Evolution of the mitochondrial ATPase 6 gene in Drosophila: unusually high level of polymorphism in D. melanogaster

We have determined 1990 bp mitochondrial DNA sequence which extends from 3' end of the cytochrome oxidase subunit I (COI) gene to 5' end of the COIII gene from two sibling species of Drosophila, D. simulans and D. mauritiana. Analyses of the sequences and part of the NADH dehydrogenase subunit 2 gene and the COI gene together with those from D. melanogaster and D. yakuba revealed that amino-acid substitution rate of the ATPase 6 gene seems to be higher in some strains of D. melanogaster than in the other species. High level of amino-acid polymorphism in this gene was observed in D. melanogaster. Synonymous substitution rate is relatively constant in all the genes examined, suggesting that mutation rate is not higher in the ATPase 6 gene of D. melanogaster. The amino-acid substitutions found specifically in D. melanogaster are at the sites which are not conserved among mammals, yeast and E. coli. These sites of the ATPase 6 gene might lose the selective constraint in D. melanogaster, and the amino-acid substitutions can be explained by neutral mutations and random genetic drift.     

Agonists and antagonists for lipopolysaccharide-induced cytokines

Agonistic and antagonistic properties of LPS and partial structures in the induction of cytokines are reviewed. Studies on structure-activity relationships of LPS and lipid A with human mononuclear cells reveal that S- and notably R-form LPS are very potent cytokine inducers. Synthetic E. coli lipid A is somewhat less active, whereas synthetic S. minnesota-type lipid A is significantly less active. Pentaacylated forms of lipid A are less potent than hexaacylated forms, and tetraacylated synthetic precursor Ia and bisacylated disaccharides and monosaccharides are completely inactive, indicating that a structure-dependent hierarchy of LPS and lipid A partial structures determines the monokine-inducing capacity in human mononuclear cells. Precursor Ia is a potent LPS antagonist. The mechanism of its inhibitory activity is shown to be due to competitive binding to cellular binding sites (receptors). Proinflammatory and antiinflammatory cytokines, receptor antagonists, and soluble cytokine receptors influence the cytokine-inducing activity of LPS, suggesting a complex regulatory network.     

The genes for butanol and acetone formation in Clostridium acetobutylicum ATCC 824 reside on a large plasmid whose loss leads to degeneration of the strain

Degeneration is the process whereby Clostridium acetobutylicum ATCC 824 loses the capacity to produce acetone and butanol after repeated vegetative transfers or in continuous culture. Two degenerate mutants (M5 and DG1) of C. acetobutylicum ATCC 824 do not contain the four genes (ctfA, ctfB, adc, and aad) for acetone and butanol formation. Strain ATCC 824 contains a 210-kb plasmid (pSOL1) which is absent in M5 and DG1. pSOL1 carries the four acetone and butanol formation genes. A restriction map of pSOL1 was constructed by using ApaI, SmaI, SstII, and NarI digestions. M5 and DG1 could be complemented for acetone and butanol formation by expressing the corresponding genes (ctfA, ctfB, and adc for acetone; aad for butanol) on the plasmid. Degeneration of this strain thus appears to be the result of pSOL1 loss.     

Antibody-IL-2 fusion proteins: a novel strategy for immune protection

Advances in genetic engineering and expression systems have led to a rapid progress in the development of immunoglobulins fused to other proteins. These 'antibody fusion proteins' have novel properties and include antibodies fused to the cytokine interleukin-2. In the present review we describe strategies for construction of these antibody-interleukin-2 fusion proteins and discuss their in vitro and in vivo properties. Antibody-interleukin-2 fusion proteins retain both antibody associated functions such as antigen binding, complement activation and Fc gamma receptor binding as well as interleukin-2 associated functions such as the stimulation of proliferation of CTLL2 cells. In vivo, they produce strong potentiation of the host immune response against any associated antigen. In addition, these novel molecules are able to target tumor cells and produce a specific and effective T cell response capable of eliminating the tumor. These properties suggest that antibody-interleukin-2 fusion proteins will be useful in the diagnosis and/or treatment of human cancer as well as in the potentiation of human response against any associated antigen.     

Medial prefrontal lesion deficits involving or sparing the prelimbic area in the rat

OBJECTIVE: Evaluate wound healing of incisions created by the scalpel, electrocautery, CO2 laser, and potassium titanyl phosphate (KTP) laser in the upper aerodigestive tract in an animal model. STUDY DESIGN: Prospective randomized study in an animal model. METHODS: Postoperative oral intake, histologic depth of injury, and tensile mechanical strength were measured in rat tongues after creating incisions using a scalpel, electrocautery, CO2 laser, and KTP laser. An unpaired, two-tailed Student's t-test was used to compare results between the experimental groups. RESULTS: Oral intake, indirectly assessed by postoperative weight loss, by the third postoperative day was significantly decreased in the electrocautery (P = 0.004), CO2 laser (P = 0.001), and KTP laser (P = 0.0001) groups as compared with the scalpel group. The depth of the wound healing, as assessed by histologic examination, was successively greater for the scalpel (75 +/- 13 microm), electrocautery (110 +/- 10 microm), CO2 laser (145 +/- 10 microm), and KTP laser (195 +/- 23 microm) groups. However, this difference was only statistically significant for the CO2 laser (P = 0.006) and KTP laser (P = 0.01) groups relative to the scalpel group. Wounds created by the KTP laser had the lowest strength (76.5 +/- 6.9 kPa) as compared with the CO2 laser (156 +/- 28.4 kPa), electrocautery (153 +/- 15.7 kPa), and scalpel groups (249 +/- 61.8 kPa). This difference was only statistically significant for the KTP laser group (P = 0.02) when compared with the scalpel group. CONCLUSIONS: Wounds created in the upper aerodigestive tract of rats by scalpels result in the least postoperative weight loss, tissue destruction, and decrease in tensile strength, whereas wounds created by the KTP laser demonstrated a significantly greater postoperative weight loss, depth of wounding, and decrease in tensile strength.     

Stenting of "unprotected" left main coronary artery stenoses: early and late results

The effect of bone plug length and Kurosaka screw (DePuy, Warsaw, IN) diameter on graft holding strength of the bone-tendon-bone construct was determined. Random length porcine bone plugs were assigned to fixation with 7 or 9 mm Kurosaka screws. Peak load to failure was determined. There was a significant decrease in peak load to failure of the 5-mm long bone plugs compared with longer bone plugs. No difference was found between longer lengths of bone plug in either the 7- or 9-mm screw diameter groups. The 9-mm diameter screws significantly increased peak load to failure for both 1- and 2-cm bone plug lengths.     

Anti-inflammatory mystixin peptides inhibit plasma leakage without blocking endothelial gap formation

Mystixins are synthetic peptides that inhibit plasma leakage after tissue injury. We sought to determine the mechanism of the antileakage effect of mystixins, with particular reference to the formation of endothelial gaps in postcapillary venules. Intravenous administration of mystixin-7, a prototype heptapeptide (p-anisoyl-Arg-Lys-Leu-Leu-D-Thi-Ile-D-Leu-NH2), decreased Evans blue leakage induced by substance P (5 microg/kg i.v.) with an ED50 (95% confidence limits) of 130 (76-211) microg/kg in trachea and 52 (27-100) microg/kg in skin of anesthetized F344 rats. Leakage was decreased without a reduction in the number or size of endothelial gaps, visualized by silver deposits after silver nitrate staining. The number of silver deposits per tracheal endothelial cell was 11.4 +/- 0.2 (mean +/- S.E.) after vehicle pretreatment vs. 13.0 +/- 0.8 after mystixin-7 pretreatment (100 microg/kg i.v.). Silver deposit diameter was unchanged at 1.4 +/- 0.1 micron. Mean arterial blood pressure dropped by a maximum of 38% from baseline for approximately 10 min after mystixin-7 (100 microg/kg i.v.), then recovered to a plateau at about 13% below baseline. The antileakage effect of mystixin-7 pretreatment in vivo was also demonstrated in aldehyde-fixed vessels perfused in situ with Evans blue at constant flow (skin, 79% reduction; trachea, 49% reduction), which suggests that mystixin can reduce leakage independent of its hypotensive effect. We conclude that the antileakage effect of mystixin does not depend on reducing the number or size of endothelial gaps, but instead could be caused by residual hypotension, which reduces the negative interstitial fluid pressure toward zero, or clogging of endothelial gaps.