Hsp70 protein levels and thermotolerance in Drosophila subobscura: a reassessment of the thermal co-adaptation hypothesis

Theory predicts that geographic variation in traits and genes associated with climatic adaptation may be initially driven by the correlated evolution of thermal preference and thermal sensitivity. This assumes that an organism's preferred body temperature corresponds with the thermal optimum in which performance is maximized; hence, shifts in thermal preferences affect the subsequent evolution of thermal-related traits. Drosophila subobscura evolved worldwide latitudinal clines in several traits including chromosome inversion frequencies, with some polymorphic inversions being apparently associated with thermal preference and thermal tolerance. Here we show that flies carrying the warm-climate chromosome arrangement O(3+4) have higher basal protein levels of Hsp70 than their cold-climate O(st) counterparts, but this difference disappears after heat hardening. O(3+4) carriers are also more heat tolerant, although it is difficult to conclude from our results that this is causally linked to their higher basal levels of Hsp70. The observed patterns are consistent with the thermal co-adaptation hypothesis and suggest that the interplay between behaviour and physiology underlies latitudinal and seasonal shifts in inversion frequencies.

Estimating the mode of inheritance in genetic association studies of qualitative traits based on the degree of dominance index

BACKGROUND

The biological justification for the choice of the genetic mode in genetic association studies (GAS) is seldom available. Then, the mode of inheritance is approximated by investigating a number of non-orthogonal genetic contrasts making the interpretation of results difficult.

METHODS

We propose to define the mode of inheritance by the significance of the deviance of the co-dominant contrast and the degree of dominance (h), which is a function of two orthogonal contrasts (the co-dominant and additive). Non-dominance exists when the co-dominant contrast is non-significant and, hence, the risk effect of heterozygotes lies in the middle of the risk of the two homozygotes. Otherwise, dominance (including over- and under-dominance) is present and the direction of dominance depends on the value of h.

RESULTS

Simulations show that h may capture the real mode of inheritance and it is affected by deviations from Hardy-Weinberg equilibrium (HWE). In addition, power for detecting significance of h when the study conforms to HWE rule increases with the degree of dominance and to some extent is related to the mutant allele frequency.

CONCLUSION

The introduction of the degree of dominance provides useful insights into the mode of inheritance in GAS.

Pervasive genetic integration directs the evolution of human skull shape

It has long been unclear whether the different derived cranial traits of modern humans evolved independently in response to separate selection pressures or whether they resulted from the inherent morphological integration throughout the skull. In a novel approach to this issue, we combine evolutionary quantitative genetics and geometric morphometrics to analyze genetic and phenotypic integration in human skull shape. We measured human skulls in the ossuary of Hallstatt (Austria), which offer a unique opportunity because they are associated with genealogical data. Our results indicate pronounced covariation of traits throughout the skull. Separate simulations of selection for localized shape changes corresponding to some of the principal derived characters of modern human skulls produced outcomes that were similar to each other and involved a joint response in all of these traits. The data for both genetic and phenotypic shape variation were not consistent with the hypothesis that the face, cranial base, and cranial vault are completely independent modules but relatively strongly integrated structures. These results indicate pervasive integration in the human skull and suggest a reinterpretation of the selective scenario for human evolution where the origin of any one of the derived characters may have facilitated the evolution of the others.

Type-specific prevalence of Human Papillomavirus infection among women in the Northwest Territories, Canada

BACKGROUND

Certain types of Human Papillomavirus (HPV) are highly associated with cervical cancer and precursor lesions (dysplasia), but the distribution of HPVs in Northern Canada is largely unknown. This study determined the prevalences of HPV infection due to different virus types and the association of different virus types with cervical dysplasia in the Northwest Territories (NWT).

METHODS

Between April 2008 and March 2009, women who underwent routine Pap testing in the NWT were included in the study. An in-house Luminex assay detected type-specific HPV infections. The HPV prevalence rates and population attributable risk fractions were calculated.

RESULTS

In 5725 bio-samples, the overall HPV prevalence was 24.2%, and of the HPV-positive samples, 76.6% harbored high-risk types, 35.2% harbored multi-type infections, and 21.6% harbored HPV16 or 18 infections. The HPV prevalence was approximately 50% higher among Aboriginal than non-Aboriginal women. The age-specific HPV prevalence exhibited a U-shape distribution in the Aboriginal group. The prevalence of HPV16 or 18 infections found in high-grade lesions was 34.1%. Among this study population, 89.5% of the cases with cervical dysplasia were attributable to HPV infection, with 27.1% attributable to HPV16/18.

CONCLUSION

The high prevalence of high-risk HPV in this population, particularly in the Aboriginal group, will require further studies to identify specific predictors of infection.

Preoperative radiotherapy in patients with locally advanced breast cancer: Tumor response and patient outcome after 26 years of median follow-up

113

Background: Preoperative radiotherapy (PreopRT) in locally advanced breast cancer patients (LABC) has been rarely reported. The purpose of this study was to determine if pathological response to PreopRT could have prognostic value on locoregional control and survival.

Methods: From 1970 to 1984, 203 LABC patients were treated by PreopRT, delivering 45Gy in 25 fractions to the breast, supraclavicular fossa, axilla and ipsilateral internal mammary chain. After a median interval of 38 days (range: 5-121 days), radical mastectomy and axillary dissection was performed independently of radiation response. Chemotherapy or endocrine therapy was prescribed according to physician discretion in 28% and 11% of patients, respectively. Premenopausal patients underwent ovarian ablation. Median follow-up was 26 years. Locoregional control (LRC), disease-free survival (DFS), and overall survival (OS) were estimated using the Kaplan-Meier method, the comparison of survival between groups was performed using the log-rank test, multivariate analysis was performed using the Cox model.

Results: Thirty-three patients (16.2%) had a pathologic complete response (pCR) in the breast. The 10- and 20-year Kaplan-Meier LC were 90% (95% confidence interval CI: 85-94%) and 84% (95% CI: 77-89%), respectively. The 10 and 20-years DFS were 49% (CI: 42-55%) and 35% (CI: 29-42%), and the 10 and 20-years OS, 56% (CI: 49-63%) and 41% (CI: 35-48%), in that order. Patients with pCR tended to have better DFS (p=0.06) and OS (p=0.07) when compared to patients with partial response or stable/progressive disease. Having a pCR did not significantly influenced LRC (p=0.44). Multivariate analysis showed that a lower number of positive nodes on axillary dissection and younger age were associated with better DFS (p<0.0001 and p=0.02) and OS (p<0.0001 and p=0.007).

Conclusions: LCR achieved by PreopRT followed by radical mastectomy in LABC was excellent in this study, despite few patients having adjuvant systemic therapy. Complete pathologic response defined a subgroup of women with a trend toward better DFS and OS. Older patients and those with a higher number of involved axillary nodes had a worse prognosis.

Comparative study of bipolar eletrocoagulation versus argon plasma coagulation for rectal bleeding due to chronic radiation coloproctopathy

BACKGROUND AND STUDY AIM

Chronic radiation coloproctopathy (CRCP) is a well-recognized complication of radiotherapy, with rectal bleeding the most common presentation. It is frequently refractory to conservative management, but the optimal endoscopic treatment of bleeding secondary to CRCP is still controversial. The efficacy and safety of bipolar eletrocoagulation (BEC) and argon plasma coagulation (APC) in the management of bleeding from CRCP were evaluated and compared.

PATIENTS AND METHODS

30 patients (mean age 67.4 years) with active and chronic bleeding from telangiectasias, were randomly allocated to BEC or APC and stratified by severity of CRCP according to clinical severity and endoscopic findings (Saunders score). Success was defined as eradication of all telangiectasias, and therapeutic failure as need for more than seven sessions or for other treatment. Complications were categorized as minor (e.g. fever, anal or abdominal pain) or major (hemorrhagic).

RESULTS

Both treatments were equally effective for the treatment of CRCP rectal bleeding. Only one failure was observed in each group (P = 1.000). There was no significant difference between the two groups regarding number of sessions, minor or major complications, or relapse. However, overall complication rate was significantly higher in the BEC group (P = 0.003).

CONCLUSIONS

BEC and APC are both effective for the therapy of bleeding telangiectasias from CRCP. There are probably no major differences between them. Although APC seemed safer than BEC in this investigation, further studies, involving a much larger population, are needed to assess the complication rates and determine the best management option.

QA of dynamic MLC based on EPID portal dosimetry

PURPOSE

Dynamic delivery of intensity modulated beams (dIMRT) requires not only accurate verification of leaf positioning but also a control on the speed of motion. The latter is a parameter that has a major impact on the dose delivered to the patient. Time consumed in quality assurance (QA) procedures is an issue of relevance in any radiotherapy department. Electronic portal imaging dosimetry (EPID) can be very efficient for routine tests. The purpose of this work is to investigate the ability of our EPID for detecting small errors in leaf positioning, and to present our daily QA procedures for dIMRT based on EPID.

METHODS AND MATERIALS

A Varian 2100 CD Clinac equipped with an 80 leaf Millennium MLC and with amorphous silicon based EPID (aS500, Varian) is used. The daily QA program consists in performing: Stability check of the EPID signal, Garden fence test, Sweeping slit test, and Leaf speed test.

RESULTS AND DISCUSSION

The EPID system exhibits good long term reproducibility. The mean portal dose at the centre of a 10 × 10 cm(2) static field was 1.002 ± 0.004 (range 1.013-0.995) for the period evaluated of 47 weeks. Garden fence test shows that leaf position errors of up to 0.2 mm can be detected. With the Sweeping slit test we are able to detect small deviations on the gap width and errors of individual leaves of 0.5 and 0.2 mm. With the Leaf speed test problems due to motor fatigue or friction between leaves can be detected.

CONCLUSIONS

This set of tests takes no longer than 5 min in the linac treatment room. With EPID dosimetry, a consistent daily QA program can be applied, giving complete information about positioning/speed MLC.

The incidence of bacteraemia after argon plasma coagulation in patients with chronic radiation proctocolitis

AIM

Argon plasma coagulation (APC) is considered a safe treatment for haemorrhagic chronic radiation proctocolitis (CRPC), but bacteraemia is a rare complication. The study aimed to evaluate the frequency of bacteraemia after APC.

METHOD

A prospective study of 21 patients who underwent APC (30 procedures) for CRPC was carried out. Blood cultures (Bactec(®) ) were obtained before and 30 min after the procedure (60 samples total). Patients were monitored for 48 h after the procedure to detect signs of infection.

RESULTS

None of the 21 patients had fever or any sign suggestive of infection after any of the 30 sessions. All baseline blood cultures were negative and two (7%) of the 30-min blood cultures were positive (Staphylococcus hominis n = 1; Streptococcus bovis and Rhodotorula sp n = 1). The first was likely to be a contaminant and the second patient had no evidence of any other colonic disease (neoplasia or polyps) beside CRPC.

CONCLUSION

APC is a low-risk procedure regarding bacteraemia and does not warrant prophylactic antibiotic administration.

[Results of 125-iodine seed implant with preplanning system in 250 patients with prostate cancer]

INTRODUCTION

We review the experience with prostate carcinoma patients treated with permanent implants of 125-I seeds and the outcome eight years after the beginning of this technique.

MATERIAL AND METHODS

From 2002 to 2007 we have performed 250 implants with LDR brachytherapy with RapidStrand(®) and preplanning system. Mean age was 68 (49-78). Mean PSA was 7.32 (2.31 - 14.6). T1-T2a was the stage in 98%, and Gleason ≤ 6 in 96%. Low risk cases were 81% and intermediate risk 19% (ten of them received 46 Gy EBRT). Hormonal treatment was used in 42%.

RESULTS

With a mean follow-up of 48 months, 14 patients (5.7%) showed biochemical failure (BF). Eleven patients (4.5%) with theoretical BF were observed and PSA decreased without treatment. Actuarial PSA relapse-free survival at 5 years was 91%, (92% low risk, 86% intermediate cases), and 92% vs 81% with PSA <10 vs >10 (p<0.05). Rectum complications were G2 in 0.6%. A urinary catheter was necessary in 6.5%. Sexual function was conserved in 60%. Mean V100 was 89% and D90 143 Gy.

CONCLUSION

The outcome of patients with low risk prostate carcinoma treated with I-125 seed is very good with very low complications rate. Cases with PSA bounces should be controlled before starting a salvage treatment.