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Biomedical subjects

S J Brooks

Publications and source records attributed to S J Brooks.

9 recordsLinked to original sources
PubMed2003

Biotransformation of halophenols using crude cell extracts of Pseudomonas putida F6.

Crude cell extracts of Pseudomonas putida F6 transformed 4-substituted fluoro-, chloro-, bromo- and iodo-phenol without the exogenous addition of cofactors. The rate of substrate consumption decreased with increasing substituent size (F>Cl>Br>I). Biotransformations resulted in greater than 95% utilisation of the halogenated substrate. Product accumulation was observed in incubations with 4-chloro, 4-bromo- and 4-iodo-phenol. These products were identified as the corresponding 4-substituted catechols. Transformation of 4-fluorophenol did not result in the accumulation of the corresponding catechol; however, manipulation of the reaction conditions by incorporation of ascorbic acid culminated in the formation of 4-fluorocatechol. Cell extracts of P. putida F6 also showed activity towards a 3-substituted phenol, namely 3-fluorophenol, resulting in the formation of a single product, 4-fluorocatechol.

Biotransformation↗
PubMed2001

Diagnosis and measurement of adolescent depression: a review of commonly utilized instruments.

We surveyed 160 recent studies of adolescent depression (publication dates ranged from March 1996 to August 2000) and identified 33 different diagnostic and symptom measurement instruments being used by various investigators. We also found that more than one in three of the studies measuring depressive symptom severity in adolescents relied on instruments designed for use with adults. We then reviewed in detail the design features and psychometric properties of the 12 instruments most commonly used in studies of adolescent depression and attempted to characterize their strengths and weaknesses. Our main conclusions are as follows: Too many different instruments are being used by investigators, presumably due to a lack of consensus as to which are the most valid and reliable tools. Instruments designed for use in adults and never validated in adolescent populations are frequently used with no evidence for their developmental sensitivity. Many studies are using instruments that demonstrate substantial weaknesses in validity and/or reliability. The need for a parsimonious, easily administered, valid, and reliable tool(s) to diagnose and measure symptom severity in adolescent depression has not yet been met.

Adolescent↗
PubMed1984

Repression of nitrogen fixation in Klebsiella pneumoniae at high temperature.

The effect of elevated growth temperature on nif mRNA synthesis, nif protein synthesis, and nitrogenase activity was investigated in wild-type and NifL- strains of Klebsiella pneumoniae. Nitrogenase activity is not affected at 41 degrees C; however, nitrogenase is not synthesized at that temperature. Transcription of three nif operons studied is repressed at 41 degrees C. We show that the nifL protein is not required for repression by high temperature and propose that repression of nif at 41 degrees C results from a reversible inactivation of the nifA gene product.

Acetylene↗
PubMed1977

Immunization against retrograde pyelonephritis. III. Vaccination against chronic pyelonephritis due to Escherichia coli.

Vaccination with formalin-treated cells of Escherichia coli serotype O6 protected against unilateral retrograde pyelonephritis due to E. coli O6 in rats with partial ureteral obstruction. This protection was manifested not only by less parenchymal destruction and shrinkage of the pyelonephritic left kidney, but also by less secondary pyelonephritis and compensatory hypertrophy in the opposite right kidney. Vaccinated rats eliminated E. coli from the kidney more rapidly, but even when infection persisted in the kidney, the chronic pyelonephritis was less severe in vaccinated rats. High levels of antibody to E. coli lipopolysaccharide were found in vaccinated animals and may have contributed to protection. These results raise the question of whether vaccination ought to be considered for patients predisposed to chronic bacterial pyelonephritis.

Animals↗
PubMed1977

Screening for bacteriuria: Microstix and dipslides.

The Microstix system has been tested, in parallel with dipslides, for suitability as a screening technique for the detection of bacteriuria. Results obtained using each method on 228 urine specimens were assessed by comparison with the results of quantitative counts. Dipslides had a higher sensitivity (86-7%) than Microstix. The best specificity (100%) was obtained from those results (77-6%) where both components of the Microstix system were in agreement. Advantages of Microstix are its greater shelf-life and its compactness.

Bacteriological Techniques↗
PubMed1974

Immunization against retrograde pyelonephritis. I. Production of an experimental model of severe ascending Escherichia coli pyelonephritis without bacteremia in rats.

Retrograde pyelonephritis was produced in rats by introducing into the bladder a small refluxing inoculum of Escherichia coli that would enter the renal pelvis but not the blood stream. At the same time the left ureter was partially obstructed for 18 hours. This model differs from previous attempts to produce E coli pyelonephritis with large (0.6 ml) volumes infused into the bladder, because such large volumes cause bacteremia and hematogeneous pyelonephritis. Since retrograde E coli pyelonephritis in patients is not accompanied by positive blood cultures, the model described in this report is believed to accurately mimic human pyelonephritis and to allow a realistic approach to the study of immunity against retrograde infection in the urinary tract.

Animals↗
PubMed1974

Immunization against retrograde pyelonephritis. II. Prevention of retrograde Escherichia coli pyelonephritis with vaccines.

Vaccination with heat-killed or formalinized cells of E coli 0:111, or E coli 06 (Williams), prevented retrograde E coli pyelonephritis. Since there was no bacteremia and no urinary antibody, the vaccination appeared to protect by immune reactions operating in the kidney itself. The vaccine failed to protect against a highly virulent form of E coli 06 (Riffle), possibly because the amount of antibody to its lipopolysaccharide was inadequate. Since all three strains possessed K antigen in approximately equal amounts, the difference in results was not attributed to its presence.

Animals↗