The angiotensinogen gene is expressed in both astrocytes and neurons in murine central nervous system

Two transgenic mouse models were used to examine the cellular localization of angiotensinogen (AGT) in the brain. The first model was previously described in detail and consists of a human AGT genomic transgene containing all exons and introns of the gene and 1. 2 kb of the 5' flanking DNA. The second model contains a fusion between 1.2 kb of HAGT 5' flanking DNA and the beta-gal reporter gene which exhibits a similar pattern of tissue-specific expression to the HAGT transgene. Expression of both transgenes qualitatively mirrors the expression of endogenous AGT. Double staining of transgenic mouse brain sections with X-gal and GFAP revealed that a majority of beta-gal activity was localized to astrocytes in almost all brain areas. However, both beta-gal activity as identified by X-gal, and HAGT mRNA as detected by in situ hybridization, were also found in neurons in restricted areas of the brain, including the mesencephalic trigeminal nucleus (meV), subfornical organ (SFO) and the external lateral parabrachial nucleus (elPB). The expression of these transgenes provides the first convincing evidence for AGT gene expression in neurons in the brain. We further report by angiotensin II (Ang-II) immunostaining in rat brains after selective lesioning, that Ang-II is likely involved in a neuronal pathway from the PB to the amygdala (Ce). Finally, we performed double-labeling, first by retrograde labeling of HRP injected into the Ce, and then by X-gal on PB neurons in beta-gal transgenic mice, and identified doubly labeled neurons. Based on these results, we propose that AGT is generated in neurons in the elPB, transported to the Ce and converted into Ang-II locally to exert is biological functions.     

Mutator phenotype induced by aberrant replication

We have identified thermosensitive mutants of five Schizosaccharomyces pombe replication proteins that have a mutator phenotype at their semipermissive temperatures. Allele-specific mutants of DNA polymerase delta (poldelta) and mutants of Polalpha, two Poldelta subunits, and ligase exhibited increased rates of deletion of sequences flanked by short direct repeats. Deletion of rad2(+), which encodes a nuclease involved in processing Okazaki fragments, caused an increased rate of duplication of sequences flanked by short direct repeats. The deletion mutation rates of all the thermosensitive replication mutators decreased in a rad2Delta background, suggesting that deletion formation requires Rad2 function. The duplication mutation rate of rad2Delta was also reduced in a thermosensitive polymerase background, but not in a ligase mutator background, which suggests that formation of duplication mutations requires normal DNA polymerization. Thus, although the deletion and duplication mutator phenotypes are distinct, their mutational mechanisms are interdependent. The deletion and duplication replication mutators all exhibited decreased viability in combination with deletion of a checkpoint Rad protein, Rad26. Interestingly, deletion of Cds1, a protein kinase functioning in a checkpoint Rad-mediated reversible S-phase arrest pathway, decreased the viability and exacerbated the mutation rate only in the thermosensitive deletion replication mutators but had no effect on rad2Delta. These findings suggest that aberrant replication caused by allele-specific mutations of these replication proteins can accumulate potentially mutagenic DNA structures. The checkpoint Rad-mediated pathways monitor and signal the aberrant replication in both the deletion and duplication mutators, while Cds1 mediates recovery from aberrant replication and prevents formation of deletion mutations specifically in the thermosensitive deletion replication mutators.     

Metatarsus proximus and digital divergence. Association with intermetatarsal neuromas

A retrospective radiologic study was performed to determine whether there is an increased finding of metatarsus proximus and digital divergence in patients with a confirmed diagnosis of intermetatarsal neuroma when compared with an asymptomatic group. The study included 48 patients with pathologic confirmation of neuroma and 100 asymptomatic patients. Results of the study revealed no statistical relationship between the radiologic findings of metatarsus proximus and digital divergence and the physical occurrence of neuromas. An unexpected finding was an increased intermetatarsal angle of the affected interspace in the neuroma group.     

Intermolecular cleavage by UmuD-like enzymes: identification of residues required for cleavage and substrate specificity

The UmuD-like proteins are best characterized for their role in damage-induced SOS mutagenesis. An essential step in this process is the enzymatic self-processing of the UmuD-like proteins. This reaction is thought to occur either via an intramolecular or intermolecular self-cleavage mechanism. Here, we demonstrate that it can also occur via an heterologous intermolecular cleavage reaction. The Escherichia coli UmuD enzyme demonstrated the broadest substrate specificity, cleaving both E. coli and Salmonella typhimurium UmuD substrates in vivo. In comparison, the wild-type S. typhimurium UmuD (UmuDSt) and MucA enzymes catalyzed intermolecular self-cleavage, but did not facilitate heterologous cleavage. Heterologous cleavage by the UmuDSt enzyme was, however, observed with chimeric UmuD substrates that possess residues 30-55 of UmuDSt. We have further localized the residue predominantly responsible for UmuDSt-catalyzed heterologous cleavage to Ser50 in the substrate molecule. We hypothesize that changes at this residue affect the positioning of the cleavage site of a substrate molecule within the catalytic cleft of the UmuDSt enzyme by affecting the formation of a so-called UmuD "filament-dimer". This hypothesis is further supported by the observation that mutations known to disrupt an E. coli UmuD' filament dimer also block intermolecular UmuDEc cleavage.     

Dioxin in Storm-Water Runoff in Houston, Texas

Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans in runoff were measured at 10 small flood control drainage channels in the Houston area. Total toxicity equivalent concentrations in runoff ranged from 0.01?to?0.11?pg/L for the dissolved phase and from 0.02?to?0.88?pg/L for the suspended phase. The dissolved concentrations were lower than their respective suspended concentrations, with average suspended/dissolved ratios between 5 and 152 for individual congeners. Average observed logs of organic-carbon (OC)-normalized suspended sediment-dissolved partitioning coefficients (log?KOC) varied between 5.47 and 7.83?L/kg OC. Dioxin concentrations in runoff were generally at the same level or lower than those measured in the receiving water body. Principal component analyses indicated that the signatures for dissolved runoff match those observed in dissolved ambient water in the channel, while the suspended-sediment runoff signatures are similar to those observed in dry air deposition in the Houston area.     

Body-composition changes in patients who gain weight while receiving megestrol acetate

PURPOSE: Randomized placebo-controlled clinical trials have now established that megestrol acetate causes appetite stimulation and weight gain in patients with anorexia and/or cachexia. There is a paucity of available data to delineate the substance of this increased weight. PATIENTS AND METHODS: Using dual-energy x-ray absorptiometry and tritiated body water methodologies, we performed body-composition measurements in 12 patients with advanced cancer before the institution of oral megestrol acetate (800 mg/d) and at subsequent 2-month intervals. RESULTS: Seven of the 12 patients gained weight (2.1 to 16.5 kg) and had repeat body-composition measurements performed at the time of maximum weight gain. The vast majority of the gained weight was clearly from an increase in adipose tissue, while there was a suggestion that an increase in body fluid was responsible for a minority of the weight gain. CONCLUSION: Megestrol acetate-induced weight gain is primarily the result of an increase in body mass.     

Rural water supplies: what ways and means?

The development of rural water supplies in Finland is outlined, with particular reference to consumer-managed cooperatives. Lessons are drawn which could be of value in developing countries.