Relationship between pulmonary function and lung cancer surgical outcome

The British Thoracic Society and American College of Chest Physician guidelines outline criteria for investigating patients for lung cancer surgery. However, the guidelines are based on relatively old studies. Therefore, the relationship between pulmonary function test results and surgical outcome were studied prospectively in a large cohort of lung cancer patients. From January 2001 to December 2003, 110 patients underwent surgery for lung cancer. All underwent full lung function testing in order to predict post-operative lung function. The hospital mortality rate was 3% and major complication rate 22%. There was poor overall outcome in 13%. Mean pre-operative lung function values were: forced expiratory volume in one second (FEV1) 2.0 L (79.4% of the predicted value), and carbon monoxide diffusing capacity of the lung (D(L,CO)) 73.6% pred. The mean post-operative lung function values were: FEV1 1.4 L (55.6% pred), and D(L,CO) 51.3% pred. All lung function values were better predictors of poor surgical outcome when expressed as a percentage of the predicted value. Using a threshold of pre-operative FEV1 of 47% pred resulted in the most useful positive and negative predictive probabilities, 0.90 and 0.67, respectively. Lung function values expressed as a percentage of the predicted value are more useful predictors of post-operative outcome than absolute values. The threshold of predicted forced expiratory volume in one second for surgical intervention could be lower (45-50% pred) than is currently accepted without increased mortality.

Blockade of platelet-derived growth factor receptor-beta by CDP860, a humanized, PEGylated di-Fab', leads to fluid accumulation and is associated with increased tumor vascularized volume

PURPOSE

CDP860 is an engineered Fab' fragment-polyethylene glycol conjugate, which binds to and blocks the activity of the beta-subunit of the platelet-derived growth factor receptor (PDGFR-beta). Studies in animals have suggested that PDGFR-beta inhibition reduces tumor interstitial fluid pressure, and thus increases the uptake of concomitantly administered drugs. The purpose of this study was to determine whether changes in tumor vascular parameters could be detected in humans, and to assess whether CDP860 would be likely to increase the uptake of a concurrently administered small molecule in future studies.

PATIENTS AND METHODS

Patients with advanced ovarian or colorectal cancer and good performance status received intravenous infusions of CDP860 on days 0 and 28. Patients had serial dynamic contrast-enhanced magnetic resonance imaging studies to measure changes in tumor vascular parameters.

RESULTS

Three of eight patients developed significant ascites, and seven of eight showed evidence of fluid retention. In some patients, the ratio of vascular volume to total tumor volume increased significantly (P < .001) within 24 hours following CDP860 administration, an effect suggestive of recruitment of previously non-functioning vessels.

CONCLUSION

These observations suggest that inhibition of PDGFR-beta might improve delivery of a concurrently administered therapy. However, in cancer patients, further exploration of the dosing regimen of CDP860 is required to dissociate adverse effects from beneficial effects. The findings challenge the view that inhibition of PDGF alone is beneficial, and confirm that effects of PDGFR kinase inhibition mediate, to some extent, the fluid retention observed in patients treated with mixed tyrosine kinase inhibitors.

021.Identification and study of genes important for fetal germ cell biology in mice

We are using a multi-pronged approach to discovering genes and proteins that regulate the allocation, proliferation, migration, differentiation and apoptosis of primordial germ cells (PGCs) in the developing mouse embryo. First, we are using suppression PCR and microarray screening methods to identify genes whose expression is restricted to, or enriched in, gonads of a specific sex or developmental stage. In this way several genes were identified whose expression is restricted to germ cells. Second, we are using a proteomic approach to identify important proteins and the genes that encode them. Protein expression profiles are being compared between different sexes and stages of mouse fetal gonad development. Data so far indicate that this method is a useful adjunct to transcriptional profiling, capable of identifying not only proteins that are differentially expressed, but also those that are differentially modified, for example by phosphorylation. Third, in silico screening of mouse EST databases identified 23 new candidate genes whose expression appears to be limited to pluripotent cells and the germline. Many of these genes are novel uncharacterised transcripts. Preliminary in situ expression analyses show that eight of these genes are indeed limited to the germline and to pluripotent cells. These genes may have important functions in germline specification and function. We are currently developing approaches, including inducible RNAi-based methods, for examining the function of these genes, initially in vitro but also ultimately in vivo.

Treatment response in late-onset depression: relationship to neuropsychological, neuroradiological and vascular risk factors

BACKGROUND

Late-onset depressive disorder is associated with white matter lesions and neuropsychological deficits that in some studies are linked to a poorer outcome for depression. Some white matter lesions may be vascular in origin. This study investigated the relationship between response or non-response to antidepressant monotherapy and neuropsychological function, structural brain measures and vascular factors.

METHOD

This was a case control study. Fifty patients with late-onset major depressive disorder (29 who were responders to antidepressant monotherapy and 21 who were not) were compared with 35 non-depressed control subjects. Measures included assessment of vascular risk factors, neuropsychological testing and a magnetic resonance imaging (MRI) scan.

RESULTS

After adjustment for depressed mood and medication at evaluation, both patient groups had significantly more impairment compared to control subjects on verbal learning tasks involving immediate or delayed recall. Patients who did not respond to antidepressant monotherapy had significantly poorer performance than controls on tests involving visuospatial ability, language, word recognition and tests of executive function, whereas there were no differences between control subjects and responders. On two tests of executive function (verbal fluency and the Stroop test) non-responders scored significantly worse than responders. There were no significant group differences on MRI measures of atrophy or of white matter lesions apart from a higher periventricular hyperintensity score in non-responders compared to controls. There were no group differences on measures of vascular disease.

CONCLUSION

The results lend support to the emerging evidence that resistance to treatment in late-onset depression may be associated with impaired executive function. Subtle cerebrovascular mechanisms may be involved.

Optimization of Scanning Parameters for Multi-slice CT Colonography: Experiments with Synthetic and Animal Phantoms

AIM

To determine the optimal collimation, pitch, tube current and reconstruction interval for multi-slice computed tomography (CT) colonography with regard to attaining satisfactory image quality while minimizing patient radiation dose.

MATERIALS AND METHODS

Multi-slice CT was performed on plastic, excised pig colon and whole pig phantoms to determine optimal settings. Performance was judged by detection of simulated polyps and statistical measures of the image parameters. Fat and muscle conspicuity was measured from images of dual tube-current prone/supine patient data to derive a measure of tube current effects on tissue contrast.

RESULTS

A collimation of 4 x 2.5 mm was sufficient for detection of polyps 4 mm and larger, provided that a reconstruction interval of 1.25 mm was used. A pitch of 1.5 allowed faster scanning and reduced radiation dose without resulting in a loss of important information, i.e. detection of small polyps, when compared with a pitch of 0.75. Tube current and proportional radiation dose could be lowered substantially without deleterious effects on the detection of the air-mucosal interface, however, increased image noise substantially reduced conspicuity of different tissues.

CONCLUSION

An optimal image acquisition set-up of 4 x 2.5 mm collimation, reconstruction interval of 1.25 mm, pitch of 1.5 and dual prone/supine scan of 40/100 mA tube current is proposed for our institution for scanning symptomatic patients. Indications are that where CT colonography is used for colonic polyp screening in non-symptomatic patients, a 40 mA tube current could prove satisfactory for both scans.

Excessive exposure of sick neonates to sound during transport

OBJECTIVE

To determine the levels of sound to which infants are exposed during routine transport by ambulance, aircraft, and helicopter.

DESIGN

Sound levels during 38 consecutive journeys from a regional level III neonatal intensive care unit were recorded using a calibrated data logging sound meter (Quest 2900). The meter was set to record "A" weighted slow response integrated sound levels, which emulates the response of the human ear, and "C" weighted response sound levels as a measure of total sound level exposure for all frequencies. The information was downloaded to a computer using MS HyperTerminal. The resulting data were stored, and a graphical profile was generated for each journey using SigmaPlot software.

SETTING

Eight journeys involved ambulance transport on country roads, 24 involved fixed wing aircraft, and four were by helicopter.

MAIN OUTCOME MEASURES

Relations between decibel levels and events or changes in transport mode were established by correlating the time logged on the sound meter with the standard transport documentation sheet.

RESULTS

The highest sound levels were recorded during air transport. However, mean sound levels for all modes of transport exceeded the recommended levels for neonatal intensive care. The maximum sound levels recorded were extremely high at greater than 80 dB in the "A" weighted hearing range and greater than 120 dB in the total frequency range.

CONCLUSIONS

This study raises major concerns about the excessive exposure of the sick newborn to sound during transportation.

Effects of alcohol and lorazepam during extinction of alcohol self-administration in rats

Systemic injections of alcohol have previously been reported to 'prime' or to reinstate self-administration of alcohol in rats, and it has been suggested that the priming effects of drugs are related to their stimulus properties. We tested this hypothesis by investigating the effects of lorazepam, which cross-generalizes with alcohol in animal drug-discrimination studies, in rats trained to self-administer 7% alcohol in an operant paradigm. Once animals were trained, extinction tests were carried out twice weekly, before which rats were injected with either vehicle, alcohol (0.063-0.5 g/kg, i.p.) or lorazepam (0.03-0.25 mg/kg, i.p.). Alcohol did not increase responding for alcohol during extinction. Doses of 0.25 and 0.5 g/kg reduced alcohol-appropriate lever pressing (p < 0.05 versus 0 g/kg), with the largest dose also suppressing general activity (p < 0.02 versus 0 g/kg). Lorazepam also reduced alcohol-appropriate responding, in a behaviourally specific manner; doses of 0.03 mg/kg and above decreased lever pressing (p < 0.05 versus 0 mg/kg), whereas general activity was depressed at 0.06 mg/kg and larger doses (p < 0.05 versus 0 mg/kg). Although lorazepam mimicked the effect of alcohol at doses predicted to do so on the basis of their relative potency in drug discrimination studies, neither alcohol nor lorazepam primed rats to respond for alcohol. By contrast, the pattern of results suggested that, in this model, they 'satiated' or substituted for alcohol, resulting in a reduced motivation to respond.

Problem of dural scarring in recording from awake, behaving monkeys: a solution using 5-fluorouracil

In studies using single neuron recordings from awake, behaving monkeys, it is necessary to make repeated transdural penetrations using fragile microelectrodes. The tough connective tissue that accumulates after the dura mater is first exposed is often problematic because of electrode breakage and the mechanical stress to the underlying brain tissue caused by excessive dimpling during penetration. We describe the use of an antimitotic compound, 5-fluorouracil (5FU) to control the growth of this connective tissue. 5FU can be safely applied for short periods to the exposed dural tissue on a regular basis provided that it is thoroughly rinsed after application. The advantages of using 5FU are fourfold: first, it depresses fibroblast division and minimizes dural growth and scar tissue formation so that penetrations are easier with less electrode damage or breakage. Second, the frequency of surgical procedures required to remove this tissue are greatly reduced, which benefits both the experiment animal and the experiment. Third, 5FU reduces vascularization of the tissue so that its removal is far easier and without significant blood loss. Finally, 5FU seems to inhibit bacterial infections within the recording chamber. In macaque motor cortex, we performed a quantitative study of electrophysiological data recorded from monkeys with and without 5FU treatment. No significant deleterious side effects produced by 5FU could be detected. Likewise, histological examination of cortical tissue underlying treated dura did not reveal any obvious signs of damage by 5FU. We recommend this approach, with the appropriate safety precautions, to all those neurophysiologists using transdural microelectrode methods in chronically prepared experimental animals. It is also possible that this technique may be useful in other situations where there is dural scarring after surgical intervention or injury.