A WT1 antisense oligonucleotide inhibits proliferation and induces apoptosis in myeloid leukaemia cell lines

The response of the CML-BC cell line, K562, the myelomonocytic cell line MM6 and the promyelocytic leukaemia cell line HL-60, to a 15 mer WT1 antisense oligonucleotide, targeted to the translation initiation site of the WT1 mRNA was examined. K562 cells exposed to 0.4 microM antisense oligonucleotide showed markedly reduced proliferation which was associated with reduced cell viability. Sense, scrambled and mutant antisense oligonucleotides had no effect on the proliferation of K562 cells. MM6 cells exposed to 0.4 microM antisense oligonucleotide also showed significantly reduced cellular proliferation which was also accompanied by loss of cell viability. In the K562 and MM6 antisense cultures that exhibited reduced cell viability, both DNA fragmentation and morphological features consistent with apoptosis could be identified. In contrast the growth of HL-60 cells was unaffected by exposure to 0.4 microM antisense oligonucleotide. In each of the cell lines examined, WT1 antisense oligonucleotide abrogated WT1 protein expression, and analysis of WT1 coding sequence in these cells showed that no oncogenic point mutations in the gene were present. We propose therefore that in some myeloid leukaemia cell lines, the expression of a normal WT1 protein is necessary for cell proliferation and that it plays a role in maintaining the viability of some leukaemia cells.

A generalized linear model for analysing receiver operating characteristic curves

We present a continuation ratio model for analysing ordinal categorical data and we apply the model to the problem of estimating receiver operating characteristic (ROC) curves. We apply the methods to post-prandial capillary blood glucose measurements as a criterion for a potential screening test for diabetes mellitus. One can obtain point estimates of sensitivity and specificity and their associated standard errors at any value along the observed range of post-prandial capillary blood glucose measurements. Also, in comparison to the models for ROCs described by Tosteson and Begg, ROC curves based on the continuation ratio model have the desired features that allow ROCs to be concave but not necessarily symmetric.

The epidemiology and management of upper limb peripheral nerve injuries in modern practice

This paper reports an epidemiological and clinical study of 813 patients with 1,111 peripheral nerve injuries who were treated for upper limb trauma, which included nerve injury, at two plastic surgery units in south-east England, predominantly between the years 1982 and 1991. The frequency distributions of the levels of nerve injury, and the causes of nerve injury in the sample, are presented, together with the surgical management and timing of nerve repair in these patients. 1,018 clinically suspected nerve injuries in 730 patients (91.6% of nerves, 89.8% of patients) were treated by primary nerve repair, elective delayed nerve repair or primary surgical exploration alone. Divisions of 93 nerves in 83 patients (8.3% of nerves, 10.2% of patients) were treated other than by primary repair or elective delayed repair, due to delayed referral from accident and emergency departments, resulting from missed or uncertain diagnosis at presentation or otherwise unaccounted delay in the initial referral.

A new point mutation in the luteinising hormone receptor gene in familial and sporadic male limited precocious puberty: genotype does not always correlate with phenotype

Genomic DNA from two families with male limited precocious puberty was examined for mutations of the LH receptor gene. In family 1, several members of the pedigree have FMPP, whereas in family 2 there is only one affected subject. A point mutation (T --> C at nucleotide 1192) resulting in substitution of threonine for methionine 398 in the second transmembrane domain of the LH receptor protein was found in both families. In addition, one member of family 1 has the mutation, but no evidence of precocious puberty. All obligate carriers within this family were shown to have the mutation, and it was not detected in 94 chromosomes from unaffected and unrelated white subjects. In family 2, the index case was the only one to have the mutation. A previously unreported neutral dimorphism (C --> T at nucleotide 1065) is also described.

Renovating interval-censored responses

In this note we provide a general framework for describing interval-censored samples including estimation of the magnitude and rank positions of data that have been interval-censored so as to counteract the effect of censoring. This process of sample adjustment, or renovation, allows samples to be compared graphically, using diagrams (such as boxplots) which are based on ranks. The renovation process is based on Buckley-James regression estimators for linear regression with censored data.

Empirical evaluation of the transfusion medicine tutor

Previous research during the development of Antibody IDentification Assistant (AIDA) revealed that many medical technology students and other laboratory personnel have serious difficulties in determining the specificity of blood group alloantibodies, especially weak or multiple antibodies. Based on these previous results, AIDA was modified to provide a teaching environment for medical technology students. We report the results of a rigorous, objective evaluation of the resultant system, the Transfusion Medicine Tutor (TMT). The results show that the students who were taught by an instructor using TMT to provide the instructional environment went from 0 percent correct on a pretest case to 87 percent correct on posttests (n = 15). This increase compares with an improvement rate of 20 percent by a control group (n = 15) who used a passive version of the system with the tutoring functions turned off.

A non-invasive vibrating calcium-selective electrode measures acetylcholine-induced calcium flux across the sarcolemma of a smooth muscle

To determine possible sources of Ca2+ during excitation-contraction coupling in smooth muscle, a vibrating Ca2(+)-selective electrode was used to measure Ca2+ flux during the process of contraction. The smooth muscle model was the longitudinal muscle of the body wall of a sea cucumber Sclerodactyla briareus. Because acetylcholine caused slow contractions of the muscle that were inhibited by Ca2+ channel blockers diltiazem and verapamil in earlier mechanical studies, we chose a vibrating Ca2(+)-selective electrode as our method to test the hypothesis that acetylcholine may be stimulating Ca2+ influx across the sarcolemma, providing a Ca2+ source during excitation-contraction coupling. Acetylcholine treatment stimulated a net Ca2+ efflux that was both dose and time dependent. We then tested two L-type Ca2+ channel blockers, diltiazem and verapamil, and two non-specific Ca2+ blockers, cobalt (Co2+) and lanthanum (La3+) on acetylcholine-induced Ca2+ flux. All four Ca2+ blockers tested potently inhibited Ca2+ efflux induced by physiological doses of acetylcholine. We propose that the acetylcholine-induced Ca2+ efflux was the result of, first, Ca2+ influx through voltage-sensitive L-type Ca2+ channels, then the rapid extrusion of Ca2+ by an outwardly directed carrier such as the Na-Ca exchanger as suggested by Li+ substitution experiments. The vibrating Ca2+ electrode has provided new insights on the active and complex role the sarcolemma plays in Ca2+ homeostasis and regulating Ca2+ redistribution during excitation-contraction coupling.

Dealing with brittleness in the design of expert systems for immunohematology

In recent years, there has been increased discussion about the potential of expert systems to support medical decision-making tasks, including applications in clinical laboratory settings. This study provides data regarding the cognitive errors that technologists make on an important problem-solving task: the identification of antibodies in a patient's blood. It explores alternative designs for expert systems developed to reduce such errors. It also evaluates the effects of these alternative designs on the ability of the users to effectively stay "in the loop," applying their own expertise and judgment while using the computer as a tool to assist with their analyses. A pilot study was conducted involving 32 certified medical technologists, which compared two alternative roles for the computer: (1) use of the computer to automatically complete subtasks upon request, and (2) use of the computer as a monitoring device to critique technologists as they completed the analyses themselves. The system design that automatically completed subtasks for the technologist induced a 29 percent increase in errors relative to the design that critiqued technologists as they completed the analyses themselves.

Non-invasive ion probes--tools for measuring transmembrane ion flux

Ionophores, used in non-invasive vibrating electrodes, can directly monitor steady-state ion flux from single cells, even when the source is non-electrogenic.

Splicing of exon 5 in the WT1 gene is disrupted in Wilms' tumour

Using a reverse transcriptase polymerase chain reaction to examine alternate splicing at site I (exon 5) and site II (exon 9) in the Wilms' tumour suppressor gene, WT1, we found that in seven of the 10 Wilms' tumours examined, splicing at site I was disrupted. This is predicted to result in isoform imbalance in Wilms' tumours, with an increase in isoforms in which the 17 amino acids encoded by exon 5 are missing. These observations could not be explained by mutations or rearrangements in flanking introns. Disrupted alternate splicing of exon 5 may play a role in the aetiology of Wilms' tumour.

Selective blockade of M2 and M3 muscarinic receptors by hexahydrobenzyl-fourdapine and a comparison with zamifenacin

1. 4-Diphenylacetoxy-N-cyclohexylmethyl-piperidine HCl (hexahydro-benz-4DAP) is more active as an antagonist of carbachol at receptors in guinea-pig isolated ileum, log K (pA2) = 6.64 +/- 0.14 (s.e. 7 results), than at receptors in guinea-pig isolated atria, log K = 5.43 +/- 0.14 (7). In the presence of neostigmine bromide (0.2 microM) the value for atria was 5.62 +/- 0.19 (4), so the lower activity on atria cannot be attributed to hydrolysis of the compound by cholinesterases present in this tissue. 2. The limit of solubility of the free base in Krebs solution (pH 7.6) is about 50 microM for both hexahydrobenz-4DAP and benzyl-fourdapine (benz-4DAP). 3. In experiments on guinea-pig isolated ileum with hexahydro-benz-4DAP given together with 4-DAMP methobromide, the combined dose-ratio was consistent with competition: similar results were obtained with benz-4DAP. 4. In rats anaesthetized with pentobarbitone, hexahydro-benz-4DAP antagonized the effects of bethanechol on blood-pressure in doses that had little effect on heart rate or airflow. There was a limit to the effect which could be obtained, however, and the slopes of the Schild plots were less than one. The effects on rat blood-pressure had a half-life of at least 30 min. 5. In similar experiments with zamifenacin the slopes of the Schild plots were close to 1 and the compound was 10 to 20 times as active on blood-pressure at it was on heart-rate. 6. The limited solubility of the base probably accounts for the flat Schild plots obtained with hexahydro-benz-4DAP, which had about 10 fold selectivity for effects on blood-pressure and was more active than expected from tests on isolated ileum.

Applying contextual interference to the Pawlata roll

Contextual interference is manipulated by changing the practice order of a number of similar motor tasks, so that the learning context of each interferes with that of the other. The effect has been found to generalize to baseball batting, badminton serving and volleyball skills. The present study examined whether this practice technique could be applied to a Pawlata roll in a kayak. The study was further motivated by the fact that many instructors in Britain currently advocate learning the Pawlata roll in one direction only to a criterion of accuracy, thereafter transferring to the opposite direction. Contextual interference literature predicts that skill retention would be better served by practising on alternate sides. Accordingly, 16 undergraduate students with no kayaking experience were randomly allocated to either a low contextual interference group, which followed U'ren's (1993) recommendations, or a high contextual interference group, which practised the skill on alternate sides. The high contextual interference group took less time to acquire the skill, and were also quicker to achieve successful performance in retention (full roll) and transfer (half roll) tests, regardless of the direction of the roll, 1 week later. The time savings in practice were not expected, as acquisition under high contextual interference was improved rather than impaired. This finding suggests that bilateral transfer was increased by randomizing practice. These results are worthy of further investigation, in that they suggest that the recommended training methods may not be optimal.

Magnetic resonance angiography findings in the early post-carotid endarterectomy period

This preliminary study was designed to investigate the ability of multiple axial volume three-dimensional fourier transform (3DFT) time-of-flight (TOF) magnetic resonance angiography (MRA) to depict the carotid bifurcation in the early post-carotid endarterectomy period. Five patients underwent intra-operative digital subtraction angiography (DSA) and carotid MRA within 5 days of carotid endarterectomy. An axial volume fast imaging in steady-state precession (FISP) gradient-echo 3DFT TOF carotid MRA technique in this limited series appeared to display accurately the surgically significant abnormalities at the carotid bifurcation after endarterectomy. However, in normal or near-normal intra-operative DSA studies, overestimation of internal carotid artery stenoses was encountered. Postoperative MRA demonstrates potential as a useful non-invasive investigation after carotid endarterectomy but should be interpreted with caution until larger studies become available.

Corneal stromal abscesses in the horse: a review of 24 cases

The medical records of 24 horses with corneal stromal abscesses were reviewed. Twenty of the horses initially presented with a corneal ulcer, corneal opacity, or evidence of ocular pain. All of the horses were treated with topical antibiotics prior to referral. Most had also been treated with topical atropine sulphate and systemic flunixin meglumine. Ophthalmic examinations revealed focal, yellow-white corneal opacities, corneal vascularisation and evidence of iridocyclitis. Nine of the horses were treated primarily medically as the initial response to topical and systemic medication was rapid. Fifteen horses were treated both medically and surgically. Surgical treatment was undertaken when corneal rupture was imminent, the iridocyclitis was intractable or when there was minimal response to intensive medical therapy. The surgical procedure performed in most cases was a deep keratectomy with a conjunctival pedicle flap. Intraoperative specimens for cytology, culture, and/or histopathology contributed to the aetiological diagnosis in 5 of 8 cases in which preoperative cytology and cultures were nondiagnostic. All horses, excluding one that was enucleated at presentation for iris prolapse, had vision at discharge.

Lung pathology: the molecular genetics of non-small cell lung cancer

In Australia, lung cancer is the most common malignancy in males and the largest cause of cancer deaths. Conventional management has not had a dramatic impact on the mortality rates from lung cancer, which has a case-fatality rate of over 90%. Recent developments in molecular and cellular biology have however, contributed to our knowledge of lung tumorigenesis, which will hopefully translate into clinical benefit for our patients. Many molecular abnormalities are common to both non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) but there are differences between these histological types and even within the NSCLC subtypes. This review concentrates on NSCLC, which accounts for up to 85% of Australian lung cancers.

Intraocular pressure variation associated with body length in young American alligators (Alligator mississippiensis)

Using an applanation tonometer, 5 replicate intraocular pressure (IOP) measurements were obtained from each eye of 12 young clinically normal, American alligators. Alligator length ranged from 46 to 117 cm, measured from snout to tail tip. All IOP were recorded by a single observer at an ambient temperature of approximately 25 C, and ranged from 5 to 35 mm of Hg. Observer reliability was excellent (intraclass r = 0.93), and IOP did not change over the ordered sequence of 5 replicate measurements/eye. Replicate IOP) measurements were, therefore, averaged in each eye for comparison between eyes of the same alligator. Left and right eve IOP were highly correlated within individual alligators (r = 0.92), whereas the mean within animal difference between left and right eye IOP was not statistically significant (95% confidence interval [CI] for the left eye-right eye mean difference, - 1.9 to 1.3 min of Hg). Mean IOP determined for 5 confirmed females and 3 confirmed males did not differ significantly between the sexes (95% CI for the male-female difference in means, -2.1 to 3.7 mm of Hg). Mean +/- SEM IOP of 23.7 + 2.1 mm of Hg determined for 4 alligators < -50 cm long was significantly (P = 0.009) greater than mean IOP of 11.6 + 0.5 mm of Hg determined for 8 alligators > 50 cm long (95% CI for the difference in means, 8.5 to 15.7 mm of Hg). In young alligators, the relation between body length and IOP appears to be nonlinear, possibly with a negative exponent.

Loss of heterozygosity frequently affects chromosome 17q in non-small cell lung cancer

Although the short arm of chromosome 17, which contains the p53 gene, is frequently affected by loss of heterozygosity (LOH) in lung cancer, little is known about similar changes on the long arm. We found that LOH affected one or more of six loci along chromosome 17 in 59% of 102 informative non-small cell lung cancer (NSCLC) cases. Specifically, the frequency of LOH at 17q was 42%, approaching that at 17p (54%), and two distinct 17q regions were implicated. LOH at D17S4 on 17q was more frequent in adenocarcinomas than in squamous cell carcinomas, whereas squamous cell carcinomas had more LOH at 17p than at 17q, findings that indicate molecular genetic heterogeneity between the major NSCLC subtypes. In addition, LOH at 17q correlated with higher T stages and a significantly worse prognosis. In comparison, 25% of cases had mutations of p53 exons 5-8 but these were not associated with stage or survival. The data suggest that independent of p53, there are important tumor suppressor gene(s) on 17q that may influence NSCLC pathogenesis, progression, and survival.

On plotting renovated samples

In this note we use the Buckley-James method for censored regression in the p sample problem where the samples are subject to right-censoring. The samples are reconstructed so as to remove the effect of censoring, and graphical procedures based on quantiles (such as boxplots) may then be used as a standard data-analytic tool to describe the variable being measured.