Evaluation of Non-ST Segment Elevation Acute Chest Pain Syndromes with a Novel Low-Profile Continuous Imaging Ultrasound Transducer

Background: This investigation was designed to test the hypothesis that continuous cardiac imaging using an ultrasound transducer developed in our laboratory (ContiScan) is superior to electrocardiogram (ECG) monitoring in the diagnosis of coronary artery disease (CAD) in patients with acute non-ST segment elevation chest pain syndromes. Methods: Seventy patients with intermediate to high probability of CAD who presented with typical anginal chest pain and no evidence of ST segment elevation on the ECG were studied. The 2.5-MHz transducer is spherical in its distal part mounted in an external housing to permit steering in 360 degrees. The transducer was placed at the left sternal border to image the left ventricular short-axis view and recorded on video tape at baseline, during and after episodes of chest pain. Two ECG leads were continuously monitored. The presence of CAD was confirmed by coronary arteriography or nuclear or echocardiographic stress testing. Results: Twenty-four patients had regional wall motion abnormalities (RWMA) on their initial echo which were unchanged during the period of monitoring. All had evidence of CAD. Twenty-eight patients had transient RWMA. All had evidence of CAD. Eighteen patients had normal wall motion throughout the monitoring period, 14 of these had no evidence of CAD, and four had evidence of CAD. These four patients did not have chest pain during monitoring. The sensitivity, specificity, and accuracy of echocardiographic monitoring for diagnosing non-ST elevation myocardial infarction was 88%, 100%, and 91% respectively. The sensitivity, specificity, and accuracy of the ECG for diagnosis of CAD were 31%, 100%, and 52%, respectively. Echocardiography was superior to ECG (P < 0.001). Conclusions: The data indicate that continuous cardiac imaging is superior to ECG monitoring for the diagnosis of CAD in patients presenting with acute non-ST segment elevation chest pain syndromes. This technique could be a useful adjunct to ECG monitoring for myocardial ischemia in the acute care setting.     

Electromagnetic navigation system for acetabular component placement in total hip arthroplasty is more precise and accurate than the freehand technique: a randomized,controlled trial with 84 patients

Background and purpose — The accuracy of conventional navigation systems depends on precise registration of bony landmarks. We investigated the clinical use of electromagnetic navigation (EMN), with a unique device for precise determination of the anterior pelvic plane.Patients and methods — We randomly allocated patients scheduled for total hip arthroplasty into 2 groups of 42 patients each. In the study group, cups were placed at the predetermined target angles (inclination: 42.5°; anteversion: 15°) with the support of EMN. In the control group, cups were placed freehand aiming at the same target angles. Postoperatively the true position of the cup was determined using computed tomography scan of the pelvis. Precision (root mean squared error, RMSE) bias (mean bias error, ME), accuracy, and duration of surgery were compared between the methods.Results — Cup anteversion was more accurate and precise in the navigated group. The ME in the navigated and freehand group was –1.7° (95% CI –2.4 to 1.1) and –4.5° (CI –6.5 to 2.5), respectively. The RMSE in the navigated and freehand group was 2.8° (CI 2.3–3.2) and 8.0° (CI 6.3–9.5), respectively. The inclination was also more precise in the navigated group, with the RMSE in the navigated and freehand group at 4.6° (CI 3.4–5.9) and 6.5° (CI 5.4–7.5), respectively. The accuracy of the inclination and the duration of surgeries were similar between the groups.Interpretation — Cup placement with the help of EMN is more precise than the freehand technique and it does not affect the duration of surgery.

Optimal cup placement is crucial to the success of total hip arthroplasty (THA) since it is associated with lower rates of dislocation, prolonged implant survival, and better quality of life of the patient (Learmonth et al. 2007). For cup position in THA the safe zone was defined by Lewinnek et al. (1978), with recommended inclination and anteversion angles of 40° ± 10° and 15° ± 10°, respectively. Several studies have demonstrated that using the freehand technique for cup placement within the safe zone remains a challenge even for high-volume surgeons. More than 75% of cups are still inadvertently placed out of the safe zone (Digioia et al. 2002, Saxler et al. 2004, Bosker et al. 2007). Several studies have reported that the cup placement could be optimized using imageless navigation, which is a more reproducible technique compared with a freehand THA (Digioia et al. 2002, Kalteis et al. 2006a, Hohmann et al. 2011, Lass et al. 2014). Those studies were mostly performed with different producers’ stereo-optical navigation systems with the same basic concept (Renkawitz et al. 2009). To assure the accuracy of such a system, the tracker must be large, and therefore placed outside the surgical incision. This is related to additional morbidity (Dorr et al. 2005, Kamara et al. 2017). The accuracy depends on precise registration of bony landmarks (Dorr et al. 2005, Lass et al. 2014), which are necessary for the determination of the reference plane. The registration of the reference points is mostly affected by the thickness of the overlying soft tissues. This can tilt the virtual reference plane and contribute to the systemic error (Hohmann et al. 2011), especially in obese patients (Parratte and Argenson 2007, Wassilew et al. 2012, Buller et al. 2019). To avoid imprecise reference plane determination, a different imageless navigation concept was introduced. This system consists of an electromagnetic transmitter and sensors, which are placed inside the incision and on instruments. Additionally, we developed a particular tool (Navi-frame) to overcome the difficulties in the registration of bony landmarks for correct anterior pelvic plane (APP) determination. The basic idea was that at least 3 non-collinear points describe a plane. In THA these 3 points are represented by the two anterior superior iliac spines (ASIS) and the pubic tubercle. The real APP is registered with the placement of the Navi-frame on these 3 points (Figure 1). This presents a major improvement compared with the stereo-optical systems.Open in a separate windowFigure 1.Position of the Navi-frame on the sawbones model of the pelvis.Our 2 hypotheses for this study were:

1. An electromagnetic navigation (EMN) system enables more accurate and precise cup placement in THA than the freehand technique, regardless of the patient’s BMI.
2. The EMN system does not affect the duration of surgery.

     

Screening markers for chronic atrophic gastritis in Chiapas, Mexico.

Intestinal-type gastric adenocarcinomas usually are preceded by chronic atrophic gastritis. Studies of gastric cancer prevention often rely on identification of this condition. In a clinical trial, we sought to determine the best serological screening method for chronic atrophic gastritis and compared our findings to the published literature. Test characteristics of potential screening tests (antibodies to Helicobacter pyloni or CagA, elevated gastrin, low pepsinogen, increased age) alone or in combination were examined among consecutive subjects enrolled in a study of H. pylori and preneoplastic gastric lesions in Chiapas, Mexico; 70% had chronic atrophic gastritis. English-language articles concerning screening for chronic atrophic gastritis were also reviewed. Sensitivity for chronic atrophic gastritis was highest for antibodies to H. pylori (92%) or CagA, or gastrin levels >25 ng/l (both 83%). Specificity, however, was low for these tests (18, 41, and 22%, respectively). Pepsinogen levels were highly specific but insensitive markers of chronic atrophic gastritis (for pepsinogen I <25 microg/l, sensitivity was 6% and specificity was 100%; for pepsinogen I:pepsinogen II ratio <2.5, sensitivity was 14% and specificity was 96%). Combinations of markers did not improve test characteristics. Screening test characteristics from the literature varied widely and did not consistently identify a good screening strategy. In this study, CagA antibodies alone had the best combination of test characteristics for chronic atrophic gastritis screening. However, no screening test was both highly sensitive and highly specific for chronic atrophic gastritis.     

Detection of wall motion abnormalities during ambulatory echocardiography using a novel ultrasound transducer

Background: This investigation was designed to determine whether transient wall motion abnormalities due to myocardial ischemia induced by walking could be detected by ambulatory echocardiography. Methods: Two groups were studied. Group 1 consisted of 10 males (mean age 34 years) who had no symptoms of angina. Group 2 consisted of eight selected patients (mean 61 years) with angina and angiographic evidence of coronary artery disease. The 2.5 MHz transducer is spherical in its distal part and mounted in an external housing to permit steering in 360°. The external housing was attached to the chest wall using an adhesive patch. The transducer was placed in the 3rd or 4th intercostal space at the left sternal border to permit imaging of the left ventricle (LV) in its short axis and attached to the chest wall. The transducer was interfaced with an Acuson Cypress echocardiography system which was placed on a mobile cart. To permit portability, the echocardiography system was powered by a capacitor (UPS device). The subjects were asked to walk along the corridor as fast as possible for 10 minutes or until the onset of symptoms while pushing the cart. The short axis of the LV was displayed on a monitor and recorded on optical disks. Results: The heart rate, systolic blood pressure (SBP), and double product of Group 1 at rest were 77 ± 3 beats/min, 119 ± 13 mmHg, and 9,150 ± 868, respectively, and increased to 106 ± 8 beats/min, 129 ± 15 mmHg, and 1,3793 ± 2,176 with walking. The baseline heart rate, SBP, and double product were 71 ± 12 beats/min, 130 ± 14 mmHg, and 8,555 ± 1,928 in Group 2 and increased to 94 ± 14 beats/min, 135 ± 20 mmHg, and 12,480 ± 3,830 with walking. All patients in Group 1 had normal wall motion at rest and during walking. Patients in Group 2 had normal wall motion during rest and new wall motion abnormalities were noted in all subjects during walking (anterior septum and/or anterolateral wall in seven, posterolateral wall in one). The wall motion abnormalities resolved shortly after discontinuation of walking. Conclusion: Ambulatory echocardiography permitted the detection of transient wall motion abnormalities in patients with coronary artery disease (CAD). This technique could be potentially useful in evaluating selected patients for myocardial ischemia. (Echocardiography 2012;29:509‐512)     

Triple-negative breast cancer in Hispanic patients: high prevalence, poor prognosis, and association with menopausal status, body mass index, and parity

BACKGROUND:

Triple‐negative breast cancer (TNBC) is defined as breast cancer that is negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. TNBC represents 15% of all invasive breast cancers, but some studies have suggested that its prevalence differs between races. To the authors' knowledge, no previous studies have determined the prevalence of TNBC and its risk factors among Hispanic women.

METHODS:

The authors identified 2074 Hispanic women with breast cancer who attended the National Cancer Institute in Mexico City from 1998 to 2008. All histopathologic and immunohistochemical diagnoses were rereviewed by a breast cancer pathologist. The prevalence of TNBC, its association with clinicopathologic characteristics, and its prognostic impact were determined.

RESULTS:

The median patient age at diagnosis (±standard deviation) was 50 ± 12 years. The overall prevalence of TNBC was 23.1%. Younger age (P < .001), premenopausal status (P = .002), increased parity (P = .029), hormonal contraceptive use (P = .04) high histologic grade (P < .001), and advanced disease (P < .001) were associated independently with TNBC. Postmenopausal patients who had a body mass index (BMI) <25 kg/m² (P = .027) or <30 kg/m² (P < .001) were more likely to have TNBC. In multivariate analysis, patients with TNBC had a higher risk of locoregional recurrence (LRR), lower disease‐free survival (DFS) (hazard ratio, 1.62; 95% confidence interval, 1.13‐2.32; P = .009), and a lower cancer‐specific survival (CSS) rate (hazard ratio, 1.66; 95% confidence interval, 1.20‐2.30; P = .002) than patients with non‐TNBC.

CONCLUSIONS:

The median age at diagnosis of Hispanic women with breast cancer was 11 years younger than the average age reported in the United States. The prevalence of TNBC in this study population was higher than that reported in white women with breast cancer. TNBC was associated with a higher risk of LRR and with lower DFS and CSS than those in patients with non‐TNBC. Cancer 2011;. © 2011 American Cancer Society.     

Proteomic analysis of acetaminophen-induced changes in mitochondrial protein expression using spectral counting

Comparative proteomic analysis following treatment with acetaminophen (APAP) was performed on two different models of APAP-mediated hepatocellular injury in order to both identify common targets for adduct formation and track drug-induced changes in protein expression. Male C57BL/6 mice were used as a model for APAP-mediated liver injury in vivo, and TAMH cells were used as a model for APAP-mediated cytotoxicity in vitro. SEQUEST was unable to identify the precise location of sites of adduction following treatment with APAP in either system. However, semiquantitative analysis of the proteomic data sets using spectral counting revealed a downregulation of P450 isoforms associated with APAP bioactivation and an upregulation of proteins related to the electron transport chain by APAP compared to the control. Both mechanisms are likely compensatory in nature as decreased P450 expression is likely to attenuate toxicity associated with N-acetyl-p-quinoneimine (NAPQI) formation, whereas APAP-induced electron transport chain component upregulation may be an attempt to promote cellular bioenergetics.     

Atherosclerosis in chronic kidney disease: lessons learned from glycation in diabetes

In diabetes, glycation is a nonenzymatic posttranslational modification resulting from the bonding of a sugar molecule with a protein or lipid followed by oxidation, resulting in the development of advanced glycation end products (AGE). Like glycation, carbamylation is a posttranslational protein modification that is associated with AGE formation. Glycation of extracellular matrix proteins and low-density lipoprotein with subsequent deposition in the vessel wall could contribute to inflammatory response and atheroma formation. It is logical to extrapolate that carbamylation may result in modification of vessel wall proteins similar to glycation, and predispose to atherosclerosis.