Inflammatory malignant fibrous histiocytomas and dedifferentiated liposarcomas: histological review, genomic profile, and MDM2 and CDK4 status favour a single entity

Inflammatory malignant fibrous histiocytoma (inflammatory MFH) is a very rare tumour that occurs most often in the retroperitoneum. So far, it has been considered to be a special subtype of MFH. As it is now widely accepted that most retroperitoneal pleomorphic MFHs are dedifferentiated liposarcomas, the present study compared histological features, genomic profile (CGH analysis), and MDM2 and CDK4 status (immunohistochemistry, FISH, and quantitative PCR) in inflammatory MFHs from 12 patients and dedifferentiated liposarcomas that had an inflammatory MFH component from eight patients. Metaphase cytogenetic and FISH analyses were also performed on one inflammatory MFH. Histological review showed areas of well-differentiated liposarcoma in nine inflammatory MFHs. CGH analysis showed 12q13-15 amplification or gain in six of seven inflammatory MFHs and in seven of seven dedifferentiated liposarcomas. Immunohistochemistry showed positivity of tumour cells for MDM2 in every tumour in both groups and for CDK4 in ten and seven inflammatory MFHs and dedifferentiated liposarcomas, respectively. Metaphase cytogenetic and FISH analysis performed on one inflammatory MFH showed the presence of a supernumerary large marker chromosome and ring chromosome with high-level amplification of both MDM2 and CDK4 genes. FISH analysis on paraffin wax-embedded sections showed amplifications of MDM2 and CDK4 in seven of seven inflammatory MFHs and in seven of seven dedifferentiated liposarcomas. Quantitative PCR showed amplification of MDM2 in six and of CDK4 in seven of nine inflammatory MFHs. In conclusion, this study strongly suggests that most so-called inflammatory MFHs are dedifferentiated liposarcomas.     

Functional proteomics mapping of a human signaling pathway

Access to the human genome facilitates extensive functional proteomics studies. Here, we present an integrated approach combining large-scale protein interaction mapping, exploration of the interaction network, and cellular functional assays performed on newly identified proteins involved in a human signaling pathway. As a proof of principle, we studied the Smad signaling system, which is regulated by members of the transforming growth factor beta (TGFbeta) superfamily. We used two-hybrid screening to map Smad signaling protein-protein interactions and to establish a network of 755 interactions, involving 591 proteins, 179 of which were poorly or not annotated. The exploration of such complex interaction databases is improved by the use of PIMRider, a dedicated navigation tool accessible through the Web. The biological meaning of this network is illustrated by the presence of 18 known Smad-associated proteins. Functional assays performed in mammalian cells including siRNA knock-down experiments identified eight novel proteins involved in Smad signaling, thus validating this integrated functional proteomics approach.     

Heart tumors in children and adults: clinicopathological study of 59 patients from a surgical center.

BACKGROUND: Heart tumors are rare lesions with variegated histological types. Their clinicopathological features could be more comprehensively categorized. METHODS: This is a 19-year retrospective study of 17 infants/toddlers (<2 years of age) and 42 patients aged between 14 and 79 years (mean = 51.5) in a surgical center. RESULTS: Congenital tumors (n = 17; 29%), including rhabdomyomas (n = 9), ventricular fibromas (n = 6), and hemangiomas (n = 1), required surgery mainly because of mass effect. Familial myofibromatosis was the only embolic congenital lesion. Acquired benign tumors (n = 28; 47%) included myxomas (n = 21), fibroelastomas (n = 3), myofibroblastic inflammatory tumors (n = 2), and lipomas (n = 2). Eight (29%) were revealed by systemic embolization. These benign noncongenital tumors were all treated by complete resection, except for an incompletely resected lipoma of the mitral valve. Postoperative arrhythmia (n = 1) and pericardial effusion (n = 3) were the only complications. Primary sarcomas (n = 8; 14%) were mostly vascular tumors (five of eight), and patients with high-grade tumors had a mean survival of 15 months (n = 5). Cardiac metastases (n = 6; 10%) were from carcinomas (n = 3) or sarcomas (n = 3); apart from a necrotic metastasis, all patients died (mean survival of 6 months). CONCLUSIONS: This study shows that, regardless of patients' age, heart tumors can be classified as: (a) congenital lesions, which are spontaneously nonprogressive or regressive lesions possibly requiring surgery mainly because of mass effect; (b) acquired benign tumors, which are lesions requiring surgery often because of embolization risk; and (c) primary and secondary malignant tumors, which are lesions with globally poor prognosis but with some indications for resection.     

Molecular epidemiology of Pseudomonas aeruginosa colonization in a burn unit: persistence of a multidrug-resistant clone and a silver sulfadiazine-resistant clone

To study the epidemiology of Pseudomonas aeruginosa colonization in a 32-bed burn wound center (BWC), 321 clinical and 45 environmental P. aeruginosa isolates were collected by prospective surveillance culture over a 1-year period and analyzed by serotyping, drug susceptibility testing, and amplified fragment length polymorphism (AFLP) analysis. Among 441 patients treated at the center, 70 (16%) were colonized with P. aeruginosa, including 12 (17%) patients who were colonized on admission and 58 (83%) patients who acquired the organism during their stay. Of the 48 distinct AFLP genotypes found, 21 were found exclusively in the environment, 15 were isolated from individual patients only, and 12 were responsible for the colonization of 57 patients, of which 2 were also isolated from the environment, but secondary to patient carriage. Polyclonal P. aeruginosa colonization with strains of two to four genotypes, often with different antibiotic susceptibility patterns, was observed in 19 patients (27%). Two predominant genotypes were responsible for recurrent outbreaks and the colonization of 42 patients (60% of all colonized patients). The strain with one of those genotypes appeared to be endemic to the BWC and developed multidrug resistance (MDR) at the end of the study period, whereas the strain with the other genotype was antibiotic susceptible but resistant to silver sulfadiazine (SSD(r)). The MDR strain was found at a higher frequency in sputum samples than the SSD(r) strain, which showed a higher prevalence in burn wound samples, suggesting that anatomic habitat selection was associated with adaptive resistance to antimicrobial drugs. Repeated and thorough surveys of the hospital environment failed to detect a primary reservoir for any of those genotypes. Cross-acquisition, resulting from insufficient compliance with infection control measures, was the major route of colonization in our BWC. In addition to the AFLP pattern and serotype, analysis of the nucleotide sequences of three (lipo)protein genes (oprI, oprL, and oprD) and the pyoverdine type revealed that all predominant strains except the SSD(r) strain belonged to recently identified clonal complexes. These successful clones are widespread in nature and therefore predominate in the patient population, in whom variants accumulate drug resistance mechanisms that allow their transmission and persistence in the BWC.     

Assessing the magnitude of the HIV/AIDS epidemic in Burma

OBJECTIVES: Estimates of the HIV/AIDS burden in Burma (Myanmar) are uncertain. Using data from the 1999 national HIV sentinel surveillance and available population data, we generated estimates of Burma's HIV burden in 1999. METHODOLOGY: The 1999 sentinel surveillance included women attending antenatal clinics, male military recruits, blood donors, injecting drug users, patients of sexually transmitted disease clinics, and sex workers. We used data for women attending antenatal clinics and male recruits aged 20-29 years to estimate HIV prevalence among women and men, respectively. Data points were merged to give five regional estimates of prevalence for men and women. Census figures were used to obtain national population estimates of the numbers of Burmese living with HIV infection, along with confidence intervals (CIs). RESULTS: HIV prevalence varied by region, with the lowest rates in the West, intermediate rates in the central region, and highest rates in the North, East, and South. The highest rates were in the East (Shan State), with female prevalence of 3.0% (95% CI, 1.9-4.5). The total number of infected women nationwide was 218,300 (95% CI, 159,400-277,100), and that of men was 468,700 (95% CI, 343,300-594,200). We estimated HIV prevalence of at least 3.46% (95% CI, 2.72-4.19) among adults aged 15-44 years; 5700 infants were born with HIV infection in 1999. DISCUSSION: Burma has a generalized epidemic of HIV-1 in reproductive age adults. We estimated that there were 687,000 (95% CI, 541,100-832,900) Burmese adults living with HIV infection in 1999, or about one of every 29 adult citizens. This estimate is higher than the UNAIDS estimate for the same year of 530,000 adults and children living with AIDS, or a population prevalence of about one in 50 adults. HIV prevention and care programs are urgently needed in Burma.     

Daytime sleepiness during Ramadan intermittent fasting: polysomnographic and quantitative waking EEG study

During the lunar month of Ramadan, Muslims abstain from eating, drinking and smoking from sunrise to sunset. We reported previously that Ramadan provokes a shortening in nocturnal total sleep time by 40 min, an increase in sleep latency, and a decrease in slow-wave sleep (SWS) and rapid eye movement (REM) sleep duration during Ramadan. During the same study, the effects of Ramadan intermittent fasting on daytime sleepiness were also investigated in eight healthy young male subjects using a quantitative waking electroencephalograph (EEG) analysis following the multiple sleep latency test (MSLT) procedure. This procedure was combined with subjective alertness and mood ratings and was conducted during four successive experimental sessions: (1) baseline (BL) 15 days before Ramadan, (2) beginning of Ramadan (R11) on the 11th day of Ramadan, (3) end of Ramadan (R25) on the 25th day of Ramadan, (4) recovery 2 weeks after Ramadan (AR). During each session, four 20-min nap opportunities (MSLTs) were given at 10:00, 12:00, 14:00 and 16:00 h and were preceded by rectal temperature readings. Nocturnal sleep was recorded before each daytime session. Subjective daytime alertness did not change in R25 but decreased in R11 at 12:00 h, and subjective mood decreased at 16:00 h, both in R11 and R25. During the MSLT, mean sleep latency decreased by an average of 2 min in R11 (especially at 10:00 and 16:00 h) and 6 min in R25 (especially at 10:00 and 12:00 h) compared with BL. There was an increase in the daily mean of waking EEG absolute power in the theta (5.5-8.5 Hz) frequency band. Significant correlations were found between sleep latency during the MSLT and the waking EEG absolute power of the fast alpha (10.5-12.5 Hz), sigma (11.5-15.5 Hz) and beta (12.5-30 Hz) frequency bands. Sleep latency was also related to rectal temperature. In conclusion, Ramadan diurnal fasting induced an increase in subjective and objective daytime sleepiness associated with changes in diurnal rectal temperature.     

POL32, a subunit of the Saccharomyces cerevisiae DNA polymerase δ, defines a link between DNA replication and the mutagenic bypass repair pathway

Pol32 is a subunit of Saccharomyces cerevisiae DNA polymerase δ required in DNA replication and repair. To gain insight into the function of Pol32 and to determine in which repair pathway POL32 may be involved, we extended the analysis of the pol32Δ mutant with respect to UV and methylation sensitivity, UV-induced mutagenesis; and we performed an epistasis analysis of UV sensitivity by combining the pol32Δ with mutations in several genes for postreplication repair (RAD6 group), nucleotide excision repair (RAD3 group) and recombinational repair (RAD52 group). These studies showed that pol32Δ is deficient in UV-induced mutagenesis and place POL32 in the error-prone RAD6/REV3 pathway. We also found that the increase in the CAN1 spontaneous forward mutation of different rad mutators relies entirely or partially on a functional POL32 gene. Moreover, in a two-hybrid screen, we observed that Pol32 interacts with Srs2, a DNA helicase required for DNA replication and mutagenesis. Simultaneous deletion of POL32 and SRS2 dramatically decreases cellular viability at 15 °C and greatly increases cellular sensitivity to hydroxyurea at the permissive temperature. Based on these findings, we propose that POL32 defines a link between the DNA polymerase and helicase activities, and plays a role in the mutagenic bypass repair pathway. Received: 25 May 2000 / Accepted: 3 July 2000     

Construction and characterization of affibody-Fc chimeras produced in Escherichia coli

Affibody-Fc chimeras were constructed by genetic fusion between different affibody affinity proteins with prescribed specificities and an Fc fragment derived from human IgG. Using affibody ligands previously selected for binding to respiratory syncytial virus (RSV) surface protein G and Thermus aquaticus (Taq) DNA polymerase, respectively, affibody-Fc fusion proteins showing spontaneous Fc fragment-mediated homodimerization via disulfide bridges were produced in Escherichia coli and affinity purified on protein A Sepharose from bacterial periplasms at yields ranging between 1 and 6 mg/l culture. Further characterization of the chimeras using biosensor technology showed that the affibody moieties have retained high selectivities for their respective targets after fusion to the Fc fragment. Avidity effects in the target binding were observed for the affibody-Fc chimeras compared to monovalent affibody fusion proteins, indicating that both affibody moieties in the chimeras were accessible and contributed in the binding. Fusion of a head-to-tail dimeric affibody moiety to the Fc fragment resulted in tetravalent affibody constructs which showed even more pronounced avidity effects. In addition, the Fc moiety of the chimeras was demonstrated to be specifically recognized by anti-human IgG antibody enzyme conjugates. One application for this class of "artificial antibodies" was demonstrated in a western blotting experiment in which one of the anti-RSV surface protein G affibody-Fc chimeras was demonstrated to be useful for specific detection of the target protein in a complex background consisting of a total E. coli lysate. The results show that through the replacement of the Fab portion of an antibody for an alternative binding domain based on a less complicated structure, chimeric proteins compatible with bacterial production routes containing both antigen recognition domains and Fc domains can be constructed. Such "artificial antibodies" should be interesting alternatives to, for example, whole antibodies or scFv-Fc fusions as detection devices and in diagnostic or therapeutic applications.     

Mouse macrophage development in the absence of the common γ chain: defining receptor complexes responsible for IL-4 and IL-13 signaling

The common γ chain (γ_c) forms a critical component of the receptors for interleukins (IL)-2, IL-4, IL-7, IL-9, and IL-15. We analyzed γ_c-deficient mice to define a role for γ_c signaling in the development and function of the macrophage lineage. No major differences in absolute cell numbers, cell surface phenotype, or in vitro function of γ^?_c compared to γ⁺_c macrophages were observed. We therefore conclude that signaling through the γ_c chain is not essential for the differentiation of mouse macrophages. Although B and T cells require γ_c for IL-4 responses, IL-4 up-regulated major histocompatibility class II molecules and inhibited nitric oxide production from γ^?_c macrophages following stimulation with lipopolysaccharide and interferon-γ. γ^?_c macrophages could also respond to IL-13, consistent with the model of a type II IL-4 receptor α/IL-13R which can function in the absence of γ_c. Both IL-4 and IL-13 responses could be completely inhibited with the mouse IL-4 antagonist QY, suggesting that all of the observed IL-13 responses pass through the type II receptor, making it the primary signaling receptor complex for IL-13 in mouse macrophages.