TWENTY YEARS' EXPERIENCE OF MYOCARDIAL INFARCTION: THE VALUE OF A HEART ATTACK REGISTER

SUMMARY Registers of disease serve a multitude of purposes, but are of particular importance to those interested in audit, in monitoring the introduction of new treatment or training programmes, in health service research, and in the planning of hospital services. The Nottingham Heart Attack Register has been in operation since 1973 and is proving to be an important data source. We present a brief history of the Register, describe how to set up a disease register and demonstrate how it can be of value to a wide range of health service staff using examples from our experience.     

Lactoferrin decreases monocyte-induced fibroblast production of myeloid colony-stimulating activity by suppressing monocyte release of interleukin-1

Lactoferrin (Lf) is a negative regulator of myelopoiesis which operates by suppressing the release from mononuclear phagocytes of GM colony- stimulating factor (GM-CSF) or monokines which can then induce the release of GM-CSA from accessory cells. In this study, endotoxin- depleted, purified iron-saturated human Lf was assessed for its effect on the production of interleukin-1 by cultured monocytes and their subsequent effect on colony-stimulating factor release from cultured fibroblasts. Monocytes were grown with or without Lf and Lf that had previously been incubated with monoclonal anti-Lf. The monocyte- conditioned medium was then either assayed for the presence of interleukin-1 (IL-1) with an enzyme-linked immunosorbent assay or for its ability to stimulate fibroblasts to release growth factors for CFU- GM, BFU-E, or CFU-Mix colonies. In the presence of Lf (10(-7) or 10(-8) mol/L), GM colony-stimulating activity (GM-CSA) was suppressed by 31% to 73%, whereas stimulating activities for BFU-E and CFU-mix colony formation were suppressed by 93% to 100%. Antibody to Lf completely abrogated the suppressive effects observed with Lf, whereas antibody to IL-1 ablated the induction by monocyte-conditioned medium of CSA release by fibroblasts. Lf at 10(-7) and 10(-8) mol/L also reduced IL-1 synthesis by cultured monocytes from 60% to 77%. The inhibitory effects of Lf were only observed when Lf was added before adherence of the monocytes for culture. If Lf was added at the time of adherence or after adherence, no suppression was observed. We conclude that the inhibition of GM-CSA production/release by Lf is mediated through inhibition of the synthesis/release of IL-1 by mononuclear phagocytes. This inhibition of IL-1 prevents accessory cells from producing and/or releasing GM-CSA.     

A New Sock Electrode for Recording Epicardial Activation from the Human Heart: One Size Fits All

Simultaneous recording of epicardial activation from multiple sites during open heart surgery is essential for studying unstable ventricular arrhythmias. A previously described sock electrode array for this purpose requires custom-woven nylon sock material and expensive machined button electrodes. The limited compiiance and elasticity of nylon requires that a new sock be individually fitted for each heart. Despite careful fitting, 17–20% of electrodes do not make satisfactory epicardial contact in dogs. Further, electrodes frequently dislodge from the sock and wires break at the button electrode solder joint. Recognizing these limitations, we formed a new sock from Xspan* tubular dressing material and devised electrodes that attach securely to the sock. In six dogs. 90%± 3% of electrodes made satisfactory contact using the same Xspan* sock. significantly (p < .01) more than with the nylon sock despite far less labor. The same size X span* sock with 60 snap electrodes was used to record from 27 human hearts of widely different dimensions. Satisfactory epicardial contact was obtained in 90%± 14% of electrodes in the 18 patients with Wolff-Parkinson-White syndrome (WPW) and 75%± 15% of electrodes in the nine patients with coronary artery disease. In no case did an accessory pathway fail to conduct following sock placement. The hemodynamic effect of the Xspan* sock was evaluated in four dogs and was found to be minimal. Both the Xspan* sock and the snap electrodes are easily made from inexpensive, readily available materials. The same Xspan* sock accommodates o wide range of heart sizes, and the electrodes supported by the Xspan* sock record significantly better and with less dislodgement and wire breakage than previous socks.     

Development of a retroviral construct containing a human mutated dihydrofolate reductase cDNA for hematopoietic stem cell transduction

A double-copy Moloney leukemia virus-based retroviral construct containing both the NeoR gene and a mutant human dihydrofolate reductase (DHFR) cDNA (Ser31 mutant) was used to transduce NIH 3T3 and mouse bone marrow (BM) progenitor cells. This resulted in increased resistance of these cells to methotrexate (MTX). The transduced BM progenitor cells were returned to lethally irradiated mice. The recipients transplanted with marrow cells infected with the recombinant virus showed protection from lethal MTX toxicity as compared with mock- infected animals. Evidence for integration of the proviral DNA was obtained by amplification of proviral DNA by polymerase chain reaction (PCR) and Southern analysis. Sequencing a portion of the PCR-amplified human DHFR cDNA showed the presence of the mutation. These studies with the human Ser31 mutant DHFR cDNA gave results comparable with those obtained with the mutant murine DHFR cDNA (Leu to Arg22) in developing MTX-resistant BM. The Ser31 mutant human DHFR cDNA is currently being tested for infection of human CD34+ human BM and peripheral blood stem cells in vitro.     

Cardiovascular and Adrenal Proliferative Lesions in Fischer 344 Rats Induced by Long-term Treatment with Type III Phosphodiesterase Inhibitors (Positive Inotropic Agents), Isomazole and Indolidan

Male and female Fischer 344 rats were treated with the positiveinotropic agents, isomazole or indolidan, in the diet for 104weeks. The doses were 0.0, 11.5, 23.5, or 48.0 mg\kg and 0.0,0.12, 0.40, or 1.3 mg\kg, respectively. Only 17% of the malestreated with 48.0 mg\kg isomazole survived the duration of thestudy. The male component of the indolidan study was terminatedat 22 months, with only 18% of the high-dose males surviving.Sixty-five percent of the males treated with 48.0 mg\kg isomazoleand 70% of the males treated with 1.3 mg\kg indolidan were foundto have severe periarteritis, often with thrombi located mainlyin the mesenteric arteries. Fifty-four percent of the male ratstreated with 48.0 mg\kg isomazole and 55% of the male rats treatedwith 1.3 mg\kg indolidan died from cardiovascular disease comparedto 1–2% among the control males. Animals in the low- andmiddle-dose groups of both studies had a lower incidence ofcardiovascular disease than did those in the high-dose group.Additional lesions associated with the long-term administrationof both drugs were markedly increased incidence of adrenal medullaryproliferative lesions (both hyperplasia and pheochromocytomas)and increased incidence of chronic progressive glomerulonephrosis.These lesions, like those in the cardiovascular system, occurredin a dose-dependent manner and were more frequent in males thanin females. Treatment-related effects in these studies werejudged to be related to the pharmacologic action of these compounds.     

Triphenyl Phosphite and Diisopropylphosphorofluoridate Produce Separate and Distinct Axonal Degeneration Patterns in the Central Nervous System of the Rat

This study compared the neurotoxic effects of triphenyl phosphite(TPP) in the rat with those seen after exposure to diisopropylphosphorofluoridate(DFP), a compound known to produce organophosphorus-induceddelayed neurotoxicity (OPIDN). Animals received either threesubcutaneous injections of TPP (1184 mg/kg body wt each dose)administered at 3-day intervals or a single subcutaneous injectionof DFP (4 mg/kg body wt). TPP-induced clinical signs were initiallyobserved 2 to 18 days after the last injection and includedataxia, flaccid paresis, stereotyped alternating side-to-sidemovements, and circling behavior. Axonal and terminal degenerationwere present in the cerebellum, vestibular nuclear complex,cochlear nuclei, and superior and inferior colliculi. The subthalamicnucleus, substantia nigra, septal region, hypothalamus, thalamus,hippocampus, and cerebral cortex also contained degeneratingaxons and terminals. Degeneration was particularly evident inthe sensorimotor cerebral cortex, mediodorsal, ventromedial,and medial geniculate thalamic nuclei and in the magnocellularpreoptic and medial mammillary nuclei of the hypothalamus. Verylight degeneration was present in the gracile fasciculus andnucleus. In contrast, rats injected with DFP showed moderatedegeneration in the gracile fasciculus and nucleus but did notdisplay degeneration in any other brain region. Injections ofDFP did not produce delayed onset clinical signs. The resultsindicate that in the rat, different central nervous system cellgroups are affected by these two organophosphorus compoundsand that TPP affects nuclei and tracts at all levels of theneuraxis, including those associated with higher-order processingand cognitive functions. In addition, the distinct degenerationpatterns produced by these two compounds support the view thatTPP-induced neurotoxicity should not be considered as a typeof OPIDN, but rather as a separate category of organophosphorus-inducedneurotoxicity.