Optimality and fairness of partisan gerrymandering

We consider the problem of optimal partisan gerrymandering: a legislator in charge of redrawing the boundaries of equal-sized congressional districts wants to ensure the best electoral outcome for his own party. The so-called gerrymanderer faces two issues: the number of districts is finite and there is uncertainty at the level of each district. Solutions to this problem consists in cracking favorable voters in as many districts as possible to get tight majorities, and in packing unfavorable voters in the remaining districts. The optimal payoff of the gerrymanderer tends to increase as the uncertainty decreases and the number of districts is large. With an infinite number of districts, this problem boils down to concavifying a function, similarly to the optimal Bayesian persuasion problem. We introduce a measure of fairness and show that optimal gerrymandering is accordingly closer to uniform districting (full cracking), which is most unfair, than to community districting (full packing), which is very fair.

Colloidal transport in bacteria suspensions: from bacteria collision to anomalous and enhanced diffusion

Swimming microorganisms interact and alter the dynamics of Brownian particles and tend to modify their transport properties. In particular, dilute colloids coupled to a bath of swimming cells generically display enhanced diffusion on long time scales. This transport dynamics stems from a subtle interplay between the active and passive particles that still resists our understanding despite decades of intense research. Here, we tackle the root of the problem by providing a quantitative characterisation of the single scattering events between a colloid and a bacterium, a smooth running E. coli. Based on our experiments, we build a minimal model that quantitatively predicts the geometry of the scattering trajectories, and enhanced colloidal diffusion at long times. This quantitative confrontation between theory and experiments elucidates the microscopic origin of enhanced transport. Collisions are solely ruled by stochastic contact interactions and the ratio of the drag coefficients of the colloid and the bacteria. Such description accounts both for genuine anomalous diffusion at short times and enhanced diffusion at long times with no ballistic regime at any scale.

Acromegaly in Carney complex

PURPOSE

Carney complex (CNC) is a rare autosomal dominant syndrome, characterized by mucocutaneous pigmentation, cardiac, cutaneous myxomas and endocrine overactivity. It is generally caused by inactivating mutations in the PRKAR1A (protein kinase cAMP-dependent type I regulatory subunit alpha) gene. Acromegaly is an infrequent manifestation of CNC, reportedly diagnosed in 10% of patients.

METHODS

We here report the case of a patient who was concomitantly diagnosed with Carney complex, due to a new mutation in PRKAR1A ((NM_002734.3:c.80_83del, p.(Ile27Lysfs*101 in exon 2), and acromegaly. In parallel, we conducted an extensive review of published case reports of acromegaly in the setting of CNC.

RESULTS

The 43-year-old patient was diagnosed with an acromegaly due to a GH-secreting pituitary microadenoma resistant to somatostatin analogs. He underwent transsphenoidal surgery in our tertiary referral center, which found a pure GH-secreting adenoma. In the literature, we identified 57 cases (24 men, 33 women) of acromegaly in CNC patients. The median age at diagnosis was 28.8 ± 12 year and there were 6 cases of gigantism. Acromegaly revealed CNC in only 4 patients. 24 patients had a microadenoma and two carried pituitary hyperplasia and/or multiple adenomas, suggesting that CNC may result in a higher proportion of microadenoma as compared to non-CNC acromegaly.

CONCLUSIONS

Although it rarely reveals CNC, acromegaly is diagnosed at a younger age in this setting, with a higher proportion of microadenomas.

P13.09 Genomic analysis of paired IDHwt glioblastoma (GB) reveals recurrent alterations of MPDZ at relapse after radiotherapy and temozolomide (RTCT)

BACKGROUND

GB are highly aggressive tumors which systematically relapse. Our objective was to identify disease progression mechanisms and genomic drivers of GB treatment resistance.

MATERIAL AND METHODS

Ten paired frozen tumors from initial and recurrent surgery after RTCT were screened by CGH Array. Next, NGS of the selected genes was performed on 19 paired tumors (38 samples). Molecular alterations were correlated with patient data. TCGA was used to characterize the molecular profile of MPDZ.

RESULTS

Nineteen IDHwt GB patients with a median age of 54.5 years (37.2–72.8) were included. Using CGH array, unsupervised analysis clustered the whole samples by paired of initial and recurrent tumors. However only 44% of CGH Array alterations were shared between initial and recurrent tumors (amplifications: 55%; deletions: 30%). The new alterations detected at relapse were amplifications in 25% and deletions in 23% of tumors. Two regions corresponding to 171 genes were lost at relapse (p=0.03): 19q13.33 and 19q13.41. Using DAVID genome, 3/171 genes (related to neutrophil chemotactic factors) were identified: FPR1, FPR2, FPR3. Moreover, 24 genes were lost (including MPDZ) and 2 genes were gained in 20% of recurrent tumors. Totally, 29 genes were analyzed by NGS and 4 genes showed pathogenic mutations shared by initial and recurrent tumors: FPR2, REL, TYRP1 and MPDZ. Only MPDZ showed, at relapse, an increasing rate of mutated variants and a new mutation affecting the splicing site. These alterations were independent from classical prognostic factors (age, sexe, karnofsky performans status, MMS and MGMT status) and from patient survivals. To explore MPDZ expression, we used TCGA initial dataset and observed that a lower RNA expression of MPDZ was associated with IDHwt (p<0.001) and grade IV (p<0.001) gliomas, reinforcing the potential pejorative impact of MPDZ loss.

CONCLUSION

Our results suggest that MPDZ is frequently altered at initial diagnosis with increased alterations in recurrent IDHwt GB after RTCT, suggesting that MPDZ impairment could contribute to the resistance/relapse mechanisms. Further investigations are needed to validate these results. Our results suggest that MPDZ is frequently altered at initial diagnosis with increased alterations in recurrent IDHwt GB after RTCT, suggesting that MPDZ impairment could contribute to the resistance/relapse mechanisms. Further investigations are needed to validate these results.

The capillary interaction between pairs of granular rafts

When an object is placed at the surface of a liquid, its weight deforms the interface. For two identical spherical objects, such a deformation creates an attractive force, leading to the aggregation of the two-body system. Here, we experimentally investigate the interaction between two granular rafts, formed by the aggregation of dense millimeter-sized beads placed at an oil-water interface. The interfacial deformation created by such a two-dimensional object exceeds by at least an order of magnitude the deformation of a single bead. This leads to unusually high capillary forces which strongly depend on the number of particles. Likewise, because the raft grows in size as more particles are added, the viscous drag experienced increases along with the capillary attraction, leading to a non-trivial dependence of the balance of forces on the number of beads. By studying the relative motion of two granular rafts in relation with the interfacial deformation they generate, we derive a model for the observed speed profiles. With this work, we generalize how the capillary interaction between two non-identical complex structures evolves with their respective geometry.

Insulin-like growth factor binding protein 1 level in amniotic fluid: correlation with birth weight

Insulin-like growth factor binding protein 1 is the predominant insulin-like growth factor binding protein in amniotic fluid. It is produced by the decidua and by fetal tissues, and it is thought to play an important role in fetal growth. We have measured this protein in 58 samples of amniotic fluid, from 13 to 19 gestational weeks, and found a highly significant negative correlation with fetal weight at birth. We conclude that the level of insulin-like growth factor binding protein 1 in amniotic fluid at midpregnancy is a good marker of fetal growth failure.

Diagnostic sensitivity of three tumour markers in non-small cell lung cancer: a pilot study

BACKGROUND

Three tumour markers (CEA, CYFRA 21.1 and CA125) were evaluated for diagnostic sensitivity in newly diagnosed, untreated non-small cell lung cancer.

METHODS

In the 24 patients studied, the tumours were classified histologically as 15 squamous cell carcinomas and 9 adenocarcinomas. In 19 cases, the disease was confined to the lung (M0); 5 cases presented with metastatic disease at the time of diagnosis (M1).

RESULTS

CA125 displayed the best overall sensitivity (62%) and also when only localised disease was evaluated (63%). CA125 was the most sensitive marker for adenocarcinomas (89%), with values differing significantly with histological type (p < 0.005). CYFRA 21.1 was most sensitive in squamous cell carcinomas (53%); this was the only marker which was elevated in all cases involving metastatic disease, and exhibited a significant correlation with stage (p<0.02). CEA presented the poorest overall sensitivity (42%). The overall sensitivity of the three-tumour marker association was 79% and the best combination of two markers was CYFRA 21.1 + CA125 (75%).

CONCLUSIONS

This pilot study allows recommendation of the associated use of these two markers as first choice of diagnostic aid in non-small cell lung cancer. Further measurements, including specificity studies in benign lung diseases, should be performed to confirm these results.

Genetics of hereditary colon cancer: a model for prevention

Accompanying the explosion of genetic information about cancer is the technology to allow a better understanding of carcinogenesis and tools that can be exploited in the diagnosis and management of cancers. The familial forms of colorectal cancer, including familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer offer the most tangible examples of potential improvements in mortality and morbidity incorporating molecular markers. This article reviews the current direct applications of molecular genetics in identifying the risk, prevention and management of colon cancer. The limitations and current controversies in the field are discussed, including research strategies being adopted to solve the remaining problems. Parallel strategies in familial breast cancer and ovarian cancer are being developed to bring the medical profession into the molecular age of cancer management.

[Use of a medium and long chain triglyceride mixture for parenteral nutrition in a university hospital: results of an internal audit]

OBJECTIVES

The aim of this study was to determine whether a medium and long chain triglyceride mixture for parenteral nutrition is used in accordance with indications and contraindications in hospital practice.

METHODS

Patient data recorded in 30 consecutive patients included illness, nutritional status, laboratory findings before nutrition as well as indications and contraindications for parenteral nutrition.

RESULTS

When expressed in g.kg-1.day-1 maximal recommended doses of the mixture were exceeded in 32% but there was no excess when expressed in g.kg-1.hr-1. Serious hepatic insufficiency was present in 11% of the patients, 38% had hypertriglyceridemia and one had serious coagulopathy. There were 3 contraindications for the mixture.

CONCLUSION

Indications for using this emulsion were respected, but there were contraindications in 45% of the cases. These contraindications are however questionable as is the daily dosage. Because the mixture seems better for use in many cases of parenteral nutrition, it would appear best to discuss the prescription case by case.

Three-dimensional shape reconstruction by phase-shifting shadow moire

Shadow moiré shows contour lines of an object with respect to a master grating plane; they result from the interference between the lines of the master grid and their shadow projected by a point source of light. In best cases the sensitivity of this procedure is a few tenths of a millimeter. The introduction of a phase-shifting procedure gives a better resolution, but the problem in practice is how can we shift the phase of the interferogram into shadow moiré? A complete study is presented showing the influence of different parameters. It is shown that only one possibility is available. Some applications to threedimensional shape reconstructions are presented with an accuracy of 0.01 mm, showing that the potentiality of shadow moiré is greatly improved.

[Anomalies of enamel formation in subjects with maxillary clefts]

A structural and ultrastructural study of teeth located in the vicinity of maxillary cleft and teeth located outside the cleft region, was made in 12 cases, using correlated light microscopy, microradiography and SEM. All teeth directly involved in cleft process presented gross hypoplasia of the crown where the enamel surface was hypomineralized. Globular calcified masses of different radiodensity were seen on the hypomineralized enamel surface. The teeth located outside the cleft region presented less pronounced anomalies constituted by isolated or group microhypoplasia on hypomineralized enamel. The observation of enamel pearl was not pathognomonic of maxillary cleft.

Structural and ultrastructural study of the teeth in a suspected case of pseudohypoparathyroidism

Two premolars removed from a 14 year old girl, with suspicion of pseudohypoparathyroidism (PHP) have been studied, using several of the correlated techniques applied to the study of calcified tissues (light microscopy, microradiography and scanning electron microscopy). Enamel gross and micro hypoplasia, hypomineralization of the enamel surface and dentin hypocalcification were similar to dental abnormalities observed in pseudohypoparathyroidism. Microradiography showed for the first time calcifications present in blood vessels of the dental pulp. Light microscopy and SEM revealed dystrophic globular calcifications within enamel hypoplastic pits. Cemental changes consisting of hypoplasia, aplasia, localized hyperplasia and cementicules were described for the first time. It is suggested that enamel, dentine and pulp abnormalities observed in the present case might be pathognomonic of PHP.

Genetic evidence for progressive selection and overgrowth of primary tumors by metastatic cell subpopulations

We have exploited random insertions of transfected DNA as unique clonotypic markers to follow cell lineages during primary and metastatic tumor growth of a mouse mammary adenocarcinoma, SP1. Southern analysis was undertaken of primary solid tumors and metastases obtained after injection of a pooled population of individual SP1 transfectants, or reconstituted mixtures of genetically marked metastatic and unmarked nonmetastatic cells. Here we provide evidence for the reproducible selection and eventual overgrowth of primary tumors by genotypically distinct metastatic clones, thereby illustrating that late-state, advanced primary tumors can evolve to become biologically similar, or even identical, to distant metastases. The selective growth advantage of metastatic cells within primary tumors was shown to occur despite the fact that tumors generated by both metastatic and nonmetastatic SP1 cell populations grew at comparable growth rates when injected and analyzed separately. The extent of the local growth advantage manifested by individual metastatic clones varied considerably, from 5- to 50-fold. Clonal overgrowth was also observed whether the tumor cells were injected ectopically, or orthotopically (i.e., into the mammary fat). This type of experimental approach should provide new insights into the dynamics of tumor progression and metastasis, the lineage relationship of primary tumors to metastases, the influence of clonal interactions on tumor behavior, and the physiological changes which are causative of malignant disease.

v-fps protein-tyrosine kinase coordinately enhances the malignancy and growth factor responsiveness of pre-neoplastic lung fibroblasts

The v-fps oncoprotein was expressed in a pre-neoplastic, growth factor-dependent Chinese hamster lung fibroblast line (CCL39) to study its effect on growth controls and on the induction of malignancy. Two transfectants were characterized which expressed low (39FPS-8) or high (51FPS-6) levels of P130gag-f ps protein-tyrosine kinase activity. 39FPS-8 cells still arrested in quiescence when deprived of growth factors, but developed an increased sensitivity to the mitogenic actions of epidermal growth factor (20-fold) and alpha-thrombin (50-fold), although not to insulin. In contrast, 51FPS-6 cells completely escaped growth controls, divided in serum-free medium, and were insensitive to further growth factor stimulation. Both transfectants produced rapidly growing tumors in nude mice that formed pulmonary metastases from a subcutaneous site, unlike the parental cells which are non-metastatic. 51FPS-6 cells were comparatively more efficient than 39FPS-8 cells in colonizing the lungs after intravenous inoculation. The v-fps tyrosine kinase therefore induces a partial to complete relaxation of growth factor-mediated controls on the CCL39 cell cycle, with the extent of factor independence reflecting the amount of P130gag-f ps synthesized. This reduction in growth factor requirements correlates with the capacity of v-fps to confer the attributes of metastatic tumors upon preneoplastic CCL39 fibroblasts. We speculate that increased sensitivity to growth factor stimulation represents a common mechanism by which tumor cells acquire metastatic properties.

Deregulation of hamster fibroblast proliferation by mutated ras oncogenes is not mediated by constitutive activation of phosphoinositide-specific phospholipase C

Stable expression of high levels of activated forms of Haras (T24) or v-Ki-ras by transfection of Chinese hamster lung fibroblasts (CCL39) yielded cells highly tumorigenic in nude mice. Two classes of transformed cells were distinguished, one with moderate p21 expression (10-fold increased) had retained growth factor dependency, the second with higher level of p21 (greater than 50-fold) appeared autonomous for growth. Neither class of transformants expressing Ki-ras or Ha-ras displayed a significant basal activity of polyphosphoinositide-specific phospholipase C, measured either in serum-starved cells or during exponential growth in the presence of growth factors of the tyrosine kinase family (EGF, FGF, insulin). In the growth-factor-dependent class of T24-Ha-ras-transfected cells (clone 39THaB), phospholipase C could be stimulated normally by serum, thrombin and AlF-4. In the more growth autonomous class (clones 39THaC and 39Ki9), release of inositol phosphates after stimulation with thrombin or serum was drastically reduced. This desensitization, apparently at the receptor level since the response to AlF-4 persisted, is, however, not specific to ras expression. We observed it to the same degree in polyoma virus-transformed CCL39 cells. Finally, expression of mutated forms of p21 ras did not abrogate the sensitivity of phospholipase C activation to pertussis toxin. We conclude that the transforming potential of activated forms of p21ras does not result from persistent activation of phospholipase C and that ras GTP-binding proteins cannot substitute for Gp.

[Murine cloned cells related to basophil-mast cell granulocytes, spontaneously cytotoxic toward tumor cells]

Two independent cloned cell lines were derived following the in vitro expansion of spleen and bone-marrow cells suspensions from DBA/2 Mice in the presence of a conditioned medium containing interleukin II. They exhibit a spontaneous cytotoxicity towards two tumors of leukemic origin. The presence of cytoplasmic granules, their staining properties, the typing of surface markers and enzyme activities suggest that they belong to the basophil-mast cell lineage.

Evidence for an electrogenic 3-deoxy-2-oxo-D-gluconate--proton co-transport driven by the protonmotive force in Escherichia coli K12

Evidence is presented indicating that the carrier-mediated uptake of 3-deoxy-2-oxo-D-gluconate and D-glucuronate in Escherichia coli K12 is driven by the deltapH and deltapsi components of the protonmotive force. 1. Approximately two protons enter the cells with each sugar molecule, independent of the sugar and the strain used. 2. In respiring cells, the magnitude of the pH gradient alone, as measured by distribution of [3H]acetate, appears to be insufficient to account for the chemical gradient of 3-deoxy-2-oxo-D-gluconate that is developed between pH 6.0 and 8.0. 3. If the external pH is varied between 5.5 and 8.0, 3-deoxy-2-oxo-D-gluconate uptake is gradually inhibited by valinomycin plus K+ ions, whereas the inhibition caused by nigericin is concomitantly relieved, thus reflecting the relative contribution of deltapH and deltapsi to the total protonmotive force at each external pH. 4. 3-Deoxy-2-oxo-D-gluconate can be transiently accumulated into isolated membrane vesicles in response to an artificially induced pH gradient. The process is stimulated when the membrane potential is collapsed by valinomycin in the presence of K+ ions.