Isolation of HIV from cultures of purified CD4+ lymphocytes.

Isolation of HIV from cultures of CD4+ lymphocytes purified from peripheral blood by indirect panning was optimized and evaluated. Infectious HIV was isolated by single isolation attempts in 98% of 102 HIV-antibody-positive patients (55 had AIDS or ARC and 47 were clinically healthy). The average culture time required for positive cultures was largely independent of the CD4 count of the patients and 87% of the positive isolation cultures from both groups of patients became positive within 14 days of culture. An evaluation of the possible influence of media additives on propagation of HIV showed that: amphotericin-B had a suppressive effect on HIV replication at concentrations recommended for anti-fungal activity; recombinant and human interleukin-2 were equally suitable for both isolation cultures and for propagation of HIV, and polybrene, at a concentration of 2 micrograms/ml in the culture medium had a beneficial effect.     

The final follow-up plain radiograph is sufficient for clinical evaluation of polyethylene wear in total hip arthroplasty: A study of validity and reliability

Background and purpose

Radiostereometric analysis (RSA) is a highly accurate tool for assessment of polyethylene (PE) wear in total hip arthroplasty (THA); however, PE wear measurements in clinical studies are often limited to plain radiographs. We evaluated the agreement between PE wear measured with PolyWare software, which uses plain radiographs, and by model-based RSA, which uses stereo radiographs.

Methods

Measurements of PE wear postoperatively and at final follow-up (after mean 6 years) on plain radiographs of 12 patients after cementless THA were evaluated with PolyWare software and the results were compared with those from RSA as the gold standard (Model-based RSA using elementary geometrical shape models; EGS-RSA). With PolyWare, we either used the final radiographic follow-up (PW1) only or both the postoperative follow-up and the final follow-up (PW2).

Results

The 2D mean wear measured (in mm) was 0.80, 1.07, and 0.60 for the PW2, PW1, and RSA method. 2D intra-method repeatability was similar for PW1 and RSA with limits of agreement (LOAs, in mm) of ± 0.22, and ± 0.23, respectively. 2D inter-method concurrent validity was best between PW1 and EGS-RSA with LOAs of ± 0.55. For 2D linear wear measurements, the PW1 method had a clinical repeatability similar to that of RSA.

Interpretation

PW1 is sufficient for retrospective determination of 2D wear from medium-term wear measurements above 0.5 mm, It alleviates the need for baseline plain radiographs, has a clinical precision similar to that of RSA, and is easy and inexpensive to use.Wear of polyethylene (PE) components is widely regarded as the main factor limiting longevity of total hip arthroplasty (THA) (Cooper et al. 1992). Clinical studies have shown that periprosthetic osteolysis and aseptic loosening is strongly related to wear rates of above 0.2 mm/year (Sochart 1999, Dowd et al. 2000).Radiostereometric analysis (RSA) is the most accurate tool for in vivo assessment of PE wear (Kärrholm et al. 1997, von Schewelov et al. 2004, Bragdon et al. 2006), and it is regarded as the gold standard (Ilchmann et al. 1995). However, many radiographic in vivo studies of PE wear in THA are restricted to measurements on plain radiographs because the RSA set-up is expensive and not widely available. Measurement of PE wear on plain radiographs is often limited to 2D analysis because poor quality of cross-table lateral radiographs is a common problem (Sychterz et al. 1999b, 2001). Although PE wear is known to occur multidirectionally (Yamaguchi et al. 1997, Akisue et al. 1999), the bulk of the wear is detectable on the anterior-posterior radiographs alone (Sychterz et al. 1997, Hui et al. 2003, Martell et al. 2003). Based on the availability of radiographs and investigator preferences, some authors favor analysis of serial radiographs (Sychterz et al. 1997, Kim et al. 2001, Hernigou and Bahrami 2003) to describe the pattern of wear and the steady-state wear (Sychterz et al. 1999a, Bragdon et al. 2006), whereas others use 2 radiographic follow-ups (postoperative and latest) (Kraay et al. 2006), or only the latest radiographic follow-up with the assumption of zero wear at baseline (Norton et al. 2002)Little is known about the conformity between PE wear results measured with RSA and computerized methods using plain radiographs (Ilchmann et al. 1995, von Schewelov et al. 2004, Bragdon et al. 2006). Our group has questioned the conformity of 2D PE wear measurements based on serial, 2, or 1 radiographic follow-up (Stilling et al. 2009b). We determined that there was a statistically significant difference between all approaches, but we were unable to determine which strategy best reflected the true extent of wear (Stilling et al. 2009b). In addition, we recently showed that model-based RSA is an accurate tool for measurement of PE wear in good agreement with the true wear (Stilling 2009).We have now studied the intra-method repeatability and concurrent validity between 2 methods (PolyWare and EGS-RSA) for measurement of PE wear in THA, in a group of patients with an average follow-up of 6 years. We wanted to determine (1) whether there would be a difference in repeatability between the methods, (2) whether there would be a difference in wear measured using 1 or 2 radiographic follow-ups with the PolyWare method, and (3) whether either of the 2 PolyWare measurement strategies (1 or 2 radiographic follow-ups) would give results similar to the wear measured by RSA (concurrent validity).     

Preparation of the Femoral Bone Cavity for Cementless Stems: Broaching vs Compaction. A Five-Year Randomized Radiostereometric Analysis and Dual Energy X-Ray Absorption Study

Background

Short-term experimental and animal studies have confirmed superior fixation of cementless implants inserted with compaction compared to broaching of the cancellous bone.

Reliability of computer-assisted periacetabular osteotomy using a minimally invasive approach

Background

Periacetabular osteotomy (PAO) is the treatment of choice for younger patients with developmental hip dysplasia. The procedure aims to normalize the joint configuration, reduce the peak-pressure, and delay the development of osteoarthritis. The procedure is technically demanding and no previous study has validated the use of computer navigation with a minimally invasive transsartorial approach.

Methods

Computer-assisted PAO was performed on ten patients. Patients underwent pre- and postoperative computed tomography (CT) scanning with a standardized protocol. Preoperative preparation consisted of outlining the lunate surface and segmenting the pelvis and femur from CT data. The Biomechanical Guidance System was used intra-operatively to automatically calculate diagnostic angles and peak-pressure measurements. Manual diagnostic angle measurements were performed based on pre- and postoperative CT. Differences in angle measurements were investigated with summary statistics, intraclass correlation coefficient, and Bland–Altman plots. The percentage postoperative change in peak-pressure was calculated.

Results

Intra-operative reported angle measurements show a good agreement with manual angle measurements with intraclass correlation coefficient between 0.94 and 0.98. Computer navigation reported angle measurements were significantly higher for the posterior sector angle (\(1.65^{\circ }\), \(p=0.001\)) and the acetabular anteversion angle (\(1.24^{\circ }\), \(p=0.004\)). No significant difference was found for the center-edge (\(p=0.056\)), acetabular index (\(p=0.212\)), and anterior sector angle (\(p=0.452\)). Peak-pressure after PAO decreased by a mean of 13% and was significantly different (\(p=0.008\)).

Conclusions

We found that computer navigation can reliably be used with a minimally invasive transsartorial approach PAO. Angle measurements generally agree with manual measurements and peak-pressure was shown to decrease postoperatively. With further development, the system will become a valuable tool in the operating room for both experienced and less experienced surgeons performing PAO. Further studies with a larger cohort and follow-up will allow us to investigate the association with peak-pressure and postoperative outcome and pave the way to clinical introduction.

     

Comparison of Caspofungin MICs by Means of EUCAST Method EDef 7.1 Using Two Different Concentrations of Glucose

According to the product insert for Cancidas (caspofungin acetate), the drug must not be diluted in solutions containing glucose as this decreases caspofungin stability. The aim of this study was to compare caspofungin MICs for a collection of yeasts by means of EUCAST method EDef7.1 but using two different concentrations of glucose: 2% versus 0.2%. MICs were identical or within one 2-fold dilution for 93 out of 95 strains (97.9%), showing that glucose does not interfere with susceptibility.In a previous work, a comparison of the major susceptibility testing methods for echinocandins was performed using a well-characterized panel of Candida strains (1). EUCAST method EDef 7.1 performed as one of the best methods for discriminating wild-type strains from isolates with mutations in FKS hot spot regions. However, for caspofungin the MICs obtained by EUCAST method EDef 7.1 were in general higher than those obtained using the CLSI M27A3 methodology. In addition, the number of very major errors (number of FSK hot spot mutants classified as susceptible according the wild-type upper limit values) was 50% for EUCAST method EDef 7.1 (1), while 7% of very major errors were obtained by means of CLSI M27A3 at 24 h (1, 2). Finally, this previous work also found that caspofungin MICs obtained by means of EUCAST method EDef 7.1 and CLSI M27A3 were, in general, higher than those obtained by Pfaller et al. in a previous work using CLSI M27A3 methodology (4), indicating a possible variability associated with caspofungin antifungal susceptibility testing (1). Thus, it was of interest to explore which variables influence the reproducibility of the susceptibility tests for caspofungin. Although it has been proven that both the EUCAST EDef 7.1 and CLSI M27 A3 (2, 5) methodologies generate similar results for amphotericin B and azole drugs (3, 6), this does not appear to be the case for caspofungin. The main differences between EUCAST method EDef 7.1 and CLSI M27A3 include different inocula (10⁵ versus 10³ CFU/ml, respectively) and glucose concentrations (2% versus 0.2%, respectively) (3, 6).The product insert for Cancidas states that the compound must not be diluted in solutions containing glucose because it decreases drug stability. As stated previously, the glucose concentration in the growth medium recommended for method EDef 7.1 in RPMI 1640 is 10 times higher than that recommended by the CLSI (5). As this concentration could have influenced the MIC values obtained by means of EUCAST method EDef 7.1 (5), the Antifungal Susceptibility Testing Subcommittee of EUCAST decided to set up a comparison test to examine whether the increased glucose concentration affects the MIC results. The test compared caspofungin MICs for a collection of well-characterized yeast isolates by means of EUCAST method EDef 7.1 (5) but using growth medium with two different concentrations of glucose: 2% versus 0.2%.     

HIV-1 infection of in vitro cultured human monocytes: early events and influence of anti HIV-1 antibodies

Summary To characterize the role of the humoral immune response on HIV-1 infection of monocytes and macrophages (Ms) we examined the susceptibility of in vitro cultured monocyte/Ms to various HIV-1 isolates and the influence of heterologous and particularly autologous anti HIV-1 sera on this infection. Depending on the period of in vitro cultivation and the virus isolate used different patterns of susceptibility were detected. One week old monocyte/Ms were highly susceptible to HIV-1 infection, in contrast to monocyte/Ms cultured 4 weeks. The infection by virus isolated immediately after seroconversion lead to persistent infection with high level of antigen production in contrast to infection by homologous virus isolated later. MAb against the V3-IIIB loop and sCD4 inhibited the infection of monocyte/Ms in a dose dependent manner, indicating that infection requires binding to CD4 and that post binding events may be common to the infection of lymphocytes. Anti HIV-1 sera showed neutralizing activity against heterologous and even autologous escape virus. This finding, together with the observation that monocytes and Ms are infected in vivo, suggests that protection against HIV-1 infection of monocytes and Ms in vivo may not be obtainable by the humoral immune response alone.     

Ear measurement of temperature is only useful for screening for fever in an adult emergency department

Background

A new generation of ear thermometers with preheated tips and several measurements points should allow a more precise temperature measurement. The aim of the study was to evaluate if the ear temperature measured by this ear thermometer can be used to screen for fever and whether the thermometer is in agreement with the rectal temperature and if age, use of hearing devices or time after admission influences the temperature measurements.

Methods

Open cross-sectional clinical single site study patients, >?18?years old, who were acutely admitted to the short stay unit at the ED. A sample size of 99 patient per subgroup was recruited as random convenience series. As ear thermometer Braun Thermoscan Pro 4000® and as rectal thermometer Omron Flex Temp Smart ® was used. For different cut off of temperature the AUC was calculated and Bland-Altman analysis for calculation of 95% limits of agreement with rectal temperature, with subgroup analysis concerning age, time span from admission time and use of hearing aid.

Results

Among 599 patients the sensitivity to detect fever with an ear thermometer varied between 68 and 70% with AUC from 0.88–0.97. If the ear temperature was ≥37.5 oC, the sensitivity to detect patients with ≥38.0 oC rectally was 95% which raised to 100% for a rectal temperature of ≥38.3 oC. For the ear thermometer’s ability to determine the exact temperature the 95% limits of agreement were +/??0.8 oC. with no influence from age, duration of hospital stay or hearing aids.

Conclusion

The examined ear thermometer is able to detect fever, defined as ≥38 oC rectally in an adult ED population by using an ear cut-point of 37.5 oC, but not to measure the exact temperature. Used in this way around a fifth of the patients will still be in need of a rectal temperature measurement, but less than 5% with fever ≥38.0 oC will remain undetected and none with fever ≥38.3 oC. Age, admission time and use of hearing aid did not influence the temperature measurements.

Trial registration

Clinical Trials: ID NCT02977481, date 11/18/2016.