Deciphering oxygen distribution and hypoxia profiles in the tumor microenvironment: a data-driven mechanistic modeling approach.

Objective. The distribution of hypoxia within tissues plays a critical role in tumor diagnosis and prognosis. Recognizing the significance of tumor oxygenation and hypoxia gradients, we introduce mathematical frameworks grounded in mechanistic modeling approaches for their quantitative assessment within a tumor microenvironment. By utilizing known blood vasculature, we aim to predict hypoxia levels across different tumor types.Approach. Our approach offers a computational method to measure and predict hypoxia using known blood vasculature. By formulating a reaction-diffusion model for oxygen distribution, we derive the corresponding hypoxia profile.Main results. The framework successfully replicates observed inter- and intra-tumor heterogeneity in experimentally obtained hypoxia profiles across various tumor types (breast, ovarian, pancreatic). Additionally, we propose a data-driven method to deduce partial differential equation models with spatially dependent parameters, which allows us to comprehend the variability of hypoxia profiles within tissues. The versatility of our framework lies in capturing diverse and dynamic behaviors of tumor oxygenation, as well as categorizing states of vascularization based on the dynamics of oxygen molecules, as identified by the model parameters.Significance. The proposed data-informed mechanistic method quantitatively assesses hypoxia in the tumor microenvironment by integrating diverse histopathological data and making predictions across different types of data. The framework provides valuable insights from both modeling and biological perspectives, advancing our comprehension of spatio-temporal dynamics of tumor oxygenation.

Automated Measurements of Key Morphological Features of Human Embryos for IVF.

A major challenge in clinical In-Vitro Fertilization (IVF) is selecting the highest quality embryo to transfer to the patient in the hopes of achieving a pregnancy. Time-lapse microscopy provides clinicians with a wealth of information for selecting embryos. However, the resulting movies of embryos are currently analyzed manually, which is time consuming and subjective. Here, we automate feature extraction of time-lapse microscopy of human embryos with a machine-learning pipeline of five convolutional neural networks (CNNs). Our pipeline consists of (1) semantic segmentation of the regions of the embryo, (2) regression predictions of fragment severity, (3) classification of the developmental stage, and object instance segmentation of (4) cells and (5) pronuclei. Our approach greatly speeds up the measurement of quantitative, biologically relevant features that may aid in embryo selection.

Lactoferrin concentration in breast milk of mothers of low-birth-weight newborns.

OBJECTIVES: Lactoferrin (LF) is a breast milk glycoprotein with protective effects against neonatal infections, mainly in premature and low-birth-weight (LBW) neonates. The aims of this study were to determine LF concentration in breast milk of mothers of LBW infants during the first 2 months postpartum, and to identify the factors associated with LF concentration. STUDY DESIGN: Prospective study conducted as a part of an ongoing clinical trial in three Neonatal Units in Peru. We included 346 mothers of neonates with a birth weight <2000 g. We measured LF concentration in four stages of lactation using a commercial enzyme-linked immunosorbent assay kit. Multivariate analysis was performed to assess the association between maternal and neonatal factors, and LF concentration. RESULTS: We collected 695 milk samples. LF mean concentration±standard deviation was 14.92±7.96 mg ml-1 in colostrum (n=277), 10.73±5.67 in transitional milk (n=55), 10.34±6.27 at 1 month (n=259) and 8.52±6.47 at 2 months (n=104). There was a significant difference in LF concentration between different stages of lactation (P<0.001). Mothers with higher LF concentration in colostrum had higher values in the following 2 months. High maternal income and multiple gestation were significantly associated with higher LF levels; in contrast, maternal peripartum infections and male neonatal gender were associated with lower LF levels. CONCLUSIONS: LF concentration in breast milk of mothers of LBW infants was high and remained elevated even at 1 and 2 months postpartum. LF concentration in colostrum was higher in mothers with higher income and multiple pregnancies, and lower in mothers with peripartum infections.

Manejo endovascular de las complicaciones agudas de la disección aórtica tipo B / Endovascular management of acute complications of type b aortic dissection

Background: Type B aortic dissection is usually managed by intensive care medical therapy and surgery is reserved for treating the complications that can occur during the evolution of a case. Aim: To assess the endovascular management of acute complications of type B aortic dissection and the closure of the intimal defect and aortic false lumen. Material and Methods: Retrospective analysis of 8 consecutive patients aged 40 to 57 years (seven males) treated for acute complications in the initial episode of a type B aortic dissection between August 2006 and July 2008. Results: Six/eight were known hypertensive patients. The indications for surgery were intractable pain in one, hypertension refractory to treatment in two and distal hypoperfusion in fve. Five patients required covering of the left subclavian artery ostium, without need for surgical repair. One patient was subjected to renal angioplasty and stenting. Technical success was achieved in all cases, with complete closure of the proximal aortic tear and thoracic aortic false lumen, although 7 of patients had a persistent distal aortic false lumen. One case had a transient lower limb paraparesis. No patient died. Conclusions: Endovascular treatment is effective in closing the aortic tear as well as the thoracic aortic false lumen in aortic type B dissections with a low complication rate. Due to the high frequency of distal aortic false lumen persistence, it is not a defnitive treatment for this condition but it is useful for the acute complications of the initial phase of type B aortic dissection.

The impact of social desirability biases on self-report among college student and problem gamblers.

The impacts of two types of social desirability bias, self-deceptive enhancement (SDE) and impression management (IM), were examined on self-reports of gambling problems, measured by the South Oaks Gambling Screen (SOGS), and recent gambling behavior, as measured by the Timeline Followback (TLFB) method, in a sample of college students (N = 191), and a sample of treatment-seeking problem gamblers (N = 49). Consistent with our expectations, IM was negatively associated with SOGS scores in both samples. IM was most highly correlated with SOGS scores among treatment-seeking participants (r = -.44, p < .01). Substantial numbers of participants in both samples had high enough IM scores as to call into question the validity of their self-report gambling data, according to published interpretive guidelines. With respect to SDE, we had predicted that it would be positively related to gambling behaviors and gambling-related problems, but found that SDE was inversely related to SOGS scores in both samples. Very little evidence was found for social desirability effects on TLFB scores. Thus, preliminary evidence was obtained that self-report data on gambling problems, but not on gambling behavior (frequency of gambling and amount of time and money spent), may be susceptible to the effects of impression management in both college students and treatment-seeking gamblers.

The LIM-only protein FHL2 is a negative regulator of E4F1.

The E1A-targeted transcription factor E4F1 is a key player in the control of mammalian embryonic and somatic cell proliferation and survival. Mouse embryos lacking E4F die at an early developmental stage, whereas enforced expression of E4F1 in various cell lines inhibits cell cycle progression. E4F1-antiproliferative effects have been shown to depend on its capacity to repress transcription and to interact with pRb and p53. Here we show that full-length E4F1 protein (p120(E4F1)) but not its E1A-activated and truncated form (p50(E4F1)), interacts directly in vitro and in vivo with the LIM-only protein FHL2, the product of the p53-responsive gene FHL2/DRAL (downregulated in rhabdomyosarcoma Lim protein). This E4F1-FHL2 association occurs in the nuclear compartment and inhibits the capacity of E4F1 to block cell proliferation. Consistent with this effect, ectopic expression of FHL2 inhibits E4F1 repressive effects on transcription and correlates with a reduction of nuclear E4F1-p53 complexes. Overall, these results suggest that FHL2/DRAL is an inhibitor of E4F1 activity. Finally, we show that endogenous E4F1-FHL2 complexes form in U2OS cells upon UV-light-induced nuclear accumulation of FHL2.

Atrapamiento de la arteria poplítea: Comunicación de un caso / Popliteal artery entrampment: Report of one case

Popliteal artery entrampment is a rare condition, occurring in young subjects, that causes ischemia of the extremity. The anatomical background is the compression or occlussion of the popliteal artery caused by forced plantar or dorsal flexion. We report a 32 year-old sportsman who presented with gangrene of the right first toe and a history of three months of progressive claudication. The Ankle-Brachial index and pulse volume curve registries showed a severe ischemia below the knee. Angiography showed a medial deviation of the popliteal artery associated to stenosis and aneurysm formation. A CT scan of the contralateral artery was normal. The patient was operated using a posterior approach, performing a reverse saphenous vein bypass graft and excising the popliteal artery. The postoperative period was uneventful.

Node-link-mapping-enhanced group treatment for pathological gambling.

Two experiments evaluated a group treatment for pathological gambling that used node-link mapping techniques to enhance treatment effectiveness. In Experiment 1, 13 (8 female) pathological gamblers were randomly assigned to either a mapping group (n=4), a nonmapping group (n=4), or a wait-list control group (n=5). The treatments were conducted by Master's level counselors during 90-min sessions conducted twice per week for 8 weeks. Participants were assessed pre- and post-8 weeks and then 6 months later on Diagnostic and Statistical Manual of Mental Disorders 4th ed. (DSM-IV) pathological gambling criteria, three self-ratings of control of gambling, gambling expenditure, and gambling bout duration. Experiment 2 replicated the mapping (n=9; 8 female) and wait-list (n=10; 8 female) conditions of Experiment 1 and expanded the dependent measures to include assessment of changes in cooccurring depression and anxiety. The node-link-mapping-enhanced group treatment produced improvements in more of the dependent measures of pathological gambling than treatment without maps (Experiment 1) or an equivalent-length waiting period (Experiments 1 and 2). It also produced larger decreases in cooccurring depression and anxiety than an equivalent-length waiting period (Experiment 2). The results are consistent with previous treatment research with substance abusers.

A current review of Ebola virus: pathogenesis, clinical presentation, and diagnostic assessment.

Ebola hemorrhagic fever (EHF) is an acute viral syndrome that presents with fever and an ensuing bleeding diathesis that is marked by high mortality in human and nonhuman primates. Fatality rates are between 50% and 100%. Due to its lethal nature, this filovirus is classified as a biological class 4 pathogen. The natural reservoir of the virus is unknown. As a result, little is understood about how Ebola virus is transmitted or how it replicates in its host. Although the primary source of infection is unknown, the epidemiologic mode of transmission is well defined. A variety of tests have proven to be specific and useful for Ebola virus identification. There is no FDA-approved antiviral treatment for EHF. Incubation ranges from 2 to 21 days. Patients who are able to mount an immune response to the virus will begin to recover in 7 to 10 days and start a period of prolonged convalescence. Supportive management of infected patients is the primary method of treatment, with particular attention to maintenance of hydration, circulatory volume, blood pressure, and the provision of supplemental oxygen. Since there is no specific treatment outside of supportive management and palliative care, containment of this potentially lethal virus is paramount. In almost all outbreaks of EHF, the fatality rate among health care workers with documented infections was higher than that of non-health care workers.

Puentes infrainguinales en enfermedad arterial oclusiva / Infrainguinal bypass in occlusive arterial disease

Los puentes infrainguinales se ha constituido en una alternativa de manejo reconstructivo de la enfermedad arterial oclusiva de las extremidades inferiores, especialmente en casos de isquemia crítica (necrosis o dolor de reposo). En un período de 3 años (1995 a 1997) se realizaron 91 puentes infrainguinales en el Servicio de Cirugía del Hospital Salvador, la mayoría por isquemia crítica (93,4 por ciento). Los pacientes tenían un promedio de edad de 68,6 años. En relación a la técnica quirúrgica, en 76 casos se utilizó material autólogo, principalmente vena safena. En serie 2 pacientes fallecieron (2,2 por ciento mortalidad), por complicaciones médicas, que fueron las más frecuentes y graves, especialmente las cardiovasculares. Al alta, 78 puentes estaban funcionando (85,7 éxito inicial) y el salvamento de las extremidades revascularizadas fue del 81 por ciento, 79 por ciento a los 12,24 y 48 meses de seguimiento, respectivamente, lo que constituye un muy buen resultado del tratamiento, especialmente si se considera que la alternativa es la amputación y que se trata de una población de alto riesgo por edad y frecuencia de patología asociadas

Tromboembolismo pulmonar como causa de muerte intrahospitalaria: correlación clinicopatológica / Pulmonary thromboembolism as cause of hospitalary death: clinic-pathological correlation

Se estudió la frecuencia de tromboembolismo pulmonar (TEP) fatal entre los pacientes fallecidos entre 1989-1998 en 4 establecimientos del Servicio de Salud Metropolitano Oriente (SSMO) sometidos a autopsia, el diagnóstico antemortem, correlacionar la clínica con diagnóstico y estudiar profilaxis y tratamiento. Se revisaron las necropsias entre 1989-1998, identificando las que tenían como causa de muerte o factor contributivo importante el TEP venoso. Se efectuaron 1.510 autopsias entre 6.147 fallecidos (25 por ciento), encontrándose 99 TEP venoso: 6,6 por ciento intervalo de confianza (IC) 95 por ciento; 6,61-6,59 por ciento, como causa de muerte o factor contributivo importante. El TEP no se sospechó en 70 casos (70,6 por ciento, IC 95 por ciento; 70,69-70,51 por ciento), sí en 29 (29,4 por ciento IC 95 por ciento; 29,49-29,31 por ciento). El diagnóstico continúa siendo difícil por la inespecificidad de los síntomas. El TEP aparece como complicación final en algunos enfermos terminales, pero un grupo mucho más numeroso vería disminuida su morbimortalidad si aumentara el conocimiento de esta entidad y se hiciera habitual el uso de profilaxis

Processing of the insulin-like growth factor-II-mannose 6-phosphate receptor in isolated liver subcellular fractions.

A truncated, soluble form of the insulin-like growth factor-II-mannose 6-phosphate (IGF-II-M6P) receptor has been identified in serum and shown to be released from cultured tissues and cells, liver being the main contributor to serum receptor in adult rats. In the present study, the processing of the IGF-II-M6P receptor has been characterized in isolated liver subcellular fractions using ligand binding, affinity crosslinking, and Western immunoblotting techniques. The receptor in plasma membrane fractions differed from that in Golgi-endosomal fractions by: (i) a lower molecular size upon reducing polyacrylamide gel electrophoresis (245 vs. 255 kDa); (ii) a less tight membrane association as judged upon extractibility by NaCI; and (iii) the inability to recognize antibody anti-22C, directed against the cytoplasmic domain of the receptor. Incubation of cell fractions at 30 degrees C led to a pH- and time-dependent release of the receptor into the medium. The pH optimum for release was 5.5 in the Golgi-endosomal fraction and 7.5 in plasma membrane fractions; at this pH, approximately 2% and 20%-30% of total receptors were released per hour, respectively. Receptor release was inhibited in a dose-dependent manner by aprotinin, benzamidine, and leupeptin in the Golgi-endosomal fraction, and by 1,10 phenanthroline in plasma membrane fractions, although high concentrations were required for inhibition. The receptor released from Golgi-endosomes showed a 5-10 kDa reduction in size and a loss of ability to recognize antibody anti-22C, but that released from plasma membranes showed little or no changes in size. We conclude that soluble, carboxy-terminally truncated forms of the IGF-II-M6P receptor are generated from the intact receptor in isolated Golgi-endosomal and plasma membrane fractions. However, receptor processing in these fractions exhibits different properties, suggesting the involvement of different proteases.

The periodic down regulation of Cyclin E gene expression from exit of mitosis to end of G(1) is controlled by a deacetylase- and E2F-associated bipartite repressor element.

The expression of cyclin E and that of a few other bona fide cell cycle regulatory genes periodically oscillates every cycle in proliferating cells. Although numerous experiments have documented the role of E2F sites and E2F activities in the control of these genes as cells exit from G(0) to move through the initial G(1)/S phase transition, almost nothing is known on the role of E2Fs during the subsequent cell cycles. Here we show that a variant E2F-site that is part of the Cyclin E Repressor Module (CERM) (Le Cam et al., 1999b) accounts for the periodic down regulation of the cyclin E promoter observed between the exit from mitosis until the mid/late G(1) phase in exponentially cycling cells. This cell cycle-dependent repression correlates with the periodic binding of an atypical G(1)-specific high molecular weight p107-E2F complex (Cyclin E Repressor Complex: CERC2) that differs in both size and DNA binding behaviors from known p107-E2F complexes. Notably, affinity purified CERC2 displays a TSA-sensitive histone deacetylase activity and, consistent with this, derepression of the cyclin E promoter by trichostatin A depends on the CERM element. Altogether, this shows that the cell cycle-dependent control of cyclin E promoter in cycling cells is embroiled in acetylation pathways via the CERM-like E2F element.

pRB binds to and modulates the transrepressing activity of the E1A-regulated transcription factor p120E4F.

The retinoblastoma protein pRB is involved in the transcriptional control of genes essential for cell cycle progression and differentiation. pRB interacts with different transcription factors and thereby modulates their activity by sequestration, corepression, or activation. We report that pRB, but not p107 and p130, binds to and facilitates repression by p120(E4F), a ubiquitously expressed GLI-Kruppel-related protein identified as a cellular target of E1A. The interaction involves two distinct regions of p120(E4F) and the C-terminal part of pRB. In vivo pRB-p120(E4F) complexes can only be detected in growth-arrested cells, and accordingly contain the hypophosphorylated form of pRB. Repression of an E4F-responsive promoter is strongly increased by combined expression of p120(E4F) and pRB, which correlates with pRB-dependent enhancement of p120(E4F) binding activity. Elevated levels of p120(E4F) have been shown to block growth of mouse fibroblasts in G(1). We find this requires pRB, because RB(-/-) fibroblasts are significantly less sensitive to excess p120(E4F).

A CDE/CHR-like element mediates repression of transcription of the mouse RB2 (p130) gene.

The bipartite repressor elements, termed cell cycle-dependent element (CDE)/cell cycle regulatory element (CCRE)-cell cycle homology region (CHR) control the growth-dependent transcription of the cyclin A, cdc25C, cdc2 genes. Here, we have identified a functional element displaying the signature of the CDE-CHR in the promoter of the mouse RB2 (p130) gene, encoding the retinoblastoma protein family (pRB)-related protein p130. This element locates close to the major transcription start site where it makes major groove contacts with proteins that can be detected in a cellular context using in vivo genomic footprinting techniques. Inactivation of either the CDE or CHR sequence strongly up-regulates the p130 promoter activity in exponentially growing cells, a situation where endogenous p130 gene expression is almost undetectable. Electrophoretic mobility shift assays suggest that two different protein complexes bind independently to the p130 CDE and CHR elements, and that the protein(s) bound to the CDE might be related to those bound on cyclin A and cdc2 promoters.

Human E2F5 gene is oncogenic in primary rodent cells and is amplified in human breast tumors.

E2F transcription factors (E2F1 to 6) are central players in the control of animal cell proliferation as regulators of genes involved in cell cycle progression and in transformation. In this report, we have investigated the potential involvement of the E2F5 gene in tumorigenesis. We show that E2F5 can promote the formation of morphologically transformed foci in primary baby rat kidney cells (BRK) when it is overexpressed in the presence of its heterodimeric partner DP1 and activated RAS. This suggests that E2F5 behaves like a MYC-type cooperating oncogene in functional assays, prompting us to monitor potential amplifications of the E2F5 gene in primary human tumors. We mapped the human E2F5 gene to 8q21.1-21.3 equidistant from the MOS (8q12) and MYC (8q24) oncogenes. Since the long arm of chromosome 8 is frequently the site of increased gene copy number (ICN) in breast cancer, we screened 442 breast tumor DNAs for gains of E2F5, MOS, and MYC genes. The three genes showed ICN, albeit at variable incidence and levels of amplification, with the ICN of E2F5 occurring concomitantly with those of MOS and/or MYC in almost half of the cases. Moreover, a marked increase of the 2. 5-kb E2F5 transcript was also detected in some tumors and tumor cell lines. In conclusion, the evidence that sustained unregulated expression of E2F5 can cooperate with other oncogenes to promote cell transformation in functional assays, together with the detection of chromosomal amplifications and overexpressions of the E2F5 gene in breast tumors, provides the first indications that E2F5 deregulation may have a role in human tumor development.

Insulin-induced redistribution of the insulin-like growth factor II/mannose 6-phosphate receptor in intact rat liver.

The ability of acute insulin treatment to elicit a redistribution of the liver insulin-like growth factor-II/ mannose 6-phosphate (IGF-II/M6P) receptor has been studied in rats, using cell fractionation. Injection of insulin (0.4-50 microg) led to a time- and dose-dependent decrease in IGF-II binding activity in Golgi-endosomal (GE) fractions, along with an increase in activity in the plasma membrane (PM) fraction; only receptor number was affected. Quantitative subfractionation of the microsomal fraction on sucrose density gradients showed that IGF-II binding activity distributed similarly to galactosyltransferase (a Golgi marker), at slightly higher densities than in vivo internalized (125)I-insulin, and at lower densities than 5' nucleotidase and alkaline phosphodiesterase (two plasma membrane markers). Insulin treatment led to a slight time-dependent and reversible shift of IGF-II binding activity toward higher densities. Subfractionation of the GE fraction on Percoll gradients showed that IGF-II binding activity was broadly distributed, with about 60% at low densities coinciding with galactosyltransferase and early internalized (125)I-insulin and with 40% at high densities in the region of late internalized (125)I-insulin. Insulin treatment caused a time-dependent and reversible shift of the distribution of IGF-II binding activity toward low densities. On SDS-PAGE, the size of the affinity-labeled IGF-II/M6P receptor was comparable in GE and PM fractions (about 255 kDa), but on Western blots receptor size was slightly lower in the latter (245 kDa) than in the former (255 kDa). Insulin treatment did not affect the size, but modified the abundance of the IGF-II/M6P receptor in a manner similar to that of IGF-II binding. In vivo chloroquine treatment fully suppressed the changes in IGF-II binding activity in liver GE and PM fractions observed in insulin-treated rats. We conclude that insulin elicits a time-dependent and reversible redistribution of liver IGF-II receptors from Golgi elements and endosomes to the plasma membrane, presumably via early endosomes.

Erythroid-specific inhibition of the tal-1 intragenic promoter is due to binding of a repressor to a novel silencer.

The basic helix-loop-helix tal-1 gene plays a key role in hematopoiesis, and its expression is tightly controlled through alternative promoters and complex interactions of cis-acting regulatory elements. tal-1 is not expressed in normal T cells, but its transcription is constitutive in a large proportion of human T cell leukemias. We have previously described a downstream initiation of tal-1 transcription specifically associated with a subset of T cell leukemias that leads to the production of NH(2)-truncated TAL-1 proteins. In this study, we characterize the human promoter (promoter IV), embedded within a GC-rich region in exon IV, responsible for this transcriptional activity. The restriction of promoter IV usage is assured by a novel silencer element in the 3'-untranslated region of the human gene that represses its activity in erythroid but not in T cells. The silencer activity is mediated through binding of a tissue-specific nuclear factor to a novel protein recognition motif (designated tal-RE) in the silencer. Mutation of a single residue within the tal-RE abolishes both specific protein binding and silencing activity. Altogether, our results demonstrate that the tal-1 promoter IV is actively repressed in cells of the erythro-megakaryocytic lineage and that this repression is released in leukemic T cells, resulting in the expression of the tal-1 truncated transcript.

Inhibition of mammalian cell proliferation by genetically selected peptide aptamers that functionally antagonize E2F activity.

The p16-cyclin D-pRB-E2F pathway is frequently deregulated in human tumors. This critical regulatory pathway controls the G1/S transition of the mammalian cell cycle by positive and negative regulation of E2F-responsive genes required for DNA replication. To assess the value of the transcription factors E2Fs as targets for antiproliferative strategies, we have initiated a program aiming to develop inhibitors targeting specifically these proteins in vitro and in vivo. The cellular activity of E2F is the result of the heterodimeric association of two families of proteins, E2Fs and DPs, which then bind DNA. Here, we use a two hybrid approach to isolate from combinatorial libraries peptide aptamers that specifically interact with E2Fs DNA binding and dimerization domains. One of these is a potent inhibitor of E2F binding activity in vitro and in mammalian fibroblasts, blocks cells in G1, and the free variable region from this aptamer has the same effect. Our experiments argue that the variable region of this aptamer is structured, and that it functions by binding E2F with a motif that resembles a DP heterodimerization region, and blocking E2F's association with DP. These results show that cell proliferation can be inhibited using genetically-selected synthetic peptides that specifically target protein-protein interaction motifs within cell cycle regulators. These results also emphasize the critical role of the E2F pathway for cell proliferation and might allow the design of novel antiproliferative agents targeting the cyclin/CDK-pRB-E2F pathway.