Rapid identification of compound mutations in patients with Philadelphia-positive leukaemias by long-range next generation sequencing

An emerging problem in patients with Philadelphia (Ph)-positive leukaemias is the occurrence of cells with multiple mutations in the BCR-ABL1 tyrosine kinase domain (TKD) associated with high resistance to different tyrosine kinase inhibitors. Rapid and sensitive detection of leukaemic subclones carrying such changes, referred to as compound mutations, is therefore of increasing clinical relevance. However, current diagnostic methods including next generation sequencing (NGS) of short fragments do not optimally meet these requirements. We have therefore established a long-range (LR) NGS approach permitting massively parallel sequencing of the entire TKD length of 933bp in a single read using 454 sequencing with the GS FLX+ instrument (454 Life Sciences). By testing a series of individual and consecutive specimens derived from six patients with chronic myeloid leukaemia, we demonstrate that long-range NGS analysis permits sensitive identification of mutations and their assignment to the same or to separate subclones. This approach also facilitates readily interpretable documentation of insertions and deletions in the entire BCR-ABL1 TKD. The long-range NGS findings were reevaluated by an independent technical approach in select cases. Polymerase chain reaction (PCR) amplicons of the BCR-ABL1 TKD derived from individual specimens were subcloned into pGEM®-T plasmids, and >100 individual clones were subjected to analysis by Sanger sequencing. The NGS results were confirmed, thus documenting the reliability of the new technology. Long-range NGS analysis therefore provides an economic approach to the identification of compound mutations and other genetic alterations in the entire BCR-ABL1 TKD, and represents an important advancement of the diagnostic armamentarium for rapid assessment of impending resistant disease.

Effect of diltiazem on lid tension during light-flash-induced eye blinks in the rabbit

PURPOSE

The purpose of this study was to examine the effect of the Ca blocker diltiazem in combination with the Ca chelator EGTA (ethyleneglycol-bis-ta-amino-ethyl ether]N,N'-tetraacetic acid) on eyelid tension generated during the light-induced eyeblink reflex in the adult rabbit. The goal is to develop nontoxic, nonsurgical therapies for blepharospasm.

METHODS

Blinks were triggered in the alert rabbit, and tension was measured with a strain gauge attached to the eyelid. Strain gauge output was amplified, digitized, and stored on computer for later analysis. Experiments consisted of a set of trials in which identical light stimuli were delivered at 0.1 Hz for 5 min.

RESULTS

In control trials, blink tensions decreased dramatically for the first seven to nine blinks and then levelled off, indicating that with respect to muscle tension output, blinks contained both rapidly habituating and nonhabituating components. After diltiazem and EGTA were injected in the lid, blinks were reduced 30% to 90% over those in control trials. Reductions could not be explained by injection trauma or irritation due to fluid volume, because injections of saline alone did not produce such tension depression.

CONCLUSIONS

Diltiazem-EGTA produces a transient reduction in blink tension. A clinical application will depend on developing methods for the sustained release of these drugs in the eyelid.

Hyaline globules and intracellular lumina in a hepatocellular carcinoma

The authors report ultrastructural findings on the morphogenesis of hyaline globular inclusions (HG) of a moderately well-differentiated hepatocellular carcinoma, with the features of a fibrolamellar variant. Pale blue cytoplasmic inclusions (pale bodies) of the tumor cells were shown to be intracellular lumina lined with numerous microvilli. Our findings suggest that HG were formed apparently by the successive deposition of fine granular materials in the lumina. Small accumulations were present in the intracellular lumina, which were seen on light microscopy as central hyaline cores of pale inclusions. Larger globular deposits, corresponding to HG and presumably mature ones, were lined closely with membranes devoid of microvilli that were probably shed intraluminally. Our observation was discussed with relation to the previous findings on the inclusions.

Training of expatriate refugee health workers: Principles and practices

Abstract-This paper describes in detail the separate components of an ideal expatriate refugee health worker training course. Emphasis is given to organizational aspects of such courses.

Abnormal glow discharge detection of visible radiation

Extension of abnormal glow discharge detection of electromagnetic radiation to visible wavelengths is observed with inexpensive commercial indicator lamps. The spectral response and mechanisms of detection are discussed and advantages over gas-filled photodiodes noted. Responses from different discharge regions are observed and their implications considered.