Same day CT angiography in a nurse-led Rapid Access Chest Pain Clinic

Funding Acknowledgements

None

Background

Rapid Access Chest Pain clinics (RACPCs) were established in the UK in 2000 following the publication of the National Service Framework for Coronary Heart Disease. Patients underwent an exercise test (ETT) in the clinic as part of a ‘one-stop’ protocol with follow-up only if further investigation was required. In 2010, the National Institute for Health and Care Excellence (NICE) produced guidelines for the assessment and diagnosis of chest pain of recent onset (CG95),  replacing the recommendation for ETT with non-invasive functional testing for patients with an intermediate pre-test probability of coronary artery disease (CAD), necessitating multiple appointments to evaluate the patient’s symptoms. The guidelines were updated in 2016, with a new recommendation that patients with atypical or typical chest pain should undergo CT coronary angiography (CTCA) as the first diagnostic test.

Purpose

The aim of this study was to investigate the feasibility and potential benefit of performing same -day CTCA in the RACPC.

Method

From November 2016 all patients with atypical or typical chest pain attending the RACPC at this tertiary cardiac centre were referred for CTCA unless alternative investigation was clinically indicated.  From February 2018, same day CTCA was offered to some patients. Up to two scans could be performed in each clinic, which was increased to up to three in June 2018.

Results

A total of 985 patients were seen in the nurse-led clinic between 12/02/2018 and 30/11/2019. 473 patients were referred for CTCA (48.0%) and 314 scans were carried out in the clinic (66.4%). Of those scans carried out in clinic, 128 patients had a CTCA which showed no evidence of CAD (40.8%) and 34.4% of scans showed non-obstructive CAD. In 18.2% of patients, the CTCA showed significant CAD and in 21 patients (6.7%) the scan was inconclusive. Patient with inconclusive scans underwent further testing which was negative in all cases. The outcome for patients with significant CAD (57 patients) is shown in the table.

Conclusion

CTCA on the same day as the RACPC appointment is feasible and facilitates rapid further investigation and treatment of patients with potentially significant CAD. It also enables patients with non-significant or no CAD to be reassured that their symptoms are unlikely to be cardiac which will reduce anxiety and allow timely investigation of other causes of the chest pain. Nurses need training in the risks of radiation in order to be able to request the scans and enable the clinic to be nurse-led.

Discharging patients; does it need to be done by a doctor?

Funding Acknowledgements

None

Background

Patients undergoing angiography and percutaneous coronary intervention (PCI) were historically reviewed post procedure by a member of the medical team who assesses the patient’s suitability for discharge and completes the discharge letter. Over the past 10 years, the number of patients admitted for these procedures as day cases has increased significantly. In addition, there has been an expansion in nursing roles in the UK with the development of a variety of clinical nurse specialist (CNS) posts which have taken over many of the traditional medical roles.

The majority of patients undergoing elective angiography and PCI are admitted to a day case unit at this tertiary cardiac centre. There is no designated medical cover for the unit and medical staff from the acute cardiac unit are called to review patients and complete their discharge paperwork in addition to their other duties. This frequently results in delayed discharge and patients going home without a discharge summary.

It was therefore proposed that suitably qualified CNSs could be trained to discharge these patients and others undergoing day case cardiology procedures.  From June 2017, the CNS team took over the role of reviewing patients post procedure and completing the discharge letter.

Purpose

The aim of the study was to evaluate if CNSs were able to discharge patients and provide a timely and effective service following elective cardiology procedures and to obtain patient feedback.

Method

Data on the number of patients reviewed by the CNSs from June 2017 to the end of December 2019, were prospectively collected in a dedicated database. A pilot study of patient experience was carried out in January 2020. Patients were given a questionnaire which asked about the explanation they received from the CNS regarding the procedure they had undergone, if their medication was reviewed and discussed with them, and if they received a discharge summary to take home.

Results

1287 patients were reviewed by the CNS team during the above period. 811 (63.0%) patients had undergone angiography and 423 (32.9%) PCI.  Informal feedback from the staff working on the day case unit included that patients were discharged earlier, had improved knowledge about their procedure and that the discharge letter was more detailed when completed by the CNS team.

Eight patients completed the pilot questionnaire. Six were discharged by one of the CNS team, one by a doctor and one patient was not sure who did their discharge. All patients were very satisfied with the process and the information they were given.

Conclusion

Experienced CNSs can deliver high-quality, timely discharge of patients following cardiology procedures.  This process is being used as a template to expand nurse-led discharge to other areas in cardiology. Patient experience will continue to be audited with a larger sample size in 2020.

A sea change in our view of overturning in the subpolar North Atlantic

To provide an observational basis for the Intergovernmental Panel on Climate Change projections of a slowing Atlantic meridional overturning circulation (MOC) in the 21st century, the Overturning in the Subpolar North Atlantic Program (OSNAP) observing system was launched in the summer of 2014. The first 21-month record reveals a highly variable overturning circulation responsible for the majority of the heat and freshwater transport across the OSNAP line. In a departure from the prevailing view that changes in deep water formation in the Labrador Sea dominate MOC variability, these results suggest that the conversion of warm, salty, shallow Atlantic waters into colder, fresher, deep waters that move southward in the Irminger and Iceland basins is largely responsible for overturning and its variability in the subpolar basin.

The Venom of the Boomslang (Dispholidus Typus): In Vivo and in Vitro Studies

An account is given of the effects of boomslang venom in man. Evidence was found of a fibrinolytic state apparently secondary to the coagulant action of the venom. These features rapidly responded to the administration of specific antivenom. In vitro studies, using a homogenate of boomslang parotids, confirmed the coagulant properties of the venom and showed them to be of much greater potency than the proteolytic actions.

Runx1 Orchestrates Sphingolipid Metabolism and Glucocorticoid Resistance in Lymphomagenesis

The three‐membered RUNX gene family includes RUNX1, a major mutational target in human leukemias, and displays hallmarks of both tumor suppressors and oncogenes. In mouse models, the Runx genes appear to act as conditional oncogenes, as ectopic expression is growth suppressive in normal cells but drives lymphoma development potently when combined with over‐expressed Myc or loss of p53. Clues to underlying mechanisms emerged previously from murine fibroblasts where ectopic expression of any of the Runx genes promotes survival through direct and indirect regulation of key enzymes in sphingolipid metabolism associated with a shift in the “sphingolipid rheostat” from ceramide to sphingosine‐1‐phosphate (S1P). Testing of this relationship in lymphoma cells was therefore a high priority. We find that ectopic expression of Runx1 in lymphoma cells consistently perturbs the sphingolipid rheostat, whereas an essential physiological role for Runx1 is revealed by reduced S1P levels in normal spleen after partial Cre‐mediated excision. Furthermore, we show that ectopic Runx1 expression confers increased resistance of lymphoma cells to glucocorticoid‐mediated apoptosis, and elucidate the mechanism of cross‐talk between glucocorticoid and sphingolipid metabolism through Sgpp1. Dexamethasone potently induces expression of Sgpp1 in T‐lymphoma cells and drives cell death which is reduced by partial knockdown of Sgpp1 with shRNA or direct transcriptional repression of Sgpp1 by ectopic Runx1. Together these data show that Runx1 plays a role in regulating the sphingolipid rheostat in normal development and that perturbation of this cell fate regulator contributes to Runx‐driven lymphomagenesis. J. Cell. Biochem. 118: 1432–1441, 2017. © 2016 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc.

The Badge of the Scottish Society of Physicians

This short article has been written to ensure that the origin and history of the Badge of the Scottish Society of Physicians is well documented, lest this knowledge be lost.

Pyruvate dehydrogenase phosphatase 1 (PDP1) null mutation produces a lethal infantile phenotype

Pyruvate dehydrogenase phosphatase deficiency has previously only been confirmed at the molecular level in two brothers and two breeds of dog with exercise intolerance. A female patient, who died at 6 months, presented with lactic acidemia in the neonatal period with serum lactate levels ranging from 2.5 to 17 mM. Failure of dichloroacetate to activate the PDH complex in skin fibroblasts was evident, but not in early passages. A homozygous c.277G > T (p.E93X) nonsense mutation in the PDP1 gene was identified in genomic DNA and immunoblotting showed a complete absence of PDP1 protein in mitochondria. Native PDHC activity could be restored by the addition of either recombinant PDP1 or PDP2. This highlights the role of PDP2, the second phosphatase isoform, in PDP1-deficient patients for the first time. We conclude that the severity of the clinical course associated with PDP1 deficiency can be quite variable depending on the exact nature of the molecular defect.

A novel mitochondrial DNA mutation in COX1 leads to strokes, seizures, and lactic acidosis

Cytochrome c oxidase (COX) is the terminal enzyme of the respiratory chain, with subunits originating both from the mitochondrial and nuclear genome. An eleven-year-old female presented initially with a seizure followed two months later with tonic-clonic seizures, weakness and aphasia. MRI of the cerebral hemispheres showed multiple infarcts. Previous history suggested gross and fine motor control deficits with learning difficulties. A muscle biopsy showed a specific decrease of COX staining in all fibres and pleomorphic mitochondria. Respiratory chain studies confirmed an isolated complex IV defect in muscle, whilst fibroblasts showed an initial COX activity below normal which rapidly came up to the normal range on culture. Sequencing of mtDNA revealed an heteroplasmic m.7023G>A mutation in the COX1 gene, with levels of 96% in muscle, 70% in blood and 50% in the initial skin fibroblast culture dropping to 10% in later passages. The mutation was present in a critical region of the COX1 gene, the V374M change being close to the two histidine residues His376 and His378 co-ordinating with the heme a and a (3), and His367 which co-ordinates a magnesium ion. This case highlights that a MELAS-like syndrome can occur with isolated COX deficiency.

A dedicated intravenous cannula for postoperative use effect on incidence and severity of phlebitis

A prospective, randomised, controlled clinical study was performed to compare the incidence and severity of postoperative peripheral venous thrombophlebitis associated with a single intravenous cannula used for both intra-operative and postoperative purposes, and two cannulae, one used intra-operatively and the other postoperatively. Sixty American Society of Anaesthesiologists (ASA) physical status I or II patients aged 18-65 years undergoing elective surgery were studied. The technique of cannula insertion was standardised. After surgery, the cannulation sites were examined daily by a blinded investigator for the presence and severity of thrombophlebitis using the Baxter Scale. The two groups were similar in terms of age, gender, weight, type and duration of surgical procedures, and drugs and fluids administered both intra-operatively and postoperatively. The proportion of patients that developed phlebitis was significantly less in the two cannulae group (26.1%) than in the single cannula group (63.3%) (p < 0.0001). The severity of phlebitis was greater in the single cannula group than in the two cannulae group. These results indicate that the use of a dedicated cannula for postoperative use decreases the incidence and severity of postoperative, peripheral, cannula-related phlebitis.

Runx2: a novel oncogenic effector revealed by in vivo complementation and retroviral tagging

The Runx2 (Cbfa1, Pebp2alphaA, Aml3) gene was previously identified as a frequent target for transcriptional activation by proviral insertion in T-cell lymphomas of CD2-MYC transgenic mice. We have recently shown that over-expression of the full-length, most highly expressed Runx2 isoform in the thymus perturbs T-cell development, leads to development of spontaneous lymphomas at low frequency and is strongly synergistic with Myc. To gain further insight into the relationship of Runx2 to other lymphomagenic pathways, we tested the effect of combining the CD2-Runx2 transgene either with a Pim1 transgene (E(mu)-Pim1) or with the p53 null genotype, as each of these displays independent synergy with Myc. In both cases we observed synergistic tumour development. However, Runx2 appeared to have a dominant effect on the tumour phenotype in each case, with most tumours conforming to the CD3(+), CD8(+), CD4(+/-) phenotype seen in CD2-Runx2 mice. Neonatal infection of CD2-Runx2 mice with Moloney murine leukaemia virus (Moloney MLV) also led to a dramatic acceleration of tumour onset. Analysis of known Moloney MLV target genes in these lymphomas showed a high frequency of rearrangement at c-Myc or N-Myc (82%), and a significant number at Pim1 or Pim2 (23%), and at Pal1/Gfi1 (18%). These results indicate that Runx2 makes a distinct contribution to T-cell lymphoma development which does not coincide with any of the oncogene complementation groups previously identified by retroviral tagging.

Vaccination with inactivated virus but not viral DNA reduces virus load following challenge with a heterologous and virulent isolate of feline immunodeficiency virus

It has been shown that cats can be protected against infection with the prototypic Petaluma strain of feline immunodeficiency virus (FIV(PET)) using vaccines based on either inactivated virus particles or replication-defective proviral DNA. However, the utility of such vaccines in the field is uncertain, given the absence of consistent protection against antigenically distinct strains and the concern that the Petaluma strain may be an unrepresentative, attenuated isolate. Since reduction of viral pathogenicity and dissemination may be useful outcomes of vaccination, even in the absence of complete protection, we tested whether either of these vaccine strategies ameliorates the early course of infection following challenge with heterologous and more virulent isolates. We now report that an inactivated virus vaccine, which generates high levels of virus neutralizing antibodies, confers reduced virus loads following challenge with two heterologous isolates, FIV(AM6) and FIV(GL8). This vaccine also prevented the marked early decline in CD4/CD8 ratio seen in FIV(GL8)-infected cats. In contrast, DNA vaccines based on either FIV(PET) or FIV(GL8), which induce cell-mediated responses but no detectable antiviral antibodies, protected a fraction of cats against infection with FIV(PET) but had no measurable effect on virus load when the infecting virus was FIV(GL8). These results indicate that the more virulent FIV(GL8) is intrinsically more resistant to vaccinal immunity than the FIV(PET) strain and that a broad spectrum of responses which includes virus neutralizing antibodies is a desirable goal for lentivirus vaccine development.

Factors influencing cellular immune responses to feline immunodeficiency virus induced by DNA vaccination

Virus-specific effector cytotoxic T lymphocytes (CTL) were elicited in the peripheral blood of domestic cats following a single intramuscular inoculation of replication defective feline immunodeficiency virus proviral DNA (FIVDeltaRT). Higher levels of virus-specific cytolysis were observed in the blood when cats were co-inoculated with feline gamma-interferon (IFN) DNA. The responses declined by 12 weeks following the first DNA inoculation and were, with the exception of FIV Gag-specific responses in some cats, refractory to repeated DNA inoculations. Nevertheless, a significant proportion of the cats were protected from challenge with homologous virus. The effects of interval between inoculations, route of DNA delivery, and promoter used to regulate viral gene expression on the induction of virus-specific CTLs were evaluated. The highest levels of virus-specific lysis were recorded following intramuscular co-inoculation of FIVDeltaRT and gamma-IFN DNA, where FIV gene expression was under the control of a cytomegalovirus (CMV) promoter. However, the highest levels of protection were observed using the viral 5'LTR as the promoter. These results suggest that a single intramuscular inoculation of FIVDeltaRT DNA together with gamma-IFN DNA may be sufficient to induce virus-specific CTLs and protection.

Training initiative list scheme (TILS) for minimal access therapy: the MATTUS experience

The objective of the MATTUS intercollegiate exercise was to set up and audit a training initiative list scheme (TILS) by which funds are awarded to Trust hospitals for operative sessions used specifically for the training of staff in minimal access therapy (MAT). A prospective centralized audit of TILS involving nine Trust hospitals in Scotland over a 12-month period (1 March 1995-end of February 1996) was carried out. These hospitals had contracted for 510 4-h training sessions (389 for minimal access surgery, 121 for allied interventional techniques) by MATTUS accredited consultant tutors. The scheme covered training in technical competence for Minimal Access Surgery (MAS), interventional flexible endoscopy and interventional radiology within Scottish Hospitals. The main outcome measures used in the audit were trainee completion rates, conversion rates, morbidity and mortality, assessment of training received by trainees and assessment of aptitude by the trainers. The results were as follows. Of 510 sessions, 482 (95%) were completed within the deadline. Of these, 463 sessions were audited (367 for MAS, 69 for flexible endoscopy and 27 for interventional radiology). During these sessions, 817 operations/procedures were performed (781 training and 36 developmental). A total of 544 operations were performed during 339 MAS training sessions and 237 radiological/flexible endoscopy procedures in 96 MAT training sessions. The trainee was the principal operator in 643 (82%) procedures and completed the task in 581 (74%) cases. Four per cent of the MAS operations (22/544) required conversion. Post-operative complications occurred in 42 out of 817 patients (5%). Four patients, all with advanced malignancy, died within 30 days of the procedure. Trainees graded 355 sessions as excellent, 109 good, two as average and one as unsatisfactory. The tutors graded their trainees' aptitude to perform the operation as excellent in 34%, good in 53%, average in 11% and poor in < 1%. The training initiative list scheme which allows unhurried training in MAT by consultant tutors using operating sessions that are extra to the service lists is operationally and educationally viable. Furthermore, it can be implemented within a pre-determined budget. The audit of TILS has also demonstrated that the immediate clinical outcome of patients is not compromised by this type of training.

Comparative efficiency of feline immunodeficiency virus infection by DNA inoculation

Direct inoculation of genetic material in DNA form is a novel approach to vaccination that has proved efficacious for a number of viral agents. We are interested in the potential of this approach for the delivery of vaccines based on attenuated or replication-defective retroviruses. Toward this goal, we tested the effect of intramuscular inoculation of a plasmid containing the entire genome of feline immunodeficiency virus (FIV-Petaluma, F14 clone). DNA delivery was compared with intramuscular or intraperitoneal inoculation of virus reconstituted from the same molecular clone. The outcome was monitored by serological analysis and quantitative virus load determination over a 31-week period. DNA inoculation was found to be a reliable means of infection, although seroconversion and the rise in PBMC virus load were delayed relative to intramuscular or intraperitoneal inoculation of virus. At 31 weeks, similar levels of proviral DNA were detected in central lymphoid tissue of all infected animals. In conclusion, DNA inoculation of proviral DNA will be of use as a novel method of cell-free virus challenge and may have further potential for the delivery of lentiviral vaccines.

Immunogenicity of a peptide from a major neutralising determinant of the feline immunodeficiency virus surface glycoprotein

The third variable region (V3) of the feline immunodeficiency virus (FIV) surface glycoprotein is predicted to have similar physical properties to that of HIV and has been shown to contain immunodominant and neutralizing epitopes. Immunological characteristics of this region were investigated further using a peptide corresponding to the middle of the putative FIV V3 loop. The peptide was recognized in ELISA by sera from the majority of naturally FIV-infected cats, and absorbed a significant fraction of the virus neutralizing activity from a pool of sera of cats naturally infected with FIV, confirming the immunogenic nature of this region. A sheep immunized with an octameric form of the peptide (multiple antigenic peptide; MAP) in Freund's complete adjuvant generated neutralizing antibody to a higher titre than infected cats. However, immunization of cats with the same MAP in an acceptable adjuvant formulation (Quil A) induced antibody and cytotoxic T-cell responses to the immunizing peptides but only minimal neutralizing activity. These responses did not significantly alter the kinetics of infection or the proviral load after challenge with a homologous strain of FIV, compared with naive controls. While the potential efficacy of peptide vaccines to lentiviruses remains to be determined, this study shows that the immune response evoked may be highly dependent on the delivery and adjuvant regime used.

Enteric adenovirus type 40: complementation of the E4 defect in Ad2 dl808

The enteric adenovirus type 40 cannot be passaged in HeLa cells, but will grow productively in cells that express the E1B region of adenovirus types 2 or 5. Even in such permissive cells, the lytic cycle is prolonged, there is an abnormal pattern of E1B early gene expression and a failure to switch off host cell functions, suggesting that other gene functions might be impaired in Ad40. For Ad2, E4 ORF 6 and ORF 3 proteins are known to have an essential role in progressing from the early to the late phase of lytic infection and the shutoff of host functions requires an interaction between the E4 ORF 6 34K protein and the E1B 55K protein. To test whether E4 functions of Ad40 are impaired, complementation tests have been made between Ad40 and the E4 deletion mutant Ad2 dl808, which lacks all but ORF 1 of the E4 region. In HeLa and Vero cells, Ad40 complements dl808 to levels equivalent to an Ad2 wild-type infection, as demonstrated by measuring virion packaged DNA, virus titration, and viral protein synthesis. Surprisingly, Ad2 dl808 fails to reciprocally complement Ad40. The results show that Ad40 produces functional E4 ORF 6 and/or ORF 3 activity, and that their expression precedes DNA replication.

Isolation, characterization and chromosomal localization of cDNA clones for the E1 beta subunit of the pyruvate dehydrogenase complex

A full-length cDNA clone for the E1 beta subunit of the human pyruvate dehydrogenase (PyrDH) complex was isolated from a human skin fibroblast cDNA library. When sequenced, it showed differences from the nucleotide sequence already published [Koike, K., Ohta, S., Urata, Y., Kagawa, Y. & Koike, M. (1988) Proc. Natl Acad. Sci. USA 85, 41-45], such that 19 amino acids were different in the translated open reading frame. Northern blotting of human fibroblast cell lines revealed a major mRNA species of 1.6 kb and a weaker band of 5.5 kb. In a series of nine PyrDH-complex-deficient cell lines from patients with this deficiency, no patients had severely reduced amounts of mRNA, but there was one patient cell line with an increased amount of abnormal-size mRNA. Chromosome localization carried out with DNA blots from man-mouse hybrid cell lines indicated that the E1 beta subunit of pyruvate dehydrogenase is located on chromosome 3. A motif AXGXXXXGL(R/K)X15(D/E)Q was found in common with a variety of other oxo-acid oxidoreductases, but its function is not known.

Enteric adenovirus type 40: expression of E1B mRNA and proteins in permissive and nonpermissive cells

The enteric adenovirus type 40 (strain Dugan) grows well in tissue culture only when the E1B 55K protein of Ad5 or Ad12 is supplied in trans, either constitutively expressed in an established cell line or by coinfection with an appropriate helper virus (V. Mautner, N. Mackay, and V. Steinthorsdottir, 1989, Virology 171, 619-622). The synthesis of Ad40 E1B mRNAs and proteins has been examined under permissive and nonpermissive conditions: At late times postinfection in permissive cells, E1B-specific mRNA species of 22 and 13-14 S are made, as well as 15 and 9 S messages for the late IVa2 and ppIX proteins. None of these are detected before the onset of DNA replication and none of them accumulate in the presence of a cytosine arabinoside block to DNA replication. The failure to detect cytoplasmic mRNAs as early times cannot be attributed to a failure of mRNA transport from the nucleus as there is no accumulation of nuclear E1 RNA. In nonpermissive Hela cells only traces of E1B- and ppIX-specific mRNAs are detectable, at very late times postinfection. Antibodies raised to synthetic oligopeptides corresponding to the N- and C-terminal domains of the putative E1B 19K and 55K proteins show a high titer against the cognate peptide by ELISA, but only the E1B 19K C-terminus-specific sera have detected a unique polypeptide in Ad40-infected cells, at late times postinfection. There is no shut-off of host protein synthesis in permissive cells, despite the expression of Ad2 55K protein.

Complementation of enteric adenovirus type 40 for lytic growth in tissue culture by E1B 55K function of adenovirus types 5 and 12

The enteric adenovirus type 40 strain Dugan (Ad40) cannot be passaged in HeLa cells, but will grow in 293 cells, which express Ad5 E1 functions. To determine the reason for this limited host range, KB cell lines expressing Ad2 E1A, E1B, or E1A + E1B (L. E. Babiss, C. S. H. Young, P. B. Fisher, and H. S. Ginsberg, 1983, J. Virol. 46, 454-465) have been tested for their ability to support Ad40 replication. Only cell lines which supply E1B functions, but not those expressing E1A alone, are permissive for Ad40, suggesting that Ad40 may require some function supplied by E1B or induced in E1B-containing cells. In coinfection assays Ad40 complements Ad5 dl312 (delta E1A) but not Ad5 dl313 (delta E1B) and is itself complemented by dl312 but not by dl313. Mutants of Ad2 and Ad12 with lesions in E1B 55K or 19K protein have been used to further delineate the requirements for Ad40 growth in HeLa cells. For mutants lacking 55K function there is minimal complementation in either direction, whereas those lacking only the 19K product are able to complement Ad40.

Recombination in adenovirus: analysis of crossover sites in intertypic overlap recombinants

Overlap recombination has been used as a means of generating intertypic recombinants with crossover sites located within a defined region of the adenovirus genome. Using terminal DNA fragments of adenovirus type 2 and type 5 that overlap within the vicinity of the hexon coding region (51.6-59.7 map units), two different crosses could be studied; in one the overlap entirely encompasses the hexon and there are homologous regions at either side of the overlap where recombination is expected, and in the other only one side of the overlap is capable of sustaining recombination. The overall distribution of crossover sites within the overlap has been determined by restriction endonuclease mapping, and analysed in terms of the extent of homology between Ad2 and Ad5 in this region as defined by the DNA sequences (R. Kinloch, N. Mackay, and V. Mautner (1984). J. Biol. Chem., 259, 6431-6436; G. Akusjärvi, P. Aleström, M. Pettersson, M. Lager, H. Jörnvall, and U. Pettersson (1984). Submitted). Crossovers are found only in regions of relatively high DNA homology, as previously shown for intertypic recombination between temperature-sensitive viruses (M. E. G. Boursnell and V. Mautner (1981). Virology 112, 198-209). The presence of a free DNA end within the heterologous zone is insufficient to overcome the barrier to recombination. In crosses where recombination is confined to a relatively small homologous zone (45.9-53.0 mu) there is no special distribution of crossovers within the interval; no "hot spot" is discernible at the free DNA end, suggesting that a free DNA end is not especially recombinogenic, nor at the junction between the homologous and heterologous zones, suggesting that branch migration up to the heterology does not always occur. A cross designed to furnish evidence for gene conversion gave rise to a "conventional" recombinant with a crossover located within a 21-nucleotide tract of homology.

Adenovirus hexon. Sequence comparison of subgroup C serotypes 2 and 5

The group C adenoviruses type 2 (Ad2) and type 5 (Ad5) are distinguished serologically by the antigenic determinants of the hexon and fiber capsomers . The hexon-coding region of the viral genome (map units 51.6-59.7) can be divided into three major zones with regard to DNA sequence homology between Ad2 and Ad5 on the basis of fine structure disclosed by restriction endonuclease site mapping ( Boursnell , M.E.G., and Mautner , V. (1981) Virology 112, 198-209). At the NH2-terminal end, there is almost complete restriction enzyme site homology between Ad2 and Ad5, the COOH terminus displays partial homology, and a central zone (map units 52.7-56.0) is heterologous and has no common restriction sites. We report here the DNA sequence of the Ad5 hexon gene (map units 51.6-59.7). This sequence is compared to that established for Ad2 (G. Akusj arvi , P. Alestr öm, M. Pettersson , H. Jornvall , and U. Pettersson , manuscript submitted for publication), and the heterologous zone is shown to encode an amino acid sequence that differs from that of Ad2 at many different loci within the zone (map units 52.7-56.0), interspersed with short stretches of highly conserved sequence.

Determination of platelet and fibrinogen half-life with [75Se]selenomethionine: studies in normal and in diabetic subjects

1. Simultaneous platelet and fibrinogen survival studies were carried out on a group of seven normal persons and eleven diabetic patients. 2. Survival time was calculated: (a) by measuring the interval between 50% of the maximum radioactivity in the anabolic phase and 50% of the maximum radioactivity in the catabolic phase, and (b) by fitting an exponential function to the decay phase of the curve. 3. With the first method, the normal group had a mean plaetelet survival which did not differ significantly from that in the diabetic group. With the second method, however, the platelet half-life in the diabetic patients was significantly shorter than in the normal subjects. 4. Fibrinogen survival was significantly shorter in the diabetic group with either method. 5. It is concluded that there is an increased utilization of platelets and fibrinogen in diabetic subjects.

Effect of feeding fat on fibrinolysis, stypven time, and platelet aggregation in elderly Africans

The effects of acute fat feeding on fibrinolytic activity, platelet aggregation, and stypven time in six elderly Africans are presented. These indicate that there is no alteration in the pattern of response seen in Africans with advancing age.

Effect of feeding fat on fibrinolysis, Stypven time, and platelet aggregation in Africans, Asians, and Europeans

The effects of acute fat feeding on fibrinolytic activity, platelet aggregation, and Stypven time in 10 Africans and 10 Asians are presented and compared with the results previously obtained in 10 Europeans. These indicated that the inhibition of fibrinolytic activity seen in Europeans does not occur in either Africans or Asians although the Stypven time was shortened in all three groups. Platelet aggregation, as measured by the Chandler's tube technique, was inhibited by fat feeding in Europeans but was unchanged in Africans and Asians. The results also indicate that the fibrinolytic activity of Africans and Asians is greater than that of Europeans.