Denervation of transplanted porcine lung causes airway obstruction

Lung transplantation can be complicated by a form of small airway obstruction known as bronchiolitis obliterans. We tested the hypothesis that lung denervation causes small airway obstruction in young pigs (10 +/- 1 weeks). Control pigs had an innervated native lobe, and study pigs had either a denervated native lobe or a denervated transplant lobe. Transplanted pigs received standard immunosuppression. At 10 weeks we measured isolated left lobe pulmonary mechanics. Dynamic resistance in both study groups was significantly higher than in the lobectomy group, whereas dynamic compliance in both study groups was significantly lower than in the lobectomy group. No significant difference in resistance or compliance was noted between the transplant and reimplant groups. Histologic changes consistent with rejection were noted in the transplant lobes. We conclude that the small airway obstruction noted in this model is due to operative denervation rather than to immunosuppression or rejection.

[The results of serological studies in different foci of tropical and tertiary malaria]

Attempt was made to determine the value of serologic indices of malaria surveys. Following uniformed methodological and technical approaches 3 foci of P. vivax and 6 foci of P. falciparum malaria were surveyed in different endemic zones of Vietnam and the USSR. It was shown that the most objective criteria for a foci classification is its serologic mean geometric titre. The latter in its turn directly depends of transmission longevity in a foci.

The organization of open complexes between Escherichia coli RNA polymerase and DNA fragments carrying promoters either with or without consensus -35 region sequences

Transcription initiation at the Escherichia coli galP1 promoter does not depend on specific nucleotide sequences in the -35 region. Footprint analysis of transcriptionally competent complexes between E. coli RNA polymerase and DNA fragments carrying galP1 shows that RNA polymerase protects sequences as far upstream as -55, whereas sequences around the -35 region are exposed. In contrast, with galP1 derivatives carrying -35 region sequences resembling the consensus, RNA polymerase protects bases as far as -45, and the -35 region is fully protected. Taken together, our data suggest that the overall architecture of RNA polymerase-promoter complexes can vary according to whether or not consensus -35 region sequences are present; in the absence of these sequences, open complex formation requires distortion of the promoter DNA. However, the unwinding of promoter DNA around the transcription start is not affected by the nature of the -35 region sequence. With a galP1 derivative carrying point mutations in the spacer region that greatly reduce promoter activity, the protection of bases by RNA polymerase around the -10 sequence and transcription start site is reduced. In contrast, protection of the region upstream of -25 is unaffected by the spacer mutations, although sequences from -46 to -54 become hypersensitive to attack by potassium permanganate, indicating severe distortion or kinking of this zone. We suggest that, with this galP1 derivative, RNA polymerase is blocked in a complex that is an intermediate on the path to open complex formation.

Unwinding of duplex DNA during transcription initiation at the Escherichia coli galactose operon overlapping promoters

We have used potassium permanganate as a probe to detect DNA duplex unwinding in vitro, in open complexes between E. coli RNA polymerase and DNa fragments carrying the E. coli galactose operon regulatory region. This zone contains 3 overlapping promoters which specify transcription initiation at 3 distinct startpoints. We have used mutant gal derivatives carrying different single point mutations, each of which allows initiation from only one of the 3 start sites. This has allowed us to compare duplex unwinding in open complexes at the 3 different promoters, and to show that the extent of the unwinding is similar in each case. Further, the pattern of DNA modification by potassium permanganate suggests a model for discrimination between the upper and lower strands. Finally, we show that DNA modification by potassium permanganate at the gal promoters is the same in vivo as in vitro.

Comparison of promoter activities in Escherichia coli and Pseudomonas aeruginosa: use of a new broad-host-range promoter-probe plasmid

The broad-host-range plasmid, pRW2, is a derivative of pRK 2501 carrying the Escherichia coli lac operon without a promoter, downstream of a polylinker sequence. We have cloned a number of DNA fragments carrying promoters into this plasmid and measured promoter activity in both E. coli and Pseudomonas aeruginosa. Promoters carrying consensus -10 and -35 sequences were active in both backgrounds and the dependence of activity on the nucleotide sequence of the 35 region was the same in both cases. We also measured the activity of two promoters at which transcription in E. coli was totally dependent on the E. coli activators CRP and FNR: both promoters were found to be active in P. aeruginosa.

Recognition of nucleotide sequences at the Escherichia coli galactose operon P1 promoter by RNA polymerase

Specific nucleotide (nt) sequences in the -35 region are not essential for galP1 promoter activity, whereas nt sequences in the spacer region are needed for transcription initiation: a G:C base pair at nt -14 and sequences upstream from this position are necessary. In the absence of these sequences, transcription initiation is dependent on the insertion of oligodeoxyribonucleotides carrying -35 region consensus hexamer sequences. Additionally, for maximal promoter activity, specific sequences just upstream from nt -49 are required. Because galP1 carries no sequence resembling the -35 region consensus hexamer, we propose that recognition by RNA polymerase proceeds via an unusual mechanism involving contacts upstream from the -10 hexamer, distortion of the spacer region and a contact upstream from nt -49.

Macrophage/monocyte receptor for nonenzymatically glycosylated protein is upregulated by cachectin/tumor necrosis factor

Proteins of extracellular matrix undergo over time multiple reactions with glucose to form advanced glycosylation endproducts (AGEs) which are highly active in protein crosslinking, and have been implicated in tissue damage associated with aging and diabetes. A macrophage/monocyte receptor for AGE moieties mediates the uptake of AGE-modified proteins by a process that also induces cachectin/tumor necrosis factor (TNF) and IL-1 secretion. Reasoning that cytokines might regulate this AGE-receptor system, we have evaluated the effect of cachectin/TNF, IL-1, and IFN-gamma on AGE-protein processing. We report that cachectin/TNF induced a severalfold enhancement of binding, endocytosis, and degradation of AGE-BSA by both murine peritoneal macrophages and human blood monocytes in vitro, and that cachectin/TNF enhanced the rate of disappearance of AGE-modified red blood cells in vivo. IL-1 and IFN-gamma alone did not increase AGE processing, but IFN-gamma consistently enhanced cachectin/TNF-induced changes in AGE-receptor kinetics. Similar effects were induced by AGE-BSA and FFI-BSA, a chemically synthesized AGE, when used as macrophage stimulants, possibly via cachectin/TNF induction. All upregulatory responses were blocked by anticachectin/TNF monoclonal antibody. These data suggest that AGE-induced cachectin/TNF, in addition to influencing tissue regeneration and remodelling, may also normally regulate the disposal of tissue damaging AGE-proteins through an autocrine upregulation.

Dissociation of authentic and artifactual effect of circulating heparin on drug protein binding

The purpose of this study was to dissociate the authentic and artifactual effect of in vivo heparin on drug protein binding using protamine as an inhibitor of ex vivo lipolysis. A mixture of ethylenediamine tetra-acetic acid (EDTA, 5 mg ml-1) and protamine in the concentration range of 0 to 7.5 mg ml-1 was added to blood samples from 23 cardiac catheterized patients before (control) and 10 min after 3000 IU of intravenous heparin. In control samples, protamine does not interfere with the protein binding of lidocaine (L), quinidine (Q) or propranolol (P) when plasma pH is readjusted to 7.4. In the absence of protamine, heparin induced a significant increase in the free fraction by 40, 130, and 30 per cent for L, Q, and P, respectively (p less than 0.001), while free fatty acid (FFA) levels increased 2 to 6 fold. When protamine was present, the heparin-induced elevation in free fraction was significantly lower for L (16 per cent) and Q (77 per cent) but not for P; FFA levels were decreased at all protamine concentrations. Residual increases in free fraction and FFA levels compared to control values may represent the true in vivo effect of heparin at the peak activity of lipoprotein lipases. For L and Q, variations in free fraction were strongly associated with variations in FFA, but for P, no significant correlation was observed (r = 0.492). These results indicate that variations in free fraction of L and Q caused by heparin are, to a large extent, artifactual but may be prevented by use of protamine in collection tubes (5 to 7.5 mg ml-1). For P, the increase in free fraction was not mediated by variations of FFA indicating that another mechanism must be involved.

Alterations in the binding site of the cyclic AMP receptor protein at the Escherichia coli galactose operon regulatory region

Gene manipulation techniques have been used to alter the binding site for the cyclic AMP-cyclic AMP receptor protein complex (cAMP-CRP) at the regulatory region of the Escherichia coli galactose (gal) operon. The effects of these changes on CRP-dependent stimulation of expression from the galP1 promoter in vivo have been measured, and gel binding assays have been used to measure the affinity of cAMP-CRP for the modified sites. Firstly we have deleted progressively longer sequences from upstream of the gal CRP site in order to locate the functional limit of the site. A deletion to -49, removing the first base that corresponds to the consensus sequence for a CRP binding site, is sufficient to reduce CRP binding and block CRP-dependent stimulation of P1. Secondly, we used synthetic oligonucleotides to invert the asymmetric nucleotide sequence at the gal CRP binding site or to make the sequence symmetric. Inversion of the site has little effect on CRP binding, the architecture of open complexes at P1 revealed by DNAase I footprinting, or the stimulation of transcription from P1. Making the site symmetric increases the affinity for CRP by over 50-fold and leads to increased transcription from P1, whilst hardly altering the DNAase I footprint of open complexes. Our results confirm that the strength of binding of CRP depends on the nature of the site and show that it is this that principally accounts for differences in CRP-dependent stimulation of transcription.

Changes in circulating alphafetoprotein and human chorionic gonadotrophin following chorionic villus sampling

Chorionic villus sampling (CVS) is rapidly becoming established as a routine procedure for first-trimester fetal diagnosis. The technique can result in fetomaternal haemorrhage and this might sensitize Rhesus-negative mothers and on occasion lead to spontaneous abortion. Serial sampling indicates that there is a rapid rise in alphafetoprotein (AFP) levels following CVS; however, this is not reflected by raised levels at 16-18 weeks and does not influence the subsequent pregnancy outcome. Unlike AFP, alterations in hCG levels are small and variable. Anti-D prophylaxis for non-sensitized Rhesus negative mothers should be given after CVS and the procedure may be contra-indicated in patients who are already sensitized.

Functional analysis of different sequence elements in the Escherichia coli galactose operon P2 promoter

Starting with a DNA fragment containing the galactose operon P2 promoter, we made a series of deletions that progressively replaced DNA sequences upstream of the transcription startpoint and determined their effects on P2 activity. The results show that specific sequences upstream of -32 are not important. Removal of the sequence 5'-CACA-3' from -32 to -28 reduces P2 activity by 50%: longer deletions to -16 further reduce activity but do not remove the information specifying the transcription startpoint. DNA sequences between -32 and -16 at gal P2 assist the isomerization of RNA polymerase from closed to open complexes rather than contributing to the initial binding of RNA polymerase. The activity of gal P2 in the absence of -35 region sequences is dependent on the sequence TG just upstream of the -10 hexamer, TATACT: a mutation at -14 changing the TG sequence to TT totally inactivates P2. However, P2 activity can be restored if the consensus -35 region sequence TTGACA is cloned 17 bp upstream of the -10 hexamer. Thus, for transcription initiation, the -10 hexamer, TATACT, must 'cooperate' with upstream sequences that may be located either around -35 or -14.

A novel whole blood capillary technic for measuring the prothrombin time

The prothrombin time (PT) is frequently performed to monitor anticoagulant therapy. Although relatively simple to perform, it requires venipuncture and laboratory resources for sample handling and analysis. A recently developed capillary whole blood device that uses fingerstick samples was evaluated. Paired capillary whole blood and reference plasma PTs were performed in 858 samples from 732 subjects. The PT for normal volunteers (n = 193) was 11.8 +/- 0.9 seconds with the use of the new instrument and 12.1 +/- 0.5 seconds with the use of the reference method. In samples from 539 patients receiving anticoagulants, the correlation coefficient between the two methods was 0.96. Venous whole blood without anticoagulant and capillary whole blood gave equivalent results, which suggests that the fingersticks do not effect the quality of the specimen. Variation in hematocrit between 23.4% (0.34) and 53.8% (0.538) did not alter the performance of the instrument. The new instrument is easy to use and may allow testing by nonlaboratory personnel and patients. It obviates the need for venipuncture, provides immediate results, and appears to be comparable in accuracy to current reference methods.

RNA polymerase makes important contacts upstream from base pair -49 at the Escherichia coli galactose operon P1 promoter

A G:C to T:A transversion at bp position -19 in the gal operon promoter region relieves the dependence of galP1 promoter activity on the cAMP-CRP complex. Deletion analysis shows that expression from the promoter is decreased on replacement of the sequence between 49 and 54 bp upstream from the P1 start point. Moreover, protection experiments show that RNA polymerase interacts with this region in open complexes at P1. We propose that this contact is necessary for optimal P1 activity; point mutations in the gal promoter region can alter DNA flexibility and hence the strength of this contact; CRP factor activates P1 transcription by favouring formation of this contact; and the gal repressor blocks P1 activity by binding to this zone.

Scatter distribution in transmission measurements with positron emission tomography

The distribution of scattered radiation was measured for transmission scans in positron emission tomography by adding the scattered radiation distributions in different projections from line source experiments. It is shown that in a 20 cm diameter water-filled phantom the scattered radiation effects contribute approximately one-third of the events centrally in the field of view. This may lead to systematic errors of the order of 15-25% in reconstructed images. A scheme for correction for scattered radiation effects in the transmission scans is described and tested in phantom experiments.

Mutations that reduce expression from the P2 promoter of the Escherichia coli galactose operon

We describe the isolation and characterisation of twelve different mutations that reduce gene expression from the galP2 promoter, starting with a gal regulatory region with a mutation that inactivated galP1, the cAMP-CRP-dependent promoter. Seven of the new mutations reduce the initiation of transcription at P2 whereas the others reduce translation initiation of the first gal operon gene, galE. Two of the mutations affecting translation fall in the galE initiation codon and the Shine-Dalgarno sequence. Mutations that allow the formation of a stem-loop structure in the messenger including this sequence also reduce translation. A deletion of 11 bp, upstream of the Shine-Dalgarno sequence, almost totally prevents translation. Although none of the point mutations that reduced transcription initiation at P2 fall in the -35 region, we repeatedly isolated insertions in this zone. The point mutations all fell around the -10 region: the strongest effects were found with mutations that altered the sequence away from the consensus that has been established for Escherichia coli promoters. The effects of the two strongest P2 mutations were investigated in the absence of the P1 mutation used for their isolation. One mutation, a T:A to C:G transition at -12, inactivates both P2 and P1. In contrast the other, a T:A to G:C transversion at -19, specifically inactivates P2, but leaves P1 partially active even in the absence of cAMP-CRP. The implications of this are discussed in the context of how cAMP-CRP controls the balance between transcription from P2 and P1 at the gal operon regulatory region.

Effect of vagal blockade on food- and hormone-stimulated release of pancreatic polypeptide and motilin in dogs

Vagal control of food- and hormone-stimulated release of pancreatic polypeptide (PP) and motilin was investigated in four conscious dogs by examining the effect of cryogenic vagosympathetic blockade. The postprandial PP response of 189 +/- 7 pM was totally, although reversibly, inhibited to 58 +/- 11 pM with the vagi blocked. Similarly, bombesin-, CCK-OP-, or neurotensin-stimulated PP release was abolished. Although the PP response to intraduodenal perfusion of an elemental diet was also reduced by blockade, the 52 +/- 15% inhibition was less than observed with the meal. In contrast to PP, plasma motilin fell after the meal from a fasting level of 128 +/- 16 pM to a nadir of 52 +/- 7 pM. Vagal blockade reversed this decline as plasma motilin rose to a peak of 121 +/- 18 pM with a pattern resembling the motilin response in the interdigestive state. This motilin increment during blockade was inhibited by atropine and by infusion of porcine PP. Plasma motilin also fell with the elemental diet, but this response was not affected by blockade. During infusion of bombesin, plasma motilin rose by 60 +/- 9 pM; vagal blockade augmented this increment twofold. Thus, the PP response to a meal and to hormonal stimulation is controlled by a vagal cholinergic excitatory pathway. However, intestinal release of PP is mediated in part by the vagus and in part by a vagally independent mechanism which may be neural or hormonal. Alternatively, vagal noncholinergic inhibition is a major mechanism modulating the motilin response after oral food but motilin release exclusively from intestinal nutriments is mediated by nonvagal, noncholinergic mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Can potentially infectious specimens containing hepatitis B virus be identified on the basis of their biochemical profile?

The potential infectivity of 1129 randomly selected plasma specimens was directly assayed by hepatitis B virus (HBV) DNA dot-hybridization. Presence or absence of HBV was then correlated with a biochemical profile of 20 common analytes obtained on these same specimens. We found that potentially infectious specimens could not be identified on the basis of any combination of simple biochemical tests; indeed, the infectious specimens were more "normal" in some tests of liver function than were the non-infectious specimens.

Can potentially infectious specimens containing hepatitis B virus be identified on the basis of their biochemical profile?

The potential infectivity of 1129 randomly selected plasma specimens was directly assayed by hepatitis B virus (HBV) DNA dot-hybridization. Presence or absence of HBV was then correlated with a biochemical profile of 20 common analytes obtained on these same specimens. We found that potentially infectious specimens could not be identified on the basis of any combination of simple biochemical tests; indeed, the infectious specimens were more "normal" in some tests of liver function than were the non-infectious specimens.

The role of vagal integrity in gastrin releasing peptide stimulated gastroenteropancreatic hormone release and gastric acid secretion

The role of the vagus nerve in the control of gastrin releasing peptide (GRP) stimulated gastroenteropancreatic hormone release and gastric acid secretion was investigated in four conscious gastric fistula dogs using a technique of bilateral cryogenic vagal blockade. A 90-min infusion of GRP at a dose of 400 pmol X kg-1. h-1 produced significant elevations in plasma levels of gastrin, motilin, GIP, enteroglucagon, insulin, pancreatic glucagon, pancreatic polypeptide and VIP. Vagal blockade reversibly inhibited the rise of plasma PP and significantly blunted the elevation of plasma VIP. However, the GRP stimulated response of the other hormones investigated was not modified by vagal blockade. Similarly, the substantial secretion of gastric acid observed with GRP was not influenced by vagal blockade. Thus GRP acts predominantly via mechanisms which are independent of vagal integrity, findings that are in support of a major role for the local neuromodulation of hormone release and gastric acid secretion.

Simultaneous or sequential expression of lymphoid and myeloid phenotypes in acute leukemia

Acute mixed myeloid-lymphoid leukemia is uncommon. We report four cases in which myeloid and lymphoid cell markers were observed simultaneously or sequentially when 94 patients with acute leukemia were phenotyped according to the French-American-British (FAB) classification system, with cytochemical stains, and with immunologically defined differentiation markers (identified by monoclonal antibodies and antiterminal deoxynucleotidyl transferase [TdT]). In one case, conversion from acute lymphoblastic leukemia to acute myeloid leukemia was noted (FAB L1, TdT+ to FAB M4, Auer rods, TdT-). In another patient, two distinct populations of myeloid and lymphoid blast cells were observed simultaneously (TdT-, LeuM1+/TdT+, LeuM1-). In two additional patients, acute leukemia was characterized by the expression of both lymphoid and myeloid markers on the same cell (TdT+/Leu M1+, B4+/Leu M1+ and greater than or equal to 70% TdT+, T11+, My9+). The Philadelphia (Ph1) chromosome was negative in all cases, though other chromosomal abnormalities were noted in three out of four cases. Malignant transformation of a pluripotential stem cell for both lymphoid and myeloid lineages, with or without the Ph1 chromosome marker, could explain the coexistence of distinct populations of lymphoblasts and myeloblasts in acute leukemia. Acute leukemia with a biphenotypic profile may reflect genome depression accompanying neoplasia.

Acoustic properties of polyvinyl chloride gelatin for use in ultrasonography

Visualization of superficial structures with conventional rapid scanners has been difficult. A solid flexible polyvinyl chloride (PVC) gelatin slab used as a stand-off material can provide a constant scan distance and thus overcome the problem of poor near field resolution. PVC gelatin expands the capability of the 3-4 MHz transducer to delineate superficial structures. We report on the acoustic properties of the PCV gelatin, including the values of velocity and attenuation as a function of both frequency and temperature, and the comparison of data with published values of velocity and attenuation for water, soft tissue, and a phantom material.

Specific binding of vasoactive intestinal peptide to human circulating mononuclear cells

The interaction of the neuropeptide vasoactive intestinal peptide with human circulating mononuclear cells has been studied. Mononuclear cells were able to bind radiolabelled vasoactive intestinal peptide; the binding was rapid, reversible, saturable, and specific for vasoactive intestinal peptide. A fragment of vasoactive intestinal peptide (10-28) was 25-fold less effective than intact peptide as a competitor for the binding of the tracer. Secretin was 100-fold less effective as a competitor and glucagon competed poorly even at concentrations 10 000 times greater than that of the tracer molecule. In tracer dilution studies, the binding suggested a single class of binding sites with an apparent dissociation constant (Kd) of 2.4 X 10(-10) M and a capacity of 2 000 sites per cell. In the presence of vasoactive intestinal peptide, there was a dose-dependent augmentation of cyclic AMP in the mononuclear cells. The concentration of vasoactive intestinal peptide which produced a half-maximal effect was the same as the Kd for the peptide binding. We conclude that mononuclear cells have specific high-affinity binding sites for vasoactive intestinal peptide. Interactions between mononuclear cells and vasoactive intestinal peptide may be an important mechanism modulating local immune responses within tissues innervated by vasoactive intestinal peptide containing neurons.

Partial purification of [3H]mianserin binding sites

Frontal cortex membranes were solubilized with digitonin, prelabelled with 4 nM [3H]mianserin, and partially purified by isoelectric focussing. Bound [3H]mianserin separated from free [3H]mianserin as a single radioactive peak with a pI value of 5.03. A 14-fold purification was achieved. Focussing in the presence of 1 microM ketanserin (R 41468) or 1 microM chlorpyramine (a histamine H1-antagonist) or 10 microM spiperone (an S2-antagonist) completely abolished the peak of radioactivity at pH 5. Pharmacological characterization of the eluted radioactive peak revealed both histaminergic and serotonergic binding properties. The data suggest that the serotonergic and histaminergic components of [3H]mianserin binding to frontal cortex are not separable by solubilization, gel filtration or isoelectric focussing.