Identification of the gene encoding the human mitochondrial RNA polymerase (h-mtRPOL) by cyberscreening of the Expressed Sequence Tags database

A gene cloning strategy based on the screening of the Expressed Sequence Tags database (dbEST) using sequences of mitochondrial housekeeping proteins of yeast was employed to identify the cDNA encoding the precursor of the human mitochondrial RNA polymerase (h- mtRPOL). The 3831 bp h-mtRPOL cDNA is located on chromosome 19p13.3 and encodes a protein of 1230 amino acid residues. The protein sequence shows significant homologies with sequences corresponding to mitochondrial RNA polymerases from lower eukaryotes, and to RNA polymerases from several bacteriophages. The mitochondrial RNA polymerase carries out the central activity of mitochondrial gene expression and, by providing the RNA primers for replication- initiation, is also implicated in the maintenance and propagation of the mitochondrial genome. Genes involved in the control of mtDNA replication and gene expression are attractive candidates for human disorders due to abnormalities of nucleo-mitochondrial intergenomic signalling. The availability of the h-mtRPOL cDNA will allow us to test its role in mitochondrial pathology. In addition, we propose the 'cyberscreening' of dbEST, based on yeast/human cross-species comparison, as a powerful, simple, rapid and inexpensive method, that may accelerate several-fold the molecular dissection of the human mitochondrial proteome.      

Bullous eosinophilic cellulitis (Wells'' syndrome) associated with Churg–Strauss syndrome

We report a patient with Churg-Strauss syndrome (CSS) with asthma, eosinophilia, nasal polyposis and ANCA-associated multisystem vasculitis, who's skin eruption started with erythematous urticarial-plaques followed by haemorrhagic bullae. Histology of the plaques revealed 'flame figures' in the dermis with no granulomatous or vasculitic process, consistent with the diagnosis of eosinophilic cellulitis or Wells' syndrome. The association of CSS and Wells' syndrome observed in this patient may have a common pathogenesis. CSS may induce Wells' syndrome by an unknown factor.     

Intrinsic circuit organization of the major layers and sublayers of the dorsolateral prefrontal cortex in the rhesus monkey

Intrinsic connections are likely to play important roles in cognitive information processing to in the prefrontal association cortex. To gain insight into the organization of these circuits, intracortical connections of major laminar and sublaminar divisions were retrogradely labeled in Walker's area 9 and 46 in rhesus monkeys by using cholera toxin (B-subunit) conjugated to colloidal gold. Microinjections placed within particular cortical laminae produced unique patterns of retrograde labeling. Injections in layers II/III yielded labeling which was laterally widespread (2–7 mm) in supragranular layers, and more narrowly focused, i.e., conforming to a column, in layers IV–VI. In contrast, local circuits associated with layers IV and Vb displayed a regular, cylindrical organization, whereas intrinsic connections of layer Va were laterally extensive (3–5 mm) in layers III and Va. Finally, injections in layer VI gave rise to a narrow column of cell labeling traversing all layers, augmented by laterally extensive labeling (～ 7 mm) in layer VI. The intrinsic connections of the prefrontal cortex were arrayed within mediolaterally elongated stripes which were often distributed asymmetrically in either the medial or lateral direction. In addition, labsled cells within these mediolaterally oriented fields were frequently grouped within discrete clusters or narrow bands. The intrinsic connections identified in this study differ from the local circuits of corresponding layers reported for primary visual cortex; the unique intrinsic wiring diagram of the prefrontal cortex may be related to its specialized cognitive and mnemonic functions. © 1995 Wiley-Liss, Inc.     

Low seminal zinc bound to high molecular weight proteins in asthenozoospermic patients: evidence of increased sperm zinc content in oligoasthenozoospermic patients [published erratum appears in Hum Reprod 1998 Jun;13(6):1750]

Total seminal zinc concentration, seminal zinc fraction bound to high molecular weight proteins (HMW-Zn%) and zinc content in spermatozoa were assayed in the ejaculates of 90 asthenozoospermic patients subdivided into two study groups: normoasthenozoospermics (group I: n = 50) and oligoasthenozoospermics (group II: n = 40). The zinc concentrations of patients were compared with those of a control group of donors showing normal semen parameters. All samples were also investigated for their sperm membrane functional integrity by the hypo- osmotic swelling test (HOS). The results showed normal total zinc concentrations but very low HMW-Zn% values (P < 0.001) in seminal plasma of the two groups of asthenozoospermic patients compared to the controls. Furthermore higher zinc amounts (P < 0.001) were measured in spermatozoa of oligoasthenozoospermic patients compared to group I and to the control group. Oligoasthenozoospermics also displayed a lower HOS score (P < 0.001) compared to the other two groups. These data suggest that the increased unbound seminal zinc could contribute to the decrease of sperm motility in normoasthenozoospermic and oligoasthenozoospermic patients. A further impairment in sperm motility could occur in the oligoasthenozoospermic patients where the increase of seminal free zinc was followed by a major zinc uptake by spermatozoa. The higher intrasperm zinc content in these patients could be a reflection of their low sperm membrane functionality.