Fetal biometry in ultrasound: A new approach to assess the long-term impact of simulation on learning patterns.

CONTEXT: Simulation-based education (SBE) has demonstrated its acceptability and effectiveness in improving ultrasound training. Because of the high cost of its implementation (investment in equipment and supervision), a pragmatic assessment of the transfer of skills learned in SBE to clinical practice and the identification of its optimal scheduling conditions have been requested to optimize its input. OBJECTIVES: To quantify the long-term impact of simulation-based education (SBE) on the adequate performance of ultrasound fetal biometry measurements (I). The secondary objective was to identify the temporal patterns that enhanced SBE input in learning (II). METHODS: Trainees were arbitrarily assigned to a 6-month course in obstetric ultrasound with or without an SBE workshop. In the SBE group, the workshop was implemented 'before' or at an 'early' or a 'late-stage' of the course. Those who did not receive SBE were the control group. The ultrasound skills of all trainees were prospectively collected, evaluated by calculating the delta between OSAUS (Objective Structured Assessment of Ultrasound Skills) scores before and after the course (I). Concomitantly, the accuracy of trainees' measurements was assessed throughout the course by verifying their correlation with the corresponding measurements by their supervisors. The percentage of trainees able to perform five consecutive sets of correct measurements in the control group and in each SBE subgroup were compared (II). RESULTS: The study included 61 trainees (39 SBE and 22 controls). Comparisons between groups showed no significant difference in the quantitative assessment of skill enhancement (difference in the pre- and post-internship OSAUS score: 1.09 ± 0.87 in the SBE group and 0.72 ± 0.98 in the control group) (I). Conversely, the predefined acceptable skill level was reached by a significantly higher proportion of trainees in the 'early' SBE subgroup (74%, compared with 30% in the control group, P<0.01)(II). CONCLUSIONS: The quantitative assessment does not support the existence of long-term benefits from SBE training, although the qualitative assessment confirmed SBE helped to raise the minimal level within a group when embedded in an 'early' stage of a practical course.

Diagnosis of vertical HIV-1 transmission using the polymerase chain reaction and dried blood spot specimens.

We have used the polymerase chain reaction (PCR) to detect HIV proviral sequences in minute amounts of peripheral blood collected onto newborn screening blotters. Forty-three newborns, infants, and children of HIV-infected mothers were serially studied: dried blood spot (DBS) specimens were processed for PCR; serum was assayed for HIV antibodies, p24 antigen, and immunoglobulins; mononuclear cells were cultured and CD4 cells were quantitated by immunofluorescence. There was excellent agreement between the results of blood spot PCR, viral culture, and clinical and immunological indicators of HIV infection. Eighteen of 19 infected children tested positive by both PCR and culture, including six asymptomatic infants who were less than 10 weeks of age. As expected, p24 antigen capture assays were insensitive, detecting only 13 of the 19 infected children. One infected infant tested positive by PCR, but negative by culture and antigen. This infant was seropositive at 27 months and had pronounced hypergammaglobulinemia in association with non-specific symptoms. Twenty-four of the 43 infants were asymptomatic with normal immune profiles, declining antibody levels and no evidence of infection. These children tested repeatedly negative by PCR, culture, and p24 antigen assays. Our results indicate that DBS PCR is a sensitive, specific, and cost-effective alternative to viral culture for the early diagnosis (or exclusion) of perinatal HIV infection. DBS sampling opens the way for large-scale prospective studies to determine the exact rates of vertical HIV transmission in industrialized, as well as, nonindustrialized countries.

Absence of prolonged immunosilent infection with human immunodeficiency virus in individuals with high-risk behaviors.

PURPOSE: The presence in some individuals of a prolonged phase of infection with human immunodeficiency virus type 1 (HIV-1) before seroconversion remains controversial. This study was undertaken to determine with a sensitive in vitro amplification technique, the polymerase chain reaction (PCR), whether seronegative individuals with high-risk behaviors could harbor HIV-1 sequences in their peripheral blood mononuclear cells (PBMCs) and remain seronegative for more than 6 months. PATIENTS AND METHODS: Seronegative individuals who engaged in unprotected anogenital intercourse with HIV-1-infected partners or with more than 10 individuals per year, and seronegative individuals who shared needles with seropositive partners, were recruited prospectively over 18 months. HIV-1 DNA and RNA sequences were detected in PBMCs of these individuals with three PCR assays using SK38/SK39, SK145/SK431, and SK68/SK69. Seronegative but PCR-positive patients were also evaluated with p24 antigen capture assay, radioimmunoprecipitation assay, and Western blot. The latter patients were followed prospectively to reproduce PCR-positive results and monitor serologic responses. RESULTS: Sixty-one men and 18 women, with an average age of 34.1 +/- 7.6 years, were recruited: 56 were homosexual men, 18 were heterosexual women, and 5 were heterosexual men. Amplification reactions for HIV-1 of 104 PBMC specimens from 79 patients with negative or indeterminate serologies revealed that 4 patients (5.1%) were positive with PCR for HIV-1 DNA and RNA at the time of enrollment. Positive amplification reactions could not be reproduced in prospective samples for one patient. The analysis of a variable human genomic locus in this patient's PBMCs demonstrated that the first PCR-positive sample and following PCR-negative samples originated from different patients, suggesting a specimen mix-up. Two of the three PCR-positive seronegative patients had symptoms suggestive of acute retroviral disease. Sera from all three patients contained p24 antigen. Two patients seroconverted within 1 month whereas one patient could not be followed prospectively. CONCLUSION: Prolonged infection with HIV-1 without seroconversion was not found in our population of patients at very high risk for HIV-1 infection. All PCR-positive patients seroconverted in less than 1 month.

Immune electron microscopy of arboviruses.

Representative members of four arbovirus taxons were studied by immune electron microscopy (IEM) in an attempt to determine whether the technique can be applied to the specific identification of arboviruses. Alphavirus, flavivirus, bunyavirus, and rhabdovirus antigens were prepared by propagation in tissue culture. The viruses were used to titrate homologous antibody and test heterologous antibody in the IEM test. Specific clumping together with visualization of antibody attachment was observed for all homologous systems studied. For the alphaviruses, titers of antibody, as determined by IEM, were comparable with the titers obtained by hemagglutination inhibition. Alphavirus cross-reactions were observed at low antibody dilutions by IEM. However, further dilution of antibody resulted in specific clumping only of homologous virus, allowing specific identification of alphavirus unknowns. For all viruses studied, positive IEM reactions were obtained with homologous grouping ascitic fluids but not with heterologous grouping fluids.

[Prognostic value at 12 months of two-dimensional echocardiography performed during the acute phase of myocardial infarction. A prospective study of 140 patients]. / Valeur pronostique à 12 mois d'une échocardiographie bidimensionnelle réalisée en phase aiguë d'un infarctus du myocarde. Etude prospective de 140 patients.

A two-dimensional echocardiography was performed in the acute phase of myocardial infarction in 140 consecutive patients admitted to hospital for transmural infarction 12 +/- 3 days on average after necrosis was formed. The examination consisted of 4 ventricular sections, including 2 through the apex: 8 ventricular segments were individualized, to be interpreted only when 50 p. 100 of the endocardium was visualized. An echocardiographic score was devised for the kinetics of each ventricular segment, i.e.: -1:dyskinetic, 0:akinetic, +1:hypokinetic, +2: normal, +3:hyperkinetic. The maximum score corresponding to normal contraction of all segments was 16. The hospital results were a mean score of 6.52 +/- 2.90 for 73 anterior and/or lateral infarctions and a mean score of 12.5 +/- 2.38 for 67 inferior infarctions (p less than 0.001). Correlations between echographic scores and angiographic ejection fractions were studied in 99 of the 140 patients. Good correlation between the two examinations was found in 91 cases, with a less than or equal to 6/16 score corresponding to a less than or equal to 40 p. 100 ejection fraction, and a greater than or equal to 7/16 score to a less than or equal to 40 p. 100 ejection fraction. This showed that echocardiography can be relied upon to detect abnormalities of left ventricular kinetics in myocardial infarction. 137 patients were followed up for a mean period of 16.4 months (range: 12 to 25 months). The follow-up was clinical and included angina, recurrent or extended infarction, heart failure, aorto-coronary bypass and mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

[Prognostic indices of the normalization of left ventricular function in chronic aortic insufficiency following valve replacement]. / Indices prédictifs de normalisation de la fonction ventriculaire gauche dans les insuffisances aortiques chroniques après remplacement valvulaire.

The aim of this study of 31 patients was to identify M mode echocardiographic parameters predictive of normalisation of left ventricular function after valvular replacement for chronic aortic incompetence in order to determine the optimal time for surgery. Only patients with chronic, pure aortic incompetence (ventriculo-aortic pressure gradient less than or equal to 30 mmHG) were considered. At the time of investigation 4 patients were in functional Class I, 6 in Class II, 10 in Class III and 11 in Class IV (NYHA). M mode echocardiography was performed on an Echovideorex or an Irex System II echocardiograph. The following measurements were made and corrected for body surface area according to the recommendations of the American Society of Echocardiography; end systolic and end diastolic dimensions (mm), fractional shortening (%), end systolic and end diastolic wall thickness (mm), diastolic radius to wall thickness ratio, short axis myocardial surface area (cme), wall stress, end systolic stress (mmHg). The study comprised pre and postoperative studies with an interval of 22.7 +/- 12.5 months (range 5 to 46 months); the data obtained was compared with a control group of 10 normal subjects. The results showed that preoperative fractional shortening less than 28% was associated with an increased risk of persistent postoperative left ventricular dysfunction.

[Systemic fibrinolytic treatment in the acute phase of myocardial infarction. Effects on coronary repermeation and left ventricular function]. / Traitement fibrinolytique par voie générale à la phase aiguë de l'infarctus du myocarde. Effets sur la reperméabilisation coronaire et sur la fonction ventriculaire gauche.

Coronary angiography and 2D echocardiography were performed at the 24th hour and 21st day of acute myocardial infarction in 18 patients to study the effects of peripheral fibrinolytic therapy on coronary repermeabilisation and left ventricular function. The treatment was the same for all patients included in the study. The left ventricular ejection fraction and sequential left ventricular contractility were analysed. The first coronary angiographic control study (24th hour) showed coronary repermeabilisation in 18 cases, occurring in significantly stenosed vessels in 15 cases and in angiographically normal vessels in 3 cases, demonstrating appearances of thrombosis. Transluminal coronary angioplasty was performed in 8 cases. Coronary angiography at the 21st day showed 4 secondary occlusions in patients who had not undergone angioplasty. The comparative study of left ventricular function did not show a statistically significant difference between the 24th hour and the 21st day studies. Biochemical studies showed on early massive elevation of the specific myocardial enzyme CPK MB and a rapid fall in the fibrinolytic activity of all patients. The treatment was well tolerated and mortality was nil.

[Echocardiographic evaluation of intravenous streptokinase in myocardial infarction in the acute phase]. / Evaluation échocardiographique de la streptokinase intraveineuse dans l'infarctus du myocarde en phase aiguë.

The effects of intravenous fibrinolysis on left ventricular function in acute myocardial infarction were investigated by two-dimensional echocardiography in patients aged less than 70 for whom fibrinolysis was not contra-indicated and who were admitted less than 6 hours after the onset of a first myocardial infarction without heart failure. The 12 patients thus recruited were male; their mean age was 55 years and the infarct was anterior in 6 cases and posterior in 6 cases. Streptokinase was administered first by bolus intravenous injection (250,000 IU over 20 min), then by intravenous infusion (100,000 IU over 12 hours); this was followed by heparin. No other medication was given, except for intravenous lidocaine and oral nifedipine. Two-dimensional echocardiography was performed after 24 hours and on the 21st day, using the apical, two-cavities projection. The ejection fraction and the percentage of shortening in 16 ventricular segments (8 in the anterior and 8 in the inferior territories) were evaluated from systolic and diastolic ventricular contours. Ventricular angiography and coronary arteriography were performed concomitantly with echocardiography. No significant improvement in ejection fraction was observed. On both day 1 and day 21, the kinetics of the lower segments was improved and that of the anterior segments was distinctly reduced in inferior infarcts. The kinetics of all segments, irrespective of their territory, was significantly improved in anterior infarcts.

[Primary failure of pericardial valvular heterografts]. / Défaillance primitive des hétérogreffes valvulaires péricardiques.

From July 1981 to October 1984, 79 Hancock pericardial valves were implanted in 74 patients surviving the hospital period and with a mean age of 64.2 years. Fifty-two patients underwent aortic valve replacement, 16 had mitral valve replacement, 5 bad a double replacement and 19 associated procedures were performed. The mean survival is 48 months. Until 1st June 1987, 11 primary failures have required reoperation (14.9%), 4 in the mitral position (4.6% patient-years), 7 in the aortic position (3.01% patient-years). The time to reoperation was 48.4 months for the aortic orifice and 36.5 months for the mitral orifice. The lesions most frequently encountered were tears (7 cases), calcifications (5 cases) and stretching of valvular tissue (2 cases); two patients died during the postoperative phase of this operation. Despite the small number of patients followed, this series demonstrates of high incidence of dysfunction due to primary tissue degeneration as, after the 5th year, the actuarial rate of absence of primary lesion is 85.3 +/- 8% with no significant difference between the aortic and the mitral orifices, although dysfunction appears to occur more rapidly in mitral prostheses. These results are much less favourable than those obtained with Ionescu bioprostheses in the aortic position of those obtained with porcine bioprostheses in either position. This justifies very regular clinical and echocardiographic follow-up of patients with Hancock pericardial valvular heterografts.

[Interruption of the inferior vena cava by the DIL filter. Experience apropos of 34 cases]. / Interruption de la veine cave inférieure par le filtre DIL. Expérience à propos de 34 cas.

Endocaval filters are often used to prevent pulmonary embolism but they have a number of disadvantages. The DIL filter, made of a memory metal wire, is intended to male up for some of these disadvantages. It acts by modifying the shape of the inferior vena cava, which it filters through its meshed loops. It is inserted percutaneously, causes little trauma, and its release is progressive. However, it requires measuring the caliber of the inferior vena cava. This filter was inserted in thirty-four patients over a period of 13 months. One filter has migrated. No recurrence of pulmonary embolism and no thrombosis of the inferior vena cave occurred.

Detection of core antibody in hepatitis B infection.

Hepatitis B core antigen (HBcAg) is found on the decoated Dane particle and on a morphologically similar particle detected mainly in the nucleus of hepatocytes of patients with hepatitis B. HBcAg prepared from the liver of a chimpanzee infected with hepatitis B virus was used to test human serum for core antibody (anti-HBc) by complement fixation. Anti-HBc was found in serum collected from patients with hepatitis B in both the acute and convalescent stages, from carriers of hepatitis B surface antigen (HBsAg) and from patients with chronic liver or renal disease who were carriers of HBsAg. It was not found in patients with hepatitis A or infectious mononucleosis, or in healthy persons who were not carriers of HBsAg.

Performance and reliability of five commercial enzyme-linked immunosorbent assay kits in screening for anti-human immunodeficiency virus antibody in high-risk subjects.

Anti-human immunodeficiency virus enzyme-linked immunosorbent assay kits marketed by Electro-Nucleonics Inc. (ENI), Genetic Systems Corp. (GSC), Organon Teknika Inc. (OTI), Ortho Diagnostic Systems Inc. (ODSI), and Wellcome Diagnostics (WD) were evaluated by using 289 randomly selected serum samples from a high-risk population and 53 serum samples likely to produce false-positive results. The radioimmunoprecipitation assay was used as the reference test. Sensitivities ranged from 96.51% (ODSI, WD) to 97.67% (ENI, GSC, OTI). Sera showing antibodies to viral glycoproteins only produced the false-negative results. Specificities ranged from 99.6% (ENI, GSC, ODSI, OTI) to 100% (WD). False-positive results were obtained with sera from patients with autoimmune disease or Epstein-Barr virus infection. Only results from GSC and OTI kits were distributed in two compact clusters well segregated on either side of the cutoff point. ODSI and GSC kits had the best intralot reproducibility. The GSC kit had the best interlot reproducibility. Cutoff values for ODSI and GSC kits were the least variable. Intraplate repeatability was good for all kits. Sample localization was not an important source of variability. Our results do not point out one outstanding kit among the five evaluated. However, the GSC kit showed the best overall results.

Immunofluorescence assay for human immunodeficiency virus antibody: investigation of cell fixation for virus inactivation and antigen preservation.

Four cell fixation procedures were investigated for their abilities to inactivate human immunodeficiency virus (HIV) and preserve its antigenicity for antibody detection by immunofluorescence in MOLT-4-T4 cells. Air-dried cell smears were fixed in cold acetone, in acetone-methanol (1:1), in acetone-methanol (1:1) followed by 70% ethanol and then methanol, or in paraformaldehyde-acetone. Acetone alone did not inactivate cell-associated HIV, but the other three procedures did. HIV inactivation was achieved by storage of acetone-fixed cells at -70 degrees for 40 days. Antigenicity was measured by immunofluorescence assay titrations of selected human sera, a cerebrospinal fluid, and a gp41 monoclonal antibody. Acetone provided the best fixation as measured by fluorescence intensity and antibody titers. The other fixation methods all yielded weaker fluorescence signals and/or decreased titers. Acetone fixation and storage for 40 days at -70 degrees C provides safe and accurate immunofluorescence assay reagents.

Comparison of Counterimmunoelectrophoresis and electron microscopy for laboratory diagnosis of human reovirus-like agent-associated infantile gastroenteritis.

Counterimmunoelectrophoresis was compared with electron microscopy for detection of human reovirus-like agent in fecal specimens. Both tests gave very similar results.

Preparation of a dane core (hepatitis B) antigen from human plasma.

Hepatitis B surface antigen (HBsAg) positive plasma, obtained from blood donors, was used to prepare an antigen (HBcAg) from the inner core of the Dane particle, the larger of the two spherical particles found in the blood in hepatitis B infection. The antigen was prepared by a series of centrifugation procedures on caesium chloride and sucrose gradients. Dane particle-rich fractions obtained from these gradients and concentrated by centrifugation were treated with Tween 80 to remove the outer coats from the particles. The remaining Dane particle cores were recovered by velocity sedimentation on a sucrose gradient. Preparations containing the Dane cores were used as antigens in the immune electron microscopy and complement fixation tests to demonstrate the specificity of HBcAg and lack of fross relationship with HBsAg. HBcAg will be used for the study of hepatitis B infections in man.

Comparison of rotavirus strains by hemagglutination inhibition.

Rotaviruses have been shown to be of importance as aetiologic agents of gastroenteritis in infants and in domestic animals of several species. Hemagglutinins were prepared from two Canadian isolates of bovine rotavirus and from one isolate of a simian rotavirus. A United Kingdon isolate of bovine rotavirus was shown not to possess hemagglutinating activity, indicating a strain difference between a Canadian and United Kingdom bovine rotavirus. In hemagglutination-inhibition (HAI) tests a rabbit hyperimmune (two injections) serum, prepared to one of the bovine rotaviruses, was not helpful in distinguishing the two bovine viruses because of cross-reactions between the viruses. However, it was possible to distinguish the bovine viruses from the simian virus with this serum. When guinea pig immune sera were prepared to the four rotavirus strains and tested with the three hemagglutinins in the HAI test, antigenic differences between the four strains of rotavirus were demonstrated. Hyperimmune guinea pig serum prepared to a strain of human rotavirus did not inhibit any of three hemagglutinins indicating that the human strain is different from the three rotavirus strains which gave hemagglutinins.

Typing of herpes simplex virus isolates with selected monoclonal antibodies.

On the basis of their reactivity with a large panel of clinical isolates of herpes simplex viruses, three monoclonal antibodies were selected as serotyping reagents. By indirect immunofluorescence, the type 1 specific (6D4) and the group specific (1B5) reacted with a cytoplasmic antigen while the type 2 specific (G3) reacted with a nuclear antigen. These three monoclonal antibodies have not failed so far in identifying and typing 257 culture isolates. For rapid serotyping by immunofluorescence, all antibodies gave unambiguous results on 95 additional isolates tested as soon as cytopathic effect appeared after inoculation on primary monkey kidney cells.

Studies of the antigenic variation in poliovirus type 1. Selection and analysis of variant strains with monoclonal antibodies by neutralization.

Nine neutralizing monoclonal antibodies were used in a preliminary study of the antigenic variation of poliovirus type 1. Six antigenic variants were selected and five distinct epitopes involved in neutralization were identified. Four of these epitopes are thought to be clustered within a single antigenic site. In kinetic studies, the neutralization of poliovirus by monoclonal antibodies was shown to be a single hit process.

Reproducibility and performance of the second-generation branched-DNA assay in routine quantification of human immunodeficiency virus type 1 RNA in plasma.

We examined the reproducibility of a second-generation branched-DNA (bDNA) assay (Quantiplex HIV RNA 2.0) for quantification of human immunodeficiency virus type 1 (HIV-1) RNA in plasma by retesting 325 specimens on separate runs and on different lots. The performance of the bDNA test was also assessed by data analysis obtained during routine testing of 15,365 specimens. Upon retesting, 96 and 86% of specimens displaying RNA levels above 5,000 and between 500 and 5, 000 copies/ml, respectively, showed less than a 0.3 log10 (twofold) difference with their initial values. Assay variability was found to increase as viral load decreased. Overall, the bDNA version 2.0 assay was found to be a reproducible and efficient test for routine quantification of HIV-1 RNA in plasma.