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Notes: Sealing characteristics of commonly used water well annular space grouts were investigated using a large-scale laboratory model. The investigation was carried out in two phases. In the first phase, a bentonite drilling mud, often used as a well sealant, was investigated both in the laboratory well model and in the field. For this purpose, Quik-Gel® mud with different amounts of formation material (in this case sand) entrained in it was used as a sealant. In the second phase, an evaluation of four grouts: neat cement, bentonite-cement, powder bentonite (Volclay®), and granular bentonite (Benseal® and bentonite slurry mixed according to the “Ohio” recipe) was undertaken with respect to their effectiveness in sealing the annular space. A well model consisting of a sand-filled plexiglass container was constructed in this investigation. Four metal well casings were installed in boreholes formed in the sand. The annular space between the well casings and the boreholes formed in the sand were filled with various grouts. The effectiveness of these materials in sealing the annular space was evaluated by observation of their structural stability, infiltration of water placed on top of the sealants, and inspection of the sealants dissected during disassembling of the models. A finite-element computer program modeling the seepage in these well experiments was used to assist in the interpretation of the experimental results. The results indicate that the final success of a sealant depends on its structural stability as much as its permeability. Benseal®-bentonite slurry grout behaved best; neat cement and bentonite-cement grouts also provided good seals. Volclay® and various Quik-Gel® slurries formed poorer seals compared to these. Among the Quik-Gel® slurries, best results were obtained in the laboratory when a Marsh Funnel Viscosity of about 70 sec/qt was achieved and a mud weight of about 10 to 11 Ib/gal resulted from mixing of formation soils. However, field observations of drilling mud slurries with entrained cuttings exhibited problems of excessive settling even when the slurries had heavy mud weight, greater than 11 Ib/gal. The extent of settling appears to be positively correlated with the relative permeability of the native formation. This limits the types of well construction where these slurries may be used as annular space seal.

Notes: Arf (ADP-ribosylation factor) proteins, which mediate vesicular transport, have little or no intrinsic GTPase activity. They rely on the action of GTPase-activating proteins (GAPs) and guanine nucleotide exchange factors (GEFs) for their function. In the present study the OsAGAP gene in rice, which encoded a protein with predicted structure similar to ArfGAP, was identified. The purified OsAGAP-GST fusion protein was able to stimulate the GTPase activity of rice Arf. Furthermore, OsAGAP can rescue the defect of vesicular transport in the yeast gcs1Δglo3Δ double-mutant cells. Transgenic Arabidopsis with OsAGAP constitutively expression showed reduced apical dominance, shorter primary roots, increasing number of longer adventitious roots. Many of the phenotypes can be phenocopied by treatment of exogenous indoleacetic acid level (IAA) in wild-type plants. Determination of whole-plant IAA level showed that there is a sharp increase of free IAA in OsAGAP transgenic Arabidopsis seedlings. In addition, removal of the 4-day-old shoot apex could inhibit the adventitious root formation in the transgenic seedlings. These results suggest OsAGAP, an ARF-GAP of rice, may be involved in the mediation of plant root development by regulating auxin level.

Notes: 1. We examined the effect of three doses (0.03, 0.3 and 3 mg/kg per day) of the angiotensin converting enzyme (ACE) inhibitor, perindopril, on the long-term blood pressure of spontaneously hypertensive rats (SHR) of the Okamoto strain after treatment during the developmental stage of hypertension development.2. While the 0.03 mg/kg per day dose, given between the ages of 4–10 weeks of age, failed to lower blood pressure, the two higher doses resulted in normotension over this treatment period as did the highest dose given between the ages of 4–20 weeks of age.3. Only the 0.3 mg/kg per day dose resulted in a moderate (17%) long-term fall in blood pressure upon cessation of treatment when compared to untreated SHR controls. The highest dose, given over the 4–20 week period resulted in a significant rebound hypertension above the blood pressure level of untreated, control SHR.4. The 3 mg/kg per day dose, whether given over the 4–10 or 4–20 week treatment period, resulted in 100% mortality in these groups by 52 weeks of age. There were no deaths in the groups receiving the two lower doses.5. We conclude that treatment of SHR with perindopril during the developmental phase of hypertension development results in only a modest fall in long-term blood pressure upon cessation of treatment and that the relationship between the dose of this ACE inhibitor and long-term blood pressure is not linear. The 100% mortality in the two groups receiving the highest dose of perindopril may be due to either a toxic action of this drug or vascular rupture due to insufficient hypertrophy for the rapid rise in blood pressure upon cessation of treatment.

Notes: 1. Four single base mutations unique to the spontaneously hypertensive rat (SHR) were identified in the first 1100 base pairs of its renin gene first intron when compared to that of Wistar-Kyoto and Sprague-Dawley normotensive rats.2. These mutations were found to fall within the consensus sequences for a number of transcription factors and thus may alter the affinity of these putative transcription factor binding sites.3. The reported overexpression of the renin gene in the SHR may therefore result from these structural abnormalities and, in turn, result in a tissue angiotensin-dependent hypertension in this strain.

Notes: 1. The first 1100 base pairs of the first intron of the renin gene was amplified from the spontaneously hypertensive rat (SHR), Wistar-Kyoto (WKY) and Sprague-Dawley (SD) rats. A Bgl II restriction fragment length polymorphism (RFLP) was identified in this region of the SHR renin gene.2. Sequence analysis located the Bgl II RFLP between positions 500 and 505 of the reported rat renin gene. The new Bgl II cut site was produced by a single base mutation from G to A.3. Whether this mutation in the first intron of the SHR renin gene plays a role in the reported overexpression of the renin gene in this strain remains to be elucidated.

Notes: 1. We have determined the optimal polymerase chain reaction (PCR) conditions for the amplification and detection of mRNA for a new vascular growth factor—vascular endothelial growth factor (VEGF)–-and determined its size and tissue distribution in genetically normotensive and hypertensive rats.2. Multiple VEGF mRNA subtypes were obtained which were 625, 520 and 480 base pairs in length.3. All three species of VEGF mRNA were found in heart, kidney, aorta, adrenal and brainstem and the size and tissue distribution of VEGF mRNA subtypes were not different between spontaneously hypertensive rats (SHR) of the Okamoto strain and normotensive Wistar-Kyoto (WKY) controls.4. Thus multiple forms of VEGF mRNA can be readily detected by PCR in a variety of tissues. While these preliminary results suggest no difference in size and tissue distribution between SHR and WKY, sequencing and quantitative studies will be required to confirm this.