LACE-conditioned autologous stem cell transplantation for relapsed or refractory Hodgkin's lymphoma: treatment outcome and risk factor analysis in 67 patients from a single centre

High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is a recognized treatment option for patients with relapsed Hodgkin's lymphoma. We have analysed 67 patients who underwent ASCT after LACE (lomustine (CCNU), cytarabine (Ara-C), cyclophosphamide, etoposide) conditioning for relapsed (n=61) or primary refractory (n=6) Hodgkin's lymphoma. The 100-day treatment-related mortality was 3%. With a median follow-up of 67 months (range 3.3-161.0) the probabilities of overall survival (OS) and progression-free survival (PFS) at 5 years were 68 and 64%, respectively. Probabilities for OS and PFS at 5 years for patients with chemosensitive relapse (n=40) were 81 and 78% versus 50 and 35%, respectively, for patients (n=27) with chemoresistant relapse (P=0.012 for OS, P=0.002 for PFS). In multivariate analysis mixed cellularity classical or lymphocyte-depleted classical histology subtype and haemoglobin level of 10 g/dl or less at the time of ASCT were identified as risk factors for worse OS, whereas stage III or IV disease at diagnosis and disease status at ASCT other than complete or partial remission predicted inferior PFS. LACE followed by ASCT is an effective treatment for the majority of patients with chemosensitive relapsed Hodgkin's lymphoma and a proportion of chemorefractory patients also benefit.

Neuroanatomical and pharmacological assessment of Fos expression induced in the rat brain by the phosphodiesterase-4 inhibitor 6-(4-pyridylmethyl)-8-(3-nitrophenyl) quinoline

A major obstacle in the therapeutic development of phosphodiesterase-4 (PDE4) inhibitors is the production of adverse side effects such as nausea and vomiting. Immunohistochemical detection of Fos-like immunoreactivity (FLI) was used to address the neuroanatomical basis for the pharmacological actions of PDE4 inhibitors. The potent and selective PDE4 inhibitors 6-(4-pyridylmethyl)-8-(3-nitrophenyl) quinoline (PMNPQ) and rolipram elevated FLI in brain regions potentially relevant to the anti-depressant and emetic effects of PDE4 inhibition. PMNPQ and rolipram elevated FLI in the locus coeruleus, habenula, paraventricular nucleus of the thalamus, amygdala and nucleus accumbens, all structures with strong limbic connectivity implicated in arousal, memory and affective aspects of behaviour. Consistent with the emetic effects of PDE4 inhibitors such as PMNPQ and rolipram, these compounds elevated FLI in caudal brainstem nuclei such as the area postrema and nucleus of the solitary tract. Administration of the NK(1) antagonist RP 67580 prior to PMNPQ reversed increases in FLI produced by PMNPQ in these regions. RP 67580 did not, however, reduce PMNPQ-induced FLI in limbic structures. These findings suggest that PDE4 inhibitors produce emesis by increasing NK(1) receptor activation in the AP/NTS and implicate brain regions associated with reward and mood such as the amygdala, paraventricular nucleus of the thalamus, habenula and nucleus accumbens in the anti-depressant activity of such compounds.

Determination of human brain tumour therapy response using an ex vivo invasion assay provides a potential step toward individualized treatment

11509

Background: Malignant brain tumours are the 6th leading cause of pre-mature death in Ontario with over 10,000 potential years of life lost each year. Improved treatment for malignant brain tumours is needed. Models assessing chemotherapy response employ clonal malignant human tumour cells while patient responses are heterogeneous. Tumour spreading is dependent on tissue invasion and in this study, a surgical sample of each patient’s tumour was used to assess invasion and growth while exposed to a panel of clinically relevant chemotherapies. Methods: Tissue specimens were placed into a nutrient-rich collagen gel that mimics the tumour environment in the body. Chemotherapy treatments were suspended in the matrix surrounding the tumour. Growth and invasion in the presence of chemotherapies was assessed for 5 days following surgical removal in this 3 dimensional matrix and compared to control conditions using student t- test. Results: 12 patient’s individual tumour response was assessed. 4 patients tumours did not respond to any chemotherapy tested. Table 1 shows the number of responders to each therapy tested. Conclusions: Individual response to chemotherapy is highly variable both clinically and in our ex vivo assessment of tissue fragments. Several patients (8/12 or 67%) tumour assessment displayed significant (p<.05) response to one or more therapies. Results from this data will continue to be compared to patient response, The overall predictive value of the data obtained using this ex vivo model will be determined by continuing to collect information time to recurrence and survival at 3, 6, 12 and 24 months) from 90 solid tumour patients per year. Pre-assessment each patient’s responsiveness to chemotherapies could lead to more individualized and therefore more effective treatment.

[Table: see text]

[Table: see text]

Characterization of a novel founder rearrangement mutation of BRCA1 in high-risk Hispanic families

10015

Background: Large rearrangements are estimated to account for 5–10% of all mutations in BRCA1 and BRCA2. Prevalent founder rearrangement mutations have been described in European populations. We sought to identify rearrangements in the BRCA genes in a cohort of Hispanic patients. Methods: We identified 34 deleterious BRCA mutations via full sequence analysis among 110 unrelated high-risk Hispanic families enrolled in an IRB approved registry who underwent cancer risk assessment (CEBP 2005;14:1–6). DNA from 67 of 76 patients without an identifiable mutation was subjected to multiplexed quantitative differential PCR (MQDP, per B. Erickson and T. Scholl, Myriad Genetics Laboratory) for detection of large rearrangements. An apparent deletion of BRCA1 exons 9–12, indicated by a 50% loss of signal was identified by MQDP in 3 unrelated families (ASHG, 2005). Long range PCR resulted in the generation of a 2.7kb product in these samples, consistent with a deletion event of 15.1kb. This putative mutation was further characterized by cloning and sequencing the breakpoint in all 3 families. RNA splicing was evaluated by sequencing RT-PCR products from lymphoblastoid cell line RNA for each family. Results: Sequence analysis identified the breakpoint within Alu elements in introns 8 and 12, and all 3 unrelated families shared the same breakpoint. Analysis of cDNA demonstrated direct splicing of exons 8–13 predicting a frameshift mutation and premature truncation of the BRCA1 protein, thus confirming the deleterious nature of this mutation. Conclusion: We identified the same novel large deletion in three unrelated families of Mexican ancestry, suggesting potential founder effect. The frequency was 2.7% of the 110 high-risk Hispanic families screened for BRCA mutations, bringing the overall prevalence of deleterious mutations to 33.6%(37/110) in this cohort. This BRCA1 rearrangement may account for a substantial proportion of high-risk Hispanic families, and should be included in all subsequent studies of this ethnic group.

No significant financial relationships to disclose.

Structural basis for broad DNA-specificity in integron recombination

Lateral DNA transfer--the movement of genetic traits between bacteria--has a profound impact on genomic evolution and speciation. The efficiency with which bacteria incorporate genetic information reflects their capacity to adapt to changing environmental conditions. Integron integrases are proteins that mediate site-specific DNA recombination between a proximal primary site (attI) and a secondary target site (attC) found within mobile gene cassettes encoding resistance or virulence factors. The lack of sequence conservation among attC sites has led to the hypothesis that a sequence-independent structural recognition determinant must exist within attC. Here we report the crystal structure of an integron integrase bound to an attC substrate. The structure shows that DNA target site recognition and high-order synaptic assembly are not dependent on canonical DNA but on the position of two flipped-out bases that interact in cis and in trans with the integrase. These extrahelical bases, one of which is required for recombination in vivo, originate from folding of the bottom strand of attC owing to its imperfect internal dyad symmetry. The mechanism reported here supports a new paradigm for how sequence-degenerate single-stranded genetic material is recognized and exchanged between bacteria.

Hais cuaj txub kaum txub--to speak of all things: a Hmong cross-cultural case study

Cross-cultural medicine is a field that describes how disparate value and belief systems concerning health and disease affect the delivery of health care. This report describes the conflict between a Hmong immigrant family and the Western medical establishment over the care of their child with end stage renal disease [ESRD]. The health care providers, social service agencies and medical center failed to adequately respond to the needs of the family. The medical staff [nephrologist, nurse coordinator, dietician, social worker, and CPS worker] worked with a transcultural nurse, Hmong community health worker and the family, to design and negotiate a treatment plan that would be acceptable to the family and the health care team. Trust was reestablished between the family and the healthcare providers and the medical outcome for the child improved.

A clinical trial of creatine in ALS

BACKGROUND

Mitochondrial dysfunction occurs early in the course of ALS, and the mitochondria may be an important site for therapeutic intervention. Creatine stabilizes the mitochondrial transition pore, and is important in mitochondrial ATP production. In a transgenic mouse model of ALS, administration of creatine prolongs survival and preserves motor function and motor neurons.

METHODS

The authors conducted a randomized double-blind, placebo controlled trial on 104 patients with ALS from 14 sites to evaluate the efficacy of creatine supplementation in ALS. The primary outcome measure was maximum voluntary isometric contraction of eight upper extremity muscles, with secondary outcomes including grip strength, ALS Functional Rating Scale-Revised, and motor unit number estimates. Patients were treated for 6 months, and evaluated monthly.

RESULTS

Creatine was tolerated well, but no benefit of creatine could be demonstrated in any outcome measure. CI analysis showed that the study, although powered to detect a 50% or greater change in rate of decline of muscle strength, actually made an effect size of greater than 23% unlikely. It was also demonstrated that motor unit number estimation was performed with acceptable reproducibility and tolerability, and may be a useful outcome measure in future clinical trials.

CONCLUSION

Any beneficial effect of creatine at 5 g per day in ALS must be small. Other agents should be considered in future studies of therapeutic agents to address mitochondrial dysfunction in ALS. In addition, motor unit number estimation may be a useful outcome measure for future clinical trials in ALS.

Ascaridole-less infusions of Chenopodium ambrosioides contain a nematocide(s) that is(are) not toxic to mammalian smooth muscle

Infusions of Chenopodium ambrosioides (L.) have been used for centuries in the Americas as a popular remedy against intestinal worm infections. The essential oil of Chenopodium ambrosioides contains high levels of ascaridole, which is a potent anthelmintic, but which has also been responsible for human fatalities, leading to its disuse. Almost 90% of the nematocidal activity of Chenopodium ambrosioides infusions was due to a hydrophilic component different from ascaridole. Synthetic ascaridole and the ascaridole from infusions, extracted into hexane, caused a reduction of carbachol-induced contractions in rat gastrointestinal smooth muscle at concentrations required to kill Caenorhabditis elegans (L.). The herbal infusion and the ascaridole-free hexane-extracted aqueous residue of the above infusion, at nematocidal concentrations, had no detectable effect on smooth muscle contraction in the above system. It would appear that the traditional form of usage of Chenopodium ambrosioides infusions as a vermifuge is safer than the use of the herb's essential oil.

MRI diagnosis of bilateral adrenal vein thrombosis

We report a case of bilateral adrenal vein thrombosis in an adult female who had a history of breast cancer. The patient does not have clinical, serological or imaging evidence of metastatic disease 14 months from the initial diagnosis. Adrenal vein thrombosis is a rare entity. There have been no previous reports specifically stating an association between adrenal vein thrombosis and hypercoaguability, but there are many cases in the literature documenting venous thrombosis elsewhere within the body in patients with hypercoaguable states. Laboratory testing performed to exclude a hypercoaguable state, revealed heterozygosity for the Factor V Leiden mutation/activated protein C resistance and elevated factor VIII levels [3660 IU l(-1) (<1500)]. This is the first reported case of bilateral metachronous adrenal vein thrombosis in which MRI established the diagnosis.

Role of hydration in the binding of lac repressor to DNA

The osmotic stress technique was used to measure changes in macromolecular hydration that accompany binding of wild-type Escherichia coli lactose (lac) repressor to its regulatory site (operator O1) in the lac promoter and its transfer from site O1 to nonspecific DNA. Binding at O1 is accompanied by the net release of 260 +/- 32 water molecules. If all are released from macromolecular surfaces, this result is consistent with a net reduction of solvent-accessible surface area of 2370 +/- 550 A. This area is only slightly smaller than the macromolecular interface calculated for a crystalline repressor dimer-O1 complex but is significantly smaller than that for the corresponding complex with the symmetrical optimized O(sym) operator. The transfer of repressor from site O1 to nonspecific DNA is accompanied by the net uptake of 93 +/- 10 water molecules. Together these results imply that formation of a nonspecific complex is accompanied by the net release of 165 +/- 43 water molecules. The enhanced stabilities of repressor-DNA complexes with increasing osmolality may contribute to the ability of Escherichia coli cells to tolerate dehydration and/or high external salt concentrations.

Determination of DNA structure in solution: enzymatic deuteration of the ribose 2' carbon

An enzymatic solution to the problem of obtaining 13C/15N-labeled nucleotides that are deuterated uniquely at the H2' ' position within the ribose ring is presented. Selective deuteration occurs with an overall yield of >80%. The deuteron at the H2' ' position allows measurement of the scalar and residual dipolar couplings for the bond vectors attached to the C2' carbon of each ribose sugar. These data allow the accurate determination of sugar conformation. Interesting DNA double helices of 2-3 turns are now within the reach of solution NMR spectroscopy. As an example, these labeled nucleotides are incorporated uniquely at positions 6-14 in a 20-bp DNA sequence containing the adenovirus major late promoter.

Residual dipolar couplings in nucleic acid structure determination

Solution NMR spectroscopy of nucleic acids has been limited by the short-range nature of the nuclear Overhauser effect and scalar coupling restraints normally used in structure determination. The addition of residual dipolar couplings, obtained from slightly oriented mixtures, provides bond vector angles relative to a universal alignment tensor. The accurate determination of helix curvature, domain orientation and the stoichiometry of homomultimeric nucleic acid complexes is now possible.

Uses and limitations of quantitative structure-activity relationships (QSARs) to categorize substances on the Canadian domestic substance list as persistent and/or bioaccumulative, and inherently toxic to non-human organisms

Under sections 73 and 74 of the revised Canadian Environmental Protection Act (CEPA 1999), Environment Canada and Health Canada must "categorize" and "screen" about 23,000 substances on the Domestic Substances List (DSL) for persistence (P), bioaccumulation (B), and inherently toxic (iT) properties. Since experimental data for P, B and iT are only available for a few DSL substances, a workshop was held to address issues associated with the use of Quantitative Structure-Activity Relationships (QSARs) to categorize these substances. This paper describes the results of an 11-12 November 1999 International Workshop sponsored by Environment Canada to discuss potential uses and limitations of QSARs to categorize DSL substances as either persistent or bioaccumulative and iT to non-human organisms and to recommend future research needed to develop methods for predicting the P, B and iT of difficult-to-model substances.