Endotension: an explanation for continued AAA growth after successful endoluminal repair

PURPOSE

To present and analyze several cases that illustrate persistent sac pressurization following endovascular abdominal aortic aneurysm (AAA) repair.

METHODS AND RESULTS

Four patients with successful endovascular AAA exclusion presented in follow-up with an expanding aneurysm. Two had initial sac diameter decrease, but by 18 and 24 months, respectively, the AAA had enlarged and become pulsatile. There was no endoleak evident, but the proximal attachment stents had mig rated distally in both cases. One patient developed endoleak with aneurysm expansion at 6 months; contained rupture occurred at 12 months. The last case had slowly evolving aneurysm expansion over 36 months but no endoleak. All endografts were removed and successfully replaced with conventional grafts. Intrasac thrombus was implicated as the means of pressure transmission that precipitated AAA expansion in these cases.

CONCLUSIONS

Excluded AAAs can increase in size owing to persistent or recurrent pressurization (endotension) of the sac even when there is no evidence of endoleak. One proposed mechanism is pressure transmission via thrombus that lines the attachment site. Endotension may also represent an indiscernible, very low flow endoleak that allows blood to clot at the source of leakage.

Isolation, characterization, and mapping of four novel polymorphic markers and an H3.3B pseudogene to chromosome 9p21-22

Alterations in chromosomal region 9p21-22 are among the most frequently encountered cytogenetic changes present in a number of human malignancies. In addition, the causative genes of a number of hereditary cancers have been genetically mapped to this region. We describe the isolation and precise localization of four novel polymorphic markers and a previously identified marker, D9S1846, from this region. Moreover, we have identified a retroposon-rich area within this oncogenic region containing a processed H3.3B pseudogene flanked by an L1 sequence and an Alu element. Together, these finely mapped and ordered reagents should prove useful for genetic mapping, sequencing, and loss of heterozygosity studies of the 9p21-22 region.

A histologic pattern of nonspecific interstitial pneumonia is associated with a better prognosis than usual interstitial pneumonia in patients with cryptogenic fibrosing alveolitis

This study aimed to investigate whether there was a difference in outcome related to histologic pattern in cryptogenic fibrosing alveolitis (CFA) and to see whether there were correlations between clinical and radiologic findings and histology. One hundred thirteen lung biopsies from consecutive patients taken for the diagnosis of diffuse lung disease were reviewed and reclassified using the Katzenstein and Myers criteria for interstitial pneumonias. Patients lacking full investigational data at presentation and those with conditions predisposing to lung fibrosis were excluded, leaving 15 patients diagnosed with nonspecific interstitial pneumonia (NSIP) and 15 with usual interstitial pneumonia (UIP). Clinical and radiologic findings at presentation and serial lung function information and survival status in November 1998 were compared for the two groups. Survival was found to be significantly greater in the NSIP group compared with the UIP group (p < 0.001). This could not be explained by differences in treatment. Patients with UIP showed a progressive deterioration in lung function whereas those with NSIP remained stable. CT scans of patients with UIP showed more fibrosis than those of patients with NSIP (p < 0.011). A histologic diagnosis of NSIP is associated with a better prognosis than UIP. This subclassification of CFA is clinically useful.

Pre-T cell receptor signals are responsible for the down-regulation of Syk protein tyrosine kinase expression

Thymocyte development proceeds through two critical checkpoints that involve signaling events through two different receptors, the TCR and the pre-TCR. These receptors employ two families of protein tyrosine kinases to propagate their signals, the Src and Syk families. Genetic and biochemical evidence has shown that the Src family kinases are critical for normal T cell maturation. ZAP-70, a Syk family kinase, has similarly been implicated as a critical component in thymocyte development. Although genetic evidence has suggested that Syk is involved during thymocyte development, a definitive study of Syk expression has not been performed. In this paper we report our reanalysis of Syk expression in subpopulations of murine and human thymocytes by intracellular staining and flow cytometry using anti-Syk mAbs. Syk is expressed at increased levels during the stages in which pre-TCR signaling occurs. Furthermore, Syk is down-regulated after the pre-TCR checkpoint has been passed. Syk may play an important role in thymic development during pre-TCR signal transduction. Finally, incomplete down-regulation of Syk expression was noted in human thymocytes, offering a possible explanation for the distinct phenotypes of mice and humans deficient in ZAP-70.

Precious fertility and third-trimester tests

Are some pregnancies more 'precious' than others? Should amniocentesis be offered late in pregnancy with the possibility looming of a late abortion, and if such tests should be offered, to whom and in what circumstances should this be done? These are some of the important ethical questions raised in the paper by Shalev et al. (1999). In what follows, an analysis and resolution will be offered for all these important issues.

Breast augmentation: compression--a very important factor in preventing capsular contracture

The incidence of capsular contracture is reduced when smooth-surfaced, saline-filled implants are placed subpectorally, avoiding contamination and the presence of blood. In addition, since the authors began using compression, they have not had one single capsular contracture requiring surgery. The authors' technique, their preoperative and postoperative regimens, an explanation of how they use compression, and the scientific and mathematical explanation of why compression could be the most important factor in preventing capsular compression are described. Of more than 1700 augmentations performed in our private clinic, only 830 could be included in the study. The patients were followed clinically for 1 year, after which time they completed a questionnaire, the results of which showed the authors that capsular contracture had not developed.

The nuclear receptor corepressor N-CoR regulates differentiation: N-CoR directly interacts with MyoD

Classical ligand-activated nuclear receptors (e.g. thyroid hormone receptor, retinoic acid receptor), orphan nuclear receptors (e.g. Rev-erbAalpha/beta), Mad/Max bHLH (basic helix loop helix)-LZ proteins, and oncoproteins, PLZF and LAZ3/BCL6, bind DNA and silence transcription by recruiting a repressor complex that contains N-CoR (nuclear receptor corepressor)/SMRT (silencing mediator of retinoic acid and thyroid hormone receptor), Sin3A/B, and HDAc-1/-2 proteins. The function of the corepressor, N-CoR, in the process of cellular differentiation and coupled phenotypic acquisition, has not been investigated. We examined the functional role of N-CoR in myogenesis (muscle differentiation), an ideal paradigm for the analysis of the determinative events that govern the cell's decision to divide or differentiate. We observed that the mRNA encoding N-CoR was suppressed as proliferating myoblasts exited the cell cycle, and formed morphologically and biochemically differentiated myotubes. Exogenous expression of N-CoR (but not RIP13) in myogenic cells ablated 1) myogenic differentiation, 2) the expression of the myoD gene family that encode the myogenic specific bHLH proteins, and 3) the crucial cell cycle regulator, p21Waf-1/Cip-1 mRNA. Furthermore, N-CoR expression efficiently inhibits the myoD-mediated myogenic conversion of pluripotential C3H10T1/2 cells. We demonstrate that MyoD-mediated transactivation and activity are repressed by N-CoR. The mechanism involves direct interactions between MyoD and N-CoR; moreover, the interaction was dependent on the amino-terminal repression domain (RD1) of N-CoR and the bHLH region of MyoD. Trichostatin A treatment significantly stimulated the activity of MyoD by approximately 10-fold and inhibited the ability of N-CoR to repress MyoD-mediated transactivation, consistent with the involvement of the corepressor and the recruitment of a histone deacteylase activity in the process. This work demonstrates that the corepressor N-CoR is a key regulator of MyoD activity and mammalian differentiation, and that N-CoR has a multifaceted role in myogenesis.

Hospital discharge. Smooth passage

The introduction of care co-ordinators into a medical directorate two years ago has reduced bed blocking and cut length of stay from 8.5 to 5.9 days. All those appointed were already working in the hospital. There have been some tensions over boundaries with nursing and social work.

Marimastat in patients with advanced pancreatic cancer: a dose-finding study

Patients with solid tumors, including carcinoma of the pancreas, express high levels of matrix metalloproteinases (MMP), and these enzymes are believed to be important for the growth, spread, and dissemination of most solid malignant tumors. Marimastat is the first orally available MMP inhibitor (MMPI) to be tested in humans and has been shown to inhibit the spread and growth of pancreatic cancer in animal models. The purpose of the present study was to define the toxicities, safety, and tolerance of various doses of marimastat and also to get an early indication of potential biologic activity in patients with advanced pancreatic cancer. The authors prospectively studied 64 patients with advanced carcinoma of the pancreas in whom standard treatments had failed. Eligible patients had a progressive rise in CA 19/9 levels of >25% over the 4-week period preceding their entry into the study. Patients were studied in groups of 8 to 10, with each group receiving escalating dosages ranging from 5 mg twice daily to 75 mg twice daily and 10 to 25 mg daily. Patients were considered for long-term (beyond 4 weeks) continuation treatment if clinical benefit, in the view of the investigator, was derived. Study endpoints were safety, tolerance, and changes in the rate of rise of CA 19/9, which were used as surrogate markers for disease progression. Marimastat was well tolerated. Musculoskeletal pain, stiffness, and tenderness emerged as dose-limiting toxicity. No other dose-related toxicities were observed. A reduced rate of rise of CA 19/9 was observed at dose levels of 5, 10, and 25 mg twice daily. The overall median survival was 160 days, with a 1-year survival of 21%. Marimastat was associated with an acceptable toxicity profile, and these preliminary data suggest that long-term oral administration is feasible and safe. Doses of 5, 10, and 25 mg twice daily were identified as the optimal doses to be tested in larger randomized studies.

Strand displacement amplification and homogeneous real-time detection incorporated in a second-generation DNA probe system, BDProbeTecET

BACKGROUND

Amplified DNA probes provide powerful tools for the detection of infectious diseases, cancer, and genetic diseases. Commercially available amplification systems suffer from low throughput and require decontamination schemes, significant hands-on time, and specially trained laboratory staff. Our objective was to develop a DNA probe system to overcome these limitations.

METHODS

We developed a DNA probe system, the BDProbeTecTMET, based on simultaneous strand displacement amplification and real-time fluorescence detection. The system uses sealed microwells to minimize the release of amplicons to the environment. To avoid the need for specially trained labor, the system uses a simple workflow with predispensed reagent devices; a programmable, expandable-spacing pipettor; and the 96-microwell format. Amplification and detection time was 1 h, with potential throughput up to 564 patient results per shift. We tested 122 total patient specimens obtained from a family practice clinic with the BD ProbeTecET and the Abbott LCx(R) amplified system for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae.

RESULTS

Based on reportable results, the BDProbeTecET results for both organisms were 100% sensitive and 100% specific relative to the LCx.

CONCLUSIONS

The BDProbeTecET is an easy-to-use, high-throughput, closed amplification system for the detection of nucleic acid from C. trachomatis and N. gonorrhoeae and other organisms.

Adding nursing facility beds: impact on hospital nonacute care

The study evaluated the impact of admitting 235 nonacute patients who had been backed up in hospitals to new nursing facility beds in the metropolitan area of Syracuse, New York, during a 12-month period. The data indicated that these admissions reduced the hospital nonacute census by 53 percent and produced substantial declines in numbers of nonacute patients with postacute stays longer than one month and with Medicaid as principal payer. Numbers of patients waiting for Medicaid eligibility were not affected by admissions to the new beds. The data also indicated that substantial numbers of new admissions were required to generate these changes.

Human cloning and child welfare

In this paper we discuss an objection to human cloning which appeals to the welfare of the child. This objection varies according to the sort of harm it is expected the clone will suffer. The three formulations of it that we will consider are: 1. Clones will be harmed by the fearful or prejudicial attitudes people may have about or towards them (H1); 2. Clones will be harmed by the demands and expectations of parents or genotype donors (H2); 3. Clones will be harmed by their own awareness of their origins, for example the knowledge that the genetic donor is a stranger (H3). We will show why these three versions of the child welfare objection do not necessarily supply compelling reasons to ban human reproductive cloning. The claim that we will develop and defend in the course of our discussion is that even if it is the case that a cloned child will suffer harms of the type H1-H3, it is none the less permissible to conceive by cloning so long as these cloning-induced welfare deficits are not such as to blight the existence of the resultant child, whoever this may be.

The principles of medical ethics and medical research

In this paper I discuss the application of the principles of medical ethics and of medical research to the case of children and others whose consent to treatment and to research is problematic. Public health depends substantially on the possibility of ongoing research into all conditions which affect the health of the people. Constraints on this research are therefore a public health issue. Moreover and more importantly the possibility of predictive testing and indeed of screening for health-relevant conditions is an important public health tool, and limitations on the use of this tool are of great significance to public health medicine. Having considered the particular problems created by research and predictive testing on children for late-onset conditions I go on to discuss research on those whose consent is problematic more generally. I conclude with radical recommendations for the reform of The Declaration of Helsinki and of the International Ethics Guidelines for Biomedical Research Involving Human Subjects, prepared by the Council for International Organizations of Medical Sciences (CIOMS).

Domestic aeroallergen exposures among infants in an English town

A multicentre, prospective cohort study of childhood asthma was established in three European countries; the purpose of the project is the examination of factors which modify the relationship between allergen exposure in infant life and subsequent atopy and asthma. Dust samples were collected from the homes of 643 infants in a single town in the UK (the first cohort) and assayed for house dust mites (Der p 1) and cat allergen (Fel d 1) concentrations by enzyme-linked immunosorbent assay. A questionnaire with potential relevance to the development of atopy and asthma was completed. A wide variation in exposure to both allergens was observed. Carpeted, double-glazed or damp living rooms, and those sampled in the winter months, had higher levels of Der p 1, but these features did not predict Fel d 1 concentrations. Measures of high home occupancy were positively related to Der p 1 concentrations; and inversely with levels of Fel d 1, a finding which could not be explained by cat ownership. Homes in which one or more persons smoked had significantly lower concentrations of Der p 1, but not Fel d 1. There were no consistent differences in allergen levels between homes where one or more parent or sibling was either atopic or asthmatic. These findings indicate complex interactions among domestic, behavioural and seasonal factors and early allergen exposure in British children.

Why and how to combine chemotherapy and radiation therapy in breast cancer patients

The ideal sequencing of CT and radiation therapy in early-stage breast cancer treated with breast-conserving surgery and RT is not known. There is evidence that delaying CT might have an adverse impact on systemic control, while delaying RT might adversely affect local control. Concurrent CT and full-dose RT might minimize the above tradeoffs, but is associated with increased toxicity. Concurrent CT and reduced-dose RT is a novel approach to address these issues, but requires additional formal evaluation before clinical use. In the absence of definitive information, clinicians should balance each patient's risk for systemic recurrence and local-regional recurrence. For example, a patient with a large number of positive nodes but clearly negative margins would be an appropriate candidate for adjuvant therapy starting with CT and continuing with RT at the completion of CT. Alternatively, a patient with node-negative disease with close or focally positive margins might be an appropriate candidate for initiating RT sooner. Current treatment regimens which deliver CT in a "short" time period [i.e., Adriamycin (doxorubicin) and Cytoxan (cyclophosphamide) delivered in four 3-week cycles] may represent a reasonable tradeoff with regard to promptly starting systemic therapy while initiating RT within 3 months of surgery. It is possible that optimizing the way RT and CT are combined is important in achieving the highest survival rate and in reducing long-term adverse effects. There is unfortunately very little solid information from randomized clinical trials addressing this question, and considerable controversy remains regarding the optimal approach to integrating these modalities. Additional randomized clinical trials addressing this important clinical question are needed.

Interdisciplinary rural health training for health professional students: strategies for curriculum design

Interdisciplinary rural health program offer a promising solution to the challenge of preparing graduates for rural practice, with the ultimate goal of promoting better health care for rural populations. This article focuses on the three-year experience of a model interdisciplinary rural health curriculum implemented in eastern North Carolina. Ten strategies are presented as a framework for the design and implementation of an effective practice-based curriculum for interdisciplinary rural health training. Allied health educators should examine existing curriculum models to build upon their strengths and explore new models to meet evolving delivery system and consumer needs.