Design and hydraulic characteristics of a field-scale bi-phasic bioretention rain garden system for storm water management.

A field-scale bioretention rain garden system was constructed using a novel bi-phasic (i.e. sequence of anaerobic to aerobic) concept for improving retention and removal of storm water runoff pollutants. Hydraulic tests with bromide tracer and simulated runoff pollutants (nitrate-N, phosphate-P, Cu, Pb, and Zn) were performed in the system under a simulated continuous rainfall. The objectives of the tests were (1) to determine hydraulic characteristics of the system, and (2) to evaluate the movement of runoff pollutants through the system. For the 180 mm/24 h rainfall, the bi-phasic bioretention system effectively reduced both peak flow (approximately 70%) and runoff volume (approximately 42%). The breakthrough curves (BTCs) of bromide tracer suggest that the transport pattern of the system is similar to dispersed plug flow under this large runoff event. The BTCs of bromide showed mean 10% and 90% breakthrough times of 5.7 h and 12.5 h, respectively. Under the continuous rainfall, a significantly different transport pattern was found between each runoff pollutant. Nitrate-N was easily transported through the system with potential leaching risk from the initial soil medium, whereas phosphate-P and metals were significantly retained indicating sorption-mediated transport. These findings support the importance of hydraulics, in combination with the soil medium, when creating bioretention systems for bioremediation that are effective for various rainfall sizes and intervals.

Expression of Six1 homeobox gene during development of the mouse submandibular salivary gland.

BACKGROUND: Members of the Six family of homeoproteins are expressed in numerous tissues during vertebrate embryogenesis, and are critical regulators of both cell proliferation and survival. Here we report the temporal and spatial expression of Six1 during maturation of the mouse submandibular salivary gland (SSG) from embryonic day 18.5 (E18.5) to postnatal day 28. Additionally, we examine the role of Six1 during SSG development using Six1-deficient mice. METHODS: Six1 expression was assessed by reverse transcription-polymerase chain reaction, Western blot, and immunofluorescence. Proliferation was measured by bromodeoxyuridine (BrdU) incorporation index, and apoptosis was evaluated by TUNEL assay. RESULTS: Six1 mRNA and protein levels are high in the epithelial SSG cells at E18.5 and decrease progressively in the postnatal maturing SSG. Although SSGs from Six1(-/-) embryos are significantly smaller than wild type SSGs, the histological structures of the SSG acini and ducts are similar. Six1(-/-) salivary epithelial cells exhibit an intrinsic defect in cell proliferation accompanied by a significant reduction in the Six1 target gene cyclin A1, previously shown to be a critical mediator of Six1-induced proliferation. CONCLUSION: Our results suggest that the reduction in size of Six1(-/-) SSGs is result of a decrease in cell proliferation during development/maturation.

Comparison of Directigen Group A Strep Test with a traditional culture technique for detection of group A beta-hemolytic streptococci.

The Directigen Group A Strep Test (DGAST), a new rapid method of detecting group A beta-hemolytic streptococci directly from throat swabs, was compared with a traditional culture technique for the detection of group A beta-hemolytic streptococci. Five hundred oropharyngeal swabs from pediatric and adult patients were cultured and then processed by using the DGAST. Of the 144 specimens positive by culture, 131 were DGAST positive (sensitivity, 90.9%). Of the 356 specimens negative by culture, 353 were DGAST negative (specificity, 99.2%). Twelve of the 13 false-negative DGAST results were from pediatric patients. One hundred isolates of non-group A beta-hemolytic streptococci were recovered, primarily groups C, F, and G. The DGAST is easy to perform, rapid, sensitive, and very specific for detection of group A beta-hemolytic streptococci directly from swabs. Supplementing the DGAST with a culture on a 5% sheep blood agar plate would enhance detection of group A beta-hemolytic streptococci, especially in pediatric patients.

Opportunistic mycotic infection caused by Chaetomium in a patient with acute leukemia.

Patients with acute leukemia are susceptible to a variety of opportunistic infections. A patient with acute lymphocytic leukemia who developed a Chaetomium-caused empyema, which may have subsequently contributed to his death is reported.

Gluteal abscess caused by Phialophora hoffmannii and review of the role of this organism in human mycoses.

Infections caused by members of the Phialophora hoffmannii (Beyma) Schol-Schwarz fungal aggregate (a group of related taxa, especially species of uncertain circumscription) are not reported frequently. This case report concerns the development of a gluteal abscess after multiple intramuscular injections of antimicrobial agents. Microbiological examination of the abscess material yielded a pure growth of the mold P. hoffmannii. Hyphal elements in the purulent exudate were only demonstrated when the specimen was digested by an N-acetyl cysteine-NaOH digestion-decontamination procedure or in stained paraffin block sections of the exudate. Other cases of disease caused by members of this fungal aggregate and the status of the mycology of this organism are reviewed.

Corynebacterium pseudotuberculosis. A new cause of infectious and eosinophilic pneumonia.

A 28 year old veterinary medical student experienced spiking fever, cough, peripheral blood eosinophilia and an eosinophilic pulmonary infiltrate. Corynebacterium pseudotuberculosis was isolated from a transtracheal aspirate and bronchoscopy washings. C. pseudotuberculosis, a pathogen responsible for lymphadenitis in livestock, has never been reported to cause pneumonia in man. In the four cases of C. pseudotuberculosis previously reported, lymphadenitis was the chief clinical presentation. In our patient specific antibodies against the isolated C. pseudotuberculosis developed but not against the other corynebacteria. With erythromycin therapy, the peripheral blood eosinophilia and IgE anti-C. pseudotuberculosis titer decreased whereas the IgG titer continued to increase.

Use of fecal streptococci as indicators of pollution in soil.

The survival, recovery, and identification of Streptococcus isolates from soil was investigated by (i) examination of survival in soil under different moisture and temperature conditions, (ii) evaluation of media combinations for recovering fecal streptococci from soil, and (iii) partial identification of isolates from diverse habitats. Cool, moist conditions prolonged the survival of Streptococcus faecalis in soil for at least 12 weeks, whereas freezing was lethal, with the populations being reduced up to 95% when several freeze-thaw treatments occurred. Media evaluations indicated that both the efficiency of recovery and enumeration of the fecal streptococci from soil can be influenced by the combination of media used. Taxonomic data revealed a need to develop procedures to differentiate between isolates of fecal origin and plant-derived streptococci that possess many of the cultural reactions of S. faecalis. It was found that recent fecal isolates exhibited a much greater incidence of multiple antibiotic resistance than soil or vegetation isolates, and this characteristic, coupled with the use of enterococci as indicators of fecal contamination in soil systems, is discussed.