p53 loss does not permit escape from BrafV600E-induced senescence in a mouse model of lung cancer

Lung cancer arises through the acquisition of a number of genetic lesions, with a preponderance of activating mutations in the canonical mitogen-activated protein kinase (MAPK) cascade (RTK-RAS-RAF-MEK). Braf^V600E expression induces benign lung adenomas that fail to progress to adenocarcinoma because of oncogene-induced senescence (OIS). Braf^V600E expression, coupled with simultaneous p53 ablation, permits bypass of senescence and progression to lung adenocarcinoma. However, spontaneous human tumors sustain mutations in a temporally separated manner. Here, we use a mouse lung cancer model where oncogene activation (Braf^V600E expression) and tumor suppressor loss (p53 ablation) are independently controlled through the actions of Flp and Cre recombinase, respectively. We show that p53 loss before OIS is permissive for the transition from lung adenoma to adenocarcinoma. In contrast, p53 loss after senescence is established fails to enable escape from senescence and disease progression. This study demonstrates that Braf^V600E induced senescence is irreversible in vivo and suggests that therapy-induced senescence would halt further tumor progression.

Changes in ER beta versus ER alpha in short-term studies of antiestrogen therapies

Abstract #5113

Background: Fulvestrant (Faslodex™) is a novel estrogen receptor (ER) antagonist with no agonist effects used in the treatment of postmenopausal women with advanced breast cancer. Compared with other antiestrogen therapies, fulvestrant has a distinct and different mode of action; on binding to the ER it induces a rapid and dose-dependent degradation of ER alpha and concomitant decreases in progesterone receptor (PgR) levels and Ki67 labeling index (LI). The action of fulvestrant on ER beta is unknown and has been investigated in relation to other biomarkers in this study.
 Methods: This randomized, multicenter study included postmenopausal patients with previously untreated breast tumors (stage T1-T3) that were either ER+ or ER unknown. Patients were randomized to receive a single intramuscular dose of fulvestrant (50 mg [n=39], 125 mg [n=38], or 250 mg [n=44]), continuous daily tamoxifen (Nolvadex™) (20 mg/day [n=36]), or matching tamoxifen placebo (n=33) for 14–21 days prior to surgery. The effects of antiestrogen therapy on ER beta 1 and ER beta 2 levels and the relationship between these effects and changes in ER alpha, PgR and Ki67 LI were investigated. Effects on ER (alpha and beta) and PgR were determined by immunohistochemistry and expressed as mean percentage change from baseline H-score. Ki67 LI was determined as described previously1 and was expressed as median percentage change from baseline.
 Results: There was no overall treatment effect following placebo or antiestrogen therapy on ER beta 1 H-score (p=0.8537) or ER beta 2 H-score (p=0.5494). There were no significant differences between the individual fulvestrant dose groups, tamoxifen and placebo for mean changes in either ER beta 1 (50 mg: +34.8%, 125 mg: +42.8%, 250 mg: +15.5%; tamoxifen: +29.8%; placebo: +29.7%) or ER beta 2 (50 mg: +87.9%, 125 mg: +82.9%, 250 mg: +97.4%; tamoxifen: +98.1%; placebo: +64.2%). No correlations were observed between changes in ER beta 1 and changes in ER beta 2, nor between either ER beta 1 or 2 and ER alpha, PgR or Ki67 LI.
 Conclusion: Changes in ER beta did not correlate with fulvestrant dose (50 mg, 125 mg, or 250 mg) or other variables that have previously been shown to be related to fulvestrant activity. This study does not support the investigation of ER beta 1 or 2 as markers of the biological activity of fulvestrant high dose (500 mg/month) in ongoing trials such as FIRST and CONFIRM.
 1Robertson et al. Cancer Res 2001; 61: 6739-6746.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5113.

Availability of nest hollows and breeding population size of eclectus parrots, Eclectus roratus, on Cape York Peninsula, Australia

The distribution of the Australian mainland endemic subspecies of the eclectus parrot, Eclectus roratus macgillivrayi, is currently confined to the lowland rainforests of the Iron–McIlwraith Ranges of eastern Cape York Peninsula. Females breed in large hollows in emergent rainforest trees that are readily visible from above. Aerial surveys were used to sample 58% of the rainforest (454 km2) of the Iron Range region to estimate the density of these nest trees. Corrections for overcounting bias (not all observed emergent trees were active nest trees) and undercounting bias (not all active nest trees were visible from the air) were made by ground-truthing over 70 trees. The tree count data were treated in two different ways, producing estimates of 417 (s.e. = 25) and 462 (s.e. = 31) nest trees for the Iron Range region. Long-term observational data on the number of eclectus parrots associated with each nest tree were used to estimate the population size of eclectus parrots at Iron Range: 538–596 breeding females, and 1059–1173 males. These results have three implications. First, this relatively low population estimate suggests that the Australian subspecies of eclectus parrots should be considered vulnerable to habitat loss or perturbation, especially in light of their complex social system, male-biased adult sex ratio, low breeding success and high variance in reproductive success among females. Second, the low density of nest trees suggests that eclectus parrots are absent from the rainforests of Lockerbie Scrub and the Jardine dunefields because these areas are too small. Finally, if eclectus parrots persisted in the Iron–McIlwraith region during the rainforest contractions of Pleistocene glacial maxima (e.g. 14 000–17 000 years ago), the refugium in this region must have been fairly substantial in order to support a viable population – probably larger than previously assumed.

Clinical aspects of the overactive bladder and detrusor overactivity

OBJECTIVE

The overactive bladder is a widespread medical condition with significant quality of life and financial impact. Despite this much remains unknown about the epidemiology and pathophysiology of this condition. This review gives an overview of the current knowledge base and the recent terminology changes approved by the international continence society.

METHODS

Critical review of the literature regarding aetiology, epidemiology, urodynamic and clinical aspects of detrusor overactivity. Explanation of the recently adopted terminology.

RESULTS

The term "overactive bladder" has replaced the term "unstable bladder", which held no intuitive meaning. "Detrusor overactivity" is the corresponding urodynamic term, replacing "detrusor instability" and "detrusor hyperreflexia". Knowledge regarding the epidemiology of the overactive bladder is limited. The myogenic and neurogenic theories of pathophysiology require further evidence.

CONCLUSION

Massive research efforts are required into all aspects of this common chronic disease. The adoption of new ICS terminology will aid consistency in research.

Evidence-Based Follow-up after Varicose Vein Surgery

Objective:

To determine the optimum timing and need for outpatient follow-up of patients after varicose vein operations.

Methods:

Ninety-six consecutive patients undergoing varicose vein operations were enrolled. Patients completed linear analogue scales to record pain, bruising and swelling on postoperative days 1 to 10, 12, 14, 21 and 28. Return to daily activities, visits to the general practitioner (GP) and outpatient review at 6 weeks were recorded.

Results:

Maximum scores were on day 2 for swelling, day 4 for bruising, and days 1 and 6 for pain. Median time to return to work was 14 days (range 1-42 days). During the postoperative period 29 patients visited their GP, 24 (83%) within 2 weeks of operation. Median length of outpatient consultation at 6 weeks was 5 min. Although 57 patients found the appointment reassuring, none required further treatment.

Conclusions:

Outpatient follow-up after varicose vein operations cannot be justified on clinical grounds. The majority of patients who have postoperative problems develop them within the first 2 weeks, coinciding with the peaks of pain, swelling and bruising, and these problems can be dealt with in the community.

Effects of gender, body composition and birth size on IGF-I in 7- and 8-year-old children

We investigated the relationship between IGF-I, gender, height, weight, body composition and birth size in 260 healthy 7- and 8-year-old children (139 females). All children were born term at Nepean Hospital, Western Sydney. Body composition was measured using dual energy X-ray absorptiometry. IGF-I levels were determined by radioimmunoassay. Girls had higher IGF-I levels than boys (20.2 +/- 6.5 nmol/l compared to 15.9 +/- 6.1 nmol/l, p < 0.001) but there was no correlation between age and IGF-I. IGF-I was positively correlated with height SDS (R(2) = 0.12), weight SDS (R(2) = 0.19), BMI SDS (R(2) = 0.18), total body fat (%) (R(2) = 0.14), and fat-free tissue/cm (R(2) = 0.03). After adjusting for gender and current weight, IGF-I-levels were inversely related to birth size - children with the lowest birth size and heaviest current weight had the highest IGF-I levels. This correlation between birth weight and IGF-I supports the hypothesis that the IGF-I axis is altered in babies who are small for gestational age.

Vitamin D receptor alleles predict growth and bone density in girls

OBJECTIVES

Polymorphism of the vitamin D receptor (VDR), collagen alpha I type I (Col I alpha I), and oestrogen receptor (ER) genes have been shown to account for some of the heritability of bone mineral density (BMD) in adults. This study examined this relation in prepubertal children.

METHODS AND SUBJECTS

The relation between genotypes of VDR gene (Taq I, Bsm I, Fok I), Col I alpha I gene (Msc I), and ER gene (Pvu II) with areal BMD, volumetric BMD, and growth were examined in 114 (68 girls) healthy 7 year old, white children.

RESULTS

The genotype of the VDR gene (Taq I) correlated with lumbar spine (L1-4) volumetric BMD in girls only, but at no other bone sites. In girls, VDR genotype affected areal BMD at all sites. After adjusting for height and weight, however, this effect was explained completely by the independent effect of the VDR genotype on growth. Girls with genotype TT, were 3.9 kg heavier and 4.1 cm taller than those with tt, but this relation was not present at birth. No relation was found between genotypes of the VDR gene (Fok I), Col I alpha I gene (Msc I), or ER gene (Pvu II) and BMD or growth variables.

CONCLUSIONS

In prepubertal girls, VDR alleles contribute to lumbar spine volumetric BMD variance, but the areal BMD effect reflects the relation between areal BMD and growth. VDR alleles might affect postnatal growth regulation.

Uptake of screening for breast cancer in south Lancashire

STUDY OBJECTIVE

To describe and explain variation among general practices in the uptake of screening for breast cancer.

DESIGN

Analysis of the variation in uptake of screening by general practice. Uptake rates are calculated and related to a social deprivation score created for each practice, and to the presence of at least one female general practitioner.

SETTING

South Lancashire Health Authority, England.

PATIENTS

All women aged 50-64 y registered with Lancashire Family Health Services Authority and resident in South Lancashire in 1988-1995.

MAIN RESULTS

Variation in the uptake of screening for breast cancer during Round 1 of the national programme is explained partly by a deprivation score for each practice and by the presence of at least one female general practitioner. In Round 2 the deprivation index continues to explain variation, but the effect of a female GP has diminished. The number of hours worked by practice nurses has no effect on uptake of breast screening.

CONCLUSIONS

Variation in the uptake of breast cancer screening is closely related to social deprivation. Results suggest that the presence of a female general practitioner has a beneficial effect on uptake.

Dopamine D2 receptors quantified in vivo in human narcolepsy

Assays in brain tissues from humans suffering from narcolepsy, and from genetically narcoleptic dogs have suggested that dopamine function may be disturbed in this condition. We have used the specific D2 receptor ligand N-(3-[18F]fluoropropyl)-spiperone and positron tomography to study a group of 6 well-characterized medication-free, HLA-DR2 DRW15 DW6-positive narcoleptic patients and a group of age- and sex-matched control individuals during life. We found no difference in striatal D2 receptor binding between these two groups. These results suggest that narcolepsy is not associated with alterations in D2 receptor density and affinity.

Digestion, assimilation and metabolism of captive estuarine crocodiles, Crocodylus porosus

1. Digestion, assimilation and metabolism of lean and fatty pork were studied in immature C. porosus. 2. Up to 92% of protein was digested but protein digestion was adversely affected by high levels of dietary fat. 3. Protein was catabolized in preference to fat, much of which was stored, although the ratio between metabolizable energy and protein retention was still 2.73 g/100 kJ. 4. 56.8% of ingested energy was stored, maintenance requirements taking as little as 7.7%. 5. Up to 13.8% energy was spent digesting and assimilating food.

Evoked metabolic responses in the limbic-striate system produced by stimulation of anterior thalamic nucleus in man

Six human subjects (5 male, 1 female, age 23.7 + 5.7 years) with incapacitating partial seizure disorders intractable to medical therapy have been treated by ongoing pulsed electrical stimulation of anterior nucleus of the thalamus. Four of the six patients have demonstrated statistically significant clinical control of the seizure disorder. One patient (D.L.) has been seizure-free for the last two years. In two of these six patients, it was possible to study not only electrophysiological activity of the brain, but also regional cerebral glucose metabolism by the (18F) 2-fluoro-2-deoxy-D-glucose method, blood cortisol levels, and blood levels of valproic acid, diphenylhydantoin, and carbamazepine. Significant changes were seen during periods of stimulation compared with control periods without stimulation. These results imply that stimulation of the principal thalamic relay nucleus of the limbic system causes clinical, behavioral, cerebral metabolic, electroencephalographic, endocrinologic, and pharmacokinetic responses.

Striatal dopamine metabolism in living monkeys examined by positron emission tomography

Positron emission tomography, using the dopa analogue [18F]6-fluoro-L-dopa, has been used to depict the neostriatum in living monkeys. The amount of 18F that accumulated preferentially in the striatum could be augmented by a peripheral decarboxylase inhibitor. Striatal 18F could also be discharged with reserpine. This is the first time that the regional distribution of a neurotransmitter has been demonstrated in monkeys.

Rapid identification of correctly located intracerebroventricular cannula in the rat

We describe a radiographic technique to identify a correctly located cannula in the ventricular system of the rat brain during life. A suspension of thorium dioxide was infused into the left lateral ventricle through a cannula placed in the brain under stereotaxic guidance. Correctly located injections were identified by the presence of a distinct thorium shadow on lateral X-ray of the in situ brain. When 6-hydroxydopamine was co-injected with thorium the resultant depletion of striatal dopamine and the changes in a conditioned avoidance responses were correlated with the degree of spreading of thorium through the ventricular system.