Suprascapular neuropathy after distal clavicle excision

Two cases of suprascapular neuropathy after excision of the distal clavicle are reported. Both patients were treated successfully with neurolysis of the suprascapular nerve starting at the upper trunk of the brachial plexus. Anatomic dissections revealed that the suprascapular nerve is quite close (<1.4 cm) to the posterior aspect of the distal clavicle, within 2 to 3 cm of the acromioclavicular joint. To avoid the complication of suprascapular neuropathy that could be associated with this close relationship, it is recommended that no more than 1 cm of the distal clavicle be removed posteriorly. It is also recommended that minimal periosteal elevation should be performed on the posteroinferior border of the distal clavicle.     

The wzz (cld) protein in Escherichia coli: amino acid sequence variation determines O-antigen chain length specificity

The O antigen is a polymer with a repeated unit. The chain length in most Escherichia coli strains has a modal value of 10 to 18 O units, but other strains have higher or lower modal values. wzz (cld/rol) mutants have a random chain length distribution, showing that the modal distribution is determined by the Wzz protein. Cloned wzz genes from E. coli strains with short (7 to 16), intermediate (10 to 18), and long (16 to 25) modal chain lengths were transferred to a model system, and their effects on O111 antigen were studied. The O111 chain length closely resembled that of the parent strains. We present data based on the construction of chimeric wzz genes and site-directed mutagenesis of the wzz gene to show that the modal value of O-antigen chain length of E. coli O1, O2, O7, and O157 strains can be changed by specific amino acid substitutions in wzz. It is concluded that the O-antigen chain length heterogeneity in E. coli strains is the result of amino acid sequence variation of the Wzz protein.     

Serotonin receptors: subtypes, functional responses and therapeutic relevance

Recent, rapid progress in the molecular biology of serotonin (5-HT) receptors requires conceptual re-thinking with respect to receptor classification. Thus, based on operational criteria (agonist and antagonist rank order), as well as transduction mechanisms involved and the structure of the receptor protein, the Nomenclature Committee of the Serotonin Club has proposed the following classification and nomenclature: the main receptor types 5-HT1 to 5-HT4, recombinant receptors (e.g. 5-ht5 to 5-ht7) and 'orphan' receptors. The aim of the present review is to discuss the events leading to this classification, the criteria for and functional responses mediated by various 5-HT receptors, as well as the therapeutic possibilities with 5-HT ligands.     

Reaction sequence of iron sulfide minerals in bacteria and their use as biomarkers

Some bacteria form intracellular nanometer-scale crystals of greigite (Fe3S4) that cause the bacteria to be oriented in magnetic fields. Transmission electron microscope observations showed that ferrimagnetic greigite in these bacteria forms from nonmagnetic mackinawite (tetragonal FeS) and possibly from cubic FeS. These precursors apparently transform into greigite by rearrangement of iron atoms over a period of days to weeks. Neither pyrrhotite nor pyrite was found. These results have implications for the interpretation of the presence of pyrrhotite and greigite in the martian meteorite ALH84001.     

Acute myeloid leukaemia complicated by anergic tuberculosis

A case of acute myeloid leukaemia presenting as pyrexia of unknown origin and weight loss with pancytopenia is described. Initial investigations revealed trilineage myelodysplasia which evolved into acute myeloid leukaemia within 2 weeks of presentation. He was commenced on a standard induction regimen consisting of idarubicin, Ara-C and thioguanine. Throughout his hospital stay he remained febrile. In spite of exhaustive investigations no cause for the pyrexia was found nor did he respond to any form of treatment. He died after 9 weeks in hospital. His post-mortem examination revealed widespread disseminated tuberculosis without any reactive inflammatory tissue response or granuloma formation.     

Acute traumatic cardiac tamponade treated solely by percutaneous pericardial drainage

The author suggests that anxiety disorders are related to a deficiency in the endogenous opioid system. The author classifies deficiencies of the endogenous opioid system as congenital or acquired, and also as real or relative. Individuals with 'real deficiency' cannot function adequately in any situations, including situations which are natural for human beings. Persons with 'relative deficiency' are unable to function adequately under circumstances which are unnatural for humans: their 'adaptational reserve' is insufficient. The use of opioid substances and alcohol is a form of self-medication to reduce anxiety. Acupuncture and its variations, psychotherapy, and the administration of placebo can decrease anxiety because these therapeutic maneuvers activate the endogenous opioid system.