A "loop entropy reduction" phage-display selection for folded amino acid sequences

As a step toward selecting folded proteins from libraries of randomized sequences, we have designed a 'loop entropy reduction'-based phage-display method. The basic premise is that insertion of a long disordered sequence into a loop of a host protein will substantially destabilize the host because of the entropic cost of closing a loop in a disordered chain. If the inserted sequence spontaneously folds into a stable structure with the N and C termini close in space, however, this entropic cost is diminished. The host protein function can, therefore, be used to select folded inserted sequences without relying on specific properties of the inserted sequence. This principle is tested using the IgG binding domain of protein L and the lck SH2 domain as host proteins. The results indicate that the loop entropy reduction screen is capable of discriminating folded from unfolded sequences when the proper host protein and insertion point are chosen.

IHC for Her2 with CBE356 antibody is a more accurate predictor of Her2 gene amplification by FISH than HercepTest in breast carcinoma

BACKGROUND

Her2 (c-erbB-2/neu) overexpression in breast carcinoma predicts response to the anti-Her2 monoclonal antibody, trastuzumab, and is associated with a poor prognosis. When considering patients for trastuzumab treatment, Her2 protein expression is measured by imunohistochemistry (IHC) and, where staining is equivocal, by fluorescence in situ hybridisation (FISH) detection of Her2 gene amplification.

AIMS

To compare IHC using CBE356 with IHC using the Food and Drug Administration approved HercepTesttrade mark.

METHODS

CBE356 and HercepTest were analysed using 167 FISH characterised breast carcinomas. Immunohistochemical expression of Her2 was measured semiquantitatively. Sensitivity, specificity, predictive values, and overall accuracy were calculated for both IHC methods using gene amplification by FISH as the end point, and IHC and FISH assays were tested in Kaplan-Meier survival analysis.

RESULTS

The accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CBE356 positive (2+ and 3+) cases were 94%, 89%, 95%, 84%, and 97%, respectively, and of HercepTest positive (2+ and 3+) cases were 91%, 66%, 98%, 92%, and 91%, respectively. A positive result with CBE356, HercepTest, or FISH was associated with significantly decreased overall survival (log rank p = 0.005, p = 0.0017, and p = 0.0005, respectively).

CONCLUSIONS

Positive IHC staining for Her2 using CBE356 is 3% more accurate and 23% more sensitive at predicting Her2 gene amplification by FISH than positive staining with HercepTest. Negative IHC using CBE356 antibody is 6% more likely to represent a truly negative result than negative staining with HercepTest. Overall, CBE356 was a more accurate predictor of Her2 gene amplification by FISH than HercepTest.

Early experience with the PlantTan Fixator Plate for 2 and 3 part fractures of the proximal humerus

This study reports the early results for clinical and radiological outcome of fixation of completely displaced or grossly angulated (>90 degrees ) 2 and 3 part fractures of the proximal humerus using the PlantTan Fixator Plate (Medizentechnik, Aachen, Germany). Using a deltopectoral approach the humeral head articular fragment was reduced onto the humeral shaft and fixed with the implant, tuberosity fragments were held with transosseous sutures. Early passive, progressing to active, physiotherapy was instituted from the first postoperative day. No other fixation or bone graft was used. In 15 patients, with 16 injured shoulders and an average age of 63 years the mean follow up was 17 months. As a percentage of the normal side the Constant-Murley score for those patients retaining the implant was mean 74% (range 36%-100%). There were six shoulders with score >80% (Good), four shoulders with score between 60 and 79% (Satisfactory) and four shoulders <60% (Poor). Four shoulders (all in patients over the age of 70 years), developed avascular necrosis. Of these, one patient underwent shoulder replacement hemiarthroplasty and one patient underwent removal of the implant. We have demonstrated functional outcome similar to other modes of internal fixation in patients under 70 years. It cannot be recommended for elderly patients (over 70 years) as it is associated with a high incidence of avascular necrosis and fixation failure.

Recombination or heterogeneity: is there a second locus for adult polycystic kidney disease?

Twenty-four families with adult onset polycystic kidney disease were typed for markers flanking the PKD1 locus on chromosome 16. The aggregated results gave a significant lod score in favour of linkage to PKD1. Within this group of families two showed unusual features: recombinations, including double recombinations, and, in one family, an unexpectedly high proportion of affected people. We consider the evidence that in these families the disease might result from a mutation at a different locus, PKD2, not linked to PKD1. We suggest that a useful test is to compare the relative numbers of meioses apparently non-recombinant and doubly recombinant for markers flanking the normal disease locus, ignoring meioses recombinant for only a single marker. Using this test, neither our two families nor the data published so far on other families provide compelling evidence for the existence of a second locus for adult polycystic kidney disease. For genetic counselling in families too small to give internal evidence for or against linkage, the extra uncertainty can be handled by using a higher recombination rate.

Familial recurrent multiple cranial nerve palsies

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Molecular mechanisms for leptin regulation of VEGF in breast cancer cells

Abstract #3071

Background: We have previously reported that in vitro and in vivo leptin signaling mediates proliferation of mouse 4T1 mammary tumor (MT) cells and levels of VEGF and VEGFR2. Therefore, we hypothesize that leptin can contribute to MT growth by augmenting angiogenesis through the regulation of VEGF expression. To test this we assessed whether leptin regulates VEGF promoter activity in mouse MT cells and if leptin-induced factors (HIF-1α, NFκB, AP1, SP1) regulate the VEGF promoter. Materials and Methods: Mouse MT cells (4T1, EM6 and MMT) were transiently transfected with molecular engineered luciferase-reporters (pGL3) for mouse VEGF promoter (full-length) and transcription factor-binding deletions for hypoxia responsive element (HRE), AP1, SP1 and NFκB. Leptin dose-response effects on reporter activity and VEGF levels (protein and mRNA) were investigated using ELISA, Western blot and real-time PCR, respectively. To further assess leptin regulation of VEGF expression in MT cells the effects of hypoxia (CoCl2, hypoxia mimetic agent) alone and combined with leptin on VEGF promoter activity were investigated. To assess which leptin-induced signaling pathways/transcription factors are linked to VEGF regulation in MT cells inhibitors for: (1) JAK2/STAT3, MEK-1/MAPK and PI-3K/Akt-1 pathways and; (2) target molecules NFκB; SP1; AP1 and HIF-1α were used. The effects of leptin/CoCl2 and inhibitors on luciferase activity of transfected cells were compared using pRL-TK renilla luciferase as control and the Dual-Luciferase Reporter Assay System. Results: Our data suggest that leptin signaling can regulate the transcriptional activity of VEGF gene in breast cancer cells by activating gene transcription at several sites of the VEGF promoter. Leptin-induced HIF-1α has a relevant role in the regulation of VEGF expression in MT cells. Leptin can also increase VEGF-levels (protein and mRNA) through the specific activation of AP1, SP1, and NFκB. PI-3K activity was mainly linked to leptin regulatory effects on VEGF. However, diverse mechanisms for leptin regulation of VEGF expression were found in the different MT cells. Discussion: Our results provide novel information on the molecular mechanisms for leptin-induced angiogenic effects in breast cancer. Our data further suggest that disruption of leptin signaling could impact angiogenesis and MT growth by inhibiting VEGF expression. Thus targeted disruption of leptin-signaling could serve as method of prevention/treatment of breast cancer. This work was supported in part by the Susan G. Komen Foundation for the Cure (to R.R.G.; BC 504370); UAB Breast SPORE Award (to R.R.G) and Contraceptive Research and Development Program (CONRAD; CIG-07-114 to R.R.G).

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3071.

Irish neonatal mortality--12 years on

All Paediatricians in Ireland were requested to fill a questionnaire which dealt with data pertaining to all live-born infants over 500 g birth weight who died within the first 28 days of life in 1999. Deaths were categorized according to Wigglesworth Classification into Lethal Malformation, Immaturity (Prematurity), Asphyxia and "Specific". Each hospital and patient was assigned a unique ID number. Data from questionnaires was entered into a database. Results were compared with those previously published by Counahan and Clarke for 1987. Twenty one of the 23 paediatric centres in Ireland replied giving a response rate of 91%. The over-all number of neonatal deaths for 1999 was 186 compared to 310 for 1987. One hundred and two (55%) were < 1500 grams and 61 (33%) < 1000 g. The principal causes of death for 1999 were Congenital Malformations 39%, (n=72), Prematurity 37% (n=69) and Asphyxia 3% (n=5). This compares to figures of 39%, 40% and 8%, respectively for 1987. The overall Neonatal Mortality Rate for 1999 was 3.48/1000 with a Corrected Neonatal Mortality Rate of 2.1/1000. The Neonatal Mortality Rate and Corrected Neonatal Mortality Rate for 1987 were 5.3/1000 and 3.3/1000 respectively. The decrease in Neonatal Mortality in the past 12 years in Ireland is to be applauded. However it can lead to a false sense of security regarding standards of neonatal care. While the death of Extremely Low-Birth-Weight infants can now often be prevented, in many cases it is merely deferred to the post-neonatal period. Furthermore, no national data is available on the long term outcome and neurodevelopmental status of preterm or asphyxiated infants who survive. The possibility of establishing an Irish Neonatal Morbidity Register, aimed at improving the effectiveness and efficiency of medical care for newborn infants, must now be explored.