Use of 13C nuclear magnetic resonance to assess fossil fuel biodegradation: fate of [1-13C]acenaphthene in creosote polycyclic aromatic compound mixtures degraded by bacteria

[1-13C]acenaphthene, a tracer compound with a nuclear magnetic resonance (NMR)-active nucleus at the C-1 position, has been employed in conjunction with a standard broad-band-decoupled 13C-NMR spectroscopy technique to study the biodegradation of acenaphthene by various bacterial cultures degrading aromatic hydrocarbons of creosote. Site-specific labeling at the benzylic position of acenaphthene allows 13C-NMR detection of chemical changes due to initial oxidations catalyzed by bacterial enzymes of aromatic hydrocarbon catabolism. Biodegradation of [1-13C]acenaphthene in the presence of naphthalene or creosote polycyclic aromatic compounds (PACs) was examined with an undefined mixed bacterial culture (established by enrichment on creosote PACs) and with isolates of individual naphthalene- and phenanthrene-degrading strains from this culture. From 13C-NMR spectra of extractable materials obtained in time course biodegradation experiments under optimized conditions, a number of signals were assigned to accumulated products such as 1-acenaphthenol, 1-acenaphthenone, acenaphthene-1,2-diol and naphthalene 1,8-dicarboxylic acid, formed by benzylic oxidation of acenaphthene and subsequent reactions. Limited degradation of acenaphthene could be attributed to its oxidation by naphthalene 1,2-dioxygenase or related dioxygenases, indicative of certain limitations of the undefined mixed culture with respect to acenaphthene catabolism. Coinoculation of the mixed culture with cells of acenaphthene-grown strain Pseudomonas sp. strain A2279 mitigated the accumulation of partial transformation products and resulted in more complete degradation of acenaphthene. This study demonstrates the value of the stable isotope labeling approach and its ability to reveal incomplete mineralization even when as little as 2 to 3% of the substrate is incompletely oxidized, yielding products of partial transformation. The approach outlined may prove useful in assessing bioremediation performance.     

Medical history from midcoast Maine

Previous studies have shown that in vitro thyroid peroxidase (TPO) iodide oxidation activity is decreased and thyroid T4-5'-deiodinase activity is increased 15 days after induction of experimental diabetes mellitus (DM). In the present study we used thyroid histoautoradiography, an indirect assay of in vivo TPO activity, to determine the possible parallelism between the in vitro and in vivo changes induced by experimental DM. DM was induced in male Wistar rats (about 250 g body weight) by a single i.p. streptozotocin injection (45 mg/kg), while control (C) animals received a single injection of the vehicle. Seven and 30 days after diabetes induction, each diabetic and control animal was given i.p. a tracer dose of 125I (2 microCi), 2.5 h before thyroid excision. The glands were counted, weighted, fixed in Bouin's solution, embedded in paraffin and cut. The sections were stained with HE and exposed to NTB-2 emulsion (Kodak). The autohistograms were developed and the quantitative distribution of silver grains was evaluated with a computerized image analyzer system. Thyroid radioiodine uptake was significantly decreased only after 30 days of DM (C: 0.38 +/- 0.05 vs DM: 0.20 +/- 0.04%/mg thyroid, P < 0.05) while in vivo TPO activity was significantly decreased 7 and 30 days after DM induction (C: 5.3 and 4.5 grains/100 micron 2 vs DM: 2.9 and 1.6 grains/100 micron 2, respectively, P < 0.05). These data suggest that insulin deficiency first reduces in vivo TPO activity during short-term experimental diabetes mellitus.     

Morphofunctional characteristics of the endosteum in connection with bone remodeling]

HIV-related symptomatology represents both an indirect measure of immune functioning and a clinically significant indicator of disease progression. The most widely used classification system for HIV-related symptomatology is the Center for Disease Control (CDC) system. Although the CDC scale has widely recognized clinical utility, it provides only nominal-level measurement, which may be problematic for both clinicians and researchers. This article describes the revision and validation of the HIV Center Medical Staging Scale (rHCMSS), and ordinal-level physical illness scale that provides a means of independently measuring the progression of HIV-disease symptomatology and immunological decline. Concurrent use of the rHCMSS, the CDC classification system, and T-lymphocyte and viral load data will provide a more comprehensive indication of HIV-disease progression for clinical and research purposes.     

Comparison of rSP-C surfactant with natural and synthetic surfactants after late treatment in a rat model of the acute respiratory distress syndrome

1. In a previous paper we showed that an SP-C containing surfactant preparation has similar activity as bovine-derived surfactants in a rat lung lavage model of the adult respiratory distress syndrome. In this study surfactant was given ten minutes after the last lavage (early treatment). In the present investigation we were interested how different surfactant preparations behave when they are administered 1 h after the last lavage (late treatment). 2. Four protein containing surfactants (rSP-C surfactant, bLES, Infasurf and Survanta) were compared with three protein-free surfactants (ALEC, Exosurf and the phospholipid (PL) mixture of the rSP-C surfactant termed PL surfactant) with respect to their ability to improve gas exchange in this more stringent model when surfactant is given one hour after the last lavage. For better comparison of the surfactants the doses were related to phospholipids. The surfactants were given at doses of 25, 50 and 100 mg kg(-1) body weight. The surfactants were compared to an untreated control group that was only ventilated for the whole experimental period. 3. Tracheotomized rats (8-12 per dose and surfactant) were pressure-controlled ventilated (Siemens Servo Ventilator 900C) with 100% oxygen at a respiratory rate of 30 breaths min(-1), inspiration expiration ratio of 1:2, peak inspiratory pressure of 28 cmH2O at positive endexpiratory pressure (PEEP) of 8 cmH2O. Animals were ventilated for one hour after the last lavage and thereafter the surfactants were intratracheally instilled. During the whole experimental period the ventilation was not changed. 4. Partial arterial oxygen pressures (PaO2, mmHg) at 30 min and 120 min after treatment were used for statistical comparison. All protein containing surfactants caused a dose-dependent increase of the reduced PaO2 values at 30 min after treatment. The protein-free surfactants showed only weak dose-dependent increase in PaO2 values at this time. This difference between the protein-containing and the protein-free surfactants was even more pronounced when comparing the PaO2 values at 120 min after treatment. Only rSP-C surfactant, bLES and Infasurf showed a dose-dependent increase in PaO2 at this time. 5. With this animal model of late treatment it is possible even to differentiate between bovine derived surfactants. The differences between protein-containing and protein-free surfactants become even more pronounced. From the comparison of rSP-C surfactant with bovine-derived surfactants and the PL surfactant without rSP-C, it can be concluded that addition of rSP-C is sufficient to achieve the same activity as that of natural surfactants.     

Needle exchange is not enough: lessons from the Vancouver injecting drug use study

OBJECTIVE: To describe prevalence and incidence of HIV-1, hepatitis C virus (HCV) and risk behaviours in a prospective cohort of injecting drugs users (IDU). SETTING: Vancouver, which introduced a needle exchange programme (NEP) in 1988, and currently exchanges over 2 million needles per year. DESIGN: IDU who had injected illicit drugs within the previous month were recruited through street outreach. At baseline and semi-annually, subjects underwent serology for HIV-1 and HCV, and questionnaires on demographics, behaviours and NEP attendance were completed. Logistic regression analysis was used to identify determinants of HIV prevalence. RESULTS: Of 1006 IDU, 65% were men, and either white (65%) or Native (27%). Prevalence rates of HIV-1 and HCV were 23 and 88%, respectively. The majority (92%) had attended Vancouver's NEP, which was the most important syringe source for 78%. Identical proportions of known HIV-positive and HIV-negative IDU reported lending used syringes (40%). Of HIV-negative IDU, 39% borrowed used needles within the previous 6 months. Relative to HIV-negative IDU, HIV-positive IDU were more likely to frequently inject cocaine (72 versus 62%; P < 0.001). Independent predictors of HIV-positive serostatus were low education, unstable housing, commercial sex, borrowing needles, being an established IDU, injecting with others, and frequent NEP attendance. Based on 24 seroconversions among 257 follow-up visits, estimated HIV incidence was 18.6 per 100 person-years (95% confidence interval, 11.1-26.0). CONCLUSIONS: Despite having the largest NEP in North America, Vancouver has been experiencing an ongoing HIV epidemic. Whereas NEP are crucial for sterile syringe provision, they should be considered one component of a comprehensive programme including counselling, support and education.     

Antigens recognized by T-lymphocytes on human tumours

Some of the factors influencing the success of a nuclear transfer procedure are the quality of the recipient oocyte and the efficiency of the method of artificial activation. In this study we evaluated the ability of an electrical pulse to stimulate in vitro-matured porcine oocytes to develop. Maturation in Waymouth's medium resulted in significantly greater development than maturation in TCM-199 (p < 0.05), while there was no significant difference between degrees of development in Waymouth's medium and Whitten's medium. Oocytes matured in Waymouth's medium and electrically stimulated at 36 h (young oocytes) developed to the same degree as oocytes stimulated at 48 h (aged oocytes). Oocytes matured in Waymouth's medium and treated with cytochalasin B showed significantly greater development (p < 0.10) in response to electrical activation than controls. Staurosporine activation of oocytes resulted in significantly (p < 0.05) fewer morulae and blastocysts when compared to electrical stimulation. Development of parthenogenic embryos to the elongated filamentous stage (10% development beyond blastocyst) was obtained by maturing oocytes in Waymouth's medium and electrically stimulating them to develop. By obtaining development of porcine parthenotes beyond the blastocyst stage, we have identified an efficient method of oocyte maturation and oocyte activation for use in a system for nuclear transfer.     

Spontaneous and postoperative spondylodiscitis. A material concerning 23 patients

A retrospective study of 23 patients with spondylodiscitis is reported. Sixteen cases were spontaneous. Five of these were seen in the acute phase with S. aureus grown from the blood. Eleven patients were investigated with CT-guided biopsy of the spine with identification of different microorganisms in eight cases. In four of seven cases of spondylodiscitis after operation for disc herniation coagulase-negative staphyloccoci were grown after CT-guided biopsy. In spontaneous cases pain disappeared and CRP was normalized within a few weeks after treatment with antibiotics, but radiological changes might progress for several months. Antibiotics were given for two to six months, with a mean of 5.1 months in purulent bacterial infections, and all patients were considered cured after this.     

Oval cell proliferation associated with the murine insertional mutation TgN737Rpw

The Tg737 gene was identified by its direct association with a transgene-induced insertion mutation in the mouse. This mutation causes pleiotropic phenotypes including a syndrome similar to autosomal recessive polycystic kidney disease in humans. This syndrome, in addition to renal cyst formation, includes the presence of an invariably associated liver abnormality. The liver pathology in TgN737Rpw mice is characterized by a biliary hyperplasia that includes the proliferation of cells that morphologically and immunologically resemble oval cells, a liver progenitor cell. This abnormality is first observed at approximately 5 days of age in the portal region and then progresses into the periportal regions. Additionally, the formation and proliferation of dysplastic ductular structures are observed from the onset of the phenotype. Serum chemistry indicated that the primary defect is likely to be of biliary origin, and hepatic function appears normal in the mutant mice. Therefore, this mutation is unlike other causes of oval cell proliferation in that the hepatic parenchyma is relatively unaffected. The identification of the Tg737 gene associated with this mutation suggests that it functions in regulating the proliferation/differentiation of oval cells within the liver, which further indicates that this gene may function in pathological conditions that include oval cell proliferation, such as hepatocellular carcinogenesis.