Perinatally derived antiidiotypic antibodies from the antipolyfructosan immune response. Molecular analysis of idiotype regulation.
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Animals↗
Biomedical subjects
M Elliott
Publications and source records attributed to M Elliott.
Idiotypic regulation of development of the B-cell repertoire.
The mouse B-cell repertoire develops from a restricted set to an extremely diverse set of specificities. Establishment of some of the B-cell clones that constitute the adult repertoire is facilitated and guided by idiotype-directed interactions among complementary sets of B cells early during ontogeny. Through in vivo experiments described here and reported elsewhere, we have shown that the program of B-cell development involving idiotypic interactions is obligatory in the development of certain B cells that provide immunity against bacterial infections. Furthermore, this program of B-cell development is facilitated in newborn mice and not in adult mice that have been transplanted with progenitor cells from adult bone marrow. Thus the idiotype-directed selection of the adult B-cell repertoire appears to be limited to fetal-neonatal stages of development.
Aging↗
Synergistic suppression: anomalous inhibition of the proliferation of factor-dependent hemopoietic cells by combination of two colony-stimulating factors.
Cells of the continuous murine hemopoietic cell line FDC-P1 expressing macrophage-colony-stimulating factor (M-CSF) receptors following retroviral insertion of murine c-fms cDNA proliferated clonally when stimulated by granulocyte/macrophage (GM)-CSF, multipotential CSF, or M-CSF. However, M-CSF combined with either GM-CSF or multi-CSF, even at low CSF concentrations, strongly inhibited colony formation, with loss of clonogenicity in affected cells accompanied by increased macrophage differentiation. Stimulation by these CSF combinations did not induce short-term changes in CSF receptor expression or internalization. FDC-P1 cells expressing another inserted tyrosine kinase receptor, basic fibroblast growth factor receptor, did not exhibit suppression when GM-CSF was combined with fibroblast growth factor. This phenomenon of synergistic suppression may have relevance for the future clinical use of combinations of CSFs, because a potentially similar suppression is also observable with some normal macrophage progenitor cells.
Animals↗
Herpes simplex virus type 1 polypeptide ICP4 bends DNA.
ICP4, the major regulatory polypeptide of herpes simplex virus type 1, is expressed at the earliest stages of virus infection and is required for the activation of transcription from the majority of viral promoters. It is a DNA binding protein which specifically recognises bipartite sites related to the sequence ATCGTnnnnnCGG. In this report we show that both partially purified ICP4, and its isolated DNA binding domain, bend DNA at occupied binding sites. The apparent angles of bend at two different binding sites were very similar and in both cases the centre of the bend was very close to the binding site sequence.
Binding Sites↗
Technique and use of transbronchial biopsy in children and adolescents.
Since July 1988, a total of 92 transbronchial biopsies (TBB) have been performed in 18 patients (aged 3-16 years). Twelve patients (67%) were heart-lung transplant (HLT) recipients undergoing surveillance for pulmonary graft rejection and infection. The remainder included immunocompromised patients at risk of opportunistic infections (n = 4), patients with fibrosing alveolitis (n = 1) and a collagen vascular disorder with suspected lung involvement (n = 1). TBB was performed through either a fiberoptic (n = 50) or a rigid (n = 41) bronchoscope, all under general anesthesia. On one occasion a cardiac bioptome was used through an endotracheal stent. The sensitivity of TBB for diagnosing acute and chronic rejection in HLT patients was 88% and 60%, respectively (specificity, 91% and 100%). Definitive diagnoses were made in 4 (67%) of the non-HLT group. Bronchoalveolar lavage (BAL) was performed during each procedure for microbiological and cytological examination. Thirty-four pathogenic organisms including Pseudomonas aeruginosa (16/34), Staphylococcus aureus (8/34), and Candida albicans (5/34) were isolated from BAL culture. Complications included pneumothorax (8%), transient pyrexia (7%), and dyspnea (2%).
Acquired Immunodeficiency Syndrome↗
Influence of cardiopulmonary bypass on water balance hormones in children.
OBJECTIVE: To determine the changes in the endocrine mechanisms of fluid balance after cardiopulmonary bypass in children. DESIGN: Prospective study; analysis of numbered plasma samples performed blind with respect to clinical data. SETTING: Regional paediatric cardiothoracic unit. PATIENTS: Nine patients, median age 4, range 2 to 9 years, five males. Patients under the age of 1 year were excluded because of the frequent blood sampling involved. MAIN OUTCOME MEASURES: Plasma concentrations of atrial natriuretic peptide (ANP), arginine vasopressin, plasma renin activity, aldosterone, noradrenaline and adrenaline, and urinary concentrations of cyclic guanosine monophosphate (cGMP) as measured by radioimmunoassay. RESULTS: After 30 minutes of cardiopulmonary bypass plasma atrial natriuretic peptide (ANP) decreased from (mean (SEM)) 151 (71) pg/ml to 52 (44) pg/ml (NS), and urinary production of its second messenger cyclic guanosine monophosphate (cGMP) decreased from 1286 (600) pmol/ml to 151 (414) pmol (p < 0.05). Other plasma concentrations of hormones studied did not change significantly although arginine vasopressin, adrenaline, and noradrenaline increased whereas aldosterone and plasma renin activity decreased. After cardiopulmonary bypass stopped there was an immediate and significant rise in plasma ANP, but within the next 24 hours plasma ANP declined significantly (p < 0.05), decreasing from 294 (49) pg/ml to 64 (29) pg/ml at 22 hours. In the postoperative period there was a significant correlation between plasma ANP and both mean fluid balance (r = 0.96, p < 0.001) and mean urine output (r = 0.97, p < 0.001). Plasma aldosterone peaked (p < 0.05) at 22 hours after operation, and argine vasopressin peaked (p < 0.05) at two hours and then declined (p < 0.05) to a trough at 24 hours. Plasma renin activity, adrenaline, noradrenaline, and urinary cGMP concentrations, and mean central venous pressure did not change significantly in the postoperative period. CONCLUSION: The changes documented show the differing pattern of release of water balance hormones invoked by cardiopulmonary bypass. The central role of ANP is shown by its strong correlation with urinary output and its similarly strong relation to fluid balance.
Aldosterone↗
High level expression and purification of herpes simplex virus type 1 immediate early polypeptide Vmw110.
Herpes simplex virus type 1 (HSV-1) encodes five immediate early (IE) polypeptides. This paper reports the construction of a baculovirus vector which expresses large amounts of Vmw110, the product of IE gene 1. The expressed protein has been purified to near homogeneity and has a mobility on SDS polyacrylamide gels identical to that of Vmw110 produced during HSV-1 infection. Characterisation of its properties indicated that it forms dimers and perhaps higher order oligomers in solution and that the purified protein binds to both single stranded and double stranded calf thymus DNA cellulose columns. However, filter binding experiments were unable to detect any stable association of Vmw110 with DNA in solution.
Animals↗
Purification of the DNA binding domain of herpes simplex virus type 1 immediate-early protein Vmw175 as a homodimer and extensive mutagenesis of its DNA recognition site.
The herpes simplex virus type 1 (HSV-1) Immediate-Early (IE) polypeptide Vmw175 is essential for the activation of transcription from viral early and late promoters. Vmw175 also reduces the activity of its own (IE-3) promoter in transfection assays. Both transactivation and repression mediated by Vmw175 require the integrity of a conserved domain of the polypeptide which has been shown to bind to specific DNA sequences. We have investigated the DNA sequence requirements for Vmw175 binding using a randomly mutated target. The results indicate that the binding site covers a region of 13 nucleotides divided into proximal and distal parts which are consistent with the consensus ATCGTNNNNNYSG. We have also expressed several different constructs encompassing the DNA binding domain of Vmw175 in bacteria, and obtained preparations of greater than 90% purity. The DNA binding domain is a dimer in solution, and binds DNA with a specificity similar to that of the intact protein, although the smallest DNA binding competent protein has a slightly reduced specificity.
Base Sequence↗
Nucleotides within both proximal and distal parts of the consensus sequence are important for specific DNA recognition by the herpes simplex virus regulatory protein ICP4.
The herpes simplex virus type 1 regulatory protein ICP4 is a sequence specific DNA binding protein which associates with a number of different sites, some of which include the consensus ATCGTCnnnnYCGRC. In order to investigate the involvement in DNA binding of conserved bases within the consensus, we have synthesised a family of mutant oligonucleotides and tested their ability to form a complex with ICP4. We have also compared the binding specificities of bacterially expressed fragments of ICP4 which include the DNA binding domain. Mutation of most (but not all) bases in the proximal part of the consensus greatly reduced binding by ICP4, as did a mutation affecting the distal part. Most (but not all) G residues identified in methylation interference assays were required for efficient binding. While a bacterially expressed ICP4 peptide encompassing amino acid residues 252-523 bound to DNA with a specificity similar to that of the whole protein, a shorter protein (residues 275-523) had a slightly relaxed DNA binding specificity.
Base Sequence↗
Peak assignment in automatic data analysis.
Linear prediction algorithms are able to identify peaks in an NMR spectrum, but are not able to assign these peaks to components anticipated in the spectrum. We have developed an artificial-intelligence protocol which uses the output parameter list from an LPSVD algorithm, and automatically assigns the peaks on the basis of an anticipated list of components. To overcome the influence of experimental conditions on the absolute values of frequency, integrated area, and linewidth, the assignment routine performs an internal scaling of the data by comparing all possible pairs of peaks in the spectrum. Completely automated analysis of large numbers of in vivo FIDs is now possible.
Adenosine Triphosphate↗
Differential effects of concanavalin A, serum and cytokines on proteoglycan elaboration and DNA synthesis by mononuclear cells from human peripheral blood.
Human blood derived mononuclear cell (MC) cultures required concanavalin A (Con A) stimulation to synthesize and secrete into the medium high levels of a protease-resistant proteoglycan (PG) containing predominantly chondroitin sulfate (CS), which was elaborated largely by T-cells in culture. PG and DNA synthesis were studied in MC cultures in the absence and presence of Con A as well as serum and some biologically active polypeptide factors. In the presence of Con A, stimulation of PG synthesis was substantially greater in T-cell enriched cultures than in B-cell enriched cultures. DNA synthesis was also stimulated in the presence of Con A. This stimulation was concentration-dependent, but required the presence of serum for additional responses. DNA and cell proliferation were stimulated by interleukin-2 (IL-2), but PG production was not stimulated by conditioned media, IL-1, IL-2, IL-3, or transforming growth factor-beta (TGF-beta). Our results indicate that the elaboration of PG from T-cells of human MC is independent of the effects of regulatory peptides on cell proliferation and DNA synthesis.
B-Lymphocytes↗
Heart-lung transplantation for cystic fibrosis. 2: Outcome.
From March 1988 to March 1990, 11 children with cystic fibrosis (age 5-15 years) underwent combined heart-lung transplantation at our institutes. Maintenance immunosuppression consisted of cyclosporin and azathioprine with corticosteroids and antithymocyte globulin used perioperatively and during rejection episodes. Six patients (55%) survive from 1.5-23 months all of whom have improved life quality. Actuarial survival to 1 year was 55%. At six months after transplant, mean forced expiratory volume at one second was 73.5% of predicted normal, compared with 25% before transplant. There was one perioperative death, three later deaths associated with obliterative bronchiolitis at two, eight, and nine months, and one from mediastinitis at four months. Of the 15 children accepted for transplantation but not receiving grafts, 10 have died (eight within four months of being placed onto the transplant list). Early postoperative problems included acute reversible rejection (n = 10), meconium ileus equivalent (n = 3), and pancreatitis (n = 1). There was a high incidence of later pulmonary rejection with a mean of 5.7 episodes per patient in the first six months. Pulmonary infection occurred relatively infrequently, with Pseudomonas aeruginosa being the most common pathogen. Persistent diabetes mellitus requiring insulin occurred in four and systemic hypertension developed in one.
Adolescent↗
A prospective randomized study of a modified technique of ultrafiltration during pediatric open-heart surgery.
Conventional ultrafiltration (UF) fails to reverse satisfactorily hemodilution and the rise in total body water (TBW) seen after cardiopulmonary bypass (CPB). We have modified the technique, timing, and placement of UF in the CPB circuit and in pilot studies observed controlled elevation of hematocrit and a significantly reduced rise in TBW. We have carried out a prospective randomized study in 50 children undergoing open-heart surgery, comparing modified UF (MUF) with nonfiltered controls. MUF was carried out for 10 minutes after completion of CPB to a hematocrit of 36-42. Fluid balance, TBW (by bioimpedance), and hemodynamics were recorded for 24 hours postoperatively. The results were analyzed using Mann-Whitney U test, comparing controls (n = 24) to ultrafiltered (n = 24). There was one death in each group. Blood loss (ml/kg/24 hr) was 19.5 median (range, 9-30) in the controls versus 12.5 (8-22) in MUF (p = 0.0002); blood transfused (ml/kg/24 hr) 15.5 (3-35) in controls versus 3 (0-11) in MUF (p = 0.0001); colloid transfused (ml/kg/24 hr) 12 (6-56) in controls versus 12 (0-28) in MUF (p = 0.18); percent rise in TBW 11.1 (4.3-16.8) in controls versus 4.0 (1.6-7.9) in MUF (p = 0.0001). There was rise in arterial blood pressure during MUF. Percent rise of systolic blood pressure was 1 (-4 to +9) in controls versus 49 (5-81) in MUF (p = 0.0001); percent rise in diastolic blood pressure 0 (-5 to +8) in controls versus 28 (3-47) in MUF (p = 0.0001). UF reduced the rise in TBW and donor blood requirement associated with CPB in children. The blood pressure rise observed during UF is as yet unexplained, but if proven safe the technique may permit donor blood-free cardiac surgery and prevent the accumulation of potentially dangerous excess tissue fluid.
Body Water↗
The major transcriptional regulatory protein of herpes simplex virus type 1 includes a protease resistant DNA binding domain.
Herpes simplex virus type 1 expresses five immediate-early (IE) polypeptides. In the absence of functional Vmw175 (the product of IE gene 3) activation of transcription of later classes of viral genes and repression of IE gene expression does not occur. The recognition of specific DNA sequences by Vmw175 requires, as determined by sensitivity to mutation, a part of the protein highly conserved in the corresponding proteins of related herpes viruses. However, mutations in other parts of the protein can also disrupt specific DNA binding. This paper shows that the DNA binding domain of Vmw175 can be liberated as a functional unit by digestion with proteinase K. Analysis of mutant Vmw175 proteins showed that the proteinase K resistant domain has an amino terminus between amino acid residues 229 and 292, while its carboxy terminus is between residues 495 and 518. Mutations outside this region which affect DNA binding by the intact protein do not eliminate binding of the proteinase K resistant domain. This implies that direct DNA binding by Vmw175 involves a linear subsection of the polypeptide, and that mutations in other parts of the polypeptide which affect DNA binding of the whole protein do so by indirect means.
DNA, Viral↗
Intensive care management of children following heart and heart-lung transplantation.
We report the intensive care management of 23 children (age 3-15 years) following orthotopic heart (HT) and combined heart and lung transplantation (HLT) performed at our 2 institutes between February 1985 and August 1989. Cyclosporin A, azathioprine and steroids were given as routine immunosuppression, whilst anti-thymocyte globulin (ATG) was used for the first 3 post-operative days. Mean ventilation time was 24.6 h (range 4-74 h). Cardiovascular support comprised isoprenaline infusions in all patients (mean period 65.7 h) whilst dopamine and other inotropic agents were used less frequently. Sequential atrioventricular pacing was required more often in the HT patients (n = 9) than in the HLT patients (n = 4). Fluid input was restricted to maintain a plasma osmolality of 290-300 mosm/kg. There were 2 perioperative deaths both due to acute right heart failure. Other post-operative complications included: bleeding (n = 3); acute graft rejection (n = 4); infection (n = 3); systemic hypertension (n = 6); neurological abnormalities (n = 2); renal dysfunction (n = 6) and hyperglycaemia (n = 6).
Adolescent↗
Unusually early recoarctation after extended end-to-end anastomosis in a neonate.
A seven-day-old neonate with aortic coarctation and hypoplastic aortic arch underwent extended end-to-end repair with no residual gradient. Eleven hours after repair, femoral pulses were not palpable and recoarctation was confirmed by echocardiography. After failure of prostaglandin E2 infusion, a radically extended end-to-end anastomosis was performed eight days after initial repair. No recoarctation was evident 10 months after the second repair. The unusually early recoarctation was presumably due to residual and active duct tissue in the repair margins.
Anastomosis, Surgical↗
Management of congenital tracheal stenosis in infants.
Until recently congenital tracheal stenosis presenting in infants was considered to be almost invariably lethal. With improved diagnostic, anaesthetic and surgical techniques virtually all cases are potentially curable. Prompt recognition and early surgical intervention, combined with skilled perioperative management, will result in a more favourable outcome.
Anesthesia, General↗
Reproducibility and accuracy of pulmonary artery pressure measurement in supine and lateral positions.
The reproducibility and accuracy of pulmonary artery (PA) pressures in supine versus side-lying positions were compared in two groups of intensive care unit (ICU) patients. Side-lying measurements were reproducible, accurate, and clinically acceptable for surgical ICU patients, but not for medical ICU patients. The inconsistency was partly explained by the reference points used for transducer releveling in lateral positions. Surgical ICU used the fourth intercostal space and dependent midaxillary line; medical ICU used the fourth intercostal space and sternum. Reversing the leveling procedure in each ICU reduced surgical unit accuracy to an unacceptable level; medical unit accuracy was increased but was still too low for clinical acceptance. Further research is needed to identify appropriate anatomic reference points for transducer releveling in the side-lying position and to clarify which patient groups may be safely monitored by using this position.
Blood Pressure Determination↗