DNA-binding specificity and trans-activating potential of the leukemia-associated E2A-hepatic leukemia factor fusion protein.

Hybrid transcription factors, resulting from gene fusions in the wake of chromosomal translocations, have been implicated in leukemogenesis, but their precise contributions to oncogenic conversion remain unclear. The E2A-HLF fusion gene, formed by a t(17;19)(q22;p13) in childhood pro-B-cell acute lymphoid leukemia, encodes a hybrid protein that contains the trans-activation domain of E2A (E12/E47) linked to the bZIP DNA-binding and dimerization domain of hepatic leukemia factor (HLF). Here we report that both HLF and E2A-HLF bind to a 10-bp consensus sequence, 5'-GTTACGTAAT-3', with a core dyad-symmetric motif characteristic of the bZIP scissors-grip model of DNA binding. A probe containing this sequence bound chimeric E2A-HLF proteins in nuclear extracts of a leukemic cell line (UOC-B1) containing the t(17;19), as demonstrated by complexes supershifted with antibodies specific for amino-terminal epitopes of E2A or carboxyl-terminal eptiopes of HLF. E2A-HLF functioned as a potent trans activator of reporter gene expression from a plasmid that contained the consensus DNA-binding sequence. Interestingly, wild-type HLF was restricted in its capacity to act as a trans activator, functioning in human fetal kidney cells but not HepG2 hepatocarcinoma cells or NIH 3T3 mouse fibroblasts. The ability of the E2A-HLF hybrid protein to bind DNA in a sequence-specific manner and trans activate the expression of artificial reporter genes suggests that it could subvert transcriptional programs that normally control the growth, differentiation, and survival of lymphoid progenitor cells.

Splice-site mutation of the p53 gene in a family with hereditary breast-ovarian cancer.

Germline mutations within evolutionary conserved exons of the p53 gene predispose to tumor development in several familial cancer syndromes. We now report identification of a novel p53 mutation affecting the splice acceptor site of exon 6 in the germline DNA of a family with hereditary breast-ovarian cancer. This splice-site mutation, which results in omission of exon 6 and creates a frame-shift and premature stop codon in transcripts from the mutant allele, was found in seven family members--four of whom have developed breast, ovarian or choroid plexus tumors before age 35. Our finding suggests the need to examine the entire p53 gene for splice-site, frame-shift, and nonsense (as well as missense) mutations in families with early-onset hereditary breast and breast-ovarian cancers not linked to the BRCA1 gene on chromosome 17q. We propose that the term 'p53 familial cancer syndrome' be applied to clusters of tumors in families with documented germline p53 mutations, regardless of the histopathologic findings or pattern of tumor development.

Comparative cytologic yield and quality of three Pap smear instruments.

BACKGROUND: Various sampling techniques of the cervix have established false negative rates ranging from 18% to 45%. A number of studies suggest that this false negative rate can be reduced by sampling techniques that are associated with higher yields of endocervical cells. METHOD: This study enrolled 301 women, each of whom had a Pap smear obtained using three different sampling instruments (a cervical brush, a plastic spatula, and a cotton swab) in random order. RESULTS: The cervical brush yielded a better endocervical sample than either of the other instruments (P < .001), and there was no difference between the swab and spatula. In addition, the recovery of endocervical cells increased with each additional sample taken, regardless of instrument used (P < .001), although the difference in yield between the second and third samples was not significant. CONCLUSIONS: To enhance the yield of endocervical cells in Pap smear sampling, consideration should be given to using the cervical brush routinely as a sampling instrument and to taking more than one sample per screening.

Detection of N-myc gene amplification by fluorescence in situ hybridization. Diagnostic utility for neuroblastoma.

We assessed fluorescence in situ hybridization (FISH) as an alternative to Southern blot analysis for determination of N-myc gene amplification in neuroblastoma. In the 44 pediatric solid tumor cell lines examined (20 neuroblastomas), the mean number of N-myc copies determined by FISH correlated closely with Southern blot results. There was wide intercellular variability in gene copy number in tumors that had evidence of amplification; however, tumors judged to be non-amplified completely lacked any cells with high N-myc copy number. FISH provided reliable estimates of N-myc amplification in 12 clinical samples even when the percentage of tumor was low. The other advantages of FISH over Southern blot analysis were speed and technical simplicity, ability to discern heterogeneous gene amplification among tumor cells in the same specimen, and capacity to determine the source of the amplified N-myc signal, whether extrachromosomal double-minute chromosomes, expanded intrachromosomal regions, or chromosome 2 aneuploidy. We conclude that FISH would refine the analysis of N-myc amplification in neuroblastoma and thus improve the assignment of patients to prognostic groups based on this unfavorable risk factor.

Chromosomal sublocalization of the 2;13 translocation breakpoint in alveolar rhabdomyosarcoma.

A characteristic balanced reciprocal chromosomal translocation [t(2;13)(q35;q14)] has been identified in more than 50% of alveolar rhabdomyosarcomas. As the first step in characterization of the genes involved in this translocation, we constructed somatic cell hybrids that retained either the derivative chromosome 2 or the derivative chromosome 13 without a normal chromosome 13 homologue. Ten linked DNA probes known to be located within bands 13q13-q14 were mapped relative to the breakpoint on chromosome 13, allowing localization of the breakpoint region between two loci separated by 5.5 cM. A long-range restriction map extending approximately 2,300 kb around these loci failed to provide evidence of rearrangement. Additionally, we confirmed that the FMS-like tyrosine kinase gene (FLT), previously localized to 13q12 by in situ hybridization, is located proximal to the breakpoint, and we demonstrated that FLT is not a target for disruption by this tumor-specific translocation.

HIV disease: educational needs of Oregon family physicians.

Questionnaires were sent to 200 Oregon family physicians to assess their attitudes and educational needs concerning human immunodeficiency virus (HIV) related conditions. Completed questionnaires were returned by 160 (80%). Fifty-one percent had already managed patients with HIV disease or AIDS. Seventy-three percent indicated that HIV would have an effect on their future practice. Physicians were least comfortable in management areas concerning direct medical skills and most comfortable with counseling and behavioral science issues. Physicians were more likely to participate in "hotline consults," one-day regional workshops, and written protocols than in more high-tech, time-consuming methods of continuing medical education.

Using a sociomatrix to evaluate the effectiveness of small-group teaching to residents.

This article describes a 1988 pilot study in a family medicine residency program of the use of a sociomatrix to assess small-group teaching. A multidisciplinary team developed a sociomatrix coding sheet, which was used by a family physician-psychiatrist to classify behaviors seen on videotaped small-group teaching sessions, which were held at the conclusion of patient care activities. Although the sociomatrix appears to have the potential to relate specific leader behaviors to residents' feedback regarding subjective learning outcomes, the number of observations was too small to permit clear conclusions regarding optimal teaching behaviors and styles.

Dorsal penile nerve block during newborn circumcision: underutilization of a proven technique?

Newborn circumcision is the most common surgical procedure in the United States. The technique for local anesthesia, dorsal penile nerve block (DPNB), was first described in 1978. Although multiple subsequent studies have reported that DPNB can relieve pain and stress during a newborn's circumcision without any additional morbidity, many practitioners do not employ this technique. A survey of randomly selected active members of the Oregon Academy of Family Physicians evaluated their perception and use of DPNB. One hundred members were contacted, and 96 responded. Only 36 percent of those physicians performing circumcision used DPNB in circumcisions. The most common reasons given for not employing DPNB were a lack of awareness of the technique (31 percent), believing that pain response in circumcision was not significant (29 percent), and concern about risks (27 percent). The median effectiveness rate reported by those using the block was 70 percent. The majority of respondents were interested in the results of the survey as well as in more information regarding the technique. We believe further educational efforts are indicated to increase awareness and use of DPNB in performing circumcisions in the newborn. Because there is significant variation in the effect achieved, some instruction in appropriate technique also is needed as part of this educational effort.

Personality types of family practice residents in the 1980s.

This study was based on a nationwide sample of 778 family practice residents in the mid-1980s and was conducted to determine the personality types that were most common among those residents. The results showed that the single most common personality type was that in which the individual prefers to see the world in terms of challenges and future possibilities and to make decisions based upon his or her subjective values. These results showed that the sample differed significantly in Myers-Briggs personality type from both the general practitioners of the 1950s and the early family practice residents of the 1970s, who preferred to see the world in terms of the immediate facts of experience and to make decisions objectively. There were also significant differences between the civilian and military family practice residents, but not between the community-based and university-based residents. Implications regarding future practice styles, physicians' personal values, and manpower needs are discussed.

The relationship between assessed obstetric risk and maternal-perinatal outcome.

The relationship between antepartum risk assessment and subsequent maternal and perinatal outcome was examined in a retrospective study of 430 randomly selected deliveries at the Oregon Health Sciences University during the 1986 calendar year. Antepartum risk scores at the initial prenatal visit and at 37 weeks' gestation were positively correlated with each other. Antepartum risk scores were correlated with maternal length of stay and maternal hospital charges, but not with gestational age, birth weight, or Apgar scores. Increased intrapartum risk scores were strongly correlated with increasing length of stay for mother and baby, lower birth weight, and lower estimated gestational age at birth. The ability of the risk-scoring system to predict selected adverse outcomes was then assessed using a high-risk cutoff score of 5 or greater. Sensitivity and positive predictive value were found to be quite low while specificity and negative predictive value were reasonably high. The results suggest that the risk-scoring system used at this institution is effective in identifying low obstetrical risk and that prenatal care reduces the probability of poor neonatal outcome among infants of women at high obstetrical risk identified through antepartum multivariate assessment. Two antepartum risk assessments, each measuring different factors, may be redundant. Not yet known are which specific factors by their identification result in more effective prenatal care.