For comparison, rats received by intratracheal instillation either 150 microL aqueous solution of 7 microg silver nitrate (AgNO(3) (4.4 microg Ag) or 150 microL aqueous suspension of 50 microg agglomerated ultrafine EAg particles. A portion of the agglomerates remained undissolved in the alveolar macrophages and in the septum for at least 7 days. In contrast, rapid clearance of instilled water-soluble AgNO(3) from the lung was observed. These findings show that although instilled agglomerates of ultrafine EAg particles were retained in the lung, Ag was rapidly cleared from the lung after inhalation of ultrafine EAg particles, as well as after instillation of AgNO(3), and entered systemic pathways.