Biomedical subjects
Publications and source records attributed to W Mills.
Common complications associated with steroid therapy are well documented. We report a rare and fatal complication, in which oesophageal erosion secondary to the use of steroids was associated with pneumopericardium.
We analyse the evolution of X chromosome-linked imprinting by modifying our previous model of imprinting of autosomal genes that influence the trade-off between maternal fecundity and offspring viability through alterations in maternal investment (Mills and Moore, 2004). Unlike previous genetic models, we analyse X-linked imprinting in the context of populations at equilibrium for either autosomal or X-linked biallelically expressed alleles at loci that influence the fecundity/viability trade-off. We show that selection under parental conflict over maternal investment in offspring can parsimoniously explain the occurrence of sex-specific gene expression patterns, without a requirement to postulate direct selection for sexual dimorphism mediated through imprinting. We note that sex chromosome imprinting causes a small distortion of the post-weaning sex ratio, providing a possible selection pressure against the evolution of X-linked imprints. We discuss our conclusions in the context of recent reports of imprinting of mouse X-linked Xlr genes.
OBJECTIVES: To evaluate congenital syphilis surveillance in Minnesota, to assess the evaluation and management of newborns at risk for congenital syphilis, and to assess prenatal syphilis screening. DESIGN: Case ascertainment and medical record review. SETTING: The 7-county Minneapolis-St Paul metropolitan area. PATIENTS: Newborns at risk for congenital syphilis during a 3-year period (1992-1994). MAIN OUTCOME MEASURES: The completeness of congenital syphilis case ascertainment, maternal demographic data, maternal syphilis management, newborn evaluation for and management of congenital syphilis, and hospital syphilis screening practices at delivery. RESULTS: Eighty mother-infant pairs who were at risk for congenital syphilis were identified from 3 sources. Using the Centers for Disease Control and Prevention's congenital syphilis case definition, 36 infants (45%) were classified as probable cases, 42 (53%) were classified as noncases, and 2 (3%) were syphilitic stillbirths. Forty-seven women (59%) had syphilis serologic tests performed in the third trimester; only 37 (46%) had syphilis screening at delivery. Conditions of the mothers of 8 probable cases (22%) were diagnosed at delivery. Most probable cases (86%) were evaluated; only 56% were evaluated adequately. Twenty-five probable cases (69%) were treated. Most hospitals did not have formal policies for syphilis screening at delivery. The Minnesota Department of Health's congenital syphilis registry lacked sensitivity (39%) as a case ascertainment method. CONCLUSIONS: Clinicians should adhere to standardized protocols in the evaluation and management of at-risk newborns. Vigilant screening prenatally and at delivery and adequate follow-up are critical to reduce congenital syphilis. Improved surveillance data and resources are needed for the identification and follow-up of newborns at risk for congenital syphilis.
The bulk of the DNA found at human centromeres is composed of tandemly arranged repeats, the most abundant of which is alpha satellite. Other human centromeric repetitive families have been identified, one of the more recent being gamma satellite. To date, gamma satellite DNAs have been reported at the centromeres of human chromosomes 8 and X. Here, we show that gamma-X satellite DNA is not interspersed with the major DZX1 alpha-X block, but rather is organised as a single array of approximately 40-50 kb on the short-arm side of the alpha satellite domain. This repeat array is absent on two mitotically stable Xq isochromosomes. Furthermore, a related repeat DNA has been identified on the human Y chromosome. Fluorescence in situ hybridisation has localised this satellite DNA to the long arm side of the major DYZ3 alpha-Y domain, outside the region previously defined as that required for mitotic centromere function. Together, these data suggest that while blocks of highly related gamma satellite DNAs are present in the pericentromeric regions of both human sex chromosomes, this repeated DNA is not required for mitotic centromere function.
The telomere-associated protein TRF2 binds as a homodimer to double-stranded (TTAGGG)n arrays in vitro and localises to chromosome ends in vivo. Inhibition of TRF2 in human cell lines and recent electron microscopy analyses suggest that TRF2 plays a crucial role in the maintenance of telomere integrity. To study the role of TRF2 in vertebrate telomere biology using an alternative model system, we report the isolation and characterisation of the chicken TRF2 locus. The TRF2 protein is highly conserved between mammals and birds, particularly within the dimerisation and myb-type DNA binding domains. However, the chicken ORF predicts an additional protein domain consisting of 15 copies of a degenerate 13 amino acid repeat. Indirect immunofluorescence reveals the localisation of a FLAG-tagged version of the chicken TRF2 protein at chromosome ends in both chicken and human cells suggesting that the protein is functionally conserved.
A linear mammalian artificial chromosome (MAC) will require at least three types of functional element: a centromere, two telomeres and origins of replication. As yet, our understanding of these elements, as well as many other aspects of structure and organization which may be critical for a fully functional mammalian chromosome, remains poor. As a way of defining these various requirements, minichromosome reagents are being developed and analysed. Approaches for minichromosome generation fall into two broad categories: de novo assembly from candidate DNA sequences, or the fragmentation of an existing chromosome to reduce it to a minimal size. Here we describe the generation of a human minichromosome using the latter, top-down, approach. A human X chromosome, present in a DT40-human microcell hybrid, has been manipulated using homologous recombination and the targeted seeding of a de novo telomere. This strategy has generated a linear approximately 2.4 Mb human X centromere-based minichromosome capped by two artificially seeded telomeres: one immediately flanking the centromeric alpha-satellite DNA and the other targeted to the zinc finger gene ZXDA in Xp11.21. The chromosome retains an alpha-satellite domain of approximately 1. 8 Mb, a small array of gamma-satellite repeat ( approximately 40 kb) and approximately 400 kb of Xp proximal DNA sequence. The mitotic stability of this minichromosome has been examined, both in DT40 and following transfer into hamster and human cell lines. In all three backgrounds, the minichromosome is retained efficiently, but in the human and hamster microcell hybrids its copy number is poorly regulated. This approach of engineering well-defined chromosome reagents will allow key questions in MAC development (such as whether a lower size limit exists) to be addressed. In addition, the 2.4 Mb minichromosome described here has potential to be developed as a vector for gene delivery.
An evaluation of a store-and-forward electronic referral system was carried out in Cornwall to gauge its effectiveness in prioritizing dermatological patients needing secondary care. A dermatologist classified patients to be seen according to need based on information on the electronic referral form along with an image of the skin condition. Initial findings indicated that patients were more accurately triaged in at least 50% of cases and that 25% of patients did not require an outpatient dermatological appointment. Dermatologists rated image quality at 7.5 on a 10-point scale. This low-cost system has potential for more appropriate clinical management of dermatological patients in both primary and secondary care.
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A linear mammalian artificial chromosome vector will require at least three functional elements: a centromere, two telomeres and replication origins. One route to generate such a vector is by the fragmentation of an existing chromosome. We have previously described the use of cloned telomeric DNA to generate and stably rescue truncated derivatives of a human X chromosome in a somatic cell hybrid. Further rounds of telomere-associated chromosome fragmentation have now been used to engineer a human X-derived minichromosome. This minichromosome is estimated to be < 10 Mb in size. In situ hybridization and molecular analysis reveal that the minichromosome has a linear structure, with two introduced telomere constructs flanking a 2.5 Mb alpha-satellite array. The highly truncated chromosome also retains some chromosome-specific DNA, originating from Xp11.21. There is no significant change in the mitotic stability of the minichromosome as compared with the X chromosome from which it was derived.
Patients with hepatocellular carcinomas who undergo chemoembolization therapies require skilled perioperative nursing care that addresses their knowledge deficits about chemoembolization techniques, their anxieties related to chemoembolization procedures and adverse effects, and their impaired mobility resulting from the presence of arterial lines and the progression of the cancer. Perioperative nursing participation in chemoembolization procedures is an example of the expanded role of today's OR nurse.
PURPOSE: To evaluate the outcome of patients with relapsed or resistant non-Hodgkin's lymphoma (NHL) undergoing high-dose chemotherapy and autologous bone marrow transplantation (ABMT) and to determine the main prognostic factors. PATIENTS AND METHODS: One hundred seven patients with relapsed or resistant intermediate-/high-grade NHL underwent high-dose carmustine, etoposide, cytarabine, and melphalan (BEAM) chemotherapy and ABMT at University College Hospitals between September 1981 and February 1993. The minimum follow-up duration of all patients is 6 months. RESULTS: At 3 months, the overall response rate to BEAM and ABMT was 73% (41% complete response and 32% partial response). The 5-year actuarial overall survival and progression-free survival rates were 41% and 35%, respectively. The early procedure-related mortality rate was 7% (eight of 107 patients). On multivariate analysis, the main prognostic factor was disease status at the time of ABMT. Patients with chemosensitive disease had an actuarial 5-year survival rate of 49% at 5 years compared with 13% for those with chemoresistant disease (P < .001). For patients considered to have chemosensitive disease at the time of transplantation, there is a significant difference in the actuarial progression-free survival rates for those who received high-dose therapy after attaining a partial response to first-line therapy (69% at 5 years) as compared with those with sensitive but relapsed disease (32% at 5 years) (P = .003). CONCLUSION: Patients with chemosensitive disease benefit most from high-dose chemotherapy, and those who receive such therapy early after achieving a partial response to first-line therapy have a high rate of cure.
We have previously demonstrated a dose response relationship in Hodgkin's disease for the combination of BCNU, VP16, Ara C and Melphalan, with the superior efficacy of the BEAM regimen requiring haemopoietic support, compared with miniBEAM. To further exploit this, we have attempted to escalate the VP16 dose in BEAM. The standard etoposide dose is 200 mg/m2 IV for four days. Thirty seven patients with refractory lymphoma received 400 mg/m2/day of etoposide, and 13 patients 600 mg/m2/day, in addition to BCNU, cytarabine, and melphalan. Toxicity and outcome parameters were compared in the preceding 40 patients, who received 200 mg/m2/day etoposide. The toxic mortality with 400 mg/m2/day of etoposide (3%) was identical to that for the standard BEAM regimen (5%). Two procedure related deaths occurred in the highest VP16 dose group (15%). The morbidity of the lower etoposide dose regimens was comparable, but 600 mg/m2/day induced significantly greater gastrointestinal toxicity. Twelve of the 13 patients receiving this dose suffered grade II-IV mucositis, with stomatitis, dysphagia and prolonged diarrhoea; 5 haemodynamically significant gastrointestinal haemorrhage, and 1 fatal toxic colitis. Granulocyte colony stimulating factor did not influence the nonhaematological toxicity. The three month response rates were similar (91%) in all dose cohorts. The maximum tolerable etoposide dose within the BEAM regimen is thus 400 mg/m2 for four days.
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Liposomal amphotericin B (AmBisome) was used for suspected or confirmed fungal infection complicating 133 neutropenic episodes in 116 patients not tolerating, or not responding to, conventional amphotericin. Adverse effects were infrequent and no significant renal impairment resulted. Acute reactions occurred in five patients, reversible hepatic dysfunction in 23, and hypernatraemia in 17. The putative mycosis resolved with AmBisome treatment in 81 episodes (61%) and progressed with fatal outcome in 25 (19%), but the diagnosis was equivocal in most, and in 27 episodes (20%) evidence indicating nonfungal pathogenesis emerged. Treatment efficacy is, however, evaluable in those with proven aspergillosis. 13/17 patients with confirmed invasive aspergillosis responded to AmBisome (77%), conventional amphotericin having failed in 11. Treatment was successfully discontinued when the neutrophil count was < 1 x 10(9)/l in eight responders (61%). In four further patients treated for suspected aspergillosis, disseminated infection was documented at post-mortem, but the true incidence is unknown. This analysis confirms that AmBisome is well tolerated and effective against invasive mycoses in neutropenic patients, and may salvage patients when conventional amphotericin proves excessively toxic or ineffective.
Bilateral iliac crest biopsies were performed at the time of bone marrow (BM) harvest in patients with poor-risk Hodgkin's disease (HD) undergoing autologous bone marrow transplantation (ABMT). 67 consecutive patients with normal trephine biopsies (58 unilateral; nine bilateral) taken 2 weeks prior to harvest were studied. Nine (13%) of patients had BM infiltration with HD on the harvest biopsies. These patients had all previously had only unilateral biopsies. Three patients did not proceed to ABMT because disease progression became clinically apparent, but the remaining six patients were infused with involved marrow. One patient died 6 weeks post ABMT, with no evidence of disease at post-mortem. One patient showed no response to ABMT and four patients either had a partial or complete response to ABMT. Of the responders, three patients are now in complete remission at 53, 39 and 33 months past ABMT.
PURPOSE: The aims of this study were to develop a simplified, safe, and cost-effective peripheral-blood progenitor-cell (PBPC) mobilization protocol. PATIENTS AND METHODS: Twenty-six patients with relapsed or resistant lymphomas were entered onto a sequential cohort study in which schedules of various granulocyte colony-stimulating factor (G-CSF) were administered after cyclophosphamide 1.5 g/m2. Hematologic recovery after high-dose carmustine (BCNU) etoposide, cytarabine, and melphalan (BEAM) chemotherapy was compared with that of 46 patients who received autologous bone marrow transplantation (ABMT) without growth factors and 28 patients who received ABMT followed by G-CSF. RESULTS: When G-CSF (10 micrograms/kg/d) was administered from the day after the cyclophosphamide, neutropenia developed on day 8 followed by an abrupt increase in the WBC count. The optimal time for PBPC harvesting was the day on which the postnadir WBC count was greater than 8.0 x 10(9)/L, as shown by CD34+ cell counts and granulocytic-macrophage colony-forming cell (GM-CFC) assays. The reproducibility of the response was such that routine monitoring of CD34+ cell counts and GM-CFC was not necessary. A single leukapheresis on this day was adequate for prompt hematologic engraftment, and posttransplant G-CSF made little further impact on the rapid recovery. Compared with both control groups, the use of PBPC led to more rapid neutrophil recovery, markedly accelerated platelet recovery, less use of antimicrobial agents and parenteral nutrition, and more than 10 days earlier discharge from hospital. All of these differences were highly significant (P < .01). CONCLUSION: A simplified mobilization protocol is described that requires only one apheresis to achieve rapid hematologic engraftment.
We report the complications and outcome of high-dose melphalan and TBI combined with ABMT used in the treatment of multiple myeloma at a single centre. Twenty-three patients, aged 65 years or less, who underwent the procedure are reviewed. All had chemosensitive disease. Response to ABMT assessed at 3 months showed 75% of evaluable patients to have further tumour cytoreduction of at least 50%, with 24% of patients who entered ABMT with residual disease eventually achieving CR. There was one toxic death. The overall survival is 60% and the progression-free survival is 49.8% at a median follow-up time of 17 months. Relapse or disease progression has occurred in 27% of patients, of whom half have died. No significant prognostic factors affecting survival were found although those patients with IgG myeloma had a better outcome. Patients transplanted in first plateau appeared to do significantly better if they had been resistant to their first-line chemotherapy but had then responded to further conventional chemotherapy (p = 0.029).