Surgical myocardial revascularization

In conclusion, surgical myocardial revascularization has utilized diverse methods to increase blood flow to the starving myocardium. These methods initially used the microcirculation as the portal to reach myocytes until angiography showed that the obstructions were macrovascular. This resulted in a 30-year era of direct attack on the coronary blockages by coronary bypass. Surgical conduits unfortunately have longevity considerably less than that of native arteries and are limited in number. Alternative conduits, both biologic and prosthetic, have not yet proved to have the same clinical results as the ITA. More patients are living long enough to have the extensiveness of their disease exhaust conventional therapies. Newer therapy, restricted thus far to untreatables, revisits the microcirculation by making laser channels. These many innovative procedures have benefited hundreds of thousands of patients. They emerged from the probity and innovation of many individual surgeons.     

Differential effects of peptide diversity and stromal cell type in positive and negative selection in the thymus

Thymocyte positive selection results in maturation to the single-positive stage, while negative selection results in death by apoptosis. Although kinetic analyses indicate only 3-5% of CD4+ 8+ cells reach the single-positive stage, the balance of positive and negative selection and the nature and quantity of cells mediating maximal negative selection are uncertain. Here, using a system where the number and type of stromal cells and thymocytes can be controlled, we investigated the maturation of CD4+ 8+ thymocytes in the presence or absence of thymic epithelium and dendritic cells (DC) from wild-type (wt) and H-2M(-/-) mice expressing different peptide arrays. We find that titration of wt DC into reaggregates of wt epithelium has a dramatic effect on the number of CD4+ cells generated, with 1% DC causing a maximal 80% reduction. Moreover, while addition of 1% wt DC into cultures of H-2M(-/-) epithelium causes a 90% reduction in CD4+ cells, no effect was observed when similar numbers of wt thymic epithelium were added. Collectively, these data provide the first accurate indication of the quantity and quality of stromal cells required for maximal negative selection in the thymus, demonstrate the importance of peptide diversity in T cell selection, and highlight a large degree of overlap between positive and negative selection events.     

A retrospective epidemiological analysis of non-accidental head injury in children in Scotland over a 15 year period

We have made a simple 15-year retrospective epidemiological study of a part of South Moravia, district Breclav, on the basis of genetic documentation of 245 congenital defects and 28 spontaneous abortions. The whole area was worked up by computer-geographical methods, and the occurrence of congenital defects was compared both in areas of severe chronic air pollution and in less contamined areas. There were three municipal areas, Mikulov, Breclav-Postorná, Velké Bilovice and their surroundings, in which an increased number of congenital defects was recorded. In the municipal area of Breclav-Postorná there was also a greater occurrence of organic solvents and phosphoric acid and a significantly higher occurrence of spontaneous abortions and at the same time a higher occurrence of heart defects.     

Production of fibroblast proliferative cytokines from T lymphocytes stimulated by a B cell lymphoma line and their functional heterogeneity

Human mononuclear leukocytes (MNL) produced several factors with fibroblast proliferation activity (FPA) for HFL-1, a human lung fibroblast cell line, when MNL were cocultured with irradiated BALL-1, a B cell lymphoma line (BCLL), but not with other BCLL. The cellular source of BALL-1-induced FPA seemed to be CD4-positive T lymphocytes. On isoelectric electrophoresis, major activity of BALL-1-induced FPA was detected in the fractions around pH 4-5, and minor activity was present in the fractions around pH 6-7. Major BALL-1-induced FPA consisted of at least 4 different fibroblast proliferation factors (FPFs) according to their molecular weight; 320-600 kDa (P-I), 50-110 kDa (P-II), 22-38 kDa (P-III) and 4.6-11 kDa (P-IV). P-I had affinity to heparin though the rest had little or no affinity. FPA of P-I was suppressed by an antibody against acidic FGF, and FPA of P-III was suppressed by an antibody against IL-6. On the other hand, FPA of P-II and P-IV was suppressed by none of the antibodies against cytokines with FPA, such as FGF, IL-4, IL-6, IFN-gamma, TGF-beta and TNF-alpha. It was thus suggested that P-I was acidic FGF, that P-III was IL-6, and that P-II and P-IV were different cytokines from those described above. Furthermore, it was found that P-II and P-IV failed to exhibit proliferation activity for human umbilical vein endothelial cells (HUVEC).(ABSTRACT TRUNCATED AT 250 WORDS)     

God and the search for meaning among hospice caregivers

This paper examines the sexual risk behavior of female injecting drug users who participated in a 4 year longitudinal study. Both HIV+ and HIV- women showed increases in monogamy, decreases in the frequency of unprotected vaginal/anal sex, and decreases in a risk index score throughout the study. HIV+ women had fewer occasions of unprotected sex than HIV-. However, a substantial proportion of the sample continued to engage in unprotected sex. Among the HIV+ women, depressed mood was significantly related to abstinence and to fewer occasions of unprotected sex, but CD4, medical symptoms, neurological impairment, and memory test performance were not associated with sexual risk behavior.     

Morphological and molecular characterization of Giardia isolated from the straw-necked ibis (Threskiornis spinicollis) in Western Australia

Following the first report of avian Giardia infection in Australia, isolates of the parasite recovered from naturally infected straw-necked ibis (Theskiornis spinicollis) were characterized using median body morphology, scanning electron microscopy, multilocus enzyme electrophoresis, random amplified polymorphic DNA (RAPD), and small subunit ribosomal RNA (SSU-rRNA) analyses. Results were compared with Giardia from other birds and mammals, and the extent of genetic diversity between a range of ibis isolates collected in Western Australia was determined. The ibis isolates of Giardia were genetically relatively homogeneous, which is in contrast to the extensive genetic heterogeneity often displayed by mammalian Giardia isolates. Morphologically, Giardia from ibis were similar to Giardia ardeae although they differed genetically and by the fact that the ibis isolates could not be established in in vitro culture. Sequence data of the DNA coding for the SSU-rRNA found a 96% homology between the ibis isolates from Western Australia and G. ardeae, suggesting that they represent distinct strains of the same species. In contrast, the ibis isolates were genetically and morphologically very different than Giardia duodenalis and Giardia muris from mammals.     

Proton selective substate of the mitochondrial permeability transition pore: regulation by the redox state of the electron transport chain

The permeability transition pore of rat liver mitochondria can be closed by chelating free Ca2+, with respect to the passage of large molecules such as mannitol and sucrose. However, an apparent H+-conducting substate remains open under these conditions, as indicated by the persistence of maximal O2 consumption rates and by the failure to recover a membrane potential. Agents which favor a closed pore, such as cyclosporin A, ADP, Mg2+, or bovine serum albumin, do not close the H+-conducting substate, but it closes spontaneously when respiration becomes limited by the availability of O2. Closure provoked by an O2 limitation requires free Mg2+ in the sub-micromolar concentration range and becomes less efficient with increasing time spent in the presence of free Ca2+. The H+-conducting substate is apparently regulated by the redox status of the electron transport chain, with a reduced form favoring closure. A physical association (or equivalence) between the pore and one of the respiratory chain complexes is supported. These characteristics suggest that the transition is irreversible in vivo, if it involves a small fraction of total mitochondria, and would lead to their elimination and/or replacement by the cell. The implications of this proposal are considered, as they relate to a possible role for the transition in cellular apoptosis and the elimination of mitochondria containing mutated DNA.