Intracortical haematogenous osteomyelitis.

We present an unusual case of haematogenous osteomyelitis in the diaphysis of the tibia of an adult leading to a subacute presentation with an extracortical abscess. Fluid from the abscess grew methicillin resistant Staphylococcus aureus (MRSA) on culture; MRSA with the same antibiogram had been grown from the patient's blood seven years earlier following a bowel resection. Drainage of the abscess and curettage of the bone lesion together with appropriate antibiotic therapy led to resolution of the osteomyelitis.

Cautious observation or blanket scanning? An investigation into paediatric attendances to an emergency department after head injury.

In September 2007, the National Institute for Health and Clinical Excellence (NICE) in the UK issued a newly updated guideline (CG56) on the early care of adults and children with head injuries.(8) The guideline gives some new recommendations, in particular with regards to imaging of children with head injury. We undertook a study to investigate the management of children presenting with head injury to our emergency department and to assess their outcomes and the CT scanning rate. We then retrospectively applied the new NICE guidelines, using information documented in the case notes, to establish whether adherence to the guidelines would significantly affect CT scanning rates. 237 paediatric head injury cases were seen over the 2-month period that was studied. The actual CT scanning rate observed was 2.1%, rising to 18.1% after strictly applying NICE criteria. This increased scanning rate raises some important issues with regards to patient safety and service provision.

Computer modeling of gibberellin-DNA binding.

Computer modeling and molecular mechanics performed on the intercalation complexes of selected gibberellins or biosynthetic precursors with DNA dinucleotides revealed that under appropriate conditions the ligands insert (intercalate) between the base-paired double-stranded dinucleotide, 5'-dTdA-3'. Stabilization of the double-stranded dinucleotide after docking of a gibberellin between base pairs is inferred by the sum negative energy of hydrogen bonding and van der Waals contacts and the entropic changes which accompany the formation of each ligand-dinucleotide complex. In addition, the interactions of the gibberellins and dinucleotides, with the gibberellic acid-dinucleotide complex serving as the prototype, show optimum geometry and stereochemical hydrogen bonding recognition which are dependent upon the complementary chirality and stereochemistry of the individual components. Whether or not the gibberellins directly influence the uncoiling of DNA or gene expression at the transcriptional level via an intercalation mechanism is a matter of conjecture, albeit one that warrants intensive investigation.

Invertase activity and the kinetin-stimulated enlargement of detached radish cotyledons.

Cytokinin treatment is known to promote expansion of light-grown excised radish (Raphanus sativus L. cv Crimson Giant) cotyledons. This expansion, at least in part, seems to be related to an increased accumulation of osmotically active reducing sugars. Kinetin treatment did not cause increased levels of isocitrate lyase activity over the controls, but stimulated increased levels of two invertase forms, designated types I and II. Type I was soluble and type II was insoluble after homogenization in 10 millimolar tris(hydroxymethyl)aminomethane-HCl (pH 7.0). Both types were soluble after homogenization in 300 millimolar NaCl. At low salt concentration, type II was retained on a diethylamioethyl-cellulose column and type I was not. Type II was then eluted from the column at high salt concentration. Types I and II exhibited pH optima of 5.3 and 4.3, Michaelis constants of 4.96 and 1.23 millimolar sucrose, and molecular weights of 65,000 and 57,000 daltons, respectively. The kinetin promotion of reducing sugar accumulation may be related to increased levels of the two invertase forms, but is probably not a result of direct cytokinin-stimulated glyoxysomal activity.

Chirality and stereochemical recognition in DNA-phytohormone interactions: a model approach.

Space-filling molecular models of selected phytohormones and DNA, employed as described herein, illustrate possible in vivo stereochemical recognition between nucleic acids and intercalated phytohormones. In this regard, the absolute chirality of certain phytohormones, and that of DNA may be essential for the recognition process. It is speculated further that the specific interactions shown by molecular models have significance in the evolution of plant regulatory mechanisms.

The relative amounts and identification of some 2,4-dichlorophenoxyacetic Acid metabolites isolated from soybean cotyledon callus cultures.

Soybean (Glycine max L.) cotyledon callus grown on radioactive 2,4-dichlorophenoxyacetic acid (2,4-D-1-(14)C) as an auxin produced 2,4-D metabolites, which qualitatively and quantitatively changed with time. Water soluble fractions from the tissue exhibited a steady increase in radioactivity during the course of 24 days. Following beta-glucosidase treatment, at least eight aglycones were obtained from the water soluble fraction of the tissue after 8 days. The metabolite, 4-hydroxy-2,5-dichlorophenoxyacetic acid was the most abundant aglycone during the entire 32 day growth period while 4-hydroxy-2,3-dichlorophenoxyacetic acid was detected as a minor metabolite. Radioactivity in the ether soluble acidic fractions reached a maximum of 82% of the total in the tissue after 2 days. The level then decreased to 44% by the end of 24 days. A total of seven ether soluble components were detected. In addition to 2,4-D glutamic acid, which was detected in high amounts after 24 hours, 2,4-D aspartic acid was found to be the most abundant ether soluble metabolite after longer time periods. Mass spectral data and a fragmentation pattern are presented for 2,4-D aspartic acid.

Cytokinins extracted from pinto bean fruit.

Extracts from various parts of Phaseolus vulgaris L. var. Pinto plants were found to exhibit cytokinin activity with the highest levels present in extracts of the fruit tissue. To separate the cytokinins present in the fruit, extracts were chromatographed in several solvent systems. Bioassays of chromatograms indicated the presence of active factors in those regions of migration associated with several known N-6-substituted aminopurines.Ultraviolet and mass spectral studies confirm the presence of a mixture of N-6-substituted aminopurines in the active material isolated by cation exchange resin chromatography. The evidence strongly supports the conclusions that dihydrozeatin is naturally occurring as the free base and possibly as a ribonucleoside. Further, zeatin appears to occur mainly as a glycosidic compound which is altered by KMnO(4) treatment and is hydrolyzed under acid conditions.

Chromatographic analysis of a cytokinin from tissue cultures of crown-gall.

Extracts from tissue cultures of crown-gall from Parthenocissus tricuspidata (Sieb. and Zucc.) Planch. exhibited cell division activity in the soybean cytokinin assay. The chromatographic migration of one component, responsible for most of the activity, is similar to that of zeatin ribonucleoside. In addition, acid hydrolysis of the active region taken from chromatograms and of an eluate from a cation-exchange resin column resulted in the production of an active free-base-like derivative. Since the derivative and the parent compound lose activity after KMnO(4) treatment, they are believed to possess an unsaturated constituent essential for biological activity. The major active factor present in crown-gall from Parthenocissus tricuspidata is therefore distinct from the nicotinamide derivative reported to be present in Vinca rosea L. tumor cells.