Tomoscintigraphy for detecting gastrointestinal and medullary thyroid cancers: first clinical results using radiolabelled monoclonal antibodies against carcinoembryonic antigen.

Transaxial tomoscintigraphy (or single-photon emission computerised tomography) was used to detect secondary deposits of carcinoma in 17 patients who had been injected with iodine-131-labelled monoclonal antibodies against carcinoembryonic antigen. Of 17 tumor sites studied by tomoscintigraphy 16 were detected (sensitivity 94%); five sites had a volume smaller than 10 cm3. Tomoscintigraphy also detected three unknown tumour deposits later confirmed by surgery or radiology. In contrast, when 21 tumour sites in the same patients were studied by rectilinear scintigraphy, only nine tumour sites were detected (sensitivity 43%), of which eight had a volume larger than 50 cm3.     

Evidence for two forms of phospholipase A2 in human semen

The molecular weight of the active unit of phospholipase A₂ (PA₂) in human seminal plasma and spermatozoa was determined using the radiation inactivation technique. Fresh spermatozoa possess more than one form of PA₂ activity as judged by the biphasic nature of the curve obtained during enzyme inactivation. However, when stored frozen for several months followed by a period of heating for 60 min at 60 °C prior to irradiation, the sperm exhibited PA₂ activity, which corresponded to a single low molecular mass form of 12,000 d when radioactive phosphatidylcholine (PC) was used as substrate and 8,000 d when radioactive phosphatidylethanolamine (PE) was used as substrate. In fresh seminal fluid, only one active form of PA₂ was detected as judged by the linear nature of the curve obtained during enzyme inactivation by irradiation. Using PC as substrate, the active unit was again estimated to be 12,000 d, whereas it corresponded to 18,000 d when PE was used. The PA₂ activity associated with normal spermatozoa exhibited a 60% decrease in activity after storage at ?20 °C for 48 hr followed by a heating period of 10 min at 60 °C. Long-term storage of spermatozoa at ?20 °C also resulted in a similar decrease in the deacylation of PC. No further loss of activity was observed during subsequent heat treatment at 60 °C. Seminal plasma, however, showed no loss of activity following short (48 hr at 4 °C or ?20 °C) or long-term storage and subsequent heat treatment. Thus, the behavior of PA₂ when the effect of temperature was studied and in radiation inactivation experiments indicates that the low molecular weight component in the seminal plasma as well as in spermatozoa is temperature resistant. However, in fresh spermatozoa, a second form of PA₂ was found and was sensitive to changes in temperature.     

The phospholipase A2 of human spermatozoa; purification and partial sequence.

In view of its proposed key role in the acrosome reaction, phospholipase A2 has been isolated and purified from human spermatozoa. Following SDS-PAGE, a single major band was obtained with an estimated molecular mass of 16.7 kDa. Sequence analysis of the N-terminal portion of the molecule revealed the identity of the first 19 amino acids to be YNYQFGLMIVITKGHFAMV. From this partial analysis it is evident that the phospholipase A2 of human spermatozoa represents a new sequence. Of interest is the location of glutamine-4, phenylalanine-5, methionine-8 and isoleucine-9; this sequence appears to be highly conserved throughout evolution.     

Raman spectroscopic study of the effects of Ca2+, Mg2+, Zn2+, and Cd2+ ions on calf thymus DNA: binding sites and conformational changes

The interaction of Mg2+, Ca2+, Zn2+, and Cd2+ with calf thymus DNA has been investigated by Raman spectroscopy. These spectra reveal that all of these ions, and particularly Zn2+, bind to phosphate groups of DNA, causing a slight structural change in the polynucleotide at very small metal: DNA (P) concentration ratio (ca. 1:30). This results in increased base-stacking interactions, with negligible change of the B conformation of DNA. Contrary to Zn2+ and Cd2+, which interact extensively with the nucleic bases (particularly at the N7 position of guanine), the alkaline-earth metal ions are bound almost exclusively to the phosphate groups. The affinity of both the Zn2+ and Cd2+ ions for G.C base pairs is comparable, but the Cd2+ ions interact more extensively with A.T pairs than Zn2+ ions. Interstrand cross-linking through the N3 atom of cytosine is suggested in the presence of Zn2+, but not Cd2+.     

Age-dependent population diffusion with external constraint

We present a simple model for age dependent population diffusion when the dynamics is submitted to external constraints. Existence, uniqueness and dependence on the parameters of the solution are discussed.This work has been done within the framework of the cultural agreement between the Universities of Bordeaux and Rome     

Caspase activation involves the formation of the aposome, a large (approximately 700 kDa) caspase-activating complex.

In mammals, apoptotic protease-activating factor 1 (Apaf-1), cytochrome c, and dATP activate caspase-9, which initiates the postmitochondrial-mediated caspase cascade by proteolytic cleavage/activation of effector caspases to form active approximately 60-kDa heterotetramers. We now demonstrate that activation of caspases either in apoptotic cells or following dATP activation of cell lysates results in the formation of two large but different sized protein complexes, the "aposome" and the "microaposome". Surprisingly, most of the DEVDase activity in the lysate was present in the aposome and microaposome complexes with only small amounts of active caspase-3 present as its free approximately 60-kDa heterotetramer. The larger aposome complex (M(r) = approximately 700,000) contained Apaf-1 and processed caspase-9, -3, and -7. The smaller microaposome complex (M(r) = approximately 200,000-300,000) contained active caspase-3 and -7 but little if any Apaf-1 or active caspase-9. Lysates isolated from control THP.1 cells, prior to caspase activation, showed striking differences in the distribution of key apoptotic proteins. Apaf-1 and procaspase-7 may be functionally complexed as they eluted as an approximately 200-300-kDa complex, which did not have caspase cleavage (DEVDase) activity. Procaspase-3 and -9 were present as separate and smaller 60-90-kDa (dimer) complexes. During caspase activation, Apaf-1, caspase-9, and the effector caspases redistributed and formed the aposome. This resulted in the processing of the effector caspases, which were then released, possibly bound to other proteins, to form the microaposome complex.     

Oral mucosal lesions in denture wearers

doi:10.1111/j.1741‐2358.2009.00289.x
Oral mucosal lesions in denture wearers Objective: To determine the prevalence of oral mucosal lesions (OMLs) and denture‐related mucosal lesions (DMLs) in denture wearers and to co‐relate the prevalence with age, gender, type of denture and any systemic conditions. Materials and methods: Dental records of 380 denture wearers were retrospectively reviewed for OMLs and DMLs. Results: We found 45% of the denture wearers had DMLs and 60.8% had OMLs not related to denture wearing. Although the prevalence of DMLs was higher in complete denture wearers than in partial denture wearers (49% vs. 42.2%), this difference was not significant. The most common DMLs were traumatic ulcer (19.5%) and denture‐induced stomatitis (18.1%). When analysed by type, traumatic ulcer, denture hyperplasia, frictional keratosis and candidiasis were more common in complete denture wearers, whereas denture‐induced stomatitis was more common in partial denture wearers. Frictional keratosis was more common in men than in women. The prevalence of OMLs not related to denture wearing was higher in complete denture wearers than in partial denture wearers, and the most common OML was fissured tongue (27.6%). No association between DMLs and systemic conditions or xerostomic drugs was noted. Conclusion: No differences in the prevalence of DMLs in association with denture type were found. The prevalence of OMLs not related to denture wearing was higher in complete denture wearers than in partial denture wearers. This difference was affected by age, and the data were similar to the findings observed in the elderly.     

A mathematical model for indirectly transmitted diseases

We consider a mathematical model for the indirect transmission via a contaminated environment of a microparasite between two spatially distributed host populations having non-coincident spatial domains. The parasite is benign in a first population and lethal in the second one. Global existence results are given for the resulting reaction-diffusion system coupled with an ordinary differential equation. Then, invasion and persistence of the parasite are studied. A simplified model for the transmission of a hantavirus from bank vole to human populations is then analysed.     

A systematic approach for testing expression of human full-length proteins in cell-free expression systems

Background  

The growing field of proteomics and systems biology is resulting in an ever increasing demand for purified recombinant proteins for structural and functional studies. Here, we show a systematic approach to successfully express a full-length protein of interest by using cell-free and cell-based expression systems.