Five years' experience with aortocoronary bypass grafting.

During a 5-year period (Apr. 14, 1970 to Apr. 14, 1975) 930 patients underwent aortocoronary bypass grafting; the procedure was done as an emergency in 141. Of the entire group 3.3% died at operation, 1.6% died in hospital and 5.8% died later; of the patients undergoing emergency grafting 12.1% died at operation and 5.7% died later. From a detailed analysis of the first 600 patients it was found that both operative and late mortality were clearly related to two factors: severe left ventricular dysfunction at the time of operation and inadequate surgical treatment because of insertion of insufficient numbers of grafts or because of poor blood flow through the grafts.     

The phosphorylation of brain microtubular proteins in situ and in vitro

The phosphorylation of microtubular proteins isolated by reassembly in vitro from slices of guinea-pig cerebral cortex labelled with [32P]orthophosphate was investigated. Under the conditions tested, both and the alpha and beta forms of tubulin contained metabolically-active P which accounted for about one third of the total 32P incorporated into protein; the remaining protein-bound 32P was associated with 3-4 minor high MW components co-purifying with tubulin during two cycles of assembly-disassembly. Microtubular protein prepared in this way contained approx. 0.8 mol of alkalilabile P/mol of tubulin dimer (M.W. 110,000). In vitro studies showed that reassembled microtubular protein preparations catalysed the incorporation of up to 0.55 mol of P/mol of tubulin dimer during incubation with Mg2+ and [gamma 32P]ATP. The reaction was linear during the first 30 min of incubation at 37 degrees C. Cyclic AMP (10 microM, final concentration) caused a transient increase in the initial rates of tubulin phosphorylation. Little label was incorporated into the minor high M.W. components under these conditions. The in vitro phosphorylation of microtubular protein increased in a non-linear manner with respect to protein concentration: this was in contrast to earlier experiments showing linear kinetics when chromatographically isolated tubulin was tested for intrinsic kinase activity. Isolated microtubular protein preparations bound [3H]GTP, [3H]ATP and to a lesser extent, [3H]cyclic AMP, and exhibited Ca(2+)-ATPase activity (up to 60 pmol Pi released min/mg protein at 37 degrees C).     

Effect of hypertonic conditions on protein synthesis in cells productively infected with simian virus 40.

Hypertonic medium selectively suppressed the synthesis of most host cell polypeptides relative to the synthesis of simian virus 40 capsid polypeptides and a minority of cellular polypeptides, notably histones. Under optimal hypertonic conditions, the synthesis of the major capsid polypeptide (VP1) is enhanced about sevenfold relative to host polypeptide synthesis. Because of the small amounts of the other nonhistone capsid polypeptides (VP2) and VP3) present in cell lysates, it was difficult to quantitate the extent, if any, of their enhancement. The maintenance of the restricted pattern of protein synthesis caused by hypertonic medium was dependent on continual peptide chain initiations. The resistance of viral protein synthesis to hypertonic conditions provides a means of detecting relatively low levels of intracellular viral protein synthesis. Analysis of the specific activity of the acid-soluble [3H]lysine pool indicated that the rate of incorporation of [3H]lysine into protein was an overestimation of the actual rate of overall protein synthesis occurring in cells exposed to hypertonic as compared to isotonic conditions. Since it is likely that both cellular and viral protein synthesis draw lysine from a single pool, this change in pool specific activity does not affect the analysis of relative rates of protein synthesis at a given level of tonicity.     

Rigorous proof of fuzzy error propagation with matrix-based LCI

Background, aim, and scope  

Propagation of parametric uncertainty in life cycle inventory (LCI) models is usually performed based on probabilistic Monte Carlo techniques. However, alternative approaches using interval or fuzzy numbers have been proposed based on the argument that these provide a better reflection of epistemological uncertainties inherent in some process data. Recent progress has been made to integrate fuzzy arithmetic into matrix-based LCI using decomposition into α-cut intervals. However, the proposed technique implicitly assumes that the lower bounds of the technology matrix elements give the highest inventory results, and vice versa, without providing rigorous proof.     

A comparative study of cobra (Naja) venom enzymes

1. The L-amino acid oxidase, hyaluronidase, alkaline phosphomonoesterase, protease, phosphodiesterase, acetylcholinesterase, phospholipase A and 5'-nucleotidase activities of 47 samples of venoms from all the six species of cobra (Naja), including five subspecies of Naja naja, were examined. 2. The results demonstrated interspecific differences in the venom contents of phospholipase A, acetylcholinesterase, hyaluronidase and phosphodiesterase. These differences in venom enzyme contents can be used for the differentiation of species of the genus Naja. 3. Thus, our results revealed a correlation between the enzyme composition of venom and the taxonomic status of the snake at the species level for the genus Naja.     

Isolation of polyhydroxyalkanoate-producing bacteria from an integrated-farming pond and palm-oil mill effluent ponds

Bacterial isolates from two environments, an integrated-farming pond in the university and palm-oil mill effluent (POME) ponds at a local palm-oil-processing factory, were screened for polyhydroxyalkanoates (PHAs). Initially Sudan Black B staining was performed to detect lipid cellular inclusions. Lipid-positive isolates were then grown in a nitrogen-limiting medium containing 2% (w/v) glucose to promote accumulation of PHA before the subsequent Nile Blue A staining. The PHA extracted from positive isolates was confirmed by nuclear magnetic resonance (NMR) spectroscopy. The proportion of PHA-positive bacterial isolates was higher in the POME ponds compared to the integrated-farming pond.     

Synthesis of mitochondrial DNA in spermatocytes of Rhynchosciara hollaenderi

During the mid to late 4th instar period of larval development, the mitochondria of Rhynchosciara spermatocytes undergo highly characteristic morphological changes. In late meiosis the enlarged mitochondria fuse to form a single mitochondrial element which will ultimately extend the length of the spermatid tail. Our studies have shown that synthesis of a circular DNA occurs during this period of mitochondrial “differentiation.” This DNA has a density of 1.681 g/cm³; and its synthesis cannot be detected in somatic tissues such as salivary gland, fat body, or gastric cecum. From analysis of DNA extracted from mitochondrial pellets, we have shown that the circular DNA is associated with the mitochondria. The contour length of the mitochondrial DNA is 9 μm, equivalent to a molecular weight of 18 × 10⁶. Although most metazoan mitochondrial DNAs exhibit contour lengths of approximately 5 μm (10 × 10⁵ daltons), there is no extractable 5 μm circular DNA in these spermatocytes. Therefore, we conclude that either Rhynchosciara spermatocytes possess a distinct 9 μm mitochondrial DNA or that the spermatocyte mitochondrial DNA represents dimers of 5 μm monomers.