Characterization of the interactions of plasminogen and tissue and vampire bat plasminogen activators with fibrinogen, fibrin, and the complex of D-dimer noncovalently linked to fragment E

Vampire bat plasminogen activator (b-PA) causes less fibrinogen (Fg) consumption than tissue-type plasminogen activator (t-PA). Herein, we demonstrate that this occurs because the complex of D-dimer noncovalently linked to fragment E ((DD)E), the most abundant degradation product of cross-linked fibrin, as well as Fg, stimulate plasminogen (Pg) activation by t-PA more than b-PA. To explain these findings, we characterized the interactions of t-PA, b-PA, Lys-Pg, and Glu-Pg with Fg and (DD)E using right angle light scattering spectroscopy. In addition, interactions with fibrin were determined by clotting Fg in the presence of various amounts of t-PA, b-PA, Lys-Pg, or Glu-Pg and quantifying unbound material in the supernatant after centrifugation. Glu-Pg and Lys-Pg bind fibrin with Kd values of 13 and 0.13 microM, respectively. t-PA binds fibrin through two classes of sites with Kd values of 0.05 and 2.6 microM, respectively. The second kringle (K2) of t-PA mediates the low affinity binding that is eliminated with epsilon-amino-n-caproic acid. In contrast, b-PA binds fibrin through a single kringle-independent site with a Kd of 0.15 microM. t-PA competes with b-PA for fibrin binding, indicating that both activators share the same finger-dependent site on fibrin. Glu-Pg binds (DD)E with a Kd of 5.4 microM. Lys-Pg binds to (DD)E and Fg with Kd values of 0.03 and 0.23 microM, respectively. t-PA binds to (DD)E and Fg with Kd values of 0.02 and 0.76 microM, respectively; interactions were eliminated with epsilon-amino-n-caproic acid, consistent with K2-dependent binding. Because it lacks a K2-domain, b-PA does not bind to either (DD)E or Fg, thereby explaining why b-PA is more fibrin-specific than t-PA.

Substrate binding and catalytic mechanism of a barley beta-D-Glucosidase/(1,4)-beta-D-glucan exohydrolase

A beta-glucosidase, designated isoenzyme betaII, from germinated barley (Hordeum vulgare L.) hydrolyzes aryl-beta-glucosides and shares a high level of amino acid sequence similarity with beta-glucosidases of diverse origin. It releases glucose from the non-reducing termini of cellodextrins with catalytic efficiency factors, kcat/Km, that increase approximately 9-fold as the degree of polymerization of these substrates increases from 2 to 6. Thus, the enzyme has a specificity and action pattern characteristic of both beta-glucosidases (EC 3.2.1.21) and the polysaccharide exohydrolase, (1,4)-beta-glucan glucohydrolase (EC 3.2.1.74). At high concentrations (100 mM) of 4-nitrophenyl beta-glucoside, beta-glucosidase isoenzyme betaII catalyzes glycosyl transfer reactions, which generate 4-nitrophenyl-beta-laminaribioside, -cellobioside, and -gentiobioside. Subsite mapping with cellooligosaccharides indicates that the barley beta-glucosidase isoenzyme betaII has six substrate-binding subsites, each of which binds an individual beta-glucosyl residue. Amino acid residues Glu181 and Glu391 are identified as the probable catalytic acid and catalytic nucleophile, respectively. The enzyme is a family 1 glycoside hydrolase that is likely to adopt a (beta/alpha)8 barrel fold and in which the catalytic amino acid residues appear to be located at the bottom of a funnel-shaped pocket in the enzyme.

Two-dimensional tracking of ncd motility by back focal plane interferometry

A technique for detecting the displacement of micron-sized optically trapped probes using far-field interference is introduced, theoretically explained, and used to study the motility of the ncd motor protein. Bead motions in the focal plane relative to the optical trap were detected by measuring laser intensity shifts in the back-focal plane of the microscope condenser by projection on a quadrant diode. This detection method is two-dimensional, largely independent of the position of the trap in the field of view and has approximately 10-micros time resolution. The high resolution makes it possible to apply spectral analysis to measure dynamic parameters such as local viscosity and attachment compliance. A simple quantitative theory for back-focal-plane detection was derived that shows that the laser intensity shifts are caused primarily by a far-field interference effect. The theory predicts the detector response to bead displacement, without adjustable parameters, with good accuracy. To demonstrate the potential of the method, the ATP-dependent motility of ncd, a kinesin-related motor protein, was observed with an in vitro bead assay. A fusion protein consisting of truncated ncd (amino acids 195-685) fused with glutathione-S-transferase was adsorbed to silica beads, and the axial and lateral motions of the beads along the microtubule surface were observed with high spatial and temporal resolution. The average axial velocity of the ncd-coated beads was 230 +/- 30 nm/s (average +/- SD). Spectral analysis of bead motion showed the increase in viscous drag near the surface; we also found that any elastic constraints of the moving motors are much smaller than the constraints due to binding in the presence of the nonhydrolyzable nucleotide adenylylimidodiphosphate.

Mitochondrial association of a plus end-directed microtubule motor expressed during mitosis in Drosophila

The kinesin superfamily is a large group of proteins (kinesin-like proteins [KLPs]) that share sequence similarity with the microtubule (MT) motor kinesin. Several members of this superfamily have been implicated in various stages of mitosis and meiosis. Here we report our studies on KLP67A of Drosophila. DNA sequence analysis of KLP67A predicts an MT motor protein with an amino-terminal motor domain. To prove this directly, KLP67A expressed in Escherichia coli was shown in an in vitro motility assay to move MTs in the plus direction. We also report expression analyses at both the mRNA and protein level, which implicate KLP67A in the localization of mitochondria in undifferentiated cell types. In situ hybridization studies of the KLP67A mRNA during embryogenesis and larval central nervous system development indicate a proliferation-specific expression pattern. Furthermore, when affinity-purified anti-KLP67A antisera are used to stain blastoderm embryos, mitochondria in the region of the spindle asters are labeled. These data suggest that KLP67A is a mitotic motor of Drosophila that may have the unique role of positioning mitochondria near the spindle.

Specific immobilization of firefly luciferase through a biotin carboxyl carrier protein domain

Firefly luciferase (Photinus pyralis) was fused with a histidine tag and a biotin carboxyl carrier protein (BCCP) domain at its amino terminus. Highly purified recombinant luciferase was obtained by a one-step purification protocol, utilizing immobilized metal affinity chromatography. The novel BCCP-luciferase had properties, stability, and activity similar to those of native luciferase. The biotin molecule on the BCCP domain allowed specific immobilization of BCCP-luciferase on avidin-coated surfaces via the biotin-avidin interaction.

Fecolith impaction in a duplex vermiform appendix: an unusual presentation of colonic duplication

The authors report a case of colonic duplication associated with urogenital abnormalities, which presented after obstruction of its proximal communication with the intestine. The case is unusual because the proximal communication was via a partial duplication of the appendix, which became obstructed after impaction of a fecolith.

The wandering spleen

Wandering spleen is a rare condition that commonly presents with splenic infarction secondary to torsion. Splenectomy was previously advocated as the treatment of choice, though recent reports suggest that the organ may be distorted, and splenopexy performed. This paper documents how the latter procedure may be done using adherent omentum.

Vascular endothelial platelet endothelial adhesion molecule-1 (PECAM-1) expression is decreased by TNF-alpha and IFN-gamma. Evidence for cytokine-induced destabilization of messenger ribonucleic acid transcripts in bovine endothelial cells

Platelet endothelial cell-adhesion molecule-1 (PECAM-1, CD31) is constitutively expressed by vascular endothelium and concentrates at intercellular junctions. Regulation of PECAM-1 expression on endothelial cells may modulate leukocyte trafficking, angiogenesis, and vascular permeability. Given that cytokine activation induces profound alterations in endothelial phenotype, studies sought to determine whether cytokine treatment modulated PECAM-1 mRNA and protein content in macro- and microvascular endothelial cells. Northern blot analysis revealed expression of PECAM-1 mRNA transcripts in endothelial cells derived from bovine aorta, bovine glomeruli, and human umbilical vein under basal conditions. Treatment of endothelial cells with TNF-alpha and/or IFN-gamma led to dramatic decreases in steady-state levels of PECAM-1 mRNA transcripts. In contrast, reciprocal induction of ICAM-1 mRNA was evident. Actinomycin D chase experiments demonstrated that cytokines selectively destabilize PECAM-1 mRNA transcripts in bovine endothelial cells, decreasing the PECAM-1 mRNA transcript t1/2 from basal values of 15 +/- 2 h to 4 +/- 1 h in TNF-alpha- and IFN-gamma-treated cells (p < 0.005), an effect that appeared to be independent of new protein synthesis. Nuclear run-off analysis demonstrated no change in the rates of PECAM-1 gene transcription in response to cytokines treatment. Immunoblots and quantitative indirect immunofluorescence indicated decreased total cellular and cell-surface PECAM-1 protein expression following cytokine treatment. These findings provide evidence for cytokine-induced reciprocal regulation of transcripts of Ig-like adhesion molecules on vascular endothelium.

Vascular endothelial platelet endothelial adhesion molecule-1 (PECAM-1) expression is decreased by TNF-alpha and IFN-gamma. Evidence for cytokine-induced destabilization of messenger ribonucleic acid transcripts in bovine endothelial cells

Platelet endothelial cell-adhesion molecule-1 (PECAM-1, CD31) is constitutively expressed by vascular endothelium and concentrates at intercellular junctions. Regulation of PECAM-1 expression on endothelial cells may modulate leukocyte trafficking, angiogenesis, and vascular permeability. Given that cytokine activation induces profound alterations in endothelial phenotype, studies sought to determine whether cytokine treatment modulated PECAM-1 mRNA and protein content in macro- and microvascular endothelial cells. Northern blot analysis revealed expression of PECAM-1 mRNA transcripts in endothelial cells derived from bovine aorta, bovine glomeruli, and human umbilical vein under basal conditions. Treatment of endothelial cells with TNF-alpha and/or IFN-gamma led to dramatic decreases in steady-state levels of PECAM-1 mRNA transcripts. In contrast, reciprocal induction of ICAM-1 mRNA was evident. Actinomycin D chase experiments demonstrated that cytokines selectively destabilize PECAM-1 mRNA transcripts in bovine endothelial cells, decreasing the PECAM-1 mRNA transcript t1/2 from basal values of 15 +/- 2 h to 4 +/- 1 h in TNF-alpha- and IFN-gamma-treated cells (p < 0.005), an effect that appeared to be independent of new protein synthesis. Nuclear run-off analysis demonstrated no change in the rates of PECAM-1 gene transcription in response to cytokines treatment. Immunoblots and quantitative indirect immunofluorescence indicated decreased total cellular and cell-surface PECAM-1 protein expression following cytokine treatment. These findings provide evidence for cytokine-induced reciprocal regulation of transcripts of Ig-like adhesion molecules on vascular endothelium.

Reciprocal regulation of endothelin-1 and endothelial constitutive NOS in proliferating endothelial cells

The expression of endothelin-1 (ET-1) and endothelial constitutive nitric oxide synthase (ecNOS) was assessed in two independent in vitro models: asynchronously differentially proliferating cultures and wounded endothelial cell monolayers. Northern blot analysis of RNA isolated from preconfluent, confluent, and postconfluent cells revealed a fourfold rise in ET-1 mRNA transcripts, whereas levels of ecNOS mRNA transcripts were reduced twofold in proliferating cells. Nuclear run-off analysis demonstrated that increased steady-state ET-1 mRNA content in proliferating cells was mediated, in part, by increased gene transcription. In contrast, ecNOS transcription rates in proliferating cells were not decreased compared with quiescent nonproliferating cells, indicating that mRNA destabilization mediated the decreased ecNOS mRNA levels in proliferating endothelium. Concordant changes in protein expression were documented for both ET-1 and ecNOS. In injured endothelial cell monolayers, in situ cRNA hybridization demonstrated increased mRNA transcript levels for ET-1 in growth fronts of injured endothelial monolayers. These data are taken to indicate that expression of ET-1 and ecNOS is reciprocally regulated in two different models of endothelial cell proliferation.

Biologic control of the tumor necrosis factor and interleukin-1 signaling cascade

It is clear that activation of the proinflammatory cytokine cascade is both the cause and the consequence of renal injury. Recently, it has been appreciated that a rich network of signaling pathways contributes to modulation of tumor necrosis factor-alpha (TNF) and interleukin-1 (IL-1) bioactivity, both in vitro and in vivo. Insight into the checks and balances that intervene or temper endogenous cytokine effector mechanisms has arisen from an explosion of new information on the cell biology of proinflammatory cytokines. Novel mechanisms of cytokine regulation are currently being described and hold promise for therapeutic potential: soluble cytokine receptors, endogenous receptor antagonists, and anti-inflammatory cytokines such as IL-4, IL-10, and IL-13.

Audit of a screening service for fetal abnormalities using early ultrasound scanning and maternal serum alpha-fetoprotein estimation combined with selective detailed scanning

The objective of the study was the evaluation of a screening service for fetal abnormality using early ultrasound scanning to date and establish viability of the pregnancy combined with maternal serum alpha-fetoprotein estimation at 16 weeks and thereafter selective detailed scanning at 18-20 weeks based on clinical indication. The study was designed to be retrospective, emphasizing the possibility of diagnosis. Early scans were performed by radiographers and radiologists, detailed ones by radiologists and obstetricians with subspecialty training in prenatal diagnosis. The study was carried out in the ultrasound department of a large University Hospital. The subjects studied were all cases of abnormality identified pre- or postnatally in women delivering in the hospital over 4 years and to whom the screening service applied. Information was obtained from ultrasound and maternity records, birth notifications, pathology and autopsy reports and a special needs register. Cases were classified as not detectable, potentially detectable and usually detectable. Major fetal anomalies numbered 255 (total deliveries 19,497), a prevalence of 1.3%; 130 (51%) were diagnosed by ultrasound with 64% before 24 weeks and 36% later. Eleven chromosomal anomalies (4%) were diagnosed by genetic methods and 114 (45%) anomalies were not diagnosed antenatally. The sensitivity of the program was 37% before 24 weeks. Chromosomal anomalies, lesions of the central nervous system and cardiac defects were most common, followed by lesions of the gastrointestinal and urinary tracts. A large proportion of the detected and detectable anomalies were lethal.(ABSTRACT TRUNCATED AT 250 WORDS)

Minus-end-directed motion of kinesin-coated microspheres driven by microtubule depolymerization

Dynamic changes in microtubule (MT) length have long been thought to contribute to intracellular motility. Both the polymerization and depolymerization of tubulin have been shown to do work in vitro, but the biochemical complexity of objects moved, such as chromosomes, has complicated the identification of proteins that couple MT dynamics with motility. Work with MTs grown from and tethered to pellicles of lysed Tetrahymena has shown that disassembly-dependent movement of chromosomes in vitro can be inhibited with antibodies against the motor domain of kinesin. To study proteins that can function in disassembly-dependent motion, we have refined this motility assay, replacing chromosomes with protein-coated latex microspheres. We report here the ability of several enzymes, including kinesin, to support in vitro motility of latex microspheres on disassembling MTs (Fig. 1a). The polarity of kinesin's motor activity can be reversed by MT disassembly and interactions between a motor and a MT end can either slow or speed the rate of tubulin depolymerization.

Characterization of the KLP68D kinesin-like protein in Drosophila: possible roles in axonal transport

This paper describes the molecular and biochemical properties of KLP68D, a new kinesin-like motor protein in Drosophila melanogaster. Sequence analysis of a full-length cDNA encoding KLP68D demonstrates that this protein has a domain that shares significant sequence identity with the entire 340-amin acid kinesin heavy chain motor domain. Sequences extending beyond the motor domain predict a region of alpha-helical coiled-coil followed by a globular "tail" region; there is significant sequence similarity between the alpha-helical coiled-coil region of the KLP68D protein and similar regions of the KIF3 protein of mouse and the KRP85 protein of sea urchin. This finding suggests that all three proteins may be members of the same family, and that they all perform related functions. KLP68D protein produced in Escherichia coli is, like kinesin itself, a plus-end directed microtubule motor. In situ hybridization analysis of KLP68D RNA in Drosophila embryos indicates that the KLP68D gene is expressed primarily in the central nervous system and in a subset of the peripheral nervous system during embryogenesis. Thus, KLP68D may be used for anterograde axonal transport and could conceivably move cargoes in fly neurons different than those moved by kinesin heavy chain or other plus-end directed motors.

Effect of free-radical scavengers and hyperbaric oxygen on random-pattern skin flaps

OBJECTIVE

To determine whether treatment with the combination of hyperbaric oxygen and free-radical scavengers or inhibitors would result in increased skin-flap survival.

DESIGN

An animal model with male Sprague-Dawley rats was used. The flap was a cranial-based dorsal 3 x 12-cm random-pattern skin flap that included the panniculus carnosus. Rats were randomly assigned to one of 10 treatment groups.

INTERVENTIONS

The radical scavengers superoxide dismutase, catalase, and alpha-tocopherol acetate and the inhibitor allopurinol were used to combat or scavenge radicals. Oxygen (100%) treatments were for 90 minutes at 2.5 atm absolute daily.

MAIN OUTCOME MEASURES

At 7 days, the flaps were examined for survival by fluorescein injection. Lipid peroxidation as a measure of tissue damage was measured by thiobarbituric acid-malondialdehyde analysis.

RESULTS

The combination of treatments resulted in significantly increased flap survival compared with untreated controls (P < .05) except in the group treated with allopurinol and hyperbaric oxygen. Lipid peroxidation was inhibited by the superoxide dismutase plus catalase and the alpha-tocopherol treatments but not by treatment with allopurinol.

CONCLUSION

Moderate doses of radical scavengers or antioxidants coupled with a conservative hyperoxic exposure regimen can result in the increased survival of random-pattern skin flaps.

Peritoneal cytology for suspected acute appendicitis: an economic evaluation

Suspected acute appendicitis is a common reason for surgery. Unfortunately, diagnosis is not always simple and, in recent years, considerable attention has been devoted to developing better diagnostic techniques. Peritoneal cytology is one such technique. It is simple, minimally invasive, and has been established as clinically effective. This paper reports on an economic evaluation of peritoneal cytology, carried out at Wellington Hospital, New Zealand. The analysis is based on two trials totalling 192 patients. The perspective taken initially is that of a hospital financial manager, seeking to minimise costs. In the first trial, there was a marginal increase in overall cost per person presenting with suspected acute appendicitis, from using the test. In the second, there was a reduction. In both trials there were significant health benefits--unnecessary operations were avoided, and necessary operations done more quickly. Also, the practice developed, in the second trial, of sending patients home immediately following a negative test result. This further increased savings. We then discuss the results from a broader perspective. We conclude that the additional personal benefits--less time convalescing, and lower mortality, on average--ensure that the benefits outweigh the costs of the test.

Effect of radical scavengers and hyperbaric oxygen on smoke-induced pulmonary edema

Respiratory complications, especially pulmonary edema, account for over 50% of mortalities in inhalation injuries. This study was conducted to determine the effect of free radical scavengers and hyperbaric oxygen (HBO) in vivo on reducing pulmonary edema. Adult New Zealand rabbits were allowed to breath cooled, cotton smoke until a significant inhalation lung injury was produced. Five percent of body weight lactated Ringer's solution was then administered i.v. over 2 h. The following free radical scavengers were given as bolus infusions at the beginning of fluids resuscitation: superoxide dismutase, catalase, butylated hydroxytoluene/piperonyl butoxide, and mannitol. At the completion of fluid administration, half of the subjects were given HBO treatment. Pulmonary edema was then measured as extravascular lung water and wet/dry lung weight. Results indicate that free radical scavengers or HBO reduce pulmonary edema. Free radical scavengers in conjunction with HBO showed no significant improvement over HBO or free radical scavengers alone.

Vascular endothelial cell activation in models of vascular and glomerular injury

Activated vascular endothelium evidences a diverse array of responses to biochemical and physical stimuli with modulating effects on leukocyte trafficking, vascular permeability and vasomotor tone controlling microvascular blood flow. Clearly, glomerular endothelial cells share in common with large-vessel endothelium some components of the cytokine-activated phenotype. These findings provide insight into mechanisms of glomerular injury. Speculation about potentially unique aspects of microvascular regulation which might be important in glomerular injury suggests that novel aspects of cytokine-activation may be evident in microvascular endothelial cells. Molecular mechanisms underlying signal transduction of stimulus-induced alterations in endothelial phenotype implicate cis-regulatory processes that are unique in diversity and expression. Further elucidation of these mechanisms may suggest interventions directed towards inhibiting the pathophysiologic sequelae of endothelial cell activation.

Localization of NADPH diaphorase in the lumbosacral spinal cord and dorsal root ganglia of the cat

The distribution of NADPH-d activity in the spinal cord and dorsal root ganglia of the cat was studied to evaluate the role of nitric oxide in lumbosacral afferent and spinal autonomic pathways. At all levels of the spinal cord NADPH-d staining was present in neurons and fibers in the superficial dorsal horn and in neurons around the central canal and in the dorsal commissure. In addition, the sympathetic autonomic nucleus in the rostral lumbar segments exhibited prominent NADPH-d cellular staining whereas the parasympathetic nucleus in the sacral segments was not well stained. The most prominent NADPH-d activity in the sacral segments occurred in fibers extending from Lissauer's tract through laminae I along the lateral edge of the dorsal horn to lamina V and the region of the sacral parasympathetic nucleus. These fibers were very similar to VIP-containing and pelvic nerve afferent projections in the same region. They were prominent in the S1-S3 segments but not in adjacent segments (L6-L7 and Cx1) or in thoracolumbar and cervical segments. NADPH-d activity and VIP immunoreactivity in Lissauer's tract and the lateral dorsal horn were eliminated or greatly reduced after dorsal-ventral rhizotomy (S1-S3), indicating the fibers represent primary afferent projections. A population of small diameter afferent neurons in the L7-S2 dorsal root ganglia were intensely stained for NADPH-d. The functional significance of the NADPH-d histochemical stain remains to be determined; however, if NADPH-d is nitric oxide synthase then this would suggest that nitric oxide may function as a transmitter in thoracolumbar sympathetic preganglionic efferent pathways and in sacral parasympathetic afferent pathways in the cat.

A carbohydrate-carbohydrate interaction between galactosylceramide-containing liposomes and cerebroside sulfate-containing liposomes: dependence on the glycolipid ceramide composition

Galactosylceramide (GalCer) and cerebroside sulfate (CBS) are the major glycolipids found in myelin. They occur in greater concentrations in this membrane than any other. Recently, it was reported that these two glycolipids can participate in a heterotypic carbohydrate-carbohydrate interaction [Hakomori et al. (1991) Glycoconjugate J. 8, 178]. In the present study, the effect of changes in the ceramide composition of both GalCer and CBS on this interaction has been examined. The interaction was monitored by measuring the aggregation of small unilamellar phosphatidylcholine/cholesterol liposomes containing GalCer with similar liposomes containing CBS, through the increase in optical density at 450 nm. Aggregation depends on the addition of a divalent cation and varies inversely with the ionic radius of the cation. Aggregation occurred at millimolar concentrations of divalent cation and was inhibited and reversed by the addition of EDTA. A lesser degree of homotypic self-aggregation of GalCer and of CBS liposomes also occurred in the presence of divalent cations, but the sum of this self-aggregation was significantly less than the heterotypic interaction between the two types of liposomes. Changes in the ceramide composition of GalCer and CBS significantly affected the extent of their interaction with each other. Increasing the fatty acid chain length of either GalCer or CBS resulted in increased aggregation. Hydroxylation of the fatty acid also increased the degree of aggregation of GalCer and CBS liposomes. These findings indicate that a divalent cation-mediated GalCer-CBS interaction could play a role in cell recognition and membrane adhesion phenomena such as the formation of compact multilamellar myelin.(ABSTRACT TRUNCATED AT 250 WORDS)

Oesophageal duplication cyst: another cause of neonatal respiratory distress

Oesophageal duplication cysts in infants (usually males) should be recognized as a cause of respiratory distress which worsens during the neonatal period, and which is associated with feeding difficulties. Their radiological appearance is that of a right-sided posterior mediastinal mass, which is shown to be cystic on ultrasound. Excision is curative.

Structure and chromosomal localization of the human constitutive endothelial nitric oxide synthase gene

Endothelial nitric oxide (NO) synthase is a unique NO synthase isoform that is expressed constitutively by vascular endothelium both in vivo and in vitro and is believed essential to local vascular homeostasis. This calcium/calmodulin-dependent isoform is distinct from neuronal NO synthase. Genomic clones encoding the human endothelial NO synthase were isolated and the structural organization of the gene was determined. The gene contains 26 exons spanning approximately 21 kilobases of genomic DNA, encodes a messenger RNA of 4052 nucleotides, and is present as a single copy in the haploid human genome. Characterization of 5'-flanking genomic regions indicates that the endothelial NO synthase promoter is "TATA-less" and exhibits proximal promoter elements consistent with a constitutively expressed gene that is found in endothelial cells, namely Sp1 and GATA motifs. The 5'-flanking region contains putative AP-1, AP-2, NF-1, heavy metal, acute-phase response shear stress, and sterol-regulatory cis-elements. The human endothelial NO synthase gene was assigned to the 7q35-->7q36 region of chromosome 7 by Southern blot hybridization of human-rodent somatic cell hybrid lines and fluorescence in situ hybridization, whereas human neuronal NO synthase localized to the 12q24.2 region of chromosome 12.

Exposure of galactosylceramide to galactose oxidase in liposomes: dependence on lipid environment and ceramide composition

Factors which influence the accessibility, or exposure, of the carbohydrate head group of the glycolipid galactosylceramide (GalCer) at the membrane surface have been examined in lipid model membranes using the technique of galactose oxidase-tritiated sodium borohydride labeling. Both the ceramide composition of GalCer and the lipid composition of its membrane environment were varied. We have shown that GalCer is oxidized in a membrane environment, by purification of the labeled galactosyl moiety of the glycolipid by high-performance anion exchange chromatography. Using semisynthetic molecular species of GalCer with acyl chain lengths ranging from 16 to 26 carbons, incorporated into liposome membranes of egg phosphatidylcholine (PC), and reverse-phase HPLC separation of mixtures of the molecular species, we have shown that increasing the fatty acid chain length of GalCer increases its oxidation by galactose oxidase. In addition, the degree of oxidation is reduced when the fatty acid chain of GalCer is hydroxylated. GalCer incorporated into liposomes containing synthetic species of PC with different fatty acid chain lengths (together with cholesterol) was oxidized less as the PC acyl chain length, and hence the bilayer thickness, was increased. The oxidation of GalCer in liposomes composed of sphingomyelin/cholesterol was reduced compared to its oxidation in PC liposomes. Furthermore, changes in the fatty acid chain length of GalCer had no effect on its oxidation in sphingomyelin liposomes. These findings indicate that the ceramide composition and lipid membrane environment can influence the exposure of the lipid carbohydrate, and hence, they could modulate the receptor activity of glycolipids at the membrane surface.

Direction of microtubule movement is an intrinsic property of the motor domains of kinesin heavy chain and Drosophila ncd protein

The kinesin heavy chain and the ncd (non-claret disjunctional) gene product of Drosophila are microtubule-associated motor proteins related by sequence similarity within an approximately 340-aa domain. Despite the sequence similarity, the kinesin heavy chain and ncd protein move in opposite directions on microtubules. To investigate the molecular basis for direction of movement, we created a series of truncated kinesin heavy chain and ncd proteins. We found that the conserved domain of both proteins has microtubule motor activity, although the efficiency with which ATP hydrolysis is coupled to microtubule movement declines dramatically with increasing truncation. Further, the direction of movement is intrinsic to the conserved motor domains, rather than being a consequence of domain organization or adjacent sequences.

Role of hiatal hernia in delaying acid clearance

The aim of this study was to assess prospectively the relationship of a hiatal hernia to gastro-oesophageal reflux. Ninety five children with symptoms of gastro-oesophageal reflux in whom reflux was demonstrated radiologically were investigated. Oesophageal pH monitoring for 18 hours and endoscopy were performed in all patients. On the basis of radiology, patients were divided into those with hiatal hernia (n = 37) and those without (n = 58). Both groups had the same number of reflux episodes on pH monitoring. However, the median duration of the longest episode was significantly greater in the hiatal hernia group (30 min v 19 min), as was the number of reflux episodes longer than five minutes (5 v 4). The percentage with a pH < 4 just failed to be significantly different (13% v 8%). Hiatal hernia was also found to correlate with the presence of oesophagitis. The presence of a hiatal hernia delays the clearance of acid from the oesophagus and is associated with an increased incidence of oesophagitis.

Synthesis of digoxigenin-labeled cRNA probes for nonisotopic in situ hybridization using reverse transcription polymerase chain reaction

Nonisotopic methods of mRNA in situ hybridization have distinct advantages over isotopic techniques. Nonisotopically labeled probes are stable and nontoxic, have short detection times, demonstrate excellent spatial resolution of their signals and have sensitivities comparable to radiolabeled probes. We developed a simple method of generating nonisotopically labeled cRNA probes which is based on the reverse transcription polymerase chain reaction (RT-PCR) and used it to synthesize a panel of probes for various murine extracellular matrix genes. Engelbreth-Holm-Swarm (EHS) tumor RNA was reverse transcribed and PCR was used to amplify defined regions of multiple extracellular matrix protein genes from the resulting first strand cDNAs. Bacteriophage promoters which had been incorporated into the PCR products were then used to generate digoxigenin-conjugated antisense and sense cRNAs. The antisense probes were employed to detect the specific extracellular matrix protein mRNAs in the EHS tumor by in situ hybridization. This technique provides a rapid and efficient alternative to conventional transcription systems which use plasmid vectors for the synthesis of digoxigenin-labeled cRNA probes.

Measurement of free radicals from smoke inhalation and oxygen exposure by spin trapping and ESR spectroscopy

Research in smoke inhalation has established that free radicals are produced from gases released during combustion and these species impair lung function. Using spin traps and their adducts in an animal model free radicals were measured. Various hyperbaric oxygen regimens were tested in an attempt to attenuate pulmonary damage caused by free radical reactions. Our data demonstrated that persistent oxygen- and carbon-centered free radicals are detectable in intravascular fluids after smoke inhalation. The smoke inhalation model showed however, clearing of spin trap adducts one hour after smoke exposure. Other researchers have found that when 100% oxygen is given at 1 atmosphere absolute (ATA) for 1 h, free radicals were not detectable. However, oxygen given at 2.5 ATA does produce detectable free radicals. With continued exposure at this pressure, the levels of free radicals increase for up to 60 min. This study suggests that the level of free radical induced oxygen toxicity may be a function of oxygen pressure and duration of oxygen exposure.

Identification and partial characterization of six members of the kinesin superfamily in Drosophila

Recent evidence has suggested that the principal polypeptide component of the microtubule motor protein kinesin may be a member of an extended superfamily of related motor proteins. To gain insight into how large the kinesin superfamily might be and to begin determining the potential functions in which various superfamily members might participate, we identified and partially characterized six additional members of the Drosophila kinesin superfamily. Genes encoding these proteins were identified by using the polymerase chain reaction with degenerate primers corresponding to highly conserved regions of the kinesin heavy-chain motor domain. Partial sequencing of the six genes revealed that they encode proteins that are 40-60% identical to the motor domain of the kinesin heavy-chain sequence. The cytogenetic locations as well as the developmental and tissue-specific expression patterns have been determined. The data suggest that each of these six kinesin-like proteins may have functions in a wide variety of cell types and tissues.

Histological changes following submucosal Teflon injection in the bladder

Histological examination following subureteric Teflon injection was carried out on 32 ureters and four granulomatous polyps. When the Teflon was correctly placed in the submucosa it remained circumscribed and reflux was more likely to be corrected. If the Teflon was placed more deeply it became diffuse, caused a giant cell reaction, and was less likely to correct the reflux. The granulomatous polyps may represent a reaction to leakage of Teflon from the injection site.

The kinesin-like ncd protein of Drosophila is a minus end-directed microtubule motor

The Drosophila ncd gene is required for chromosome segregation during female meiosis. Previous analyses suggested that the ncd gene encoded a protein with sequence similarity to the kinesin motor domain, which suggested that, like kinesin, the ncd protein might be a plus end-directed microtubule motor. Here we describe the expression of ncd protein in E. coli and the initial characterization of the ncd protein's motor properties. The ncd protein is indeed a microtubule motor, but the polarity of movement is minus end directed. The ncd protein also has microtubule bundling activity. These findings limit possible models for the in vivo functions of the ncd protein and suggest that motor proteins with similar sequence can generate movement in opposite directions along a microtubule.

Effects of ibuprofen on pulmonary oedema in an animal smoke inhalation model

The ability of ibuprofen to lower extravascular lung water significantly was examined in an animal smoke inhalation model. Adult New Zealand White rabbits weighing 3-5 kg were anaesthetized and intubated. They were then allowed to breathe cooled cotton smoke until the carboxyhaemoglobin (COHb) reached a level of 60 per cent or higher. Each ibuprofen-treated animal received a dose of 50 mg/kg either intraperitoneally or intravenously. Ibuprofen was administered to animals that received smoke inhalation alone and those that received smoke inhalation combined with a 10 per cent BSA partial skin thickness thermal injury. Control groups were established for both of the above-mentioned groups. Peak carboxyhaemoglobin levels as well as CO half-lives were not significantly different between ibuprofen-treated groups and the controls. Ibuprofen treatment resulted in significantly (P less than 0.05) decreased lung water in both smoke, and smoke plus thermal injury groups as compared to controls. These results suggest that ibuprofen promotes the reduction of early-onset lung water resulting from smoke inhalation injury alone or from smoke inhalation injury plus a thermal injury.

Unilateral cryptorchidism: an animal model

Unilateral division of the distal gubernaculum testis was performed, using hypothermic anaesthesia, in Wistar rats within 48 hours of birth. This resulted in ipsilateral abdominal testicular retention and contralateral descent. This model is suitable for the experimental study of congenital unilateral cryptorchidism and is presented in detail.

Role of GTP hydrolysis in microtubule polymerization: evidence for a coupled hydrolysis mechanism

The relationship between GTP hydrolysis and microtubule assembly has been investigated by using a rapid filtration method. Microtubules assembled from phosphocellulose-purified tubulin, double-labeled with [gamma-32P]- and [3H]GTP, were trapped and washed free of unbound nucleotide on glass fiber filters. The transient accumulation of microtubule-bound GTP predicted by uncoupled GTP hydrolysis models [Carlier & Pantaloni (1981) Biochemistry 20, 1918-1924; Carlier et al. (1987) Biochemistry 26, 4428-4437] during the rapid assembly of microtubules was not detectable under our experimental conditions. By calculating hypothetical time courses for the transient accumulation of microtubule-bound GTP, we demonstrate that microtubule-bound GTP would have been detectable even if the first-order rate constant for GTP hydrolysis were 4-5 times greater than the pseudo-first-order rate constant for tubulin subunit addition to microtubules. In a similar manner, we demonstrate that if GTP hydrolysis were uncoupled from microtubule assembly but were limited to the interface between GTP subunits and GDP subunits (uncoupled vectorial hydrolysis), then microtubule-bound GTP would have been detectable if GTP hydrolysis became uncoupled from microtubule assembly at less than 50 microM free tubulin, 5 times the steady-state tubulin concentration of our experimental conditions. In addition, during rapid microtubule assembly, we have not detected any microtubule-bound Pi, which has been proposed to form a stabilizing cap at the ends of microtubules [Carlier et al. (1988) Biochemistry 27, 3555-3559]. Also, several conditions that could be expected to increase the degree of potential uncoupling between GTP hydrolysis and microtubule assembly were examined, and no evidence of uncoupling was found. Our results are consistent with models that propose cooperative mechanisms that limit GTP hydrolysis to the terminal ring of tubulin subunits [e.g., O'Brien et al. (1987) Biochemistry 26, 4148-4156]. The results are also consistent with the hypothesis that a slow conformational change in tubulin subunits after GTP hydrolysis and Pi release occurs that results in destabilized microtubule ends when such subunits become exposed at the ends.

Evidence that the head of kinesin is sufficient for force generation and motility in vitro

Kinesin is a mechanochemical protein that converts the chemical energy in adenosine triphosphate into mechanical force for movement of cellular components along microtubules. The regions of the kinesin molecule responsible for generating movement were determined by studying the heavy chain of Drosophila kinesin, and its truncated forms, expressed in Escherichia coli. The results demonstrate that (i) kinesin heavy chain alone, without the light chains and other eukaryotic factors, is able to induce microtubule movement in vitro, and (ii) a fragment likely to contain only the kinesin head is also capable of inducing microtubule motility. Thus, the amino-terminal 450 amino acids of kinesin contain all the basic elements needed to convert chemical energy into mechanical force.

An enzyme histochemical study of large muscle fibres in the neonatal mouse

Small clusters of extra large muscle fibres were identified in hindlimb muscles of neonatal mice (strain C57BL/10ScSn). At two days of age they had a significantly greater cross-sectional area than their normal counterparts (P less than 0.01). Fibre typing methods (NADH-tetrazolium reductase, ATPase and phosphorylase) classified them as 2A fast oxidative glycolytic (FOG fibres). The activity of NADH-tetrazolium reductase and the lysosomal enzymes beta-glucuronidase, acid phosphatase and dipeptidyl peptidase II were all elevated in the large fibres. Microsomal aminopeptidase (mAPP), a membrane-bound enzyme, also showed increased activity. The fibres are probably the mouse equivalent of the Wohlfart B fibres of the human fetus, with which comparison is made.

Fertility in experimental unilateral cryptorchidism

Unilateral cryptorchidism was induced in Wistar rat pups within 48 hours of birth. Evaluation of fertility was subsequently assessed at 50, 100, and 150 days of age by paternity and daily sperm production. The descended scrotal testis was demonstrated to have a significantly diminished rate of sperm production at 150 days. Paternity studies failed to reflect this dysfunction, cryptorchid and sham-operated control animals having a 58% and 80% ability to produce offspring (P = .44).

Fine catheter aspiration cytology of the peritoneal cavity in the diagnosis of a metastatic tumor. Report of a case with immunocytochemical studies

The potential value of a new system of fine catheter aspiration (FCA) cytology of the peritoneal cavity in the diagnosis of peritoneal malignancy is illustrated by a case report. Gelman filter preparations of an FCA sample of an abdominal mass from a patient with a history of adenocarcinoma of the lung showed unequivocal malignant cells, obviating the need for further diagnostic procedures. Trial immunostaining of Cytospin preparations of part of the FCA sample showed appropriate results, suggesting that such samples may be suitable for immunoperoxidase studies to identify tumor types or to predict the source of the primary tumor in difficult cases.

Dependence of the surface expression of the glycolipid cerebroside sulfate on its lipid environment: comparison of sphingomyelin and phosphatidylcholine

The influence of the membrane lipid environment on the reactivity with antibody of the acidic glycolipid cerebroside sulfate (CBS) was examined by using a spin membrane immunoassay. Fewer antibodies in a polyclonal anti-CBS antiserum recognized the antigen in a bovine brain sphingomyelin/cholesterol (SM/CHOL) environment than in dipalmitoylphosphatidylcholine/cholesterol (DPPC/CHOL). Changes in the CBS ceramide group appeared to have less influence on antibody recognition of CBS in SM/CHOL than in DPPC/CHOL [Crook et al. (1986) Biochemistry 25, 7488-7494]. Although the fatty acid chain length of phosphatidylcholine strongly influences CBS recognition, the fatty acid chain length of sphingomyelin had only a moderate effect on CBS recognition and did not account for the decreased recognition in SM compared to in DPPC. Inhibition studies revealed that the antibodies which recognize CBS in SM/CHOL (S antibodies) form a population distinct from those which recognize CBS in DPPC/CHOL (P antibodies). The specificity of the P and S antibodies was examined further by comparing the efficacy of various substances, which share chemical features with the components of CBS in a SM/CHOL or DPPC/CHOL environment, to inhibit lysis of liposomes containing CBS. Intact CBS, cholesterol, and a phosphocholine lipid, at certain antigen densities, were required for optimal recognition of the antigen, especially by the P antibodies, suggesting that a complex of all three lipids in a multivalent array may be recognized by these antibodies. The S antibodies may recognize a smaller complex or monomers of CBS.(ABSTRACT TRUNCATED AT 250 WORDS)

The blood-testis barrier in experimental unilateral cryptorchidism

Unilateral cryptorchidism was induced in Wistar rat pups within 48 h of birth. After a period of 150 days, the blood-testis barrier was evaluated in the cryptorchid and contralateral scrotal testis, using a lanthanum immersion technique. The barrier was demonstrated to be competent, with tracer confined to the basal and intermediate compartments.

Mucinous cystadenocarcinoma of the pancreas: diagnosis by fine-needle aspiration cytology

Two cases of mucinous cystadenocarcinoma of the pancreas are described in which the diagnosis was made from the material obtained by a computed tomography-guided fine-needle aspiration cytology examination. It is strongly felt that aspiration cytology, when performed under imaging guidance, is sensitive and specific in the diagnosis of mucinous cystadenocarcinoma and allows for a relatively simple yet confident diagnostic interpretation of this uncommon pancreatic tumour.