Heavy metal removal from aqueous solution by wasted biomass from a combined AS-biofilm process.

This study evaluated the capability of metal biosorption by wasted biomass from a combined anaerobic-anoxic-oxic (A2O)-biofilm process with simultaneous nitrogen and phosphorus removal. Zinc, cadmium and nickel were rapidly adsorbed in 20 min by the harvested sludge from a continuous-flow pilot-plant. Biosorption equilibrium was then reached in 6h. The biosorption isotherm showed that metal biosorption behavior had fitted well to the Freundlich isotherm, but not Langmuir isotherm. The capacity constants k of Freundlich model for nickel, zinc and cadmium were 0.471, 0.298 and 0.726, respectively; the affinity constants 1/n were 0.444, 0.722 and 0.718, respectively. The order of metal affinity for the wasted biomass was Zn > Cd > Ni, which was in conformity to the other biosorption results with different biological sludge.

Serum and testicular testosterone and nitric oxide products in aluminum-treated mice.

The present investigation aimed to elucidate possible mechanisms of aluminum (Al)-induced reproductive toxicity in male mice. Daily intraperitoneal administrations of Al chloride (0, 1/8 and 1/3 LD(50)) were conducted for 12 or 16 days, followed by a 2-week withdrawal period. Serum Al levels significantly increased in Al-treated animals, compared to controls, whereas serum testosterone concentrations were markedly decreased. In addition, significant increases in nitric oxide products (NO(x)) were also observed during Al injection. Similar trends were found for testicular Al, NO(x) and testosterone levels. However, during the withdrawal period, when diminished testicular Al levels were observed, the changes in NO(x) and testosterone levels were indistinguishable from control values. It was concluded that: (i) Al exerted a significant adverse effect on the steroidogenesis; (ii) the process was reversible; and (iii) increased production of NO(x), induced by excessive Al, might inhibit testosterone levels.

Development of the middle ear in neonatal chinchillas. I. Birth to 14 days.

Measures of middle-ear function in humans show large differences among neonates, infants, and adults. In contrast, hearing sensitivity is essentially mature at birth. Hypotheses that have been proposed to explain the developmental changes in middle-ear function include: (i) contaminating effects of the immature neonatal ear-canal wall and (ii) persistent fetal tissue in the ear canal, tympanic membrane (TM), and middle-ear space. To better understand the relationships between middle-ear function, hearing sensitivity and the structure of the middle ear, 30 chinchillas, aged 1-14 days, were studied. Middle-ear function was assessed by multifrequency tympanometry with probe tones ranging from 226 to 2,000 Hz. Hearing sensitivity was measured by auditory brainstem response using clicks and 1, 2, 4, and 8 kHz tone bursts. Structural characteristics were analyzed from temporal bone histologic preparations. At all frequencies, the acoustic admittance of the neonatal car is very low and tympanometric patterns are complex and irregular, compared to adult animals. The admittance is essentially constant from 1 to 14 days, indicating that developmental changes occur over a much wider age span than that investigated here. Hearing sensitivity of the chinchilla appears to be mature at birth. Histologic analysis indicated that there were no age-related changes in TM thickness, TM diameter, distance from TM to promontory, and stapes footplate diameter. There were small increases in bone thickness, middle-ear area, mastoid bulla area, and in the perimeters of the middle ear and mastoid bulla. There were no significant amounts of loose mesenchyme or other fetal tissue in the middle-ear space.

Management of otitis media using Agency for Health Care Policy and Research guidelines. The Agency for Health Care Policy and Research.

Increased costs of managing otitis media and its complications may result from delays in diagnosis and treatment. The Agency for Health Care Policy and Research developed guidelines to assist in the management of chronic otitis media with effusion. We examined the medical care adherence to Agency for Health Care Policy and Research guidelines in 59 consecutive patients referred because of chronic otitis media with effusion and recurrent acute otitis media. Patient history and examination data were collected prospectively. In the group with chronic otitis media with effusion, the rate of adherence to Agency for Health Care Policy and Research guidelines was 0%; in those with recurrent acute otitis media, adherence was 5%. Delayed referral occurred in 34% of patients; 25% of patients were referred early. The average duration of effusion in patients with chronic otitis media with effusion was 5.2 months; the duration of recurrent acute otitis media immediately before referral was 9.3 months. Eighteen patients (47%) in the chronic otitis media with effusion group had a history of recurrent chronic otitis media with effusion spanning an average of 22.7 months. On referral, hearing loss was discovered in 92% of all patients, and in 69% the tympanogram was flat. The complication and sequelae rate was 49.1%, and speech delay was the most frequent at 16.9%. We conclude that in our study patients there is a significant referral delay, long history of chronic otitis media with effusion in patients before referral, high rate of hearing loss, and high complication rate. Continued efforts should be directed toward improving education of all clinicians so that diagnostic tools and timely otolaryngologic referral are better used.

The relationship between high maternal aluminum ingestion and anemia-related hematologic changes in rats.

Microcytic, hypochromic anemia in dialysis patients has been associated with aluminum toxicity. Since pregnant women and infants are high-risk groups for iron-deficiency anemia, the purpose of this study was to investigate if high maternal aluminum intake could cause anemia in dams and pups of rats. Eighteen Sprague-Dawley (SD) female weanling rats were arranged in three groups under randomized completely block design (RCBD) experiment design. Control, Low-Al and High-Al groups had 0, 500, 2000 mg Al/kg diet added in the basal diet, respectively, through growing, pregnancy and lactation. Rats were sacrificed after weanling. Results indicated that either body weight gain or feed efficiency was the lowest in High-Al groups dams (P<0.05). The body weights were the same in neonates from mothers with various aluminum intakes. However, the higher the maternal aluminum intakes, the lower the average body weight of weanling pups (P<0.05). There was a positive correlation between Al intake and serum Al concentration, Al intake and milk Al content of dams (r = 0.93 and r = 0.89, respectively; P<0.05). Average milk and serum aluminum concentrations of dams with high aluminum intake were higher than those in the Control and Low-Al groups. Nevertheless, serum aluminum concentration in pups was not different among the three groups. There was no difference in hematocrit (Hct), hemoglobin (Hb) mean corpuscular hemoglobin concentration (MCHC), total iron binding capacity, or transferrin saturation among dams. On the other hand, the pups in the High-Al group had the highest Hct and Hb per unit body weight compared with the other groups, probably due to smaller litter size.

Protein Synthesis in Isolated Mitochondria of Rice (Oryza sativa L.) Seedlings.

For studies of in organello mitochondrial protein synthesis in rice, Oryza sativa L., conventional surface-sterilization procedures were demonstrated to be ineffective. Because of the over-whelmingly efficient [(35)S]methionine utilization by contaminating bacteria, even "essentially bacteria-free" rice mitochondria were shown to be unsuitable for the study of in organello protein synthesis. We developed a procedure to obtain a bacteria-free preparation of rice mitochondria. Such mitochondria favored a membrane-dependent ATP-generating system over an external ATP-generating system as the energy supplement for in organello protein synthesis. Two distinct classes of [(35)S]methionine-labeled, cycloheximide-insensitive products were detected: an electrophoretically unresolved population and a set of some 22 to 27 discrete polypeptide species, each with a characteristic electrophoretic mobility and relative abundance.

On the DNA polymerase-a mutant: immunofluorescence assay of UV-induced thymidine dimers in Aphr-4-2 cells.

Aphidicolin inhibits purified DNA polymerases-a and -d in vitro and inhibits mitosis in animal cells. The Chinese hamster V79 cell mutant, Aphr-4-2, was selected for its ability to form colonies in cultured medium supplemented with 1.0 microM aphidicolin. At this concentration, the parental wild-type V79 cells (clone 743x) have a survival rate of less than 10(-7). The mutant DNA polymerase-a is resistant to aphidicolin at concentrations that are inhibitory to the wild-type V79 DNA polymerase-a. The apparent Km for dCTP of the mutant DNA polymerase-a is consistently lower than that of the wild-type DNA polymerase-a. This mutant exhibits slow growth, mutator activity, hypersensitivity, and hypermutability to UV. We wanted to know the basis of UV hypersensitivity in this mutant. Using the antisera (UV2) raised against UV-induced thymidine dimers and a sensitive immunofluorescence assay to measure UV-induced thymidine dimers and with detection in ACAS 570 Workstation, we observed that 50% of the thymidine dimers disappeared within 5 h after irradiation and more than 80% of the dimers were removed within 24 h in both cell lines. These results indicate that the recognition, incision, and excision steps in nucleotide excision repair pathway are normal in the mutant. In order to know if there is a difference in DNA polymerase-a or -d activities in the parental V79(wt) and Aphr-4-2 cells, DNA polymerases were partially purified from the parental and the mutant cells using sequential centrifugation and column chromatographies on DEAE-cellulose (DE23 and DE52) to remove DNA polymerases-beta and -gamma. More than 90% of the enzymatic activities from both cells showed characteristics of DNA polymerase-a type on the basis of these criteria: sensitivity to butyl phenyl dGTP (1 microM) and to IgG raised against DNA polymerase-a (SJK 132-20). The results indicate that DNA replication involving a mutant DNA polymerase-a with altered affinity for dCTP may be responsible for the UV sensitivity and mutability of the mutant.

Aphidicolin hypersensitive mutant of Chinese hamster V79 fibroblasts that underproduces DNA polymerase-alpha antigen.

Aphidicolin is a specific inhibitor of DNA polymerase-alpha and -delta from eukaryotic cells. Because of the specificity of this inhibitor, it is potentially a useful probe for the detailed studies of the function of these polymerases. DNA polymerase-alpha mutants isolated on the basis of resistance to aphidicolin have been described. We have isolated four variants that exhibit hypersensitivities to aphidicolin (Aphhs) from Chinese hamster V79/743X fibroblasts. These variants are designated aphhs-1, aphhs-2, aphhs-3 and aphhs-4. We reported here results of studies involving immunochemical characterization. The Aphhs phenotype in all mutants was stable for at least 30 days in the absence of selection pressure. The dCTP pools in the 743X and Aphhs cell lines were not significantly different. The level of total DNA polymerase activity in the crude extract from aphhs-2 cells was 30% of that observed in the parental 743X clone. We developed a method to quantitate DNA polymerase-alpha antigen at single cells in situ using monoclonal antibody SJK 132-20 and fluorescence pseudocolor image. We found that the antigen of DNA polymerase-alpha in aphhs-2 was 30-50% of that in the parental 743X cells. The underproduction of the antigen of DNA polymerase-alpha provides a basis for the observed Aphhs phenotype. Possible mechanisms for the underproduction of DNA polymerase-alpha in aphhs-2 clone are presented.