Expression of the developmental markers STRO-1 and alkaline phosphatase in cultures of human marrow stromal cells: regulation by fibroblast growth factor (FGF)-2 and relationship to the expression of FGF receptors 1-4

Autologous marrow stromal cells have been proposed as an adjuvant in the treatment of bone defects and diseases. This will require the development of culture conditions that permit their rapid expansion ex vivo while retaining their potential for further differentiation. Fibroblast growth factor (FGF)-2 has been proposed as a candidate for the ex vivo expansion of cells with enhanced osteogenic potential, and we have explored this possibility further using cells obtained from a large cohort of adult human donors. Treatment with FGF-2 (0.001-2.5 ng/mL) had no detectable effect on colony formation, but markedly increased their proliferative potential and that of their immediate progeny, as shown by the increases in colony size and cell number. Based on the observed increase in the expression of the developmental markers STRO-1 and alkaline phosphatase (AP), a major target for the actions of FGF-2 appears to be the more primitive cells of the osteoblast lineage, and that, when added in combination with the synthetic glucocorticoid dexamethasone (Dx), it interacts positively to promote further cell maturation. The maintenance of adequate levels of ascorbate was shown to be a critical component in determining the nature of the effect of FGF-2 on AP expression. Variation in the response (predominantly in the magnitude and/or sensitivity) of the cultured cell populations to treatment with FGF-2 was apparent, but a preliminary analysis indicated that this was not due to differences in the age or gender of the donors used. The cultured cell populations were found to express multiple FGF receptors (FGFRs; 1-4) and the observed changes in the spectrum and abundance of FGFRs expressed in relation to that of STRO-1 and AP are consistent with their expression being developmentally regulated during the process of osteogenic differentiation. These results provide novel insights into the mechanism of action of FGF-2 on human cells of the osteoblast lineage and support the use of this factor, alone or in combination with Dx, for the rapid, ex vivo expansion of cell populations with enhanced osteogenic potential.

Phase I/II trial of cyclophosphamide, mitoxantrone, and escalated doses of carboplatin supported by peripheral-blood stem cells in women with metastatic breast cancer

PURPOSE

To intensify a regimen of high-dose cyclophosphamide, mitoxantrone, and carboplatin that had previously produced high complete and overall response rates in metastatic breast cancer (MBC).

PATIENTS AND METHODS

Forty-four patients with a median age of 43 years (range, 25 to 57 years) and previously untreated MBC who were responding to anthracycline-based or single-agent taxane chemotherapy received cyclophosphamide 1.5 g/m(2)/d and mitoxantrone 16 mg/m(2)/d combined with escalating doses of carboplatin 200 to 500 mg/m(2)/d, each given daily from days -6 to -3. Hematopoiesis was supported by mobilized peripheral-blood stem cells infused on day 0 and by use of granulocyte-macrophage colony-stimulating factor 300 microg/d subcutaneously starting on day 1.

RESULTS

A total of six dose levels of carboplatin were examined. Grades 3 and 4 toxicity occurred in 10 patients and one patient, respectively, with grade 3 toxicity occurring in only five of 31 patients treated with < or = 400 mg/m(2) of carboplatin. Major dose-limiting toxicities were cardiac, pulmonary, and renal. Four patients developed congestive heart failure: two had persistently low ejection fraction 11 and 36 months after peripheral-blood stem-cell transplantation (PBSCT), and two recovered. Hematologic recovery to an absolute neutrophil count of greater than 0.5 x 10(9)/L occurred at a median of 11 days (range, 8 to 25 days) and to a platelet count of greater than 20 x 10(9)/L at a median of 10.5 days (range, 6 to 60 days). There were two toxic deaths from sepsis: one on day 27 (level 5) and one from cardiac arrest on day 42 (level 6).

CONCLUSION

The maximum-tolerated dose of carboplatin was 400 mg/m(2)/d in combination with mitoxantrone 16 mg/m(2)/d and cyclophosphamide 1,500 mg/m(2), all drugs given over 4 days. This regimen is being tested in a phase III trial of high-dose chemotherapy and PBSCT versus standard treatment.

Structure-directed discovery of potent non-peptidic inhibitors of human urokinase that access a novel binding subsite

BACKGROUND

Human urokinase-type plasminogen activator has been implicated in the regulation and control of basement membrane and interstitial protein degradation. Because of its role in tissue remodeling, urokinase is a central player in the disease progression of cancer, making it an attractive target for design of an anticancer clinical agent: Few urokinase inhibitors have been described, which suggests that discovery of such a compound is in the early stages. Towards integrating structural data into this process, a new human urokinase crystal form amenable to structure-based drug design has been used to discover potent urokinase inhibitors.

RESULTS

On the basis of crystallographic data, 2-naphthamidine was chosen as the lead scaffold for structure-directed optimization. This co-crystal structure shows the compound binding at the primary specificity pocket of the trypsin-like protease and at a novel binding subsite that is accessible from the 8-position of 2-napthamidine. This novel subsite was characterized and used to design two compounds with very different 8-substituents that inhibit urokinase with K(i) values of 30-40 nM.

CONCLUSIONS

Utilization of a novel subsite yielded two potent urokinase inhibitors even though this site has not been widely used in inhibitor optimization with other trypsin-like proteases, such as those reported for thrombin or factor Xa. The extensive binding pockets present at the substrate-binding groove of these other proteins are blocked by unique insertion loops in urokinase, thus necessitating the utilization of additional binding subsites. Successful implementation of this strategy and characterization of the novel site provides a significant step towards the discovery of an anticancer clinical agent.

The expression and secretion of atrial natriuretic factor and brain natriuretic peptide by rat proximal tubular cells

We examined the expression of both the natriuretic peptides and natriuretic peptide receptors (NPR) in primary cultures of rat proximal tubular (RPT) cells using Northern blot assay for peptides and receptors and radioimmunoassay and immunohistochemical analysis for atrial natriuretic factor (ANF), brain natriuretic peptide (BNP), and C-type natriuretic peptide. Freshly isolated cells expressed mRNA coding for ANF, BNP, and the NPR-C. The presence of ANF and BNP in freshly isolated cells was confirmed by immunocytochemical staining. As cells approached confluence, there was a marked increase in mRNA expression for ANF and BNP. Immunocytochemical analysis and radioimmunoassay confirmed that both these peptides were co-localised in RPT cells and present in the cell supernatant. These changes in peptide expression were associated with a concurrent decrease in the expression of the NPR-C and the appearance of the NPR-A and -B. These results confirm that freshly isolated RPT cells possess the components of an autocrine natriuretic peptide system and that growth in primary culture is associated with changes in both peptide system and that growth in primary culture is associated with changes in both peptide and receptor subtype expression, raising the possibility that the endogenous production of ANF and BNP may be involved in the control of control cell growth.

Intubation conditions and postoperative myalgia in outpatient dental surgery: a comparison of succinylcholine with mivacurium

Ninety-four patients undergoing elective outpatient third molar extraction were recruited into a double-blind, randomized, prospective trial comparing mivacurium (group M) with succinylcholine (Group S) for conditions for endotracheal intubation and the occurrence of postoperative myalgia. Anaesthesia was induced with fentanyl 1 microgram.kg-1 and propofol 2.5 micrograms.kg-1 in all patients. Group S patients were given gallamine 20 mg while group M patients were given mivacurium 0.2 mg.kg-1. Manual ventilation was commenced and anaesthesia maintained with nitrous oxide 70% and isoflurane 1 to 2% in oxygen. After two minutes, group S patients were given succinylcholine 1.5 mg.kg-1 and group M patients 0.9% saline. Nasotracheal intubation was performed 30 seconds later. Intubating conditions in group M were significantly better than those in group S (P < 0.001). The incidence of postoperative myalgia was 9.5% in group M and 26% in group S but this was not statistically significant (P = 0.09). We propose that mivacurium is a suitable neuromuscular blocker to use for endotracheal intubation in outpatient dental surgery.

Emerging models of care management for older people and those with mental health problems in the United Kingdom

Care management has emerged as a central component in the development of community-based care in many countries. It has been government policy for providers of social services to develop care management systems in the United Kingdom since 1993. This paper examines the extent to which it is possible to begin to discern models of care from the different care management arrangements which are now emerging. First, the background to changes in policy and the role of care management in the UK social care system are discussed; second, evidence from the early phases of care management development in the UK is also examined; and third, based upon the pilot phase of a major national study of care management, the key dimensions of variation in care management through which models may be constituted are identified.

Macrophages from inflamed but not normal glomeruli are unresponsive to anti-inflammatory cytokines

This study examined the properties and responsiveness to cytokines of macrophages purified from normal and nephritic glomeruli to ascertain whether macrophages activated in vivo develop programmed unresponsiveness to cytokines as do bone marrow-derived macrophages in vitro when activated by interferon-gamma (IFN-gamma), tumor necrosis factor (TNF), interleukin-4 (IL-4), or transforming growth factor-beta (TGF-beta). Macrophages from normal glomeruli did not generate nitric oxide (NO) spontaneously but only after treatment with IFN-gamma and TNF-alpha. NO generation by these macrophages was abrogated by administering IL-4, TGF-beta, or TNF-alpha before but not after IFN-gamma treatment. Glomerular macrophages also expressed beta-glucuronidase, which was increased by TGF-beta and decreased by IFN-gamma and TNF. By contrast, glomerular macrophages from rats with nephrotoxic nephritis did not express beta-glucuronidase even after exposure to TGF-beta. Furthermore, they generated NO spontaneously, and this spontaneous generation of NO was not suppressed by IL-4, TGF-beta, or TNF-alpha. Systemic treatment of nephritic rats with IL-4 reduced NO generation by 40% but did not prevent activation, which is similar to the effect of IL-4 on bone marrow-derived macrophages in vitro when given simultaneously with IFN-gamma. We conclude that macrophages infiltrating inflamed glomeruli have developed programmed unresponsiveness to activating cytokines. This may enable them to function appropriately in the complex conditions within an inflammatory focus.

Scrapie replication in lymphoid tissues depends on prion protein-expressing follicular dendritic cells

The immune system is central in the pathogenesis of scrapie and other transmissible spongiform encephalopathies (TSEs) or 'prion' diseases. After infecting by peripheral (intraperitoneal or oral) routes, most TSE agents replicate in spleen and lymph nodes before neuroinvasion. Characterization of the cells supporting replication in these tissues is essential to understanding early pathogenesis and may indicate potential targets for therapy, for example, in 'new variant' Creutzfeldt-Jakob disease. The host 'prion' protein (PrP) is required for TSE agent replication and accumulates in modified forms in infected tissues. Abnormal PrP is detected readily on follicular dendritic cells (FDCs) in lymphoid tissues of patients with 'new variant' Creutzfeldt-Jakob disease, sheep with natural scrapie and mice experimentally infected with scrapie. The normal protein is present on FDCs in uninfected mice and, at lower levels, on lymphocytes. Studies using severe combined immunodeficiency (SCID) mice, with and without bone marrow (BM) grafts, have indicated involvement of FDCs and/or lymphocytes in scrapie pathogenesis. To clarify the separate roles of FDCs and lymphocytes, we produced chimeric mice with a mismatch in PrP status between FDCs and other cells of the immune system, by grafting bone marrow from PrP-deficient knockout mice into PrP-expressing mice and vice versa. Using these chimeric models, we obtained strong evidence that FDCs themselves produce PrP and that replication of a mouse-passaged scrapie strain in spleen depends on PrP-expressing FDCs rather than on lymphocytes or other bone marrow-derived cells.

The effects of low-intensity warfarin on coagulation activation in patients with antiphospholipid antibodies and systemic lupus erythematosus

The optimal intensity of oral anticoagulant therapy for the prevention of thromboembolism in patients with antiphospholipid antibodies (APLA) and systemic lupus erythematosus is controversial. Retrospective studies have suggested that patients with APLA are resistant to oral anticoagulant therapy, with a targeted International Normalization Ratio (INR) of 2.0 to 3.0, and that a higher intensity of anticoagulation (INR: 2.6 to 4.5) is required to prevent recurrent thromboembolism. To investigate if patients with APLA are resistant to the anticoagulant effect of low intensities of warfarin therapy, we performed a randomized trial in which 21 patients with APLA and systemic lupus erythematosus were allocated to receive one of three intensities of warfarin (INR: 1.1 to 1.4, 1.5 to 1.9 or 2.0 to 2.5) or placebo for four months. The main outcome was the effect of each intensity of warfarin therapy on prothrombin fragment 1+2 level (F1+2), that was used as a marker of coagulation activation. When F1+2 levels in patients allocated to the three warfarin intensities were compared to F1+2 levels in the placebo group, there was a statistically significant decrease (p<0.05) in the patient group receiving warfarin with a targeted INR of 2.0 to 2.5 at two, three and four months, and in the patient group with a targeted of INR 1.5 to 1.9 at three months. We conclude that in patients with APLA and systemic lupus erythematosus, warfarin therapy, with a targeted INR of 2.0 to 2.5, is effective in suppressing coagulation activation, and therefore, might be effective in preventing thromboembolism.

Further characterization of cells expressing STRO-1 in cultures of adult human bone marrow stromal cells

Primitive cells of the osteoblast lineage are not well characterized but are known to be present within the STRO-1+ fraction of adult human bone and marrow. A survey of human osteosarcoma cell lines revealed that STRO-1 is expressed by MG-63 but not SaOS-2. Among murine cell lines tested, expression of STRO-1 was detected in the bipotential (adipocyte/osteoblast) line BMS-2 but not the committed osteoblast precursor MC3T3-E1. A proportion of cultured adult human bone marrow stromal cells (BMSCs) consistently expressed the STRO-1 antigen. The expression of a range of cell surface antigens was studied in relation to STRO-1 by flow cytometry and several, including the bone/liver/kidney isoform of alkaline phosphatase (ALP), were found to subtype the STRO-1+ population of BMSCs. Further, BMSCs dual-labeled with antibodies recognizing STRO-1 and ALP could be assigned to one of four fractions: STRO-1-/ALP-, STRO-1+/ALP-, STRO-1+/ALP+, and STRO-1-/ALP+. Cells from each fraction could be isolated in high purity and, when recultured, remained viable and exhibited a limited degree of phenotypic stability. Using reverse transcriptase-polymerase chain reaction, cells in the four fractions were found to express different levels of transcripts for the parathyroid hormone receptor (PTHr) and bone sialoprotein (BSP). The expression of transcripts for the nuclear transcription factor core-binding factor alpha 1/osteoblast-specific factor-2 (CBFA1/OSF2) was restricted to those fractions expressing STRO-1 and/or ALP. Treatment with 10 nM dexamethasone consistently increased the proportion of cells present in those fractions which expressed the highest levels of transcripts for PTHr and BSP (STRO-1+/ALP+ and STRO-1-/ALP+) while simultaneously decreasing the proportion present in the STRO-1+/ALP- fraction. In conclusion, the expression of STRO-1 in vitro remains a characteristic of less well differentiated cells of the osteoblast lineage; in cultures of BMSCs and in established human osteosarcoma cell lines, there is an inverse association between the expression of STRO-1 and ALP; dual labeling of BMSCs with monoclonal antibodies recognizing STRO-1 and ALP permits the identification and isolation of cells of the osteoblast lineage at different stages of differentiation.

The role of audit in making do not resuscitate decisions

Audit has been proposed as a useful means of implementing and evaluating 'Do Not Resuscitate (DNR)' policies. This paper explores the background to the introduction of DNR policies and reviews published reports of their use in clinical practice. Problems with auditing and implementing DNR policies are highlighted.

Audit of resuscitation decisions has little impact on clinical practice

OBJECTIVE

To determine if clinical audit leads to sustained improvement in resuscitation decision-making.

METHOD

Analysis of data from five studies performed over nine years between 1989 and 1998. Two of the surveys included all medical and elderly patients, while three surveys in 1993, 1994 and 1996 included only patients over 75 years of age.

RESULTS

The three surveys involving only elderly patients revealed significant improvement in recording the decisions made on resuscitation (73% vs 50%; p = 0.02) over a two-month audit cycle, but this improvement was not maintained. Clinical audit and the use of a proforma improved neither the practice of discussing resuscitation with patients nor the involvement of consultants in the decision-making process over the nine-year period.

CONCLUSION

Clinical audit may lead to short-term improvements in resuscitation decision-making, but this improvement does not appear to be sustained over time. Other measures need to be considered to improve practice in this area.

Collection of peripheral blood progenitor cells (PBPC) based on a rising WBC and platelet count significantly increases the number of CD34+ cells

The kinetics of mobilization and optimal timing of peripheral blood progenitor cell (PBPC) collection were evaluated in 190 patients with multiple myeloma undergoing stem cell harvest after mobilization with cyclophosphamide, prednisone and G-CSF. There was a strong correlation between the WBC count and the number of CD34+ cells circulating in peripheral blood (r = 0.875). Initiating leukapheresis based on rising WBC and platelet counts rather than on a fixed day increased the mean number of CD34+ cells 115% (9.7 to 20.9 x 10(6) CD34+ cells/kg; P = 0.010) for the total of all leukaphereses and 59% for the total of all CD34-selected products (5.1 to 8.1 x 10(6) CD34+ cells/kg; P = 0.011). Although the yield and purity of the CD34-selected product were not significantly affected (P > or = 0.071), the percentage of patients with concentrations of CD34+ cells in the initial leukapheresis of > 1% increased from 47% to 70% (P = 0.004). The mean purity of the selected product was related to the starting percentage: 48.9% if < 1% and 81.5% if > or = 1% (P < 0.001). Collection of stem cells based on rising WBC and platelet counts significantly increased the number of CD34+ cells in leukaphereses and CD34-selected products in comparison with collection on a fixed day.

Evaluation of a diagnostic protocol using screening diagnostic peritoneal lavage with selective use of abdominal computed tomography in blunt abdominal trauma

BACKGROUND

The optimal method of evaluating blunt abdominal trauma remains controversial. A combination of a sensitive screening test, diagnostic peritoneal lavage (DPL), and a specific test, abdominal computed tomography (CT), may be a safe, efficient approach to adult blunt abdominal trauma.

METHODS

A prospective cohort study compared a protocol using screening DPL followed by selective use of abdominal CT (DPL/abdominal CT) and the use of abdominal CT alone in the evaluation of hemodynamically stable, adult blunt trauma patients.

RESULTS

One hundred sixty-seven adult blunt trauma patients were initially evaluated by DPL (n = 71) or abdominal CT (n = 96). Emergency department evaluation required less time in the DPL/abdominal CT group than in the abdominal CT alone group (41 minutes vs. 2.5 hours; p < 0.001). There were no missed injuries in the DPL/abdominal CT group versus seven missed injuries in the abdominal CT group (p = 0.02). There were no nontherapeutic celiotomies in either study group.

CONCLUSION

Screening DPL, followed by abdominal CT if positive, is a safe, efficient method of evaluating adult blunt abdominal trauma that reduces the time required to evaluate the abdomen, does not result in increased nontherapeutic celiotomies, results in fewer missed injuries, and reduces the overall use of abdominal CT.

Phase I trial of sequential topotecan followed by etoposide in adults with myeloid leukemia: a National Cancer Institute of Canada Clinical Trials Group Study

Prolonged exposure to a topoisomerase I inhibitor may increase expression of topoisomerase II, making cells more susceptible inhibitors of that enzyme. This study was undertaken to establish the maximum tolerated dose (MTD) of a topotecan/topoisomerase II inhibitor sequential combination that may be active in acute leukemia, and to evaluate the effects of in vivo exposure to topotecan on topoisomerase II levels in leukemic blast cells as measured by image cytometry. Patients who were eligible for this phase I study had relapsed or refractory acute myeloid leukemia (< or = 2 prior regimens) or CML blast crisis (0 or 1 prior regimen). Topotecan was given as a 5 day continuous i.v. infusion and was to be escalated through three levels (1.5, 1.75 and 2.0 mg/m2 day), followed by etoposide at two dose levels (100 and 150 mg/m2) i.v. bolus days 6, 7 and 8. Topoisomerase IIalpha levels in leukemic blasts from bone marrow were measured by image cytometry prior to starting treatment, on day 5 of topotecan infusion and on day 28; and daily during topotecan in peripheral blood blasts. Dose-limiting toxicity was seen in two of six patients at the first dose level (topotecan 1.5 mg/m2/day, etoposide 100 mg/m2/day; > or = grade 3 mucositis in both cases). This cohort was expanded to 10 patients; no further non-hematologic dose-limiting toxicity was observed, but given the extent of toxicity seen, further dose escalation was judged not to be feasible. Topo IIalpha levels increased in peripheral blood blasts during the first 72 h of topotecan infusion and returned to near baseline by day 5, whereas levels appeared to decrease in bone marrow blasts by day 5 compared to pretreatment. One complete hematologic and cytogenetic remission in a patient with CML blast crisis was observed in the 10 patients evaluable for response. The sequential administration of topotecan 1.5 mg/m2/day continuous infusion for 5 days followed by etoposide 100 mg/m2/day x 3 is the recommended phase II dose for this schedule. Topotecan increases topo IIalpha expression in vivo in leukemia cells, but levels of the enzyme are cell cycle dependent. Pharmacodynamic evaluation of the sequential or combination administration of novel antileukemic agents may help improve treatment strategies in acute leukemia.

Assessment approaches for older people receiving social care: content and coverage

BACKGROUND

Assessment was identified as one of the 'cornerstones' of community care. This study presents findings from the first nationally representative analysis of assessment documents used by social services agencies in the UK.

METHOD

In this paper analysis is made of 50 assessment documents used for the 'comprehensive' assessment of older people. The documents were examined in the extent to which they covered 33 assessment domains, grouped into four areas: functional domains; cognitive, mood and psychosocial domains; social environment domains; and clinico-medical domains. The documents were analysed on three dimensions: whether the domains were covered at all; whether the domain was covered in sufficient detail; and whether it would elicit a structured response.

RESULTS

Activities of daily living were covered to some extent on the majority of documents, as were the instrumental activities of daily living. Very few documents were designed to elicit information on the potential for rehabilitation. Whilst the majority of forms were designed to collect some information on cognitive patterns, mood state and social activity, very few were designed to collect this in any detail. Although functional activities of daily living were covered in greater detail than the other domains overall, there was enormous variability between the documents, thus hampering their ability to generate any standardized information.

Predicting unsuccessful cardiopulmonary resuscitation (CPR): a comparison of three morbidity scores

The aim of the study was to assess the usefulness of three different morbidity scores in predicting unsuccessful resuscitation. We reviewed the records of adult patients who underwent CPR between September 1994 and June 1996 in The Royal Hampshire County Hospital, Winchester. Demographic data and enough clinical data to calculate the Pre-Arrest Morbidity score (PAM), the Prognosis After Resuscitation score (PAR) and the Modified PAM Index (MPI) were collected. During the study period 264 consecutive adult patients underwent inpatient CPR. Twenty-eight (11%) of the patients survived to discharge from hospital. Patients who died had significantly higher morbidity scores than those who survived. No patient with a PAM score greater than 6/25, PAR greater than 7/28 or MPI greater than 6/24 survived. There were 47/264 patients who scored above this threshold for the PAM score giving a sensitivity for predicting unsuccessful CPR of 20%. The sensitivity of the PAR was 29% and MPI was 22%. Each score identified a different group of patients for whom CPR was unsuccessful. Using all three scores in combination identified 42% of the unsuccessful CPR attempts. Morbidity scores are likely to need further refinement in order to be a useful bedside tool for predicting success for individual patient resuscitation attempts.

ABT-378, a highly potent inhibitor of the human immunodeficiency virus protease

The valine at position 82 (Val 82) in the active site of the human immunodeficiency virus (HIV) protease mutates in response to therapy with the protease inhibitor ritonavir. By using the X-ray crystal structure of the complex of HIV protease and ritonavir, the potent protease inhibitor ABT-378, which has a diminished interaction with Val 82, was designed. ABT-378 potently inhibited wild-type and mutant HIV protease (Ki = 1.3 to 3.6 pM), blocked the replication of laboratory and clinical strains of HIV type 1 (50% effective concentration [EC50], 0.006 to 0.017 microM), and maintained high potency against mutant HIV selected by ritonavir in vivo (EC50, 50-fold after 8 h. In healthy human volunteers, coadministration of a single 400-mg dose of ABT-378 with 50 mg of ritonavir enhanced the area under the concentration curve of ABT-378 in plasma by 77-fold over that observed after dosing with ABT-378 alone, and mean concentrations of ABT-378 exceeded the EC50 for >24 h. These results demonstrate the potential utility of ABT-378 as a therapeutic intervention against AIDS.

Diet design for a multicenter controlled feeding trial: the DELTA program. Delta Research Group

OBJECTIVE

To describe the process and results of diet standardization, diet validation, and monitoring of diet composition, which were key components of protocol 1 of Dietary Effects on Lipoproteins and Thrombogenic Activity (DELTA-1), the initial protocol in a program of multicenter human feeding studies designed to evaluate the effects of amount and type of fat on lipoproteins and hemostasis parameters in various demographic groups.

DESIGN

DELTA-1 was based on a randomized, blinded, crossover experimental design. Three diets were fed for 8 weeks to 103 healthy men and women aged 22 to 67 years at 4 field centers. Diet A, an average American diet, was designed to provide 37% of energy from fat, 16% of energy from saturated fatty acids (SFAs); diet B (step 1 diet) was designed to provide 30% of energy from fat, 9% of energy from SFA; and diet C (low SFA diet) was designed to provide 26% of energy from fat, 5% of energy from SFA. Key features of diet standardization included central procurement of fat-containing foods, inclusion of standard ingredients, precision weighing of foods--especially sources of fat and cholesterol--and use of standardized written procedures.

SETTING

For menu validation, a set of 12 menus for each diet was prepared in duplicate and chemically assayed. For monitoring of diet composition during the study, an 8-day diet cycle (6 weekday and 2 weekend menus) was sampled by every field center twice during each of 3 feeding periods.

STATISTICAL ANALYSES

Means (+/- standard error) were calculated and compared with target nutrient specifications.

RESULTS

DELTA-1 was able to provide a standardized diet that met nutrient specifications across 4 field centers over 24 weeks of participant feeding spanning a total of 8 months.

APPLICATIONS

Prestudy chemical validation of menus and continuous sampling and assay of diets throughout the study are essential to standardize experimental diets and to ensure that nutrient target goals are met and maintained throughout a controlled multicenter feeding study.

Do general practitioners know when living wills are legal?

BACKGROUND

There is growing public awareness of living wills or advance directives. Patients who wish to make advance directives may approach general practitioners (GPs) for advice. However, many GPs are unaware of the correct legal status of living wills.

METHODS

Questionnaires were sent to 270 GPs in London and Winchester, asking seven questions about the current legal status of living wills.

RESULTS

Of the 214 GPs (79%) who returned questionnaires, only 104 (49%) were aware that some types of advance directives could carry legal force. Many of the GPs who did know that living wills could be legally binding were unable correctly to answer further questions on the practicalities of the law; for example, 26% were wrong in believing that a lawyer had to draw up a living will, and 13% incorrectly believed that a doctor was legally required to give any treatment requested by a patient in a living will.

CONCLUSIONS

Half of the GPs surveyed were unaware that living wills currently have legal force and most of the rest were unaware of important details of the law. More attention needs to be given to the education of doctors in this area.

Structure of secreted aspartic proteinases from Candida. Implications for the design of antifungal agents

Pathogens of the genus Candida can cause life threatening infections in immuno-compromised patients. The three-dimensional structures of two closely related secreted aspartic proteinases from C. albicans complexed with a potent (Ki = 0.17 nM) inhibitor, and an analogous enzyme from C. tropicalis reveal variations on the classical aspartic proteinase theme that dramatically alter the specificity of this class of enzymes. The novel fungal proteases present: i) an 8 residue insertion near the first disulfide (Cys45-Cys50, pepsin numbering) that results in a broad flap extending towards the active site; ii) a seven residue deletion replacing helix hN2 (Ser110-Tyr114), which enlarges the S3 pocket; iii) a short polar connection between the two rigid body domains that alters their relative orientation and provides certain specificity; and i.v.) an ordered 12 residue addition at the carboxy terminus. The same inhibitor (A-70450) binds in an extended conformation in the two variants of C. albicans protease, and presents a branched structure at the P3 position. However, the conformation of the terminal methylpiperazine ring is different in the two crystals structures. The implications of these findings for the design of potent antifungal agents are discussed.

Effects of reducing dietary saturated fatty acids on plasma lipids and lipoproteins in healthy subjects: the DELTA Study, protocol 1

Few well-controlled diet studies have investigated the effects of reducing dietary saturated fatty acid (SFA) intake in premenopausal and postmenopausal women or in blacks. We conducted a multicenter, randomized, crossover-design trial of the effects of reducing dietary SFA on plasma lipids and lipoproteins in 103 healthy adults 22 to 67 years old. There were 46 men and 57 women, of whom 26 were black, 18 were postmenopausal women, and 16 were men > or =40 years old. All meals and snacks, except Saturday dinner, were prepared and served by the research centers. The study was designed to compare three diets: an average American diet (AAD), a Step 1 diet, and a low-SFA (Low-Sat) diet. Dietary cholesterol was constant. Diet composition was validated and monitored by a central laboratory. Each diet was consumed for 8 weeks, and blood samples were obtained during weeks 5 through 8. The compositions of the three diets were as follows: AAD, 34.3% kcal fat and 15.0% kcal SFA; Step 1, 28.6% kcal fat and 9.0% kcal SFA; and Low-Sat, 25.3% kcal fat and 6.1% kcal SFA. Each diet provided approximately 275 mg cholesterol/d. Compared with AAD, plasma total cholesterol in the whole group fell 5% on Step 1 and 9% on Low-Sat. LDL cholesterol was 7% lower on Step 1 and 11% lower on Low-Sat than on the AAD (both P<.01). Similar responses were seen in each subgroup. HDL cholesterol fell 7% on Step 1 and 11% on Low-Sat (both P<.01). Reductions in HDL cholesterol were seen in all subgroups except blacks and older men. Plasma triglyceride levels increased approximately 9% between AAD and Step 1 but did not increase further from Step 1 to Low-Sat. Changes in triglyceride levels were not significant in most subgroups. Surprisingly, plasma Lp(a) concentrations increased in a stepwise fashion as SFA was reduced. In a well-controlled feeding study, stepwise reductions in SFA resulted in parallel reductions in plasma total and LDL cholesterol levels. Diet effects were remarkably similar in several subgroups of men and women and in blacks. The reductions in total and LDL cholesterol achieved in these different subgroups indicate that diet can have a significant impact on risk for atherosclerotic cardiovascular disease in the total population.

Advance directives and living wills

Under certain circumstances, living wills or advance directives may carry legal force in the UK. This paper traces the development of advance directives, clarifies their current legal position and discusses potential problems with their use. Case histories are used to illustrate some of the common dilemmas which doctors may face.

Progress toward the elimination of hepatitis B virus transmission among health care workers in the United States

BACKGROUND

Hepatitis B virus (HBV) infection is a well-recognized occupational risk for health care workers (HCWs). Vaccination coverage, disease trends, and the need for booster doses after hepatitis B vaccination of adults have been the subject of intense study during the 15 years of the vaccine's availability.

METHODS

Vaccination coverage of HCWs was determined from a review of medical records on a sample of employees from 113 randomly selected hospitals. The number of HBV infections among HCWs and the general US population for 1983 through 1995 was estimated from national surveillance data. Studies on long-term protection after hepatitis B vaccination of adults were reviewed.

RESULTS

A total of 2837 employee medical records were reviewed; 2532 employees (90%) were eligible to receive hepatitis B vaccine, and 66.5% of them (95% confidence interval, 61.9%-70.9%) had received 3 doses of hepatitis B vaccine. Vaccination coverage was highest (75%) for personnel with frequent exposure to infectious body fluids (phlebotomists, laboratory personnel, and nursing staff) and lowest (45%) for employees at low risk for exposure (dietary and clerical staff). The number of HBV infections among HCWs declined from 17,000 in 1983 to 400 in 1995. The 95% decline in incidence observed among HCWs is 1.5-fold greater than the reduction in incidence in the general US population. Studies on long-term protection demonstrate that vaccine-induced protection persists at least 11 years even when titers of antibody to hepatitis B surface antigen decline below detectable levels.

CONCLUSIONS

Although a high percentage of HCWs have been fully vaccinated with hepatitis B vaccine, efforts need to be made to improve this coverage. There has been a dramatic decrease in the number of HBV infections among HCWs who are now at lower risk of HBV infection than the general US population. Vaccine-induced protection persists at least 11 years and booster doses are not needed at this time for adults who have responded to vaccination.

Severely combined immunodeficient (SCID) mice resist infection with bovine spongiform encephalopathy

Following combined intraperitoneal and intracerebral injection with bovine spongiform encephalopathy (BSE) cow brain homogenate, SCID mice show a resistance to infection in comparison with immunocompetent CB20 mice. BSE occurred in only five out of 22 challenged SCID mice, with a mean incubation period of 573 days, whereas all the CB20 mice developed the disease with a mean incubation period of 456 days. In contrast, previous studies have shown that intracerebral infection of SCID mice with a mouse-passaged scrapie strain, ME7, produces 100% incidence of disease but no replication of infectivity in spleen. The results with BSE suggest that there is little or no direct infection of the CNS in interspecies transmissions, but that processing or replication of infectivity in peripheral lymphoid tissues may facilitate subsequent spread of infection to the CNS.

Integrin expression and function on human osteoblast-like cells

The integrin family of cell adhesion molecules are a series of cell surface glycoproteins that recognize a range of cell surface and extracellular matrix (ECM)-associated ligands. To date, the precise role of individual integrin molecules in bone cell-ECM interactions remains unclear. Cell binding assays were performed to examine the ability of normal human bone cells (NHBCs) to adhere to different ECM proteins in vitro. NHBCs displayed preferential adhesion to fibronectin over collagen types I, IV, and vitronectin and showed low affinity binding to laminin and collagen type V. No binding was observed to collagen type III. The integrin heterodimers alpha 1 beta 1, alpha 2 beta 1, alpha 3 beta 1, alpha 5 beta 1, alpha v beta 3, and alpha v beta 5 were found to be constitutively expressed on the cell surface of NHBCs by flow cytometric analysis. The integrins alpha 4 beta 1 and alpha 6 beta 1 were not expressed by NHBCs. Subsequent binding studies showed that NHBC adhesion to collagen and laminin was mediated by multiple integrins where cell attachment was almost completely inhibited in the presence of a combination of function-blocking monoclonal antibodies (Mabs) to alpha 1 beta 1, alpha 2 beta 1, alpha 3 beta 1, and beta 1. In contrast, the adhesion of NHBCs to fibronectin was only partially inhibited (50%) in the presence of blocking Mabs to alpha 3 beta 1, alpha 5 beta 1, and beta 1. The attachment of NHBCs to collagen, laminin, fibronectin, and vitronectin was also found to be unaffected in the presence of a function-blocking Mab to alpha v beta 3. The results of this study indicate that beta 1 integrins appear to be the predominant adhesion receptor subfamily utilized by human osteoblast-like cells to adhere to collagen and laminin and in part to fibronectin.

Cell type-specific expression in brain cell cultures from a short human cytomegalovirus major immediate early promoter depends on whether it is inserted into herpesvirus or adenovirus vectors

Expression from a short human cytomegalovirus (HCMV) major immediate early (IE) promoter-enhancer was tested in three different virus vectors: recombinant adenovirus (Ad), recombinant herpes simplex virus type 1 (HSV-1) and HSV-1-derived amplicon vectors. The HCMV major IE promoter-enhancer within a replication-deficient recombinant Ad vector was shown to produce cell-specific expression in rat nervous system cell cultures. Recombinant Ad entered all cell types examined but the HCMV major IE promoter was silent in primary cultures of neocortical neurons and Schwann cells, although it drove transgene expression in astrocytes and fibroblasts. Moreover, in neurons and Schwann cells, expression from the HCMV major IE promoter-enhancer in the replication-deficient Ad vector was activated by superinfection with HSV-1, replication-competent Ad and HCMV. The HCMV major IE promoter-enhancer was active in neurons when inserted into HSV-1 recombinant vectors. Further experiments with HSV-1-derived amplicons strongly suggested that an IE protein was responsible for the activation of HCMV major IE-induced expression in neurons. This demonstrates that the activity of the HCMV major IE promoter-enhancer element can depend on the expression of other genes encoded in the virus vector backbone within which it is inserted, and that it can function in a neuronal cell type-specific manner when inserted into a replication-deficient Ad vector.

Uptake of alpha-(L)-iduronidase produced by retrovirally transduced fibroblasts into neuronal and glial cells in vitro

The uptake of recombinant alpha-(L)-iduronidase into glial and neuronal cells, produced by retrovirally transduced NIH3T3 fibroblasts, was studied. We demonstrate that: (1) neuronal and glial cells take up alpha-(L)-iduronidase released into the medium by retrovirally transduced fibroblasts expressing high levels of alpha-(L)-iduronidase; (2) both glial and neuronal cells express the cation independent mannose-6-phosphate receptor responsible for lysosomal enzyme uptake; and (3) uptake of the lysosomal enzyme can be blocked by excess free mannose-6-phosphate, but not glucose-6-phosphate. Thus, various brain cells take up alpha-(L)-iduronidase, possibly through a cation independent mannose-6-phosphate receptor mediated pathway, and this uptake is higher in actively dividing or immature brain cells. Consequently, (1) neuronal metabolism ought to be capable of cross correction by enzyme provided by genetically engineered and transplanted cells provided by bone marrow transplantation (BMT); (2) that BMT could have a more beneficial effect on neurological function if performed as early as possible; and (3) given that the uptake mechanism of glial cells has a higher capacity, it might be easier to target diseases like the leukodystrophies in which lysosomal enzymes are needed in glial cells, compared to diseases where lysosomal enzymes ought to be delivered into neurons.

Role of Borrelia burgdorferi in the pathogenesis of morphea/scleroderma and lichen sclerosus et atrophicus: a PCR study of thirty-five cases

Morphea (localized scleroderma), and lichen sclerosus et atrophicus (LSA) share common features with acrodermatitis chronica atrophicans (ACA), a known chronic form of borreliosis. These include similar histologic findings such as diffuse dermal fibrosis. These observations have led several investigators to consider the possibility of Borrelia burgdorferi (Bb) as a common etiologic factor among all of these diseases. The aim of this study is to investigate the role of Bb in the pathogenesis of morphea and LSA, by assaying for its presence in lesional skin biopsies from patients with these diseases. We utilized the nested polymerase chain reaction (PCR) technique to selectively amplify a longer segment of a Bb-specific somatic gene, on DNA from paraffin-embedded, formalin-fixed tissues. The results revealed no Bb-specific DNA sequence in 28 specimens of morphea/scleroderma and 7 of LSA with varying stages of disease. Furthermore, confirmatory Southern blot of the PCR product, resulted in similar findings. These data seriously question the role played by this spirochete in the pathogenesis of morphea and LSA, at least in the southeastern part of the USA.

Replication of scrapie in spleens of SCID mice follows reconstitution with wild-type mouse bone marrow

SCID mice are resistant to intraperitoneal infection with 10(3) and 10(4) intracerebral ID50 units of ME7 scrapie agent whereas they develop disease after intracerebral challenge. However, higher doses introduced, by intraperitoneal or subcutaneous routes, produce disease. Immunocompetent mice of the same strain (CB20) developed scrapie following either intracerebral or intraperitoneal infection. Bioassay of spleens from SCID mice infected with 10(-1) dilutions of ME7 scrapie by intraperitoneal, intracerebral or abdominal subcutaneous injection showed traces or low levels of infectivity in spleen. However, subcutaneous injection beneath the skin of the neck failed to infect the spleen. CB20 bone marrow reconstitution of SCID mice resulted in the regeneration of a normal lymphoid architecture in the spleen. Spleens from these reconstituted mice, infected intracerebrally with a 10(-1) dilution of ME7 contained high levels of infectivity. These results suggest that the ability to replicate scrapie agent in spleen or lymphoid tissue depends on the restoration of normal lymphoid structure and in particular the presence of differentiated follicular dendritic cells. The possibility that SCID mice can select minor strains of scrapie which are normally unrecognized in cloned ME7 is discussed.