Biomedical subjects

A Allaire

Publications and source records attributed to A Allaire.

3 recordsLinked to original sources

PubMed1999

Second-trimester presentation of placenta percreta.

Placenta percreta is diagnosed usually in the third trimester as massive postpartum hemorrhage when an attempt to remove the placenta reveals lack of a cleavage plane. However, placenta percreta may present in the second trimester with signs and symptoms of uterine rupture. The diagnosis of this event may be difficult because of mild abdominal discomfort often associated with normal pregnancy. We describe two cases that occurred in the second trimester with an unusual presentation. Both patients suffered considerable surgical morbidity. Other cases reported in the literature are mentioned as well. When a patient with risk factors for abnormal placentation presents with abdominal pain and/or vaginal bleeding in the second trimester of pregnancy, the diagnosis of placenta percreta should be considered. A laparotomy is indicated immediately when hemoperitoneum is suspected because uterine rupture has most likely occurred. Placenta percreta in the second trimester is a potentially life-threatening condition that warrants expeditious diagnosis to limit maternal postoperative morbidity.

Adult↗

PubMed1997

Identification, characterization, and chromosomal organization of cell division cycle genes in Caulobacter crescentus.

We report a detailed characterization of cell division cycle (cdc) genes in the differentiating gram-negative bacterium Caulobacter crescentus. A large set of temperature-sensitive cdc mutations was isolated after treatment with the chemical mutagen N-methyl-N'-nitro-N-nitrosoguanidine. Analysis of independently isolated mutants at the nonpermissive temperature identified a variety of well-defined terminal phenotypes, including long filamentous cells blocked at various stages of the cell division cycle and two unusual classes of mutants with defects in both cell growth and division. The latter strains are uniformly arrested as either short bagel-shaped coils or large predivisional cells. The polar morphology of these cdc mutants supports the hypothesis that normal cell cycle progression is directly responsible for developmental regulation in C. crescentus. Genetic and physical mapping of the conditional cdc mutations and the previously characterized dna and div mutations identified at least 21 genes that are required for normal cell cycle progression. Although most of these genes are widely scattered, the genetically linked divA, divB, and divE genes were shown by genetic complementation and physical mapping to be organized in one gene cluster at 3200 units on the chromosome. DNA sequence analysis and marker rescue experiments demonstrated that divE is the C. crescentus ftsA homolog and that the ftsZ gene maps immediately adjacent to ftsA. On the basis of these results, we suggest that the C. crescentus divA-divB-divE(ftsA)-ftsZ gene cluster corresponds to the 2-min fts gene cluster of Escherichia coli.

Amino Acid Sequence↗

PubMed1992

Use of descriptive and experimental analyses to identify the functional properties of aberrant behavior in school settings.

We conducted descriptive and experimental analyses of aberrant behavior in school settings with 2 children with autism, using teachers as assessors. Experimental functional analyses carried out by the investigators were followed by training teachers to conduct a descriptive analysis and a classroom experimental analysis. A comparison of the assessment procedures showed that each procedure identified negative reinforcement as a maintaining variable for aberrant behavior. The teacher implemented an intervention based on the assessment with mixed results. We then replicated the initial results by having the first teacher train a second teacher to carry out the two assessment procedures. The results of these analyses were also in agreement, again identifying negative reinforcement as a variable maintaining aberrant behavior. An intervention based on negative reinforcement was then successfully implemented. These results suggest the applicability and utility of functional analyses carried out in school settings.

Adolescent↗