Pupal development of Aethina tumida (Coleoptera: Nitidulidae) in thermo-hygrometric soil conditions encountered in temperate climates.

The pupal development of Aethina tumida Murray (Coleoptera: Nitidulidae) was studied at various combinations of thermo-hygrometric soil conditions (temperatures of 16, 18, and 20 degrees C and soil water content levels of 0.37, 0.56, and 0.73 m3 water per cubic meter of dry soil) representative of southeastern Canada. Survivorship and development duration of A. tumida pupae, as well as sex ratio and life span of emerging adults, were assessed. Assays were conducted in growth chambers on an average of 50 third-instar larvae per thermo-hygrometric combination. Results show that survivorship of pupae decreased with lower temperature and higher soil water content. Pupal development time shortened as temperature increased (69-78 d at 16 degrees C, 47-54 d at 18 degrees C, and 36-39 d at 20 degrees C), but was longer in dryer soil. Optimal soil water content for pupal development was 0.56 m3 water per cubic meter of soil. We estimated that the minimum development temperature for pupae is between 10.2 and 13.2 degrees C, depending on soil water content. The sex ratio of emerging adults was influenced by soil water content. We measured one female to one male for dry and intermediately wet soils and three females to one male for wet soils. Higher soil water content reduced the life span of emerging adults by half. This study contributes to a better understanding of A. tumida population dynamics in eastern Canada.

Pollen loads and specificity of native pollinators of lowbush blueberry.

The reproduction of lowbush blueberry (Vaccinium angustifolium Aiton) is closely tied to insect pollination, owing to self-incompatibility. Many species are known to have greater pollination efficiency than the introduced Apis mellifera L., commonly used for commercial purposes. In this study, we measured the pollen loads of several antophilous insect species, mostly Apoidea and Syrphidae, present in four lowbush blueberry fields in Lac-St-Jean, Québec. To measure pollen loads and species specificity toward V. angustifolium, we net-collected 627 specimens of pollinators, retrieved their pollen loads, identified pollen taxa, and counted pollen grains. We found that the sizes of pollen loads were highly variable among species, ranging from a few hundred to more than 118,000 pollen grains per individual. Bombus and Andrena species in particular carried large amounts of Vaccinium pollen and thus may have greater pollination efficiency. Also, two species (Andrena bradleyi Viereck and Andrena carolina Viereck) showed nearly monolectic behavior toward lowbush blueberry. Finally, we identified alternative forage plants visited by native pollinators, notably species of Acer, Rubus, Ilex mucronata, Ledum groenlandicum, and Taraxacum. Protecting these flowering plants should be part of management practices to maintain healthy pollinator communities in a lowbush blueberry agroecosystem.

Analysis of bovine sexed sperm for IVF from sorting to the embryo.

The objective of this study was to characterize bovine semen parameters and determine the best IVF conditions to produce a maximal percentage of blastocysts. Four types of semen were analyzed with CASA and flow cytometry: fresh and frozen non-sexed semen; fresh and frozen sexed semen. Semen was obtained from four Holstein bulls and two ejaculates from each bull were analyzed. Oocytes from slaughterhouse ovaries were matured and fertilized in vitro with all types of semen (for sexed semen, 2, 5 or 10microg/mL heparin was added to the IVF media while for non-sexed semen, 10microg/mL was added in the IVF medium). Presumptive zygotes were co-cultured with Buffalo rat liver cells in Menezo's B2 medium, and cleavage rates at Day 2, and blastocyst rates at Day 7 of culture, were recorded. Sexed semen resulted in fewer blastocysts than non-sexed semen (P<0.05), and certain bulls performed better in IVF. Freezing, and not sexing, had a more significant negative effect on semen quality. Compromised semen quality due to sexing and/or freezing can explain the reduced in vitro blastocyst rates when using frozen-thawed sexed semen. Sexed semen that appeared more capacitated seemed to require less heparin in IVF than sexed semen that appeared less capacitated to produce a maximal percentage of blastocyst. Flow cytometry sorting eliminates spermatozoa that possess compromised DNA, and therefore the reduced fertility seen in vitro is not due to an increased percentage of spermatozoa with compromised DNA. This study describes tools that can monitor semen parameters to optimize IVF conditions and thus obtain maximal blastocyst rates.

[Value of a new thickened formula in infants with regurgitations]. / Intérêt d'une nouvelle préparation infantile dans la prise en charge des régurgitations du nourrisson.

OBJECTIVES: The purpose of this open multicenter study was to evaluate the value of a new starch-thickened formula in infants with regurgitations in ambulatory pediatric practice. POPULATION AND METHODS: The study population comprised full-term infants with an age at inclusion of 1-90 days, who were bottle-fed and presented regurgitations. The formula tested was an infant formula-thickened with starch (2g/100mL). The primary endpoint was the frequency of bottles regurgitated, expressed in percentage of meals per day after 15 days of feeding with the preparation studied. Secondary endpoints were the assessment of regurgitations using the Vandenplas' score, as well as the daily increase in weight, height, and cranial circumference, overall and gastrointestinal tolerance, and formula acceptability. RESULTS: Sixty-four infants presenting regurgitation were included. The frequency of bottles regurgitated estimated at 80.3% at inclusion significantly decreased at D3, D15, and D30 to 40.1, 40.2 and 37.2% (P<0.0001), respectively. Thirty percent of infants did not present regurgitations at all at D30. Similarly, a significant decrease in the Vandenplas' score was observed from 1.9 at D0 to 0.9 at D30 (P<0.0001). Infant growth was similar to the French and European growth curves. CONCLUSION: The results showed rapid and lasting improvement in decreasing the frequency of feeding-bottles regurgitated by 50% from the first 3 days of using this new starch-thickened formula (2g/100mL). These satisfying results encourage the use of the tested formula in cases of infant regurgitation, in line with the European Society of Gastroenterology, Hepatology and Nutrition (ESPGHAN) recommendations.

Chronic exposure to neonicotinoids reduces honey bee health near corn crops.

Experiments linking neonicotinoids and declining bee health have been criticized for not simulating realistic exposure. Here we quantified the duration and magnitude of neonicotinoid exposure in Canada's corn-growing regions and used these data to design realistic experiments to investigate the effect of such insecticides on honey bees. Colonies near corn were naturally exposed to neonicotinoids for up to 4 months-the majority of the honey bee's active season. Realistic experiments showed that neonicotinoids increased worker mortality and were associated with declines in social immunity and increased queenlessness over time. We also discovered that the acute toxicity of neonicotinoids to honey bees doubles in the presence of a commonly encountered fungicide. Our work demonstrates that field-realistic exposure to neonicotinoids can reduce honey bee health in corn-growing regions.

[Cardiovascular ageing and ethics]. / Vieillissement cardiovasculaire et questions éthiques.

According to the results of the literature, the benefit/risk ratio of myocardial revascularisation techniques is much higher in terms of symptoms and quality of life in patients over 75 years of age with acute coronary syndromes, although it is generally accepted that the risks associated with these techniques are greater in this age group. However, the publications continue to report that inequality of access to these methods increases with age. The conclusions of these trials often denounce these practices ethically because of the loss of opportunity which these patients experience. When the results are examined more closely, the analysis which may be made of these differences based on the four founding principles of biomedical ethics lead to less definite conclusions. It is not always clear that the best medical approach in terms of ethics is to propose a massive management with myocardial revascularisation, because a medical decision does not always limit itself in ethics terms to the strict medical or, more precisely, the cardiological risk/ratio in the short-term. Before expressing a judgment on existing practices, it would be preferable to analyse the arguments, case by case, which lead to the decision not to apply the recommendations of the literature. It would be especially valuable to know what the patients think of themselves when confronted with these situations. A study using the clinical ethical method would certainly be of value in obtaining this data.

In vitro characterization of rat bone marrow-derived dendritic cells and their precursors.

Although the rat is commonly used for basic immunology and transplantation research, phenotypic and functional characterization of rat dendritic cells (DCs) lags behind similar studies in the human and mouse. Therefore, these features were examined using DCs propagated from cultures of rat bone marrow maintained in a medium supplemented with granulocyte-monocyte colony-stimulating factor. Analysis of cytospin preparations of cultured cells showd that DCs arise from OX7+ myelomonocytic precursors. Typical mature rat DCs were morphologically similar to their mouse and human counterparts and expressed major histocompatibility complex (MHC) class II (common part determinant of Ia), OX62 (integrin molecule), OX7 (CD90), ICAM-1 (CD54), and CTLA4 counterreceptor, but were negative for OX8 (CD8), OX19 (CD5), W3/25 (CD4), and ED2, a rat macrophage marker. Functional analysis of OX62+ sorted DCs showed that they could effectively present the soluble antigen ovalbumin to naive T cells in vitro. A combination of anti-MHC class II monoclonal antibody and CTLA4-immunoglobulin inhibited allostimulatory ability more effectively than either reagent alone. Implications for studying the role of DCs in immune responses in the rat are discussed.

Breast tomosynthesis: Dosimetry and image quality assessment on phantom.

PURPOSE: To evaluate using phantom study the average glandular dose (AGD) and image quality in breast tomosynthesis. MATERIALS AND METHODS: The study was performed with a full-field digital mammography system (Mammomat Inspiration(®), Siemens, Erlangen, Germany) combined with tomosynthesis equipment (3D). For AGD evaluation, polymethyl methacrylate (PMMA) plates and a dosimeter were used to directly measure the absorbed doses in 2D and in 3D. The doses were then compared to the doses displayed on the equipment using the Mann-Whitney test. Three phantoms, accredited for 2D digital mammography (MTM 100, ACR RMI 156, BR3D), were imaged three times in 2D then in 3D. For each acquisition, the AGD was recorded. For image quality assessment, scores, defined by the rate of visible inserts, obtained for each acquisition both in 2D and in 3D, and for each phantom, were compared (Kruskall-Wallis and post-hoc Dunn tests). RESULTS: There was no significant difference between the measured and displayed AGD, both in 2D and in 3D imaging (P>0.05). With identical acquisition parameters, AGD were significantly greater in 3D than in 2D P<0.01). For phantoms MTM 100 and ACR RMI 156, there was no significant difference between the rate of visible inserts in 2D and in 3D (P=0.06 and P=0.36, respectively). However for phantom BR3D, the rate was significantly higher in 3D than in 2D (P<0.0001). CONCLUSION: Doses are significantly greater in 3D than in 2D. With tomosynthesis, out of the three phantoms tested, only phantom BR3D showed a higher rate of visible inserts.

A new protocol for the propagation of dendritic cells from rat bone marrow using recombinant GM-CSF, and their quantification using the mAb OX-62.

Bone marrow (BM)-derived dendritic cells (DC) are the most potent known antigen (Ag) presenting cell in vivo and in vitro. Detailed analysis of their properties and mechanisms of action requires an ability to produce large numbers of DC. Although DC have been isolated from several rat tissues, including BM, the yield is uniformly low. We describe a simple method for the propagation of large numbers of DC from rat BM and document cell yield with the rat DC marker, OX-62. After depletion of plastic-adherent and Fc+ cells by panning on dishes coated with normal serum, residual BM cells were cultured in gelatin coated flasks using murine rGM-CSF supplemented medium. Prior to analysis, non-adherent cells were re-depleted of contaminating Fc+ cells. Propagation of DC was monitored by double staining for FACS analysis (major histocompatibility complex (MHC) class II+/OX-62+, OX-19-). Functional assay, morphological analysis and evaluation of homing patterns of cultured cells revealed typical DC characteristics. MHC class II and OX-62 antigen expression increased with time in culture and correlated with allostimulatory ability. DC yield increased until day 7, when 3.3 x 10(6) DC were obtained from an initial 3 x 10(8) unfractionated BM cells. Significant numbers of DC can be generated from rat BM using these simple methods. This should permit analysis and manipulation of rat DC functions in vivo and in vitro.

Prevalence and clinical significance of antiphospholipid antibodies in renal transplant recipients.

BACKGROUND: The prevalence and clinical significance of antiphospholipid antibodies (APAs) have not been extensively studied in non-systemic lupus erythematosus (non-SLE) renal transplant recipients. METHODS: To further define the prevalence and clinical significance of APAs in non-SLE renal transplant recipients and the appearance of dialysis-related APAs after renal transplantation, we conducted a retrospective study on 178 renal transplant recipients. Documentation of anticardiolipin antibodies (ACAs) and lupus anticoagulant in non-SLE renal transplant recipients, retrospective documentation of ACAs on pretransplant frozen plasma and standardized collection of demographic characteristics and posttransplant history of thrombosis were assessed. RESULTS: Fifty of 178 patients (28.1%) had APAs. Transplant duration was shorter and hemodialysis duration was longer in patients with APAs. A posttransplant history of both venous and arterial thrombosis was more frequent in patients with posttransplant APAs (respectively, 18% vs. 6.2% [P<0.001] and 8% vs. 2.3% [P<0.001]). Pretransplant sera were available from 55 patients. Most of patients with posttransplant ACAs had ACAs in the pretransplant period (85%). Pretransplant ACAs were associated with a posttransplant history of venous thrombosis (P<0.001). CONCLUSIONS: Our study demonstrates a high prevalence of APAs in non-SLE renal transplant recipients. Most of them have been acquired in the pretransplant period. Both pretransplant ACAs and posttransplant APAs are associated with posttransplant episodes of thrombosis. Further studies are required to determine the interest of prophylactic measures.

CD4 lymphocytopenia as a risk factor for skin cancers in renal transplant recipients.

BACKGROUND: Renal transplant recipients are at increased risk of developing skin cancer. It remains difficult to establish the actual influence of overimmunosuppression in the development of skin cancers. We investigated whether lymphocyte subset count may predict the risk of developing skin cancer in long-term renal transplant recipients. METHODS: One hundred fifty long-term renal transplant recipients were followed for a mean period of 26 months. Each patient was examined at least annually by a dermatologist. Lymphocyte subsets were measured annually. RESULTS: Fifteen patients exhibited skin cancers. Patients with and without skin cancer did not differ in age, gender, transplant duration, hemodialysis duration before transplantation, immunosuppressive regimen, and serum creatinine concentration. CD4 cell counts were significantly lower in patients with skin cancers (330+/-179/mm3 vs. 503+/-338/mm3; P<0.01), whereas total lymphocyte and CD8 and CD19 cell counts were similar between the two groups. CONCLUSIONS: CD4 cell depletion is associated with skin cancer in long-term renal transplant recipients.

Mycophenolate mofetil in renal transplant recipients with cyclosporine-associated nephrotoxicity: a preliminary report.

BACKGROUND: There is a great concern over cyclosporine (CsA) nephrotoxicity in renal transplant recipients, and the effects of conversion from CsA to azathioprine (AZA) remain controversial. Large studies have demonstrated that mycophenolate mofetil (MMF), the morpholinoethyl ester of mycophenolic acid, is superior to AZA as a posttransplant immunosuppressant. METHODS: Six patients with isolated biopsy-proven CsA nephrotoxicity were converted from CsA-AZA to MMF. RESULTS: Mean follow-up was 12+/-2 months. No patient experienced acute rejection. The mean serum creatinine concentration decreased from 225+/-58 to 159+/-66 micromol/L (P<0.0005). Hyperlipidemia and blood pressure improved after CsA withdrawal. CONCLUSION: In a selected transplant population with biopsy-proven CsA nephrotoxicity, CsA withdrawal with a concomitant switch from AZA to MMF seems to be safe and allows a significant improvement of renal function.

Recurrence of hemolytic-uremic syndrome in renal transplant recipients: a meta-analysis.

BACKGROUND: Recurrence of hemolytic-uremic syndrome (HUS) in the allograft is associated with a very poor renal prognosis. Meta-analysis of previous trials may allow us to better estimate its real frequency, to identify risk factors for recurrence, and to predict the outcome of patients with definite recurrence. METHODS: An exhaustive search was conducted of HUS recurrence in renal transplantation from January 1977 to June 1997 using MEDLINE. RESULTS: Ten studies comprising 159 grafts in 127 patients were identified. The rate of recurrence was 27.8%. One-year graft survival was 76.6% in patients without recurrence and 33.3% in patients with recurrence (P<0.001). Older age at onset of HUS (16.96+/-7.6 years vs. 9.95+/-6.55 years; P<0.02), shorter mean interval between HUS and transplantation (2.51+/-2.7 years vs. 6.03+/-6.4 years; P<0.01), shorter mean interval between HUS and end-stage renal disease (0.79+/-0.39 years vs. 2.78+/-2.47 years; P<0.01), living-related donors, and the use of calcineurin inhibitors were associated with recurrence. CONCLUSION: Risk factors for HUS recurrence in renal transplantation could be identified through this meta-analysis.

Fibrinogen A alpha chain mutation (Arg554 Leu) associated with hereditary renal amyloidosis in a French family.

A French family with hereditary renal amyloidosis (HRA) was studied. The disease presented in 7 of the 8 affected individuals with proteinuria or the nephrotic syndrome. The age of onset was in the fifth decade of life. There is currently no sign of extrarenal involvement in any affected individual. However, the nephropathy in this family is progressive and led to terminal renal failure in 4 patients. Immunohistochemistry studies of glomerular amyloid deposits suggested that the amyloid protein was the fibrinogen A alpha chain. Direct DNA sequencing revealed a G 4993 T transversion and subsequently Arg 554 Leu mutation in the fibrinogen A alpha chain. This is the first description of this fibrinogen A alpha chain mutation in Europe. This family is of French descent and cannot be related to the previously reported Peruvian/Mexican and African-American kindreds.

Therapeutic response to progabide in neuroleptic- and L-dopa-induced dyskinesias.

The results of two trials conducted in human dyskinesia with progabide, a specific gamma-aminobutyric acid (GABA) receptor agonist, are reviewed. In one trial, 13 parkinsonian patients with L-DOPA-induced dyskinesia (LDD) and "on-off" fluctuations were included in a double-blind controlled trial progabide versus placebo. No change was observed during this trial in the severity of dyskinesia on progabide treatment but the drug significantly extended the "on" period as compared with placebo. In the second trial, 20 patients with neuroleptic-induced dyskinesia (TD) entered an open dose ranging trial with progabide. Fourteen of the 16 patients who completed the trial had a good-to-excellent therapeutic response. According to these results, progabide does not seem to have the same therapeutic benefit in LDD as TD. These data suggest that the hypothesis of a dopaminergic supersensitivity as a similar pathogenic substrate for both clinical conditions should be reconsidered. If this hypothesis remains the most consistent to explain the occurrence of LDD, the therapeutic effect of progabide in TD is an argument for an implication of the GABAergic system in the appearance of TD.

The potential use of GABA agonists in psychiatric disorders: evidence from studies with progabide in animal models and clinical trials.

Progabide, a new antiepileptic GABA agonist of moderate affinity for GABA receptors, has been studied in a number of psychiatric disorders and the results compared with the action of this drug in animal models. In an animal model for anxiety (the aversive response to periaqueductal grey stimulation in the rat) progabide had a similar action to that of diazepam. However in clinical trials to date the effect of the GABA agonist was inferior to that of benzodiazepines. As progabide diminishes both the nigrostriatal dopamine neuron activity and the effects of striatal dopamine receptor activation, a trial in schizophrenic patients was undertaken. Progabide was devoid of any evident antipsychotic action. However a certain improvement in responsiveness to the environment and in social interactions was noticed in hebephrenic and schizoaffective syndromes. This lack of antipsychotic effect of progabide may be a reflection of the weak activity of GABA agonists on limbic dopamine neurons. In these various clinical trials a definite improvement of affect and mood was noted in those patients receiving progabide. In clinical trials in depressed patients progabide produces a significant reduction in depressive symptoms, an action similar to that of imipramine both for the global clinical rating and the HRSD. This antidepressant activity is reflected by the action of progabide in behavioural models of depression such as olfactory bulbectomy, learned helplessness and the sleep-wake cycle.

Hyperhomocyst(e)inemia in renal transplant recipients with and without cyclosporine.

Studies have demonstrated that hyperhomocyst(e)inemia is present in renal transplant recipients and is correlated with cardiovascular disease. It is still unclear whether hyperhomocyst(e)inemia observed in renal transplant recipients solely depends on the moderate reduction of renal function in these patients or if additional mechanisms are operative in this patient category. A recent study suggested that cyclosporine (CsA) increased plasma homocyst(e)ine concentration in interfering with folate-assisted remethylation of homocysteine. To confirm this hypothesis, we studied plasma homocyst(e)ine folic acid and cobalamin concentrations in 122 renal transplant recipients (104 on CsA and 18 not receiving CsA). After adjusting for age, gender, transplant duration and serum creatinine concentration, patients with and without CsA had similar plasma homocyst(e)ine concentrations (17.9 +/- 6.1 mumol/l in CsA(+)patients vs 17.1 +/- 5.6 mumol/l in CsA(-)patients; p = 0.3). Moreover, we found a significant inverse relationship between plasma homocyst(e)ine and folic acid concentrations in both CsA(+) (r = 0.218; p < 0.01) and CsA(-) (r = -0.678; p < 0.05) patients. Patients with a past history of cardiovascular incidents had higher plasma homocyst(e)ine concentrations than those without cardiovascular antecedent (20.5 +/- 7.8 mumol/l vs. 18.01 +/- 9.9 mumol/l; p < 0.05. To conclude: 1, We did not find any influence of CsA on plasma homocyst(e)ine concentrations. 2. We demonstrated that as in other patient category, plasma folic acid and homocyst(e)ine concentrations are significantly correlated in CsA(+) patients. 3. Homocyst(e)ine-lowering therapy would be prescribed in CsA(+) patients to allow correction of hyperhomocyst(e)inemia.

The effect of heparin on motility parameters and protein phosphorylation during bovine sperm capacitation.

It is generally accepted that incubation with heparin is required to induce capacitation of ejaculated bovine spermatozoa in vitro. The capacitation process implicates many biochemical events, and is correlated with modified sperm motility and the phosphorylation of specific proteins on tyrosine residues. To better understand the molecular basis of heparin-induced capacitation, bovine spermatozoa were incorporated with a radioactive substrate of protein kinases [gamma32P]-ATP, to observe protein phosphorylation dynamics over time. Sperm motion parameters including the percentage of motile spermatozoa, amplitude of lateral head displacement (ALH) and flagellar beat cross frequency (BCF) were assessed to determine whether the protein phosphorylation patterns induced by heparin also promote changes in motility. Capacitation was confirmed using the chlortetracycline fluorescence assay and the appearance of 'pattern B' stained spermatozoa. Evaluation of the different motility parameters during capacitation reveal that heparin has a marked negative effect, over time, on the percentage of motile spermatozoa, consistent with hyperactivation. Indeed, the presence of heparin greatly increases the BCF of bull spermatozoa and induces a significant increase in the ALH compared to spermatozoa incubated without heparin. We detected several sperm proteins that are phosphorylated over time. A 45 kDa protein is the most intensely phosphorylated of the sperm proteins. However, it is visible regardless of the presence of heparin. Interestingly, a second phosphorylated protein of approximately 50 kDa undergoes more intense phosphorylation with heparin than without. In summary, the present study demonstrated that heparin induces physiological changes in several sperm motility parameters including ALH, BCF and the percentage of motile spermatozoa. Heparin also increases the intensity of phosphorylation of a 50 kDa sperm protein. These results suggest that capacitation of bovine spermatozoa and capacitation-associated motility changes may be regulated by a mechanism that includes protein phosphorylation, and that a presently unknown protein kinase is involved.

Hemodynamic effects of the anti-hypertensive agent ketanserin in hypertension in man.

The hemodynamic changes caused by ketanserin, an anti-hypertensive agent with S2-serotonergic receptor and alpha 1-adrenoceptor blocking properties, are reviewed in patients with essential hypertension. The hemodynamic profile associates a decrease in total peripheral resistance, an unchanged cardiac output, and a modest reflex cardiac stimulation. Whether the drug reverses the other hemodynamic abnormalities of essential hypertension, such as reduced arterial and venous compliances and increased cardiac mass, remains largely unknown. Evaluation of the changes in arterial and venous systems will be important in the view that the pharmacological profile of ketanserin could be involved in the modifications of the arterial wall observed in hypertension and atherosclerosis.

[Diagnosis of a Q3 wave: value of the inspiratory test]. / Diagnostic d'une Q3 : valeur du test inspiratoire.

The aim of this study was to determine the value of the inspiratory test on isolated Q waves in Lead III. The ECGs of 25 normal young adults with isolated Q waves in Lead III were compared with those of 86 patients with documented postero-diaphragmatic myocardial infarction (62 chronic, 21 recent). The criteria of abnormality of the Q waves were : duration 0.04 sec and amplitude 25% of R3. Thirty six per cent of the ECGs of the 25 normal subjects with the Q3 pattern met these criteria. Q3 post infarction changes may lose these pathological characteristics; they were absent in 23% of patients with chronic infarction and 17% of patients with recent infarction. Isolated Q3 changes, therefore, pose a difficult diagnostic problem. Lyle 's inspiratory test which is still widely used as a discriminating factor led to a reduction of the pathological Q wave amplitude and duration, both in normal subjects and in-patients who had documented infarction. The only difference between the 2 groups was the percentage decrease. Inspiration led to a reduction in the amplitude and duration of the Q3 waves in 89% of normal subjects, 58% of patients with chronic infarction and 20% of patients with recent infarction. Inspiration may even lead to the complete disappearance of the Q3 waves (10% of chronic infarcts). No correlations were found between the severity of the anatomical lesions (coronary or ventricular) and the reduction of Q3 waves. These results suggest that Lyle 's inspiratory test is a poor method of discriminating between normal and pathological isolated Q3 waves.