Optimising the scan delay for arterial phase imaging of the liver using the bolus tracking technique

Objective:

To optimize the delay time before the initiation of arterial phase scan in the detection of focal liver lesions in contrast enhanced 5 phase liver CT using the bolus tracking technique.

Patients and Methods:

Delay - the interval between threshold enhancement of 100 hounsfield unit (HU) in the abdominal aorta and commencement of the first arterial phase scan. Using a 16 slice CT scanner, a plain CT of the liver was done followed by an intravenous bolus of 120 ml nonionic iodinated contrast media (370 mg I/ml) at the rate of 4 mL/s. The second phase scan started immediately after the first phase scan. The portal venous and delay phases were obtained at a fixed delay of 60 s and 90 s from the beginning of contrast injection. Contrast enhancement index (CEI) and subjective visual conspicuity scores for each lesion were compared among the three groups.

Results:

84 lesions (11 hepatocellular carcinomas, 17 hemangiomas, 39 other hypervascular lesions and 45 cysts) were evaluated. CEI for hepatocellular carcinomas appears to be higher during the first arterial phase in the 6 seconds delay group. No significant difference in CEI and mean conspicuity scores among the three groups for hemangioma, other hypervascular lesions and cysts.

Conclusion:

The conspicuity of hepatocellular carcinomas appeared better during the early arterial phase using a bolus tracking technique with a scan delay of 6 seconds from the 100 HU threshold in the abdominal aorta.     

Genetic variation among methicillin-resistant Staphylococcus aureus isolates from cancer patients in Saudi Arabia

One hundred and twenty methicillin-resistant Staphylococcus aureus (MRSA) isolated from cancer and non-cancer patients in Saudi Arabia were investigated for antibiotic resistance, virulence determinants and genotypes. The majority of MRSA isolates from cancer (n?=?44, 73.3 %) and non-cancer patients (n?=?34, 56.7 %) were multi-resistant to more than four classes of antibiotics. Virulence gene profiling showed that all strains were commonly positive for adhesin genes, except ebps and bbp genes, which were not detected in any isolate. Although the presence of adhesin genes varied slightly among MRSA isolates from cancer and non-cancer patients, these variations were not found to be statistically significant. In contrast, the presence of the toxin genes seb, sec, seg and sei was significantly elevated in MRSA strains isolated from cancer patients. Multilocus sequence typing (MLST) detected six and nine sequence types (STs) among isolates from cancer and non-cancer patients, respectively. Using spa typing, 12 and 25 types were detected, including four new types. The ability of different MRSA clones to become multi-resistant and their ability to acquire different virulence factors may contribute to their success as pathogens in individual groups of patients.     

Isoflavone Genistein Induces Fluid Secretion and Morphological Changes in the Uteri of Post-Pubertal Rats

A reported increase in the incidence of infertility following high genistein intake could be related to alteration in the normal fluid volume and morphology of the uterus in adult female. In view of this, we investigated the effect of this compound on fluid secretion, fluid volume and morphology of the uterus in post-pubertal rats. Methods: Ovariectomised SD rats were treated with 17-β oestradiol (E) (0.8 X 10^-4 mg/kg/day) and genistein (0.5, 5, 10, 25, 50 and 100 mg/kg/day) for three days. Following drug treatment, in-vivo uterine perfusion was performed and the rate of fluid secretion and the volume of fluid in the uterus were determined via changes in weight (μl/min) and F-dextran concentration of the perfusate respectively. The animals were then sacrificed and the uteri were removed for weight determination, morphological analyses and proliferative cell nuclear antigen (PCNA) expression analyses by Western blotting. Results: Subcutaneous genistein treatment resulted in a dose-dependent increase in fluid secretion rate, fluid volume and uterine wet weight. Treatment with 100 mg/kg/day genistein resulted in a remarkable increase in the rate of uterine fluid secretion, the volume of the uterine luminal fluid as well as the circumference of the uterine and uterine glandular lumen suggesting an excessive fluid accumulation. Meanwhile, there were evidence of glandular hyperplasia and an increase in the expression of PCNA following treatment with 50 and 100 mg/kg/day genistein. Conclusion: High genistein intake could potentially cause adverse effects on the uterus by inducing excessive fluid secretion and accumulation as well as hyperplasia.     

Evaluation of specific humoral immune response and cross reactivity against <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> antigens induced in mice immunized with liposomes composed of total lipids extracted from <Emphasis Type="Italic">Mycobacterium smegmatis</Emphasis>

The development of a new tuberculosis (TB) vaccine has become one of the main objectives of the scientific community. Protein antigens have been widely explored as subunit TB vaccines, however lipid antigens could be equally important to be used or included in such a vaccine. The aim of this study was to demonstrate the potential of a liposome formulation composed of an extract of lipids from Mycobacterium smegmatis (Ms) as a TB vaccine candidate. We evaluated the immunogenicity of this formulation as well as the cross reactive response against antigens from Mycobacterium tuberculosis (MTb) in BALB/c mice. We determined the anti-liposome IgG response in sera from TB patients and from healthy subjects who displayed a positive (PPD+) or negative (PPD-) tuberculin skin test. A significant increase in anti-liposome IgG (p<0.05) was detected in animals immunized with Bacille Calmette-Guérin (BCG) compared with all groups, and in the group immunized with liposomes from Ms (LMs) compared to animals immunized with either LMs adjuvanted with aluminium (LMs-A) or the negative control group (phosphate buffered saline, PBS) respectively. With respect to the cross reactive response against a cocktail of cell wall antigens (CWA) from MTb, significantly higher IgG levels were observed in animals immunized with BCG and LMs compared to negative controls and either, aluminium-adjuvanted liposomes (LMs-A) or montanide (LMs-M) (p<0.05). Furthermore, the anti-liposome IgG response was significantly superior in sera from pulmonary TB patients compared to PPD+ and PPD- healthy subjects (p<0.001) suggesting the expression of these antigens in vivo during active MTb infection. The results obtained provide some evidence for the potential use of liposomes containing total lipid extracts of Ms as a TB vaccine candidate.     

In Silico identification of M. TB proteins with diagnostic potential

The development of a new tuberculosis (TB) vaccine has become one of the main objectives of the scientific community. Protein antigens have been widely explored as subunit TB vaccines, however lipid antigens could be equally important to be used or included in such a vaccine. The aim of this study was to demonstrate the potential of a liposome formulation composed of an extract of lipids from Mycobacterium smegmatis (Ms) as a TB vaccine candidate. We evaluated the immunogenicity of this formulation as well as the cross reactive response against antigens from Mycobacterium tuberculosis (MTb) in BALB/c mice. We determined the anti-liposome IgG response in sera from TB patients and from healthy subjects who displayed a positive (PPD+) or negative (PPD-) tuberculin skin test. A significant increase in anti-liposome IgG (p<0.05) was detected in animals immunized with Bacille Calmette-Guérin (BCG) compared with all groups, and in the group immunized with liposomes from Ms (LMs) compared to animals immunized with either LMs adjuvanted with aluminium (LMs-A) or the negative control group (phosphate buffered saline, PBS) respectively. With respect to the cross reactive response against a cocktail of cell wall antigens (CWA) from MTb, significantly higher IgG levels were observed in animals immunized with BCG and LMs compared to negative controls and either, aluminium-adjuvanted liposomes (LMs-A) or montanide (LMs-M) (p<0.05). Furthermore, the anti-liposome IgG response was significantly superior in sera from pulmonary TB patients compared to PPD+ and PPD- healthy subjects (p<0.001) suggesting the expression of these antigens in vivo during active MTb infection. The results obtained provide some evidence for the potential use of liposomes containing total lipid extracts of Ms as a TB vaccine candidate.

     

Absolute quantification of human liver metabolite concentrations by localized in vivo 31P NMR spectroscopy in diffuse liver disease

Phosphorus-31 NMR spectroscopy using slice selection (DRESS) was used to investigate the absolute concentrations of metabolites in the human liver. Absolute concentrations provide more specific biochemical information compared to spectrum integral ratios. Nine patients with histopathologically proven diffuse liver disease and 12 healthy individuals were examined in a 1.5-T MR scanner (GE Signa LX Echospeed plus). The metabolite concentration quantification procedures included: (1) determination of optimal depth for the in vivo measurements, (2) mapping the detection coil characteristics, (3) calculation of selected slice and liver volume ratios using simple segmentation procedures and (4) spectral analysis in the time domain. The patients had significantly lower concentrations of phosphodiesters (PDE), 6.3±3.9 mM, and ATP-, 3.6±1.1 mM, (P<0.05) compared with the control group (10.0±4.2 mM and 4.2±0.3 mM, respectively). The concentrations of phosphomonoesters (PME) were higher in the patient group, although this was not significant. Constructing an anabolic charge (AC) based on absolute concentrations, [PME]/([PME] + [PDE]), the patients had a significantly larger AC than the control subjects, 0.29 vs. 0.16 (P<0.005). Absolute concentration measurements of phosphorus metabolites in the liver are feasible using a slice selective sequence, and the technique demonstrates significant differences between patients and healthy subjects.     

Postural sway changes during static standing with concurrent task in children with traumatic brain injury

Objectives:To investigate the effects of concurrent tasks (motor and cognitive) on postural control performance in children with traumatic brain injury (TBI) compared to typically developing (TD) control subjects.Methods:Sixteen children with TBI (aged 11.63±1.89 years) and 22 TD controls (aged 11.41±2.24 years) participated in this case-control study. This study was conducted between May 2016 and March 2017. Each child performed static standing under 3 different conditions: single, concurrent motor, and concurrent cognitive task. Postural control performance measure includes sway area, anterior-posterior (AP) sway velocity, medio-lateral (ML) sway velocity, AP sway distance and ML sway distance as measured using the APDM® Mobility Lab (Oregon, Portland). A repeated-measure analysis of variance was used to analyse the data.Results:We found that children with TBI showed significantly more deterioration in postural control performance than TD children (p<0.05). Both concurrent tasks (motor and cognitive) significantly decreased postural control performance in both groups with more pronounced changes in children with TBI than that of the TD controls.Conclusion:The results demonstrated that, performing concurrent tasks (motor and cognitive) during upright standing resulted in deterioration of postural control performance. The existence of cognitive and balance impairment in children with TBI will possibly cause concurrent tasks to be more complex and demands greater attention compared to single task.

Traumatic brain injury is frequently referred to as a ‘silent epidemic’, with the majority of society being unaware on the magnitude a TBI can cause on an individual’s function.1 It remains a leading cause of death and long-term disability in children worldwide with approximately 3 million children experiencing TBI annually.2 Consequently, TBI may lead to neurological impairment which contributes to long-term disability among this group of children.With the cognitive and behavioral deficit, individuals with TBI are faced with a long-term functional disability including postural control instability.3,4 Postural control refers to the act of maintaining, achieving or restoring the line of gravity or centre of mass (COM) within the base of support (BOS).5 It is a complex collaboration of sensory, motor, and central nervous system. Disruption of any components such as visual, vestibular sensory inputs, muscle weakness and loss of proprioception will result in postural control instability. This impairment could seriously interfere with the child’s level of independence and lead to increased risk of falls.5The maintenance and control of posture and balance, whether in static or dynamic conditions, are essential requirements for daily activity. Postural control requires a lot of cognitive resources.6 The more challenging postural task required more cognitive processing in order to sustain the position. Children with TBI have both cognitive and information processing deficits that impact attention and functional abilities.7,8 In daily life, children encounter situations in which they must perform cognitive and motor tasks simultaneously, such as responding to verbal instructions or manipulating objects while sitting or standing. These situations may be complex and challenging for children with TBI as they present with both attention and information processing deficit. Using dual-task methodology, it can examine the effect of adding a concurrent task during a motor task. Trials using dual-task paradigm are commonly used in a clinical setting to measure automatic control of movement indirectly. It is crucial to understand the effects of a concurrent task on postural control performance while designing a dual-task paradigm intervention program in this population. The dual-task intervention during postural control could be more challenging and may improve the postural stability better as compared to single task intervention.Since attention is a limited resource, it may become overloaded by competing for attention demands and subsequently might lead to reduced performance in one or all tasks.9 Children with TBI may need more attention during postural control and as a result might be more vulnerable to falls while doing concurrent task. A recent study among healthy children and youth 5-18 years old showed concurrent cognitive task resulted in decreased postural stability.10 Comparing the effects of different surface (firm vs. foam surface) on postural stability during concurrent cognitive task reveals that the foam surface caused greater interference in postural stability.10 A normative database was created as a result of this study, which may benefit future investigations of post-concussion performances with potential to assess post-concussion severity. In addition, it also focuses on assessing both motor and cognitive domains simultaneously. This study also reports information regarding the effect of cognitive task on postural stability in healthy children & youth. The examined effect of concurrent cognitive and motor task conditions on postural control in children with TBI is limited. Therefore, the objective of the present study was to investigate the postural control performance under concurrent tasks in children with TBI and TD controls. We hypothesized that both concurrent motor and cognitive tasks would cause significant postural control deterioration compared to single task condition.     

Bariatric Surgery in Patients with Cirrhosis and Portal Hypertension

Introduction

Studies on bariatric patients with cirrhosis and portal hypertension are limited. The aim of this study was to review our experience in cirrhotic patients with portal hypertension who had bariatric surgery.

Method

All cirrhotic patients with portal hypertension who underwent laparoscopic bariatric surgery, from 2007 to 2017, were retrospectively reviewed.

Results

Thirteen patients were included; eight (62%) were female. The median age was 54 years (interquartile range, IQR 49–60) and median BMI was 48 kg/m² (IQR 43–55). Portal hypertension was diagnosed based on endoscopy (n?=?5), imaging studies (n?=?3), intraoperative increased collateral circulation (n?=?2), and endoscopy and imaging studies (n?=?3). The bariatric procedures included sleeve gastrectomy (n?=?10, 77%) and Roux-en-Y gastric bypass (n?=?3, 23%). The median length of hospital stay was 3 days (IQR 2–4). Three 30-day complications occurred including wound infection (n?=?1), intra-abdominal hematoma (n?=?1), and subcutaneous hematoma (n?=?1). No intraoperative or 30-day mortalities. There were 11 patients (85%) at 1-year follow-up and 9 patients (69%) at 2-year follow-up. At 2 years, the median percentage of excess weight loss (EWL) and total weight loss (TWL) were 49 and 25%, respectively. There was significant improvement in diabetes (100%), dyslipidemia (100%), and hypertension (50%) at 2 years after surgery.

Conclusion

Bariatric surgery in selected cirrhotic patients with portal hypertension is relatively safe and effective.

     

Pearson Product Moment Correlation (PPMC) and Principal Component Analysis (PCA) for objective comparison and source determination of unbranded black ballpoint pen inks

The aim of this work was to evaluate the feasibility of combining Raman Spectroscopy (RS) and Fourier Transform Infrared (FTIR) spectroscopy with Pearson Product Moment Correlation (PPMC) and Principal Component Analysis (PCA) for objective comparisons of unbranded black ballpoint pen inks; more specifically, to determine the original source of an ink treated as unknown. Eleven unbranded black ballpoint pens obtained during an education fair in Malaysia in May 2014 were prepared and analysed using RS and FTIR, where one of the pens was used to write a simulated threatening note. The spectra of the ballpoint pen inks obtained from the RS and FTIR analysis, including the ink on the simulated threatening note were then subjected to PPMC and PCA. The linear correlations of r = 0.756 and r = 0.999 and the similarities in terms of PC1 and PC2 scores of one of the inks to the ink on the simulated threatening note, which indicated a strong relationship between the two inks, substantiate the feasibility of combining RS and FTIR with the statistical and mathematical techniques of PPMC and PCA for objective comparison and source determination of ballpoint pen inks.