Inhibitor of striate conditionally suppresses cell proliferation in variegated maize.

Since the work done by R.A. Emerson in the 1930s, Inhibitor of striate (Isr) has been recognized as a dose-dependent genetic modifier of variegation in chlorotic leaf striping mutants of maize such as striate2 (sr2). We have shown that Isr specifically inhibits proliferation and differentiation of plastid defective cells in sr2 mutants. Leaf narrowing is due to loss of intermediate veins and ground tissue located at leaf margins, and the few remaining plastid defective cells are of irregular size and aberrant organization. The Isr gene has been cloned by targeted transposon tagging. Isr mRNA is expressed throughout young leaves, but Isr chimeras indicate that the expression of Isr at leaf margins is sufficient to suppress both the lateral expansion of sr2 leaves and the extent of striping. Isr protein appears to encode a chloroplast protein with sequence similarity to a family of bacterial phosphatases involved in carbon catabolite repression or in carbon metabolism. We propose that the action of Isr in nuclear and plastid communication could be triggered by carbon stress.

Molecular analysis of rice plants harboring an Ac/Ds transposable element-mediated gene trapping system.

In rice, limited efforts have been made to identify genes by the use of insertional mutagens, especially heterologous transposons such as the maize Ac/Ds. We constructed Ac and gene trap Ds vectors and introduced them into the rice genome by Agrobacterium-mediated transformation. In this report, rice plants that contained single and simple insertions of T-DNA were analysed in order to evaluate the gene-tagging efficiency. The 3' end of Ds was examined for putative splicing donor sites. As observed in maize, three splice donor sites were identified at the 3' end of the Ds in rice. Nearly 80% of Ds elements were excised from the original T-DNA sites, when Ac cDNA was expressed under a CaMV 35S promoter. Repetitive ratoon culturing was performed to induce new transpositions of Ds in new plants derived from cuttings. About 30% of the plants carried at least one Ds which underwent secondary transposition in the later cultures. Eight per cent of transposed Ds elements expressed GUS in various tissues of rice panicles. With cloned DNA adjacent to Ds, the genomic complexities of the insertion sites were examined by Southern hybridization. Half of the Ds insertion sites showed simple hybridization patterns which could be easily utilized to locate the Ds. Our data demonstrate that the Ac/Ds-mediated gene trap system could prove an excellent tool for the analysis of functions of genes in rice. We discuss genetic strategies that could be employed in a large scale mutagenesis using a heterologous Ac/Ds family in rice.

Operative laparoscopy versus laparotomy for the management of ectopic pregnancy: a prospective trial.

STUDY OBJECTIVE: To compare prospectively operative laparoscopy to laparotomy in the management of hemodynamically stable patients with ectopic pregnancy (EP). DESIGN, PATIENTS, Intervention: Patients with suspected EP presenting to a university-based residency teaching program were prospectively allocated to laparoscopy (n = 26) or laparotomy (n = 37) on alternating months for operative management. RESULTS: Operative times between laparoscopy and laparotomy did not differ significantly. Laparoscopy-treated patients had a significant reduction in estimated intraoperative blood loss, postoperative hospital stay, narcotic requirement, time to normal activity, and total hospital cost. There was no statistical difference in intrauterine pregnancy rates or in EP rates. CONCLUSIONS: In a university-based residency program, operative laparoscopy is a safe alternative for the management of appropriately selected patients with suspected EP.

The efficacy of biobehavioral and compliance interventions in the adjunctive treatment of mild pregnancy-induced hypertension.

This investigation assessed the efficacy of a biobehavioral intervention in the adjunctive treatment of mild pregnancy-induced hypertension (PIH), a potentially serious complication of pregnancy in which normotensive women develop hypertension, proteinuria, and edema of unknown etiology late in gestation. Forty-five women with symptoms of PIH were randomly assigned to one of three treatment conditions: bed rest alone (the most common obstetrical treatment), bed rest with individualized compliance enhancement training, or a four-session biobehavioral treatment consisting of bed rest, compliance enhancement training, and individualized thermal biofeedback-assisted relaxation training. Results indicated that while blood pressure for the bed rest and compliance enhancement groups continued to rise and pose an increasing health risk to maternal and fetal well-being, subjects in the biobehavioral group maintained their blood pressure at a significantly lower, and presumably safer, level. The biobehavioral treatment is hypothesized to affect blood pressure levels in subjects with mild PIH through the mediation of the sympathetic nervous system, decreasing peripheral vascular resistance and cardiac output. The results of this investigation suggest that the biobehavioral intervention may be an effective adjunct to bed rest in the treatment of mild PIH remote from term.

Angiographic embolization of intractable puerperal hematomas.

Puerperal hematomas may not respond to conventional therapy, including vaginal packing, drainage, and hypogastric artery ligation. Two cases are presented in which selective angiographic arterial embolization was used to manage this potentially lethal complication.

Energetics of swimming in fishes using different methods of locomotion: I. Labriform swimmers.

The patterns relating rates of oxygen consumption to steady sustained and prolonged swimming at different speeds were determined in adults or near adults of two species of marine fishes that use the labriform mode of swimming (labriform swimmers). Effects of acute temperature changes on these patterns were measured. Species were the shiner surfperch,Cymatogaster aggregata and the señorita wrasse,Oxyjulis californica.Metabolic data were analyzed three different ways. The first (method of Brett) was based upon mass specific oxygen uptake and length specific swim speed; data in this form were analyzed both as best-fit power functions and as the mathematically equivalent least squares linear regressions for semi-log plots. The second and third methods were based upon drag based hydromechanical theory concerning power requirements for swimming in fishes: total metabolic ratesvs. absolute swimming speeds, analyzed both as best-fit power functions and least squares linear regressions for log-log plots.The main finding, demonstrated by all three methods of calculation, was that the slopes of all regression lines (both semi-log and log-log) and the exponents of almost all power functions (five out of six) were very low. The Brett method applied to subcarangiform swimmers usually produces slopes averaging 0.36 (using base-10 logarithms). The slopes calculated by that method in the present study were 0.02-0.08. Low slope values could result from the interactions of many factors. Additional data are needed to determine which combinations of factors actually produced them. On this basis metabolic rate data on intact labriform swimmers, by themselves, appear unusable as empirical tests of theory based predictions concerning power requirements for fish swimming.