Artificial intelligence-based risk stratification of atrial fibrillation among women with peripartum cardiomyopathy compared to other cardiomyopathies

Background

Atrial fibrillation (AF) is diagnosed in up to 50% of patients with heart failure. However, the prevalence of AF among patients with peripartum cardiomyopathy (PPCM) ranges from only 2–10%, with the lowest rates in Black women. An artificial intelligence enhanced electrocardiogram (AI-ECG) has previously been shown to be effective in detecting AF while in sinus rhythm, and for AF risk prediction in a population-based study.

Purpose

Our objective was to evaluate the use of an AI-ECG for AF risk stratification among women of reproductive age (18 to 49 years) with PPCM compared to other forms of cardiomyopathy.

Methods

We identified 59 reproductive age women with a diagnosis of PPCM between January 2007, and October 2018 and included matched controls in a 3:1 fashion. Matching was performed based on sex, age, race, and left ventricular ejection fraction. We excluded patients with a diagnosis of AF prior to cardiomyopathy diagnosis date. AI-ECG prediction probabilities were generated for ECGs performed within a 30-day window prior to the patient's first cardiomyopathy diagnosis date for the entire study cohort.

Results

A total of 236 patients were included in the final analysis (59 cases, 177 controls). Overall, the median age at cardiomyopathy diagnosis was 31.7 years (IQR: 18.5, 49.4), 76.3% were White, 8.5% were Black, and 15.3% represented other or unknown race. Over the period studied, 3.4% of women with PPCM developed AF compared to 5.6% of women with other cardiomyopathies. The frequency of positive AI-ECG predictions for AF was more common among women with other cardiomyopathies (40.7%) compared to women with PPCM (20.3%). The predicted odds ratio for AF development following a cardiomyopathy diagnosis based on AI-ECG results was 0.37 (95% CI: 0.18, 0.73) for PPCM compared to other cardiomyopathies (p=0.006).

Conclusion

We demonstrated that an AI-ECG model for AF prediction may play a potential role in arrhythmia risk stratification/prediction among young women with PPCM who have a demonstrable lower risk for AF compared to women with other cardiomyopathies. Mechanisms for lower AF risk among patients with PPCM remain unknown. Further studies evaluating mechanistic pathways will be essential.

Funding Acknowledgement

Type of funding sources: None.

Detecting cardiomyopathies in pregnancy and the postpartum period using ECG

Background

Cardiovascular disease (CVD) has been identified as a major threat to maternal health in the US and UK with cardiomyopathy being one of the most common acquired CVD in the pregnant and postpartum period. Diagnosing cardiomyopathy in pregnancy is challenging due to an overlap of cardiovascular symptoms with normal pregnancy symptoms.

Purpose

The purpose of this study was to evaluate the effectiveness of an ECG based deep learning model in identifying cardiomyopathy among pregnant and postpartum women.

Methods

We utilized an ECG based deep learning model to detect cardiomyopathy in a cohort of pregnant or postpartum women seen at multiple hospital sites. Model performance was evaluated using area under the curve (AUC), accuracy, sensitivity, and specificity. We compared the diagnostic probabilities of the deep learning model with natriuretic peptides and a multivariable model consisting of demographic and clinical parameters.

Results

1,807 women were included. 7%, 10% and 13% had LVEF ≤35%, <45% and <50% respectively. The ECG based deep learning model identified cardiomyopathy with an AUC of 0.92 for left ventricular ejection fraction (LVEF) ≤35%, 0.89 for LVEF <45% and 0.87 for LVEF <50%. For LVEF ≤35%, AUC was higher in Black (0.95) and Hispanic (0.98) women compared to white (0.91). Natriuretic peptides and the multivariable model had AUCs of 0.85 and 0.72 respectively.

Conclusions

A deep learning model effectively identifies cardiomyopathy in pregnant or postpartum women, outperforms natriuretic peptides and traditional clinical parameters with the potential to become a powerful initial screening tool for cardiomyopathy in the obstetric care setting.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): This study was made possible using resources supported by the Mayo Clinic Women's Health Research Center and the Mayo Clinic Building Interdisciplinary Research Careers in Women's Health (BIRCWH) Program funded by the National Institutes of Health (NIH), grant number K12 HD065987. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

IL-10 production by CLL cells is enhanced in the anergic IGHV mutated subset and associates with reduced DNA methylation of the IL10 locus

Chronic lymphocytic leukemias (CLLs) with unmutated (U-CLL) or mutated (M-CLL) IGHV have variable features of immunosuppression, possibly influenced by those CLL cells activated to produce interleukin 10 (IL-10). The two subsets differ in their levels of anergy, defined by low surface immunoglobulin M levels/signaling capacity, and in their DNA methylation profile, particularly variable in M-CLL. We have now found that levels of IL-10 produced by activated CLL cells were highly variable. Levels were higher in M-CLL than in U-CLL and correlated with anergy. DNA methylation analysis of IL10 locus revealed two previously uncharacterized 'variably methylated regions' (CLL-VMRs1/2) in the gene body, but similarly low methylation in the promoter of both U-CLL and M-CLL. CLL-VMR1/2 methylation was lower in M-CLL than in U-CLL and inversely correlated with IL-10 induction. A functional signal transducer and activator of transcription 3 (STAT3) binding site in CLL-VMR2 was confirmed by proximity ligation and luciferase assays, whereas inhibition of SYK-mediated STAT3 activation resulted in suppression of IL10. The data suggest epigenetic control of IL-10 production. Higher tumor load may compensate the reduced IL-10 production in U-CLL, accounting for clinical immunosuppression in both subsets. The observation that SYK inhibition also suppresses IL-10 provides a potential new rationale for therapeutic targeting and immunological rescue by SYK inhibitors in CLL.

Outcome of elderly patients with diffuse large B-cell lymphoma treated with R-CHOP: results from the UK NCRI R-CHOP14v21 trial with combined analysis of molecular characteristics with the DSHNHL RICOVER-60 trial

BACKGROUND

There is an on-going debate whether 2- or 3-weekly administration of R-CHOP is the preferred first-line treatment for elderly patients with diffuse large B-cell lymphoma (DLBCL). The UK NCRI R-CHOP14v21 randomized phase 3 trial did not demonstrate a difference in outcomes between R-CHOP-14 and R-CHOP-21 in newly diagnosed DLBCL patients aged 19-88 years, but data on elderly patients have not been reported in detail so far. Here, we provide a subgroup analysis of patients ≥60 years treated on the R-CHOP14v21 trial with extended follow-up.

PATIENTS AND METHODS

Six hundred and four R-CHOP14v21 patients ≥60 years were included in this subgroup analysis, with a median follow-up of 77.7 months. To assess the impact of MYC rearrangements (MYC-R) and double-hit-lymphoma (DHL) on outcome in elderly patients, we performed a joint analysis of cases with available molecular data from the R-CHOP14v21 (N = 217) and RICOVER-60 (N = 204) trials.

RESULTS

Elderly DLBCL patients received high dose intensities with median total doses of ≥98% for all agents. Toxicities were similar in both arms with the exception of more grade ≥3 neutropenia (P < 0.0001) and fewer grade ≥3 thrombocytopenia (P = 0.05) in R-CHOP-21 versus R-CHOP-14. The elderly patient population had a favorable 5-year overall survival (OS) of 69% (95% CI: 65-73). We did not identify any subgroup of patients that showed differential response to either regimen. In multivariable analysis including individual factors of the IPI, gender, bulk, B2M and albumin levels, only age and B2M were of independent prognostic significance for OS. Molecular analyses demonstrated a significant impact of MYC-R (HR = 1.96; 95% CI: 1.22-3.16; P = 0.01) and DHL (HR = 2.21; 95% CI: 1.18-4.11; P = 0.01) on OS in the combined trial cohorts, independent of other prognostic factors.

CONCLUSIONS

Our data support equivalence of both R-CHOP application forms in elderly DLBCL patients. Elderly MYC-R and DHL patients have inferior prognosis and should be considered for alternative treatment approaches.

TRIAL NUMBERS

ISCRTN 16017947 (R-CHOP14v21); NCT00052936 (RICOVER-60).

Ex vivo assays of dendritic cell activation and cytokine profiles as predictors of in vivo effects in an anti-human CD40 monoclonal antibody ChiLob 7/4 phase I trial

Immunostimulatory antibodies entering the clinic create challenge in terms of not only pharmacodynamics for monitoring anticipated mechanisms but also predetermining cytotoxicity. We show the use of ex vivo whole-blood samples to predict the activation requirements, cytokine signature, and adverse events of an anti-human-CD40 chimeric IgG1 antibody, ChiLob 7/4. Assessments were initially undertaken on human myeloid (mDC1) and plasmacytoid (pDC) dendritic cells, in which an absolute need for cross-linking was shown through the upregulation of activation markers CD83 and CCR7. Subsequent cytokine secretion evaluations of ex vivo whole blood showed the cross-linked antibody-induced increases in MIP1β, interleukin (IL)-8, IL-12, TNFα, and IL-6. This cytokine signature compared favorably with the Toll-like receptor (TLR) ligand lipopolysaccharide (LPS), in which levels of TNFα and IL-6 were significantly higher, suggesting a less intense proinflammatory response and possible modified cytokine release syndrome when used in human trials. Following first-in-human use of this agent within a dose escalation study, in vivo evaluations of dendritic cell activation and secreted cytokines closely matched the predetermined immunomonitoring endpoints. Patients showed a comparable pattern of MIP1β, IL-8, and IL-12 secretion, but no TNFα and IL-6 were identified. Mild symptoms relating to a cytokine release syndrome were seen at an equivalent dosage to that observed for dendritic cell activation and cytokine release. In summary, ChiLob 7/4 induces a distinctive pattern of dendritic cell activation and cytokine secretion in ex vivo assays that can be predictive of in vivo responses. Such preclinical approaches to monoclonal antibody evaluation may inform both the starting dosages and the anticipated cytokine release events that could occur, providing a valuable adjunct for future first-in-human assessments of immunostimulatory antibodies.

Defects in lymphocyte subsets and serological memory persist a median of 10 years after high-dose therapy and autologous progenitor cell rescue for malignant lymphoma

The number of survivors having undergone high-dose therapy (HDT) followed by auto-SCT continues to increase, although some of the long-term sequelae remain incompletely understood. The immunological status and quality of life of 37 HDT/auto-SCT survivors with lymphoma in continuous remission of ≥3 years were assessed alongside 14 age-matched controls. At a median follow-up of 10.5 years (range 2.2-20.2) following HDT/auto-SCT, the proportion of CD4(+) cells remained significantly reduced in patients compared with controls (median 43.4% vs 62.5%, respectively; P = < 0.001), predominantly a result of sustained reduction in the naive CD4(+) component (P < 0.001). Naive CD8(+) lymphocytes (P = 0.014) and transitional B cells (P = 0.008) were also significantly reduced, but differences in other lymphocyte subsets were not observed. Uptake of revaccination following HDT/auto-SCT was sporadic; between 11% and 33% of patients had serological titres outside the protective ranges for five of six routinely used vaccines. In the main, patients were found to have a good quality of life, although their EORTC QLQ-C30 questionnaire scores were significantly lower for the physical and social functioning domains compared with controls. Ten years after HDT/auto-SCT immunological deficits persist; to avoid excess risk of preventable disease, serological immunity should be assessed post HDT/auto-SCT followed by appropriate revaccination.

Observed differences in upper extremity forces, muscle efforts, postures, velocities and accelerations across computer activities in a field study of office workers

This study, a part of the PRedicting Occupational biomechanics in OFfice workers (PROOF) study, investigated whether there are differences in field-measured forces, muscle efforts, postures, velocities and accelerations across computer activities. These parameters were measured continuously for 120 office workers performing their own work for two hours each. There were differences in nearly all forces, muscle efforts, postures, velocities and accelerations across keyboard, mouse and idle activities. Keyboard activities showed a 50% increase in the median right trapezius muscle effort when compared to mouse activities. Median shoulder rotation changed from 25 degrees internal rotation during keyboard use to 15 degrees external rotation during mouse use. Only keyboard use was associated with median ulnar deviations greater than 5 degrees. Idle activities led to the greatest variability observed in all muscle efforts and postures measured. In future studies, measurements of computer activities could be used to provide information on the physical exposures experienced during computer use. Practitioner Summary: Computer users may develop musculoskeletal disorders due to their force, muscle effort, posture and wrist velocity and acceleration exposures during computer use. We report that many physical exposures are different across computer activities. This information may be used to estimate physical exposures based on patterns of computer activities over time.

Developing a framework for assessing muscle effort and postures during computer work in the field: the effect of computer activities on neck/shoulder muscle effort and postures

The present study, a part of the PROOF (PRedicting Occupational biomechanics in OFfice workers) study, aimed to determine whether trapezius muscle effort was different across computer activities in a field study of computer workers, and also investigated whether head and shoulder postures were different across computer activities. One hundred twenty participants were measured continuously for two hours each while performing their own computer work. Keyboard activities were associated with the highest intensity of left and right trapezius muscle efforts, and mouse activities were associated with the smallest variability in left and right trapezius muscle efforts. Corresponding trends in head and shoulder postures included that the greatest head flexion and left and right shoulder internal rotation was observed during keyboard activities, and that the smallest variability in head flexion, head lateral tilt, and right shoulder internal rotation was observed during mouse activities. Identifying which muscle efforts and postures are different across computer activities is the first essential step for developing prediction rules for muscle efforts and postures, which can be used to link muscle efforts and postures to musculoskeletal symptoms in epidemiological studies.

Development, validation and application of ELISAs for pharmacokinetic and HACA assessment of a chimeric anti-CD40 monoclonal antibody in human serum

As part of a Phase I chimeric anti-CD40 monoclonal antibody clinical trial, two enzyme-linked immunosorbent assays (ELISAs) were developed for secondary endpoints: 1) for the pharmacokinetic (PK) monitoring of serum antibody levels and 2) for immunogenic screening of human anti-chimeric antibody (HACA) responses. The ELISA is a well established immunoassay, with clear guidelines for validation when used as a quantitative assay. However, these parameters may not always be relevant for a semi-quantitative assay used to assess whether a sample is positive or negative for a novel marker such as an antibody developed against a therapeutic antibody. We report here the development of a quantitative PK ELISA and a semi-quantitative HACA ELISA, and the different approaches of validation to prove each assay are 'fit for purpose.' The parameters of linearity (R²>0.99), accuracy (±30%), lowest level of detection (4 μg/ml), intra-assay (coefficient of variation (CV) <20%) and inter-assay (CV<20%) variability were assessed for the quantitative PK assay. For the semi-quantitative HACA assay, parameters of linearity (R²>0.99), lowest level of detection, intra (CV<10%) and inter-assay (CV<30%) variability were assessed using a surrogate positive control. The validation outcome showed that each assay was robust, reliable and accurate to meet the requirements of the intended analytical application, that being to 1) quantitatively determine the concentration of antibody in the serum and 2) determine whether a sample is positive or negative for human anti-chimeric antibodies. Each assay has been successfully translated for use in a clinical trial with adequate quality controls and acceptance criteria set for monitoring consistency and performance.

Dissolved organic matter and heterotrophic microneuston in the surface microlayers of the north atlantic

Dissolved organic carbon, carbohydrates, and adenosine triphosphate in the size fractions 0.2 to 3 micrometers and 3 to 1000 micrometers are significantly enriched in the upper 150-micrometer surface layer compared to subsurface water, mean enrichment factors being 1.6, 2.0, 2.5, and 3.1, respectively. When calculated as a 0.1-micrometer microlayer of wet surfactants, the mean concentration of organic matter was 2.9 grams per liter, of which carbohydrates accounted for 28 percent. The data for plant pigments and particulate adenosine triphosphate indicated that bacterioneuston was enriched at seven of nine stations while phagotrophic protists were enriched at five stations. Instances of enrichment and inhibition were verified by cultural data for bacteria and amoebas. The observations indicate that the surface microlayers are largely heterotrophic microcosms, which can be as rich as laboratory cultures, and that an appreciable part of the dissolved organic carbon is carbohydrate of phytoplankton origin, released and brought to the surface by migrating and excreting phagotrophic protists.

Low mean level sustained and intermittent grip exertions: influence of age on fatigue and recovery

The goal of this study was to quantify localised muscle fatigue resulting from low mean levels of exertion in younger (< 40 years) and older (> 50 years) adults. Fatigue, elicited in the finger flexor muscles by intermittent (10% mean maximum voluntary contraction (MVC)) and sustained (8% MVC) handgrip exercises, was quantified by a muscle twitch force response before, immediately after and during 3 h following exercise. Despite greater mean loads, recovery time was shorter following intermittent than sustained contractions, which suggests that recovery from fatigue is more sensitive to rest within the work cycle than mean work. The more pronounced effects for younger than older individuals following the sustained exertion indicate that changes in muscle fibre type composition might predispose older individuals to be more resistant to fatigue resulting from sustained contractions of low level. Performing hand exertion tasks requiring low mean force levels contributes to similar long-lasting fatigue effects regardless of gender and age. Intermittent periods of complete rest reduce muscle fatigue. Since fatigue was not perceived during recovery from the tested sustained and intermittent contractions, subjective evaluations may not be a reliable indicator of localised muscle fatigue.

Low-dose lenograstim is as effective as standard dose in shortening neutrophil engraftment time following myeloablative chemotherapy and peripheral blood progenitor cell rescue

Granulocyte colony-stimulating factor (G-CSF) is widely used following myeloablative chemotherapy (high-dose therapy; HDT) and peripheral blood progenitor cell rescue (PBPCR) to reduce neutrophil engraftment time. The dose and duration required to gain maximum clinical and economic benefit has not been fully investigated. This double blind placebo-controlled randomised trial was performed to determine whether short course low-dose or standard-dose Lenograstim (L) would influence recovery of haematopoiesis following HDT and PBPCR. Sixty-one patients were randomised between May 1999 and November 2004, to receive standard-dose lenograstim (263 microg/d), low-dose lenograstim (105 microg/d) or placebo injections. These commenced on day +5 following PBPCR and continued until neutrophil engraftment [absolute neutrophil count (ANC)] > or = 0.5 x 10(9)/l. Patients received standard supportive care until haemopoietic recovery. Both standard- and low-dose lenograstim resulted in a significantly shorter median time to neutrophil recovery (ANC > or = 0.1 x 10(9)/l:10.0 vs. 11.0 d, P = 0.025; ANC > or = 0.5 x 10(9)/l:11.0 vs. 14.0 d, P = 0.0002) compared with placebo. There was no significant difference in blood product support, antibiotic usage, documented infection, overall survival or relapse-free survival between the groups. Short course low-dose lenograstim is as effective as standard-dose in reducing neutrophil engraftment time following HDT and PBPCR.

Randomised, placebo-controlled, trial comparing low dose versus standard dose Lenograstim (L) following myeloablative chemotherapy (HDT) and peripheral blood progenitor cell rescue (PBPCR) for lymphoma

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Background: This trial was performed to determine whether low-dose or standard dose L would influence recovery of haematopoiesis following HDT and PBPCR. Methods: 61 patients (pts) with non-Hodgkin lymphoma (40) or Hodgkin’s disease (21) undergoing HDT were randomised. Pts had normal peripheral blood counts prior to HDT (Hb ≥100g/L, total white cell count ≥ 3.0, neutrophils (N) ≥ 1.0 and platelets ≥ 50, and had a minimum 2.5 million CD34+ cells/kg PBPC previously collected following mobilisation with Cyclophosphamide 3g/m2 and G-CSF. All received HDT with BCNU 300mg/m2 d-7, Etoposide 200mg/m2 od d-5-d-2, Cytosine arabinoside 200mg/m2 bd d-5-d-2 and Melphalan 140mg/m2 d-1 before return of PBPC on D0. Pts were allocated standard dose L 263mcg daily (20 pts), low dose L 105mcg daily (21 pts) or placebo injections (20 pts). These commenced on day +5 following PBPCR and continued until N≥0.5. Pts received standard supportive care including prophylactic Fluconazole and Acyclovir, but not routine antibacterial prophylaxis, until haemopoietic recovery. Results: L at any dose resulted in a significantly shorter median time to N recovery ≥0.1 (10.0 vs 11.0 days, P=0.02) and ≥0.5 (11.0 vs 14.0 days, p=0.0003) compared to placebo. The only significant difference between standard- and low-dose L was in hospital stay (21.0 vs 22.0 days, p=0.04), however L at any dose showed a significant reduction over placebo (22.0 vs 23.0 days, p=0.01). Conclusions: Short course low dose L is as effective as standard dose in reducing neutrophil engraftment time following HDT and PBSCR. L at any dose reduces hospital stay when compared to placebo. This approach should be considered for those patients in whom growth factor support is indicated. Long-term follow-up data will be presented.

[Table: see text]

No significant financial relationships to disclose.

Pharmacokinetics of intravenous azithromycin and ceftriaxone when administered alone and concurrently to healthy volunteers

This study was conducted to identify whether or not a pharmacokinetic interaction existed when azithromycin and ceftriaxone were administered concurrently. This randomized, open-label, three-way crossover study in 12 healthy volunteers characterized the plasma pharmacokinetic parameter profiles of both drugs, as well as the white blood cell uptake and exposure to azithromycin, when the drugs were administered alone and together. The plasma pharmacokinetic parameters for azithromycin and ceftriaxone did not differ significantly either after a single dose or at steady state when the two were co-administered as opposed to being administered alone. Moreover, the neutrophil and monocyte/lymphocyte peak azithromycin concentrations and sampling period exposures also did not differ significantly between the study arm and the control arm. This study confirms that there is no interaction between azithromycin and ceftriaxone when they are administered concurrently.

Influence of time pressure and verbal provocation on physiological and psychological reactions during work with a computer mouse

The overall aim of this study was to investigate whether time pressure and verbal provocation has any effect on physiological and psychological reactions during work with a computer mouse. It was hypothesised that physiological reactions other than muscle activity (i.e. wrist movements, forces applied to the computer mouse) would not be affected when working under stressful conditions. Fifteen subjects (8 men and 7 women) participated, performing a standardised text-editing task under stress and control conditions. Blood pressure, heart rate, heart rate variability, electromyography, a force-sensing computer mouse and electrogoniometry were used to assess the physiological reactions of the subjects. Mood ratings and ratings of perceived exertion were used to assess their psychological reactions. The time pressure and verbal provocation (stress situation) resulted in increased physiological and psychological reactions compared with the two control situations. Heart rate, blood pressure and muscle activity in the first dorsal interosseus, right extensor digitorum and right trapezius muscles were greater in the stress situation. The peak forces applied to the button of the computer mouse and wrist movements were also affected by condition. Whether the increases in the physiological reactions were due to stress or increased speed/productivity during the stress situation is discussed. In conclusion, work with a computer mouse under time pressure and verbal provocation (stress conditions) led to increased physiological and psychological reactions compared to control conditions.

Comparison of measurement accuracy between two types of wrist goniometer systems

Studies have shown that wrist goniometers are prone to measurement errors, particularly due to crosstalk. This study compared two wrist goniometer systems: a commonly used biaxial, single transducer (System A) and a biaxial, two-transducer (System B). Wrist angles, range of movement and crosstalk results were compared. With the wrist in 90 degrees of pronation, eight subjects were placed in 20 different wrist postures between -40 degrees and 40 degrees of flexion/extension and between -10 degrees and 20 degrees of deviation. Relative to System B, System A had larger measurement errors and was more prone to crosstalk. There may be two sources of crosstalk: (1) intrinsic crosstalk associated with the design, application and twisting of the goniometer transducer when on the wrist, and (2) extrinsic crosstalk associated with the anatomy and complex movement of the wrist joint. It appears that the majority of the radial/ulnar crosstalk measured with System A was intrinsic crosstalk due to the twisting of the goniometer transducer.

Development and application of a quantitative, specific assay for Cryptosporidium parvum oocyst detection in high-turbidity environmental water samples

Chlorine-resistant Cryptosporidium parvum oocysts in drinking water play an important role in the epidemiology of cryptosporidiosis. Current methods of detecting these organisms in water are insensitive, labor-intensive, highly subjective, and severely limited by sample turbidity. We describe here an alternative technique utilizing electrochemiluminescence (ECL) technology for detecting C. parvum oocysts in environmental water samples. This method is quantitative, reproducible, and requires only minimal sample processing. Currently, the ECL assay can detect as few as one oocyst in one milliliter of concentrated test sample with sample turbidity of up to 10,000 nephelometric turbidity units. Water and sewer samples collected during a cryptosporidiosis outbreak were tested by ECL assay. Cryptosporidium parvum oocysts were found in the source water at the time of outbreak, and a sharply decreasing level of oocysts in sewer samples was observed over a three-month period following the outbreak.

The therapeutic use of antibodies for malignancy

The idea of using the specificity of antibodies to target malignant cells was put forward very soon after the discovery of techniques to generate monoclonal reagents. The responses seen with mouse anti-idiotype in patients with B-cell lymphomas indicated the potential of this approach, but it was some years before key technical obstacles were overcome and the more widespread application of these therapies became possible. Whilst they were originally conceived as having an immunotherapeutic effect, it has become clear that recruitment of immune effectors is only one component of successful antibody therapy, and their action upon the cellular target, either blocking or agonistic, is also critical. The development of immunoconjugates to deliver toxins or radiation is a further extension of the approach, and here again the intracellular effect of antibody ligation appears to be crucial. This presentation will address the central theme of antibody treatments for malignancy that are now reaching the clinic, and will use these examples to highlight ways in which antibodies may be acting in vivo.

A randomized trial of amifostine as a cytoprotective agent in patients receiving chemotherapy for small cell lung cancer

A randomized trial was conducted to determine whether administration of Amifostine with chemotherapy for small cell lung cancer could decrease the toxicity. 84 patients with small cell lung cancer of favourable prognosis (limited disease, performance status 0-1; limited disease with performance status 2 but normal sodium and alkaline phosphatase, or extensive disease with performance status 0-1, normal sodium and alkaline phosphatase) received treatment with Ifosfamide 3 g/m(2)intravenously, Carboplatin (Glomerular filtration rate + 25) x6 mg intravenously, Etoposide 50 mg orally, twice daily, for 7 days, every 3 weeks. Patients were randomized to receive amifostine 740 mg/m(2)immediately prior to the intravenous drugs (n = 42) or to receive chemotherapy alone (n = 42). The two groups were similar with respect to baseline prognostic factors. There was no significant difference in the occurrence of grade III or IV neutropenia or thrombocytopenia between the two groups, nor in the response rate or overall survival, for which the median was 11 months in the chemotherapy only group and 14 months in the group treated with amifostine. This study has not shown a protective effect from the use of amifostine with this regimen and there does not appear to be any effect upon the efficacy of treatment.

Persistence of clonal T-cell expansions following high-dose chemotherapy and autologous peripheral blood progenitor cell rescue

Analysing the regeneration of T lymphocytes after high-dose chemotherapy with autologous peripheral blood progenitor cell rescue (PBPCR) may help elucidate the mechanisms of immune recovery. The T-cell receptor variable beta chain (TCRBV) repertoire of adult patients undergoing high-dose chemotherapy was analysed by flow cytometry, before and after treatment. Four patients were found to have a stable expansion present (TCRBV3, 17, 21 and 22) ranging from 8% to 42% of the CD4(+) or CD8(+) repertoire. We demonstrated that, in these patients, following high-dose chemotherapy and autologous stem cell transplantation, the clonal expansions reappeared in peripheral blood and returned to pretransplant levels. Three expansions (CD3(+)CD8(+)TCRBV3(+), CD3(+)CD4(+)TCRBV21(+) and CD3(+)CD8(+)TCRBV22(+)) were further defined by sequence analysis of the complementarity-determining region (CDR)3 portion within the TCR rearrangements. These were shown to be predominantly clonal, with the same sequences being identified in peripheral blood before and after PBPCR, providing evidence that the overwhelming majority of T cells in these expansions arise from mature lymphocytes. This study demonstrated that patients undergoing autologous PBPCR for high-dose chemotherapy regenerate clonal expansions, consistent with pretreatment levels. They also regenerate T-cell repertoires with each TCRBV family represented to a similar level as that prior to high-dose chemotherapy.

Identification of a novel human BCL-X promoter and exon

BCL-XL is a key anti-apoptotic BCL-2 family protein that is widely expressed in human cancer cells and is induced in response to diverse survival signals. The translation initiation codon for BCL-XL is located in BCL-X exon II and previous analyses have indicated that BCL-XL RNAs initiate close to the start of exon II or additionally contain a non-coding first exon (exon IA) spliced to exon II. Using 5' RACE we have now identified a novel BCL-X non-coding exon (exon IB) which is spliced directly to exon II in place of exon IA. Exon IB-containing RNAs encoded BCL-XL and were detected in non-malignant lymphocytes and lymphoma cells from lymph node biopsies and were expressed at significant levels in cell lines derived from ovarian, colon and breast cancers. We identified two TATA-box sequences upstream of exon IB and demonstrated that surrounding genomic sequences contained strong promoter activity in lymphoma cells (approximately 300-fold active relative to controls). We have therefore identified a powerful new BCL-X promoter and a novel exon that contributes to BCL-XL expression.

Measuring and characterizing force exposures during computer mouse use

OBJECTIVES

The purpose of this study was to develop and validate a sampling strategy for characterizing the finger force exposures associated with computer mouse use.

METHODS

Mouse forces were measured from 16 subjects (8 men, 8 women), on 3 separate days, at their actual workstations while they performed (i) their regular work, (ii) a battery of standardized tasks, and (iii) simulated mouse use.

RESULTS

The forces applied to the mouse did not vary between hours or days. During regular work, the mouse was used 78.0 (SD 40.7) times per hour, accounting for 23.7 (SD 9.5)% of the worktime. The mean forces applied to the sides and button of the mouse were low, averaging 0.6 % (0.35 N) and 0.8 % (0.43 N) of the maximal voluntary contraction, respectively. The forces applied to the mouse during the standardized tasks differed from the regular work forces; however, there were moderate-to-strong correlations between the 2 measures.

CONCLUSIONS

With respect to performing exposure assessment studies, the 3 major findings were (i) mouse force measurements should be made while subjects perform their actual work in order to characterize the absolute applied force accurately, (ii) the forces applied to the mouse during the performance of a short battery of standardized tasks can be used to characterize relative exposure and identify computer operators or work situations for which higher forces are applied to the mouse, and (iii) subjects cannot accurately simulate mouse forces.

Differences between work methods and gender in computer mouse use

OBJECTIVES

The aim of this study was to investigate whether gender or different methods of operating a computer mouse have an effect on performance and musculoskeletal load in the use of a computer mouse.

METHODS

Thirty experienced computer mouse users, 15 men and 15 women, participated in the study. Electromyography (right first dorsal interossei, right extensor digitorum and right and left trapezius), a force-sensing mouse, and subjective ratings were used to register muscular load. An electrogoniometer was used to register the wrist movements. The subjects worked with 3 different methods, their own, a wrist-based method and an arm-based method. Gender comparisons were made when the subjects used their own method.

RESULTS

The women worked with greater extension and range of motion and tended to work with a greater ulnar deviation of the wrist. They also applied higher forces to the mouse when expressed as a percentage of a maximum voluntary contraction and had higher muscular activity in the right extensor digitorum. When using the arm-based method, the subjects worked with greater wrist extension, had higher muscular activity in the right and left trapezius muscles, and had the highest ratings of perceived exertion in the neck and shoulder. The wrist-based method resulted in higher forces being applied to the sides of the mouse and the highest ratings of perceived exertion in the wrist and hand-fingers.

CONCLUSIONS

Gender differences were found for musculoskeletal load, and for most of the measured variables the women worked with higher loads than the men. The work method affected performance and musculoskeletal load. Finally, subjective measures appeared to have some utility in characterizing muscular load.

Positive and negative selection to reduce tumour contamination in peripheral blood stem cell harvests

Peripheral blood progenitor cells used during high dose treatments for malignancy may be contaminated with tumour cells that could later contribute to recurrence. CD34+ selected harvests still contain tumour cells and an additional negative selection may be capable of reducing this contamination. We have assessed a two-stage technique in which a CD34+ selection is followed by a tumour specific depletion stage using a B cell or breast cancer specific antibody panel. Initial small-scale selections on 11 patients with NHL and breast cancer showed that cell loss was greatest following the CD34+ selection with a median yield of 38.8 per cent (range 17. 2-56.4 per cent). The addition of the depletion stage resulted in a minimal loss of CD34+ cells with a yield for this step of 94.2 per cent (range 77.5-99.3 per cent). Clinical scale selections were performed on seven patients with CLL and a median of 2.8x10(6)/kg CD34+ cells (range 1.5-6.1x10(6)/kg) were collected. Cell recovery was 53.3 per cent following CD34+ selection and 76.9 per cent following the tumour specific depletion stage, resulting in a final product containing a median of 1.0x10(6)/kg CD34+ cells (range 0. 55-2.0x10(6)/kg). All unmanipulated harvests were heavily contaminated with tumour cells (median contamination 10.2 per cent, range 2.0-83.1 per cent) as measured by flow cytometry and a median 4.7 log (range 3-5 log) tumour cell purge was produced following two-stage selection. Six of the patients have received cells manipulated in this way with median engraftment times of neutrophils>0.5x10(9)/l=16 days (range 13-20 days) and platelets>20x10(9)/l=16.5 days (range 11-42 days). At a median follow-up of 25 months, these transplanted patients remain well and in molecular complete remission.

Clinical trials of antibody therapy

Much of the 25 years since Kohler and Milstein first described making monoclonal antibodies (mAbs) has been spent trying to develop these reagents to treat human disease. Until recently, progress has been frustratingly slow and by 1994 only one mAb, anti-CD3 (OKT3), had been licensed for clinical use. In the past five years, however, the situation has changed dramatically, with numerous mAbs now showing clinical potential, and a further seven approved for human treatment. Furthermore, all indications are that this upward trend will continue, with a quarter of all new biological products currently undergoing clinical development being antibody based.

A phase II study to evaluate the combination of fludarabine, mitoxantrone and dexamethasone (FMD) in patients with follicular lymphoma

BACKGROUND

'Molecular response' is being investigated as a therapeutic goal in follicular lymphoma (FL). High response rates in FL with the fludarabine combination 'FMD' have been associated with 'molecular remission'. A phase II study of FMD in FL was therefore conducted.

PATIENTS AND METHODS

Fifty-four patients, ten of whom were newly diagnosed received FMD. Forty-four percent of the previously treated patients had 'chemoresistant' disease. Treatment comprised: fludarabine 25 mg/m2 days 1-3, mitoxantrone 10 mg/m2 day 1, and dexamethasone 20 mg days 1-5. Blood/bone marrow was collected for quantitation of t(14;18) by 'real-time' PCR.

RESULTS

The overall response rate was 37 of 54 (69%), complete responses being seen in 11 patients (20%), with no difference between newly diagnosed and the previously treated patients. However, the response rate in 'chemosensitive' relapse was 84% compared to 44% in patients in whom the last prior regimen had failed. Molecular responses were seen in 17 of 25 and PCR negativity in 8 of 25, although molecular and clinical responses did not always correlate. Toxicity was moderate, 19 patients required admission. However, in 6 of 12 patients, subsequent G-CSF mobilised stem cell harvests failed.

CONCLUSIONS

FMD was well tolerated but with a lower than expected response rate. Molecular responses were seen in the majority of responding patients however, 'molecular remission' was rare.

A UK multicentre phase II study of rituximab (chimaeric anti-CD20 monoclonal antibody) in patients with follicular lymphoma, with PCR monitoring of molecular response

Follicular lymphoma (FL) cells express CD20 and are associated in most cases with the t(14;18) chromosomal translocation. A multicentre study was undertaken between January 1997 and January 1998 to assess the complete response rate (CR) and overall response rate (RR) to rituximab, a chimaeric anti-CD20 monoclonal antibody. Seventy patients with previously treated FL received rituximab (375 mg/m2/week x4, by intravenous infusion). Restaging studies were performed 1 and 2 months after therapy. Molecular monitoring for the presence of cells harbouring the Bcl-2/JH gene rearrangement in the peripheral blood (PB) and bone marrow (BM) was performed before and after treatment using a two-step semi-nested polymerase chain reaction (PCR) assay. The overall RR was 32/70 (46%), being highest in patients who had received only one previous treatment (12/15, 80%). However, only two patients achieved a CR. The median duration of response was 11 months. Thirteen of 21 evaluable 'PCR-positive' patients (62%) became 'PCR-negative' in PB and/or BM samples 1 month after rituximab, although this did not correlate with clinical response. Treatment was generally well tolerated, although one patient developed Stevens-Johnson syndrome. Rituximab was shown to be active in FL, and in some cases PB and/or BM became PCR negative. Studies in combination with cytotoxic chemotherapy to increase the CR rate are warranted.

Treatment of mantle-cell lymphoma with Rituximab (chimeric monoclonal anti-CD20 antibody): analysis of factors associated with response

BACKGROUND

A retrospective analysis was performed to delineate the factors associated with response, and to determine the duration of response, in 87 patients with CD20-positive mantle-cell lymphoma (MCL) treated with Rituximab (chimeric monoclonal anti-CD20 antibody) in two prior studies.

PATIENTS AND METHODS

Patients with newly-diagnosed MCL (MCL1, n = 37), and previously-treated MCL (MCL2, n = 50), received single-agent Rituximab, in the context of two multicentre clinical studies using different schedules and doses, conducted in 1996 and 1997. A follow-up analysis was performed at the end of 1998, including all 81 patients who completed therapy. Statistical modeling of factors associated with response was performed using ordered logistic regression. The duration of complete (CR) and partial response (PR), and the time to disease progression (TTP), were also derived.

RESULTS

The overall response rate (RR) was 34% (30 of 87) (81 evaluable patients, RR 37%; CR 14%), and was equivalent for MCL1 and MCL2. On univariate analysis, elevated LDH (P = 0.004); prior therapy with alkylating agents (P = 0.01) or fludarabine phosphate (P = 0.04); WHO performance status = 2 (P = 0.02); MCL2 refractory to last prior therapy (P = 0.04); and splenomegaly (P = 0.04), each at the time of treatment with Rituximab, were significantly associated with a lower RR. On multivariate analysis, only LDH (P = 0.007) and prior alkylating agents (P = 0.03) retained statistical significance. At a median follow-up of 1.4 years, the median TTP was 7 months. The median duration of response was one year, and was significantly longer for patients achieving CR vs. PR (P = 0.04).

CONCLUSIONS

Rituximab is active in MCL, and can induce complete responses in a minority of patients. Elevated LDH at the time of therapy, and prior therapy with alkylating agents, are associated with a significantly lower RR. The duration of response of one year is similar to that previously reported in follicular lymphoma.

FLUDAP: salvage chemotherapy for relapsed/refractory aggressive non-Hodgkin's lymphoma

The aim of this study was to investigate the combination of fludarabine phosphate, dexamethasone, cytosine arabinoside and cis-platinum (FLUDAP) in the treatment of patients with relapsed/refractory aggressive non-Hodgkin's lymphoma (NHL). This regimen comprises: dexamethasone 100 mg/d continuous infusion (cont. inf.) d1-3; cytosine arabinoside (ara-C) 1 g/m2/d cont. inf. d 2,3; fludarabine phosphate 30 mg/m2 short inf. 4hr prior to each 24hr ara-C inf.; cis-platinum 50 mg/m2 4hr inf. at the start of each 24hr ara-C inf. G-CSF (lenograstim, Granocyte) is given at 263 microg s.c. daily from day 7 until the neutrophil count reaches 1.0x10(9)/l. The regimen repeats at 21 day intervals. A total of 33 patients were registered (median age 47 years; 24 males, 9 females); the majority (73%) were refractory to their previous treatment and most had advanced disease by Ann Arbor stage. Thirteen (39%) of the 33 enrolled patients (52% of the 25 fully evaluable patients who received at least 2 courses of FLUDAP) responded to treatment. A maximum response of complete remission was achieved in 5 patients, good partial remission in 3, and partial remission in 5. Twelve patients went on to successful stem cell supported intensification therapy. Median survival times were higher in the responding patients, and in those patients transplanted post-FLUDAP. The toxicity associated with the FLUDAP regimen was generally predictable; frequently reported severe events included haematological toxicity and infection. In conclusion, the FLUDAP regimen shows promise as a salvage regimen and increases the available therapeutic options in the treatment of recurrent/refractory aggressive NHL.

Autologous stem cell transplantation for malignancy: a systematic review of the literature

A systematic review of the literature was undertaken to assess what published evidence is currently available to support the increasing use of autologous stem cell transplantation (ASCT), and to evaluate the published data with regard to the comparative cost of high-dose and conventional therapy. The review aimed to identify all published, randomized controlled trials (RCTs) comparing high-dose therapy (HDT) with ASCT versus conventional chemotherapy (CC) in acute lymphoblastic leukaemia, non-Hodgkin's lymphoma, Hodgkin's disease, multiple myeloma, and breast, lung, testicular and ovarian cancer. The review also aimed to identify all studies that had compared the cost of the two treatment strategies. Reports were identified by systematic searches of Cancerlit, Embase and Medline, and handsearching of several conference proceedings. Where possible, pooled odds ratios (ORs) were calculated according to the fixed-effect model. A total of 18 randomized trials were identified in acute lymphoblastic leukaemia, non-Hodgkin's lymphoma, Hodgkin's disease, multiple myeloma, and breast, lung and testicular cancer. Trials were generally small and no disease site had sufficient information to determine reliably whether high-dose therapy with autologous transplant is more effective than CC. Five studies were identified that compared the cost of the two treatments. These found the cost of HDT to be between one and four times higher than that of CC. Further randomized trials are required. Where appropriate, these should include economic assessment and assessments of long-term toxicity.

Biomechanical analyses of paramedics simulating frequently performed strenuous work tasks

Firefighters performing emergency rescue functions are at an elevated risk of musculoskeletal injuries. The objective of the current study was to analyze the biomechanical stresses placed on the body based on simulations of the following strenuous and frequently performed emergency rescue tasks: (1) transferring a patient from a bed to a stretcher using bedsheets, (2) transferring a patient from the ambulance stretcher to a hospital gurney, (3) carrying a victim down a set of stairs and through a landing using a stairchair, (4) carrying a victim down a set of stairs and through a landing using a backboard, and (5) carrying a victim down a straight set of stairs using a stretcher. Postural data were analyzed using the University of Michigan's Three-Dimensional Static Strength Prediction Program and the relative risk of low back disorder (LBD) was quantified using the trunk motion model published by Marras et al. (1993, spine 18, 617-628). Peak compression values and the probabilities from the Marras et al. (1993) model indicated that the most hazardous tasks performed as part of this simulation included pulling a victim from a bed to a stretcher, the initial descent of a set of stairs when using the stretcher, and lifting a victim on a backboard from the floor. Overall, the two models were well correlated in their assessment of the task components modelled (r = 0.78). These data indicate where engineering changes to equipment regularly used by emergency rescue personnel would have the greatest impact in reducing the risk of musculoskeletal injury.

Postural analysis of paramedics simulating frequently performed strenuous work tasks

Paramedics who perform emergency rescue functions are highly susceptible to musculoskeletal injuries. Through an interview and survey process firefighters, many of whom are cross-trained paramedics in a consortium of 14 suburban fire departments, identified and rated tasks that were perceived to be both strenuous and frequently performed. The objective of the current study was to describe the working postures and the forces applied as firefighter/paramedics (FF/Ps) simulated specific roles within the following tasks identified by the survey: (1) transferring a patient from a bed to a stretcher using bedsheets, (2) transferring a patient from the ambulance stretcher to a hospital gurney, (3) carrying a victim down a set of stairs and around a landing using a stairchair, (4) carrying a victim down a set of stairs and around a landing using a backboard, and (5) carrying a victim down a set of stairs using a stretcher. Ten two-person teams of FF/Ps participated and were videotaped to obtain postural data for the upper and lower extremities as they performed each role in the simulated two-person tasks. Trunk postures were obtained using lumbar motion monitors. Static hand forces were estimated using a hand-held dynamometer at the most physically demanding points for each role within each task. The postural and force data were averaged across subjects performing identical roles to quantify the postures assumed by the FF/Ps at the most strenuous moments during task performance. Based on these analyses we concluded that: (1) when transferring victims from a bed to a stretcher the FF/P on the bed was able to maintain an upright and more stable posture by standing as opposed to kneeling, (2) an interface board should be used to reduce the frictional forces when transferring victims from a bed to a stretcher or from a stretcher to a gurney, thereby reducing the need to lift the victim with flexed torsos and/or shoulders, and (3) equipment and training that encourages the FF/P in the leader role to walk facing forward during victim transport, especially when descending stairs, potentially results in safer transit.

High-dose therapy with autologous bone marrow support as consolidation of remission in follicular lymphoma: long-term clinical and molecular follow-up

PURPOSE

To evaluate the long-term results of high-dose therapy (HDT) in follicular lymphoma, with specific emphasis on the prognostic significance of polymerase chain reaction (PCR)-detectable Bcl-2/IgH rearrangements.

PATIENTS AND METHODS

Between June 1985 and October 1995, 99 patients with follicular lymphoma received HDT as consolidation of second or subsequent remission. Bone marrow was treated in vitro with anti-B-cell antibodies and complement.

RESULTS

Sixty-five patients remained alive, 49 treatment-failure free, with a median follow-up of 5.5 years (range, 1.5 to 12.5 years). Four "early" and 10 "late" deaths occurred from treatment-related causes; seven of the latter were due to secondary myelodysplasia (s-MDS) or secondary acute myeloblastic leukemia. Overall, 12 (12%) of the 99 patients developed s-MDS or acute myeloblastic leukemia. Kaplan-Meier estimates of freedom from recurrence (FFR) and survival rates at 5 years were 63% (95% confidence interval [CI], 52% to 72%) and 69% (95% CI, 58% to 78%), respectively. For all 99 patients, in multivariate analysis, absence of the Bcl-2/IgH rearrangement at the time of diagnosis (hazards ratio [HR], 0.39; P =.04) and three or fewer treatment episodes before HDT (HR, 0.03; P =.001) were significant prognostic factors for improved survival. For patients bearing Bcl-2/IgH rearrangements, in univariate and multivariate analyses, absence of a PCR-detectable Bcl-2/IgH rearrangement during follow-up was associated with a significantly lower risk of recurrence (adjusted HR, 0.13; P <.001) and death (HR, 0.25; P =.02), whereas the PCR status of the reinfused bone marrow did not correlate with outcome.

CONCLUSION

Prolonged FFR can be achieved in patients with follicular lymphoma after HDT, but as yet there is no survival advantage compared with conventional treatment. These results confirm that elimination of cells bearing the Bcl-2/IgH rearrangement is highly desirable and should be attempted. The incidence of s-MDS is of increasing concern in this setting.

European phase II study of rituximab (chimeric anti-CD20 monoclonal antibody) for patients with newly diagnosed mantle-cell lymphoma and previously treated mantle-cell lymphoma, immunocytoma, and small B-cell lymphocytic lymphoma

PURPOSE

Mantle-cell lymphoma (MCL), immunocytoma (IMC), and small B-cell lymphocytic lymphoma (SLL) are B-cell malignancies that express CD20 and are incurable with standard therapy. A multicenter phase II study was conducted to assess the toxicity and the overall response rates (RR) and complete response (CR) rates to rituximab (chimeric anti-CD20 monoclonal antibody).

PATIENTS AND METHODS

Between January 1997 and January 1998, 131 patients with newly diagnosed MCL (MCL1; n = 34) and previously treated MCL (MCL2; n = 40), IMC (n = 28), and SLL (n = 29) received rituximab 375 mg/m(2)/wk for 4 weeks via intravenous infusion. Restaging studies were performed 1 and 2 months after treatment. An analysis of the duration of response was conducted in December 1998.

RESULTS

Eleven patients were unassessable, including one who died of splenic rupture after the first infusion. The RR among the 120 assessable patients was 30% (36 of 120 patients). The RR by histology was as follows: MCL1, 38%; MCL2, 37%; IMC, 28%; and SLL, 14%. Ten patients, all with MCL, achieved CR. The median duration of response in MCL was 1.2 years. Immediate side effects were common and usually responded to adjustments in the infusion rate. There were 31 episodes of infection after treatment; most cases were mild. Cardiac arrhythmia and ophthalmologic side effects occurred in 10 and nine patients, respectively, including one case of severe loss of visual acuity.

CONCLUSION

Single-agent rituximab has moderate activity in MCL and IMC but only limited activity in SLL. The duration of response in MCL was similar to that previously reported in follicular lymphoma. Its use in combination with cytotoxic chemotherapy to increase the CR rate is warranted in MCL and IMC.

Variability of polymerase chain reaction detection of the bcl-2-IgH translocation in an international multicentre study

BACKGROUND

The capacity of the polymerase chain reaction (PCR) to detect very low numbers of cells bearing a t(14;18) translocation has led to its application in assessment of the results of treatment for follicular lymphoma, and suggestions that therapy might be guided by molecular studies. To test the reliability of PCR a collaborative study was undertaken to compare results from different laboratories in Europe and North America.

METHODS

Twenty laboratories with records of publication in molecular diagnostics were sent blood from normal donors with varying numbers of t(14;18)-bearing cells added from a cell line with a translocation in the major breakpoint region (MBR) of the bcl-2 gene. Samples contained 1000, 100, 10, 1 or 0 cells per ml of whole blood and were sent blinded in duplicate. PCR methodology varied widely, with the total number of amplification cycles between 30 and 70, and 13 different primers used for the MBR region. Twelve laboratories used nested PCR and eight single round amplification.

RESULTS

The sensitivity of nested and single round PCR was similar at 100 cells/ml but below this the nested method proved significantly more sensitive. The false positive rate was 28%, with 11 samples from 9 laboratories reported as positive when no t(14;18) cells were added. PCR product size and sequence analysis showed that false positives were due to contamination from cell-line DNA rather than background translocations in the donors. There was no significant difference in false positive rates between nested and single round techniques.

CONCLUSION

The polymerase chain reaction to detect bcl-2-IgH rearrangements is presently carried out with widely disparate results. Further effort is required to bring forward a standard PCR protocol which can be re-tested in different laboratories to improve accuracy and reproducibility. The application of quantitative techniques such as real-time PCR may resolve many of the problems presently encountered.

Mutations in the heparin binding domain of fibronectin in cooperation with the V region induce decreases in pp125(FAK) levels plus proteoglycan-mediated apoptosis via caspases

Intact fibronectin (FN) protects cells from apoptosis. When FN is fragmented, specific domains induce proteinase expression in fibroblasts. However, it is not known whether specific domains of FN can also regulate apoptosis. We exposed fibroblasts to four recombinant FN fragments and then assayed for apoptosis using criteria of cellular shape change, condensed nuclear morphology, and DNA fragmentation. The fragments extended from the RGD-containing repeat III10 to III15; they included (V(+)) or excluded (V(-)) the alternatively spliced V region and contained either a mutated (H(-)) or an unmutated (H(+)) heparin binding domain. Only the V(+)H(-) fragment triggered decreases in pp125(FAK) levels and apoptosis, which was rescued by intact FN and inhibitors of caspase-1 and caspase-3. This apoptotic mechanism was mediated by a chondroitin sulfate proteoglycan, since treating cells with chondroitin sulfate or chondroitinase reversed the apoptotic cell shape changes. The alpha4 integrin receptor may also be involved, since using a blocking antibody to alpha4 alone induced apoptotic cell shape changes, whereas co-treatment with this antibody plus V(+)H(+) reversed these effects. These results demonstrate that the V and heparin binding domains of FN modulate pp125(FAK) levels and regulate apoptosis through a chondroitin sulfate proteoglycan- and possibly alpha4 integrin-mediated pathway, which triggers a caspase cascade.

Periodontal ligament cells from insulin-dependent diabetics exhibit altered alkaline phosphatase activity in response to growth factors

BACKGROUND

Insulin-dependent or Type 1 diabetes mellitus (IDDM) has been associated with an increased severity of periodontal disease. Because periodontal ligament (PDL) cells play a significant role in maintenance and regeneration of mineralized tissue, the success of procedures, such as guided tissue regeneration, is directly related to the ability of these cells to augment mineralized tissue. The objective of this study was to examine the ability of PDL cells from long-standing IDDM patients to form mineralized tissue and to determine whether these cells would exhibit altered responses to exogenously added growth factors.

METHODS

PDL cells were isolated from 4 patients with IDDM treated with insulin for at least 5 years and from systemically healthy donors. The cell isolates were tested for their ability to form mineralized nodules in vitro and to express alterations in alkaline phosphatase activity in response to exogenously added growth factors (transforming growth factor-beta (TGF-beta), platelet-derived growth factor-BB (PDGF-BB), and insulin-like growth factor-1 (IGF-1). Alkaline phosphatase activity was determined spectrophotometrically.

RESULTS

Although all PDL cell isolates formed mineralized nodules in vitro, PDL cells from diabetics formed mineralized nodules more slowly than did the controls. Alkaline phosphatase activity was not altered by exposure of diabetic PDL cells to TGF-beta for 9 days. In contrast, non-diabetic isolates exhibited increased levels of activity with increasing concentrations, from 0.5 to 1.0 ng/ml. Alkaline phosphatase activity was significantly higher in non-diabetic, but not in diabetic, cell isolates exposed to TGF-beta at 1.0 ng/ml, when compared to non-treated controls. Diabetic cell isolates exhibited significantly lower alkaline phosphatase activity than the non-diabetic isolates when exposed to either TGF-beta, PDGF-BB, IGF-1 or a combination of PDGF-BB and IGF-1.

CONCLUSIONS

These results suggest that the populations of PDL cells in insulin-dependent diabetics may be altered in their ability to form mineralized tissue and to respond to growth factors, functions affecting the maintenance and regeneration of the periodontium.