Organization, expression, and localization of the murine mdmx gene and pseudogene.

The mdmx gene is the first additional member of the mdm2 gene family to be isolated. It encodes a protein similar to MDM2 in several domains and also retains the ability to bind and inhibit p53 transactivation in vitro. However, mdmx does not appear to be transcriptionally regulated by p53. We have cloned and characterized the murine mdmx genomic locus from a 129 genomic library. The mdmx gene contains 11 exons, spans approximately 37 kb of DNA, and is located on mouse chromosome 1. The genomic organization of the mdmx gene is identical to that of mdm2 except at the 5' end of the gene near the p53 responsive element. Additionally, a pseudogene for mdmx was also identified that resides on the mouse X chromosome. Expression analysis of mdmx transcripts during mouse embryogenesis revealed constitutive and ubiquitous expression throughout development.

p73 gene alterations and expression in primary oral and laryngeal squamous carcinomas.

p73, a recently identified gene, maps to chromosome region 1p36.3, which is frequently deleted in a variety of solid tumors. Although the gene shares sequence and functional homologies with p53, its suppressor function has not been proven. We investigated for the first time the genetic and expression status of the p73 gene and analyzed its flanking microsatellite loci on chromosome 1p36.3 in 67 primary oral and laryngeal squamous cell carcinomas to determine their association with these tumors. Our results reveal two missense mutations at codons 469 and 477 and a silent mutation at codon 349 in the C-terminal domain. Site-directed mutagenesis of p73 cDNA with these mutations and a p21 transactivation assay failed to show any significant functional consequences of these mutations. Microsatellite analysis of the flanking loci of p73 in region 1p36 showed overall alterations (loss of heterozygosity and instability) frequency of 39%, 16% at the proximal marker and 46% at the distal markers. Of the 21 cases for which we did protein expression analyses, 11 tumors had a >2-fold variation compared with matching histologically normal mucosa. Our study shows that: (i) intragenic alterations in this gene are rare and lack functional significance; (ii) its variable expression argues against a tumor suppressor function; (iii) this gene plays a minor role in head and neck squamous carcinoma; (iv) a distal site to this gene on 1p36 may harbor another suppressor gene.

Two successful models for preparing competent critical care nurses. The Parkland Health and Hospital System Critical Care and Trauma Nurse Internship and Critical Care Residency.

Part of the mission statement of Parkland Health and Hospital System involves participating in educational programs dedicated to the art and science of caring for the sick and injured, the promotion of wellness, and the delivery of health services. The concept of the Nurse Internship and Nurse Residency fits well in the framework of this hospital. The continued support of these programs from the PHHS administration is visible evidence of the institution's commitment to excellence. Together these programs provide a continual supply of competent critical care practitioners to meet the never-ending demand in this large county facility as well as opportunities for new graduates to begin the exciting and rewarding journey into critical care nursing.

The challenges of recruiting African American subjects and entry strategies used in northeast Ohio.

This article focuses on the recruitment of African American subjects because there are wide gaps in health outcomes within African American communities. Historical occurrences have contributed to the distrust of the motives of researchers about the purposes and credibility of research studies. Commonly acknowledged challenges include researchers' lack of sensitivity and understanding of minority subjects (Fujimoto, 1989; El-Sadr & Capps, 1992; Pletsch, Howe & Tenney, 1995). This paper discusses some of the challenges encountered by an African American researcher in North East Ohio in recruiting mothers and adolescent daughters, with and without a child, for a community-based communication intervention entitled: Mission Possible: Parents and Kids Who Listen (Riesch, Tosi, Thurston, Forsyth, Kuenning, & Kestly, 1993). This paper also suggests strategies and makes recommendations for researchers, who must recruit African American subjects. Researchers will need to examine their role in increasing the credibility of research within minority communities and develop innovative recruitment strategies.

High metastatic potential in mice inheriting a targeted p53 missense mutation.

To understand the relevance of p53 missense mutations in vivo, we generated a mouse containing an arg-to-his substitution at p53 amino acid 172, which corresponds to the R175H hot-spot mutation in human tumors by homologous recombination. Inadvertently, this mouse contains the additional deletion of a G nucleotide at a splice junction that attenuates levels of mutant p53 to near wild-type levels. Mice heterozygous for the mutant allele differed from p53(+/-) mice in tumor spectrum, with a significant increase in the number of carcinomas and a slight decrease in the number of lymphomas. More importantly, the osteosarcomas and carcinomas that developed in these mutant mice frequently metastasized (69% and 40%, respectively). In contrast, metastasis is rare in osteosarcomas of p53(+/-) mice. Loss of heterozygosity studies of tumors indicated loss of heterozygosity in only 1 of 11 tumors. These data indicate clear differences between a p53 missense mutation and a null allele in tumorigenesis in vivo and suggest that the p53R172HDeltag mutant represents a gain-of-function allele.

TP53 mutation and haplotype analysis of two large African American families.

Two large apparently unrelated African American families with a high incidence of breast cancer and other tumors characteristic of Li-Fraumeni breast sarcoma cancer family syndrome were studied. Mutation screening revealed that in both families the affected members carried a germline mutation of the TP53 gene at codon 133 (ATG--> ACG, M133T). In order to determine whether an ancestral haplotype was shared by these two families, polymorphic markers within and flanking the TP53 gene were studied. Haplotype analysis using five markers revealed an identical haplotype shared by the two families. Loss of heterozygosity at the TP53 locus in the probands' tumor tissues from each family was observed; in each case, the retained allele carried the common haplotype. The frequency of this haplotype in the general African American population is <0.003. This unique haplotype, combined with the rare TP53 mutation, suggests that these African American families share a common ancestry. This finding suggests that other African Americans may be carriers of this mutation and thus may be at risk of early-onset breast cancer or other cancers characteristic of the Li-Fraumeni breast sarcoma cancer family syndrome. The finding of recurring mutations in African Americans may facilitate carrier screening and identification in this population.

Exclusion of a p53 germline mutation in a classic Li-Fraumeni syndrome family.

Li-Fraumeni syndrome (LFS) is characterized by a high risk of sarcomas, early onset of breast cancer, and a diversity of other cancers occurring as multiple primary tumors in multiple family members. In many families with LFS, germline mutations within the tumor-suppressor gene p53 have been identified. However, mutations in p53 have not been detected in approximately 30% of LFS families. To address the possibility either that p53 mutations were being missed or that another predisposing gene is altered in LFS, we used a variety of methods to accurately determine the p53 status in a large LFS kindred. A transcriptional activation assay on exons 4-10 of p53 excluded a mutation within the DNA-binding domain of p53. Single-stranded conformational-polymorphism analysis, using intronic primers and sequencing of all the coding exons and intron/exon junctions, also yielded no mutations. Finally, linkage analysis excluded potential mutations in the noncoding regions of p53. Our findings exclude the presence of a p53 germline mutation in a classic LFS family.

Effect of pelvic muscle exercise on transient incontinence during pregnancy and after birth.

OBJECTIVE: To test the effect of pelvic muscle exercise on postpartum symptoms of stress urinary incontinence and pelvic muscle strength in primigravidas during pregnancy and postpartum. METHODS: A prospective trial randomized women into treatment (standardized instruction in pelvic muscle exercise) or control (routine care with no systematic pelvic muscle exercise instruction). Urinary incontinence symptoms were measured by questionnaire. Pelvic muscle strength was quantified by an instrumented gynecologic speculum. Time points were 20 and 35 weeks' gestation and 6 weeks, 6 months, and 12 months postpartum. RESULTS: Outcomes are reported for 46 women with vaginal or cesarean birth and for a subsample of 37 women with vaginal birth. Longitudinal analyses are reported for cases with complete data across time points. Diminished urinary incontinence symptoms were seen in the treatment group, with significant treatment effects demonstrated at 35 weeks' gestation (F [1,43] = 4.36, P = .043), 6 weeks postpartum (F [1,43] = 4.94, P = .032), and 6 months postpartum (F [1,43] = 4.29, P = .044). A repeated measures analysis of variance showed a significant interaction between time and treatment for urinary incontinence (F [4, 41] = 2.83, P = .037). A significant effect of initial pelvic muscle strength was demonstrated; ie, pelvic muscle strength at 20 weeks' gestation predicted significantly 12-months postpartum strength (F [1, 13] = 8.12, P = .014). Group differences in pelvic muscle strength were observed (the treatment group had greater strength at 6 weeks and at 6 months postpartum than did controls), but these differences were not statistically significant. CONCLUSION: Practice of pelvic muscle exercise by primiparas results in fewer urinary incontinence symptoms during late pregnancy and postpartum.

Independent pathways of p53 induction by cisplatin and X-rays in a cisplatin-resistant ovarian tumor cell line.

The p53 tumor suppressor gene is critical in regulating cell proliferation following DNA damage, and disruption of p53 protein function by mutation has been implicated as a factor responsible for resistance of tumor cells to chemotherapeutic agents. Our studies were initiated by asking whether the translational product of the p53 gene is associated with cisplatin resistance in the 2780CP human ovarian tumor model. We have demonstrated by single-strand conformation polymorphism analysis and sequencing that p53 in parental cisplatin-sensitive A2780 cells was wild type. In 2780CP cells, however, a mutation was found in exon 5 at codon 172 (Val to Phe). Interestingly, exposure to X-rays resulted in p53 induction in both A2780 and 2780CP tumor models. The p53 increases by the ionizing radiation were accompanied by concomitant increases in levels of the p53-regulated p21Waf1/Cip1 protein and led to arrest of cells in G1 phase of the cell cycle. A yeast functional assay confirmed that p53 in A2780 was wild type, but, more importantly, it provided evidence that the p53 mutation in 2780CP cells was temperature sensitive and heterozygous. These experiments demonstrate that sensitive and resistant cells have normal p53 functions, despite the presence of p53 mutation in the 2780CP model. In parallel investigations using the Western technique, exposure of A2780 cells to clinically relevant concentrations of cisplatin (1-20 microM) resulted in time- and dose-dependent increases in p53, together with coordinate increases in p21Waf1/Cip1. In contrast, cisplatin did not induce these proteins in 2780CP cells to any significant degree. The results indicate that a defect exists in the signal transduction pathway for p53 induction following cisplatin-induced DNA damage in 2780CP cells, and this may represent a significant mechanism of cisplatin resistance. Furthermore, induction of p53 in 2780CP cells by X-rays, but not cisplatin, strongly suggests that independent pathways are involved in p53 regulation for the two DNA-damaging agents.

Afrocentric perspective of adolescent pregnancy in African American families: a literature review.

This article gives a detailed overview of the literature on adolescent pregnancy in African American families. According to the latest data available from the National Center for Health Statistics (1998), the greatest decline in adolescent pregnancy was among African Americans. In spite of the decline of 21% from 1991-1996, African American adolescent's birth rate was still almost twice the rate of European Americans. The purpose of this paper was to provide information that may assist health care professionals or others interested in repeat adolescent pregnancy to more effectively provide care and/or to conduct research from an Afrocentric perspective.

PIP: This literature review focuses on repeat pregnancy of adolescents within African American families. The paper aims to provide information, which may assist health care professional to effectively provide care and/or to conduct research from an Afrocentric perspective. Adolescent pregnancy is not a new phenomenon to the African American community; it has been a part of the socio-history of African Americans since the period of slavery. Historically, the values and norms of African American families reflect clearly that marriage was a necessary prerequisite to pregnancy. There are several factors critical to the understanding of the experiences of repeat adolescent pregnancy from an Afrocentric perspective. These include the following: oppression, societal norms, social class, view of motherhood, and differences in communication. The Afrocentric perspective of motherhood has an effect on the quality of communication between mothers and daughters. Mothers often try to balance the need for teaching their children how to survive and to transcend the boundaries that confront them in the society. This often leads to contradictions in mother/daughter relationships and has an influence on the phenomenon of repeat adolescent pregnancy. Therefore, health care providers, researchers, and educators who study and/or provide care for African American adolescents need to consider the social structure of motherhood within African American families before interventions can be effectively implemented to decrease repeat adolescent pregnancy.

Genetic analysis of structural elastic fiber and collagen genes in familial adolescent idiopathic scoliosis.

Adolescent idiopathic scoliosis is a genetic disorder of unknown etiology. Scoliosis is a clinical feature of inherited connective-tissue disorders including Marfan syndrome. Mutations within the gene of FBN1 (fibrillin 15), a component of the extracellular matrix, are now linked to Marfan syndrome and similar clinical phenotypes. This study investigated the potential association of structural genes encoding for extracellular matrix components of FBN1, elastin, and one of the polypeptides of type-I collagen (COL1A2) with familial adolescent idiopathic scoliosis. Eleven pedigrees, including 96 individuals, were identified in which adolescent idiopathic scoliosis segregated in an apparent autosomal dominant pattern. Fifty-two individuals were determined to be affected with scoliosis. Genomic DNA was analyzed by genetic linkage utilizing four intragenic markers for the structural genes of FBN1, elastin, and COL1A2. Collectively, our results exclude the structural genes of FBN1, elastin, and COL1A2 as candidate genes within these families. However, when viewed individually, specific markers cannot be excluded within all of the families. This information complements previously reported data that fibrillin production and matrix incorporation from scoliotic fibroblasts in vitro are normal in more than 80% of patients studied.

Follow-up of comprehensive geriatric assessment in a family medicine residency clinic.

BACKGROUND: The objective of this study was to evaluate the effect of outpatient geriatric consultation by referring academic physicians and to verify the results of a previous study. METHODS: We conducted a retrospective review of charts of 37 patients referred for geriatric consultation during a 7-month period of a university- and community-hospital-affiliated family practice residency clinic in urban northeast Washington, DC. The consultation involved team assessment, which led to formal recommendations to the attending physician. Main outcome measures included total number and category of recommendations made, as well as a total number and category of recommendations adhered to by referring physicians. RESULTS: There were 29 women and 8 men with an average age of 79.1 years; 5 were white and 32 were African-American. For the 23 patients for whom follow-up could be determined, the mean number of total diagnoses per patient was 11.4 (SD 3.5). The mean total number of recommendations made per patient was 18.1 (SD 5.9). The mean total number of recommendations acted upon per patient by referring physicians was 9.5 (SD 4.4). The recommendations fell into the following categories: rehabilitative 64 percent, radiologic 57.1 percent, laboratory 56.9 percent, total medication 55.6 percent, medical 50 percent, health maintenance 47.1 percent, social service 46.2 percent, sensory 33 percent, other 28.6 percent, educational 20 percent, and nutritional 14.3 percent. CONCLUSIONS: Multidisciplinary geriatric assessment in an academic outpatient setting provides a comprehensive assessment for faculty and resident physicians in training. Recommendations will be adhered to only 50 to 70 percent of the time, possibly because of the demographic and socioeconomic mix and overall health of the patient population, health care priorities of the referring physician, and costs and availability of various interventions. Physicians in training should be exposed through continuing medical education to various aspects of geriatric assessment.

The potential role of the elastic fiber system in adolescent idiopathic scoliosis.

To assess its possible role in the etiology of adolescent idiopathic scoliosis, the elastic fiber system of the ligamentum flavum was examined in twenty-three patients who had scoliosis and in five age-matched individuals who did not. Elastic fibers are composed of two components: the amorphous core of elastin and microfibrils, of which fibrillin is the primary element. Fresh-frozen histological specimens of ligamentum flavum removed at the time of an operation were examined by Verhoeff staining for elastic fibers and by immunohistochemical staining with use of a monoclonal antibody to fibrillin. Additionally, cultures of fibroblast cells from the ligamentum flavum were used to study the biosynthesis and secretion of fibrillin and its incorporation into the extracellular matrix in vitro. The specimens from one patient did not provide sufficient material for the histological studies; however, fibroblasts were harvested from this specimen. In five (23 percent) of the remaining twenty-two specimens from patients who had adolescent idiopathic scoliosis, Verhoeff staining of elastic fibers showed a marked decrease in fiber density (the number of fibers per unit area) and a non-uniform distribution of fibers throughout the ligament. Eighteen specimens (82 percent) exhibited abnormalities on immunohistochemical staining, including a marked disarrangement of the fibers and a difference in the density of staining, when compared with the control specimens from individuals who did not have adolescent idiopathic scoliosis. Studies of the biosynthesis and secretion of fibrillin and its incorporation into the extracellular matrix in vitro demonstrated that fibroblasts from four (17 percent) of the twenty-three specimens produced normal amounts of fibrillin and secreted it from the cell, but the fibrillin failed to bind to other macromolecules, to form a sedimentable complex, and to incorporate into the extracellular matrix. Collectively, the results suggest the potential role of the elastic fiber system as a component in the pathogenesis of adolescent idiopathic scoliosis in some individuals.

Third position base changes in codons 5' and 3' adjacent UGA codons affect UGA suppression in vivo.

The base sequence around nonsense codons affects the efficiency of nonsense codon suppression. Published data, comparing different nonsense sites in a mRNA, implicate the two bases downstream of the nonsense codon as major determinants of suppression efficiency. However, the results we report here indicate that the nature of the contiguous upstream codon can also affect nonsense suppression, as can the third (wobble) base of the contiguous downstream codon. These conclusions are drawn from experiments in which the two Ser codons UCU233 and UCG235 in a nonsense mutant form (UGA234) of the trpA gene in Escherichia coli have been replaced with other Ser codons by site-directed mutagenesis. Suppression of these trpA mutants has been studied in the presence of a UGA nonsense suppressor derived from glyT. We speculate that the non-site-specific effects of the two adjacent downstream bases may be largely at the level of the termination process, whereas more site-specific or codon-specific effects may operate primarily on the activity of the suppressor tRNA.

Glycine tRNA mutants with normal anticodon loop size cause -1 frameshifting.

Mutations in the acceptor stem, the 5-methyluridine-pseudouridine-cytidine (TFC) arm, and the anticodon of Salmonella tRNA2Gly can cause -1 frameshifting. The potential for standard base pairing between acceptor stem positions 1 and 72 is disrupted in the mutant sufS627. This disruption may interfere with the interaction of the tRNA with elongation factor-Tu.GTP or an as-yet-unspecified domain of the ribosome. The potential for standard base pairing in part of the TFC stem is disrupted in mutant sufS625. The nearly universal C-61 base of the TFC stem is altered in mutant sufS617, and the TFC loop is extended in mutant sufS605. These changes are expected to interfere with the stability of the TFC loop and its interaction with the D arm. The mutation in mutant sufS605, and possibly other mutants, alters nucleoside modification in the D arm. Three mutants, sufS601, sufS607, and sufS609, have a cytidine substituted for the modified uridine at position 34, the first anticodon position. None of the alterations grossly disrupts in-frame triplet decoding by the mutant tRNAs. The results show that -1 frameshifting in vivo can be caused by tRNAs with normal anticodon loop size and suggest that alternative conformational states of the mutant tRNAs may allow them to read a codon in frame or to shift reading frame.

Physiologic rationale of Sv-O2 monitoring.

Mixed venous oxygen saturation is a global indicator of the balance between oxygen transport and oxygen demand. In critically ill patients, the delivery of adequate quantities of oxygen to meet the cellular oxygen demands is paramount. While parameters such as SaO2, PaO2, and CO reveal important information about oxygen transport, the SvO2 indicates the adequacy of supply in relation to tissue oxygen demands.

Fat embolism syndrome: a variant of ARDS (continuing education credit).

Fat embolism syndrome (FES) is a relatively uncommon, life-threatening sequela of long-bone fractures. Occurring 24 to 48 hours postinjury, the syndrome manifests as hypoxemia, confusion, and petechiae. The pathophysiologic changes in the lung are consistent with those of ARDS. Nursing priorities include an awareness of risk factors, familiarity with signs and symptoms, and a high index of suspicion in patients with multiple long-bone fractures.