Resynchronization of the left atrium may play an important role in cardiac resynchronization therapy

Introduction

Left atrial (LA) dyssynchrony is a predictor of response to cardiac resynchronization therapy (CRT). It is unknown, however, if LA resynchronization contributes to response to CRT. We hypothesize that there is a relationship between correction of LA dyssynchrony and response to CRT.

Purpose

To investigate the association between LA resynchronization and response to CRT.

Methods

In a prospective study of 171 heart failure patients with LBBB, myocardial strain was measured by speckle-tracking echocardiography, before and 6 months after CRT. As indicated by the white arrows in Figure 1, LA dyssynchrony was measured as the time delay between onset systolic stretch of the interatrial septum and the LA lateral wall. Response to CRT was defined as at least 15% reduction in left ventricular (LV) end systolic volume at 6 months follow up.

Results

119 (70%) patients responded to CRT. The panels in Figure 1 shows LA strain traces in a representative LBBB patient that did respond (upper panels), and a patient that did not respond (lower panels). The white arrows in the left panels indicate that both the responder and the non-responder had marked LA dyssynchrony before CRT (198 and 171 ms, respectively). However, after 6 months with CRT, there was recovery of LA synchrony only in the responder (time delay −40 ms), and still marked LA dyssynchrony of 191 ms in the non-responder (right panels).

Figure 2 confirms similar results for the whole study population: CRT response was associated with marked reduction of LA dyssynchrony (p=0.0001). In the CRT non-responders there was, however, only a modest, non-significant reduction of LA dyssynchrony.

Conclusions

Positive CRT response was associated with resynchronization of the left atrium. These findings suggest LA resynchronization as a potential additional target for CRT.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Institute for Surgical Research, Oslo University HospitalThe Intervention Centre, Oslo University Hospital

Left atrial mechanical dyssynchrony: an independent predictor of left ventricular reverse remodelling after cardiac resynchronization therapy

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): Institute for Chirurgical Research - Oslo University Hospital

Introduction

Left bundle branch block (LBBB) leads to left ventricular (LV) mechanical dyssynchrony. Since the left atrium (LA) and the left ventricle (LV) are anatomically connected, dyssynchronous LV contractions may be transmitted to the LA causing LA dyssynchrony and disturbed LA function.

Purpose

To investigate if LA dyssynchrony induced by LBBB predicts LV reverse remodelling after cardiac resynchronization therapy (CRT).

Methods

In a prospective study, myocardial strain was measured by speckle-tracking echocardiography in 171 heart failure patients with LBBB, before and 6 months after CRT. LA dyssynchrony was measured as the time delay between onset systolic stretch of the interatrial septum and the LA lateral wall (white arrows in Figure), and LV dyssynchrony as the time from onset septal shortening to onset lateral wall shortening. Septal flash was assessed visually. Response to CRT was defined as at least 15 % reduction in LV end systolic volume at 6 months follow up.

Results

The figure shows a representative LBBB patient with LA and LV dyssynchrony which was abolished by CRT. For the whole study population, LA dyssynchrony was 104 ± 77 ms (mean ± SD) before CRT, and decreased to 43 ± 70 ms (p < 0.0001) after CRT. There was a significant correlation between LA and LV dyssynchrony (r = 0.68, p < 0.0001).

LA dyssynchrony correlated with LV reverse remodelling after CRT (p = 0.009), and multivariable analysis revealed that LA dyssynchrony was an independent predictor of CRT response (β=-0.046, p = 0.04) when combined with septal flash, QRS duration and QRS morphology (Table).

Conclusions

Patients with LBBB had marked LA dyssynchrony which was attributed to direct LV-LA mechanical interaction. Furthermore, LA dyssynchrony was an independent predictor of LV reverse remodelling after CRT. These findings suggest that assessment of LA dyssynchrony should be part of the echocardiographic evaluation in patients with dyssynchronous heart failure. Abstract Figure.

Myocardial work still reflect function while strain simply measure deformation when afterload increases

Introduction

Global longitudinal strain is recommended by the European Society of Cardiology to detect subclinical left ventricular (LV) dysfunction, but is markedly load-dependent. Myocardial work was recently introduced as a clinical tool to study LV function by pressure-strain analysis. Since myocardial work incorporates afterload, it is assumed to be less afterload-dependent than strain, but the relationship with afterload is incompletely understood.

Hypothesis

Myocardial work is a better tool than strain, to measure myocardial function during elevated afterload.

Methods

In eleven anesthetized dogs, LV volume and longitudinal strain were measured by sonomicrometry, and pressure by micromanometry. Myocardial work was calculated by pressure-strain analysis. Additionally, stroke work was calculated as the area of the pressure-volume loop. Afterload was instantly increased by aortic constriction using a pneumatic cuff around the ascending aorta. Measurements were performed at baseline, during moderate- and marked afterload elevations.

Results

Table 1 summarizes the results. LV pressure (LVP) successively increased with moderate and marked afterload elevation, while longitudinal strain was successively reduced. Myocardial work and stroke work, on the other hand, increased with moderate afterload elevation, but was then reduced at marked afterload increase (Figure 1 and Table 1). Stroke volume and ejection fraction corresponded to strain and were reduced with afterload elevation.

Conclusions

Longitudinal strain and myocardial work have qualitatively different responses to increased afterload. While moderate changes in afterload cause reductions in strain that can be falsely interpreted as reductions in contractility, myocardial work increases as it incorporates the increased workload at moderately elevated afterload.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The Norwegian Health Association

Myocardial work comes to rescue when afterload-dependency of strain cause false positives

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): The Norwegian Health Association

Introduction

Global longitudinal strain (GLS) can detect subclinical left ventricular (LV) dysfunction. GLS measurement is therefore recommended when chemotherapy-induced cardiotoxicity can be suspected. A relative, percentage reduction in GLS ≥8% may indicate subclinical LV dysfunction induced by chemotherapy. Due to afterload-dependency, moderate increase in blood pressure has the potential to cause reductions in GLS beyond this threshold. However, myocardial work incorporates afterload, and may be used to omit false positive outcomes.

Purpose

To investigate if moderate increases in afterload cause clinically relevant changes in strain, and if myocardial work is more robust to such changes.

Methods

Twenty cancer patients (41 ± 14 years) undergoing chemotherapy and twenty healthy controls (49 ± 11 years, NS) were included. All participants were free from concomitant heart disease. GLS was measured by speckle-tracking echocardiography. Global myocardial work was calculated by pressure-strain analysis using a previously validated method to estimate LV pressure (LVP) non-invasively. Recordings were performed before and after 2 minute stress by handgrip.

Results

At baseline, patients had lower GLS (20.1 ± 1.1 vs 22.1 ± 2.5%, p < 0.01) and global myocardial work (1810 ± 203 vs 2051 ± 287 mmHg·%, p < 0.01) than controls. Stress test moderately increased systolic blood pressure, similar in both groups (116 ± 10 to 146 ± 17 mmHg in patients, and 118 ± 12 to 147 ± 21 mmHg in controls). This afterload-enhancement was associated with a decrease in GLS from 20.1 ± 1.1 to 18.4 ± 1.3% in patients, and from 22.1 ± 2.5 to 20.3 ± 2.5% in controls (both p < 0.01). Every second participant, eleven patients and nine controls, experienced a relative reduction in GLS >8%. In contrast, global myocardial work increased during the stress test from 1810 ± 203 to 2002 ± 281 mmHg·% in patients, and from 2051 ± 287 to 2292 ± 398 mmHg·% in controls (both p < 0.01). Figure 1 shows changes in GLS and myocardial work at moderate increase in afterload.

Conclusions

Moderate increase in afterload caused reductions in GLS sufficient to promote over-diagnosis of chemotherapy-induced cardiotoxicity. Global myocardial work has the potential to distinguish true subclinical LV dysfunction from afterload-induced decline in GLS.

Abstract Figure.

158 Myocardial work exposes afterload-dependent changes in strain

Funding Acknowledgements

Norwegian Health Association

Background

Global longitudinal strain (GLS) is used for detection of subclinical left ventricular (LV) dysfunction, for example when screening for chemotherapy-induced cardiotoxicity. A relative percentage reduction in GLS ≥8% is considered abnormal. However, as GLS is load-dependent, modest increases in afterload can potentially prove sufficient to cause clinical implication. In contrast, global myocardial work (GMW) which incorporates afterload, may be more accurate in detecting LV-dysfunction.

Purpose

We investigated the effect of increased afterload on GLS, and if GMW may be a more accurate parameter of myocardial function during increased afterload.

Methods

In 20 healthy individuals (age 49 ± 11 years (mean ± SD), 10 men), blood pressure was increased by a 3 minute arithmetic mental stress test. GLS was measured by speckle tracking echocardiography and LV ejection fraction (EF) by biplane Simpson. GMW was calculated from LV pressure-strain analysis using a non-invasive estimate for LV pressure (LVP).

Results

During the afterload-elevation, systolic blood pressure increased by 25 ± 16 mmHg (p < 0.01), and heart rate by 16 ± 13 bpm (p < 0.01). This was followed by a decrease in EF from 62 ± 5 to 59 ± 5% (p < 0.01) and GLS from 21.9 ± 2.2 to 20.8 ± 2.0% (p < 0.01). In contrast, GMW increased from 2052 ± 278 to 2382 ± 388 mmHg·% (p < 0.01). In 5 of 20 (25%) individuals, the relative percentage reduction of GLS was >8%, despite an increase in GMW. The figure shows an individual example during rest and afterload-elevation, where an increase in systolic blood pressure of 16 mmHg was associated with a 9% relative percentage reduction in GLS, but a small increase in GMW as illustrated by the loop areas.

Conclusions

This study demonstrated that a modest increase in afterload can result in significant reduction in GLS, that may lead to overdiagnosis of LV-dysfunction. GMW did not decrease, suggesting it has a better specificity in patients at risk for subclinical LV dysfunction. Future studies should investigate if GMW is more accurate than strain in detecting LV-dysfunction.

Abstract 158 Figure.

1231 Left atrial septal and lateral wall strains contain different pressure information: Utility in pulmonary hypertension

Funding Acknowledgements

South-Eastern Norway Regional Health Authority

Background

Reduced left atrial (LA) reservoir strain is a marker of elevated LA pressure. Thus it could be a potential non-invasive marker to differentiate pre- and post-capillary pulmonary hypertension (PH) as the latter is defined by elevated pulmonary capillary wedge pressure (PCWP) > 15 mmHg. However, in pre-capillary PH patients with elevated right atrial pressure (RAP), the atrial septal geometry may be abnormal. This could lead to lower regional LA septal strain, making LA lateral wall strain more accurately reflect PCWP.

Purpose

We investigated if LA lateral wall strain can differentiate between pre- and post-capillary PH, and how LA lateral wall strain and LA septal strain are both affected by elevated RAP in pre-capillary PH. Furthermore we investigated if LA septal strain can be used in pre-capillary PH patients to identify those with elevated RAP.

Methods

We analysed 63 patients with PH, 28 pre-capillary and 35 post-capillary, who underwent right heart catheterisation. Echocardiography was performed simultaneously with or within 24 hours of the invasive pressure measurements. Regional LA septal strain and lateral wall strain were measured from the apical four chamber view.

Results

Pulmonary artery pressure was 39.5 ± 11.1 mmHg (mean ± SD) in the pre-capillary PH patients and 37.0 ± 10.1 mmHg in the post-capillary PH patients (p = ns). Mean PCWP was 9.9 ± 2.5 mmHg and 24.5 ± 6.0 mmHg (p < 0.001), respectively.

LA lateral wall strain was significantly lower in patients with post-capillary PH compared to pre-capillary PH (11.9 ± 7.7% vs 26.6 ± 9.9%, p < 0.001) (Fig. a,b). At a cut-off value of 18.0%, LA lateral wall strain could predict elevated PCWP > 15 mmHg with AUC = 0.88, sensitivity = 85.7% and specificity = 76.3%.

In the 28 patients with pre-capillary PH, we classified mean RAP ≥ 10 mmHg as elevated and < 10 mmHg as normal. Seven of these patients had elevated RAP and showed significantly reduced LA septal strain compared to the 21 patients with normal RAP (13.0 ± 6.2% vs 22.1 ± 7.6%, p < 0.01). LA lateral wall strain showed no difference in these groups of pre-capillary PH patients (25.8 ± 10.1% vs 28.9 ± 9.4%) (Fig. c).

Conclusions

LA lateral wall strain can be used for differentiating between pre- and post-capillary PH. In addition, LA septal strain may be used in pre-capillary PH patients to identify those with elevated RAP.

Abstract 1231 Figure

P4368Estimation of pulmonary artery pressure from right atrial strain and tricuspid regurgitation velocity

Background

Systolic pulmonary artery pressure (SPAP) can be estimated non-invasively as the sum of indices for right atrial (RA) pressure and tricuspid regurgitation (TR) pressure gradient. Although echocardiographic evaluation of inferior vena cava diameter and collapsibility is currently being used to estimate RA pressure (IVC method), RA strain may be an alternative since atrial strain is related to atrial pressure.

Objective

We tested if RA strain by speckle tracking echocardiography can be used as a surrogate of mean RA pressure (RA strain method), and by adding the TR pressure gradient, be used to estimate SPAP.

Methods

We retrospectively analyzed 91 patients (mean age, 58 years) referred to right heart catheterization due to unexplained dyspnea or suspected pulmonary hypertension. Echocardiography was performed within 24 hours of the invasive procedure. RA reservoir strain was calculated from apical four-chamber view. SPAP was calculated as the sum of peak TR pressure gradient and estimated RA pressure by the IVC or RA strain methods.

Results

Right heart catheterization showed SPAP and mean RA pressures of 51±20 mmHg and 9±6 mmHg, respectively. RA reservoir strain was inversely correlated with mean RA pressure (r=−0.61, p<0.01). Thus, we set mean RA pressure as 5, 10 and 15 mmHg depending on high (≥25%), middle (10–25%) and low (≤10%) values of RA reservoir strain. As shown in the figure, both the RA strain and IVC methods when combined with peak TR velocity, provided good estimates of invasively measured SPAP.

Conclusions

RA strain provides a semiquantitative measure of RA pressure, which can be used in combination with peak TR velocity to estimate SPAP. This approach can be used as an alternative when the IVC method is not available in cases with poor subcostal window.

P2452Application of left atrial strain for differentiation between pre- and post-capillary pulmonary hypertension

Background

Pulmonary hypertension (PH) is classified as pre- or post-capillary PH, and pulmonary capillary wedge pressure (PCWP) >15 mmHg is used as criterion for post-capillary PH. Elevated left atrial (LA) pressure is associated with reduced LA reservoir strain. Thus, LA strain may potentially serve to differentiate between these diagnoses.

Objectives

This study tested the hypothesis that LA strain can be used as a noninvasive parameter to differentiate between pre- and post-capillary PH.

Methods

We analyzed 103 patients (mean age: 58 years, 51 female) referred to right heart catheterization due to unexplained dyspnea or suspected heart failure. Echocardiography was performed within 24 hours of the invasive procedure. Mean pulmonary artery pressure (PAP) was noninvasively estimated from tricuspid regurgitation (TR) velocity and inferior vena cava (IVC) diameter and collapsibility. LA reservoir strain was calculated from apical four-chamber view by speckle tracking echocardiography, and was feasible in 101 patients.

Results

Twenty-eight patients were invasively confirmed with pre-capillary PH and 43 patients with post-capillary PH. The remaining 32 patients had no PH. LA reservoir strain was significantly lower in patients with post-capillary PH than patients with pre-capillary PH (9.9±5.5% vs. 24.6±8.2%, p<0.01). At a cut-off value of 15.4%, LA reservoir strain could predict elevated PCWP >15 mmHg with AUC=0.88, sensitivity=84.8% and specificity=81.8%. As shown in the figure, echocardiography with LA reservoir strain correctly differentiated 82% of patients into pre- and post-capillary PH.

Conclusions

These results suggest that LA reservoir strain can be used to predict elevated PCWP, thus allowing discrimination between pre- and post-capillary PH.

P1480Left atrial strain improves estimation of left ventricular filling pressure

Background

The current algorithm in the 2016 recommendations for echocardiographic estimation of left ventricular filling pressure (LVFP) as normal or elevated, combines traditional indices of mitral inflow velocities, tissue Doppler, left atrial volume and tricuspid regurgitation velocity (Figure A). Some of the patients remain unclassified by this algorithm. Left atrial (LA) strain is a novel index that correlates well with LVFP and may improve estimation of LVFP in these patients.

Purpose

We tested if LA strain can improve estimation of LVFP for the patients that are unclassified by the 2016 algorithm.

Methods

We analyzed data from 100 patients who were referred to right heart catheterization due to unexplained dyspnea or suspected heart failure. Echocardiography was performed simultaneously with or within 24 hours of right heart catheterization. Pulmonary capillary wedge pressure (PCWP) was used as an estimate for LVFP and defined as elevated if above 12 mmHg. Elevated LVFP was first estimated using the 2016 algorithm. In patients who were unclassified by the algorithm due to conflicting indices or unattainable indices, LA strain was subsequently used to detect elevated LVFP using a cut-off found from ROC analysis of the whole cohort.

Results

Six patients were unclassified by the 2016 algorithm. The ROC analysis of all 100 patients showed that at an LA strain cut-off of above or below 16.2%, LVFP was correctly classified as normal or elevated, respectively, with a sensitivity of 83% and specificity of 88%. All 6 unclassified patients by the 2016 algorithm were correctly classified using the LA strain cut-off, effectively increasing the accuracy of the algorithm by 6 percentage points.

Conclusions

LA strain may have a role in non-invasive estimation of LVFP, particularly in patients who remain unclassified when using the conventional echocardiographic indices.

Acknowledgement/Funding

South-Eastern Norway Regional Health Authority

Validation of acute physiologic and chronic health evaluation II scoring system software developed at The Aga Khan University, Pakistan

Objective:

To assess the predictive performance of Acute Physiologic and Chronic Health Evaluation II (APACHE II) software available on the hospital intranet and analyze interrater reliability of calculating the APACHE II score by the gold standard manual method or automatically using the software.

Materials and Methods:

An expert scorer not involved in the data collection had calculated APACHE II score of 213 patients admitted to surgical Intensive Care Unit using the gold standard manual method for a previous study performed in the department. The same data were entered into the computer software available on the hospital intranet (http://intranet/apacheii) to recalculate the APACHE II score automatically along with the predicted mortality. Receiver operating characteristic curve (ROC), Hosmer-Lemeshow goodness-of-fit statistical test and Pearson's correlation coefficient was computed.

Results:

The 213 patients had an average APACHE II score of 17.20 ± 8.24, the overall mortality rate was 32.8% and standardized mortality ratio was 1.00. The area under the ROC curve of 0.827 was significantly >0.5 (P < 0.01) and had confidence interval of 0.77-0.88. The goodness-of-fit test showed a good calibration (H = 5.46, P = 0.71). Interrater reliability using Pearson's product moment correlations demonstrated a strong positive relationship between the computer and the manual expert scorer (r = 0.98, P = 0.0005).

Conclusion:

APACHE II software available on the hospital's intranet has satisfactory calibration and discrimination and interrater reliability is good when compared with the gold standard manual method.

Abstract P5-11-02: Radiation instigates EMT, CSC self renewal and pluripotency signal transduction in non-targeted (bystander) ERa+ and triple-negative breast cancer cells

Ascertaining radiation-induced bystander response in non-targeted tumor cells, particularly on variables pertaining to resistance, relapse and tumor progression, may escort significant clinical implications. Accordingly, in this study, we investigated the radiation induced alterations in factors that drive the epithelial-to-mesenchymal transition (EMT), cancer stem cells (CSCs) self-renewal capacity and pluripotency maintenance in non-targeted breast (ERa+ MCF-7 and triple-negative MDA-MB-468) adenocarcinoma cells. Co-cultures of non-targeted breast cancer cells with irradiated (5Gy) counterparts for 24h were assessed for transcriptional regulation of 93 stem cell related molecules using QPCR profiling. Radiation-induced alterations in the expression of ABCG2, E-Cadherin, N-Cadherin, MYC, Nanog and SOX2 in bystander MCF-7 and MDA-MB-468 were assessed using western blot analysis. Radiation profoundly increased the transcriptional activation of stem-cell related molecules in distant bystander ERα+ MCF-7 (70 genes) and in triple-negative MDA-MB-468 (82 genes) cells. Interestingly, 62 of 70 genes activated in MCF-7 and 81 of 82 genes in MDA-MB-468 showed significant (&gt;2 fold) upregulation. Evidently, radiation induced 66 genes (&gt;2 fold, 58 genes) in bystander breast cancer cells independent of their hormone status. Consistently, immunoblotting revealed increase in the expression of ABCG2, N-Cadherin, MYC, Nanog and SOX2 in both MCF7 and MDA-MB-468. Together, these data demonstrates that radiation activates the EMT, CSCs self-renewal and pluripotency maintaining factors in non-targeted bystander cells and could thus play an instrumental role in breast cancer relapse and progression.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-11-02.

Breastfeeding and cognitive development of children: assessment at one year of age

Breastfeeding is the fundamental component of child survival strategy. It significantly influences neurological development of children. The study was conducted to assess whether exclusive and prolonged breastfeeding improves children's cognitive development, including low birth weight (LBW) babies, in a developing country setting like Bangladesh. This observational study was done on a cohort of newborn infants who were discharged from the special care baby unit of Dhaka Shishu Hospital during January 2006 to December 2008 with proper counseling about exclusive and prolonged breastfeeding. Their neuro-developmental follow-up was started at 4 weeks postnatal age and continued at 3-monthly intervals up to 1 year of age. At each visit, cognitive development was assessed using the Bayley Scales of Infant Development (BSID II). Cognitive development was compared between the babies of exclusive vs. non exclusive breastfeeding, normal weight vs. low birth weight and male vs. female babies. A total of 105 cases were successfully followed-up during this period. Out of these 47(44.8%) babies were exclusively breastfed up to 6 month of age and 58(55.2%) were in nonexclusive group. Overall Psychomotor Development Index (PDI) was slightly more (108.40 ± 23.06 vs. 103.23 ± 19.87) in the exclusive breast fed babies in comparison to nonexclusive breast fed babies, but was significantly more in babies having birth weight >2.5 kg in comparison to those having birth weight of <2.5 kg. Other parameters of cognitive development were more or less same in both normal and LBW groups. Mental and motor development was same in both boys and girls. In behavior ratings, cooperation was significantly high (5.89 ± 2.54 vs. 4.71 ± 3.13, p=0.05) and vocalization (5.89 ± 1.07 vs. 4.58 ± 1.16) was also high, though not significant, in girls than boys.

Vasopressin for the management of catecholamine-resistant anaphylactic shock

Severe anaesthetic anaphylaxis is relatively uncommon. Oxygen, fluids and epinephrine are considered to be the mainstay for treatment of cardiovascular collapse and current guidelines for the management of anaphylaxis list only epinephrine as a vasopressor to use in the event of a cardiovascular collapse. Recently, evidence has emerged in the support of the use of vasopressin in cardiopulmonary resuscitation; it is also recommended for the treatment of ventricular fibrillation, septic shock and post-cardiopulmonary bypass distribution shock. Currently, there is no algorithm or guideline for the management of anaphylaxis that include the use of vasopressin. We report a 24-year-old woman who developed severe anaphylactic shock at induction of anaesthesia while undergoing laparoscopic cholecystectomy. Circulation shock was refractory to epinephrine and high doses of pure alpha-agonist phenylephrine and norepinephrine. Single intravenous dose of two units of vasopressin re-established normal circulation and blood pressure.

Purification and some properties of galectin-1 derived from water buffalo (Bubalus bubalis) brain

An increasing number of galectins have been found in various animal species, the most abundant of which is galectin-1. The purpose of the present study was to purify and characterize galectin-1 from buffalo brain. We purified the galectin using a combination of ammonium sulphate fractionation and affinity chromatography and the homogeneity was determined by both native polyacrylamide gel electrophoresis (PAGE) and denaturing SDS-PAGE. The molecular weight of the galectin as determined by SDS-PAGE under reducing conditions and by gel filtration column under native conditions was 13.8 and 24.5 kDa, respectively, suggesting a dimeric form of galectin. The most potent inhibitor of the galectin activity was lactose, giving complete inhibition of hemagglutination at 0.8 mM. Galectin showed higher specificity towards human blood group A. Free thiol groups were estimated at a molar ratio of 2.9. The effects of alkylating reagents (iodoacetate and iodoacetamide) on saccharide binding of the galectin were studied. Both alkylating reagents significantly inactivated the activity of the galectin within 20 min. The temperature and pH stability of the galectin were determined. Our findings based on physico-chemical properties, carbohydrate and blood group specificities of the galectin may have future implications in biological and clinical applications.

Comparison of ketorolac with morphine for intra-operative analgesia in patients undergoing total abdominal hysterectomy

OBJECTIVE

To compare ketorolac 0.35 mg x kg(-1) with morphine 0.1 mg x kg(-1) for hemodynamic stability, efficacy of analgesia and incidence of side effects in patients undergoing elective total abdominal hysterectomy.

METHODS

Fifty ASA I and II patients, were enrolled in a prospective, randomized and double blind study. They were divided in two equal groups. Group K received Inj. Ketorolac 0.35 mg x kg(-1) while group M received Inj. Morphine 0.1 mg x kg(-1) 5 minutes before induction of anaesthesia. Hemodynamic responses to laryngoscopy, endotracheal intubation, and surgical incision were noted.

RESULTS

Data was entered and analysis was done using SPSS version 10.0. Student-t test and comparison of proportions were done where required. ANOVA was done and a p-value of <0.05 was considered statistically significant. There was a significant rise in heart rate, systolic, diastolic and mean arterial pressure in ketorolac group (K) as compared to baseline values at points of endotracheal intubation and surgical incision. Patients in Morphine group (M) showed a significant increase in heart rate only. There was no statistically significant difference between the two groups for supplemental analgesia requirement intraoperatively and postoperatively. Complications seen with group K were increased surgical wound bleeding in 2 patients (8%), nausea and vomiting in 4 patients (16%) while in group M there was nausea and vomiting in 5 patients (20%), and respiratory depression in 1 patient (4%).

CONCLUSION

Although hemodynamic stability at points of painful stimulation was lower in patients given ketorolac as compared to morphine, Ketorolac has a place in the intraoperative pain relief in Pakistan and other developing countries where availability of powerful narcotics is erratic.

Use of stents in the palliative treatment of malignant gastric outlet and duodenal obstruction

AIM

To evaluate the efficacy of stenting in the palliation of malignant duodenal and gastric outlet obstruction.

MATERIALS AND METHODS

We retrospectively reviewed our series of patients who underwent stenting for malignant upper gastrointestinal obstruction between March 1998 and December 1999. From January 2000 data have been acquired prospectively. Our series comprises 21 stents successfully deployed in 15 patients.

RESULTS

The technical and clinical success was 93% (14/15 patients). One patient required endoscopic negotiation of recurrent gastric carcinoma at the gastrojejunostomy site after failure to cross the lesion fluroscopically. Two patients required re-intervention 2 and 5 weeks after initial stent placement, for migration and ingrowth respectively. Eighteen stents were placed transorally, two stents transhepatically and one via a transgastric approach. Early complications (pain < 3 days) occurred in two patients (13%) and late complications (ingrowth, overgrowth and migration) occurred in three patients (20%). The median survival was 2.4 months (range 2-4 months).

CONCLUSION

Stenting provides a less invasive palliative option than surgery with the advantage of lower morbidity and complication rates. It has the advantage of high technical and clinical success rates facilitated by alternative routes of access into the upper gastrointestinal tract via transgastric and transhepatic routes in addition to the traditional peroral route.

Success and limitations of a naked plasmid transfection protocol for keratinocyte growth factor-1 to enhance cutaneous wound healing

Our group and others have previously reported enhancement of cutaneous wound healing following the transfection of tissue with plasmid vectors expressing the DNA for growth factors. In these experiments, growth factor treated animals were usually compared to animals treated with control plasmid vector. To achieve consistent transfection, high DNA plasmid load and repeated penetrations of the wound by needle or gene gun were required. In the current experiments, we assessed the effect of the plasmid load and repeated tissue penetrations on wound healing of excisional wounds in diabetic C57 mice. Animals received 5 mm excisional wounds, and were assigned to the following groups, no treatment, phosphate buffered saline solution injections, and plasmid vector injection with and without the keratinocyte growth factor-1 gene. Intradermal injections of 100 microg plasmid were given adjacent to the wounds at days 1-5, 7 and 11. At day 9, wound closure was more advanced in keratinocyte growth factor-1 treated animals compared to those treated with control plasmid. But a detrimental effect of the DNA plasmid injection was evident from a comparison of the DNA control group versus the non-injected group. Therefore, the challenge for developing an effective system for the enhancement of wound healing lies in improving transfection efficiency.

Dopamine induced protein damage in mitochondrial-synaptosomal fraction of rat brain

Dopamine during in vitro oxidation induced covalent cross-linking of membrane proteins in rat brain crude mitochondrial-synaptosomal fraction. The process is not inhibited by hydroxyl radical scavengers, lipid soluble anti-oxidants, metal-chelator or catalase, but reduced glutathione produced a dramatic inhibition of cross-linking. The protein cross-linking mediated by dopamine is not associated with any detectable membrane lipid peroxidation but significant formation of protein bound quinone takes place during incubation. Our results indicate that reactive quinones rather than oxygen free radicals are involved in dopamine induced protein cross-linking in rat brain membrane fraction.

Anatomical variations of internal jugular vein as seen by "Site Rite II" ultrasound machine--an initial experience in Pakistani population

OBJECTIVE

To determine the anatomical variations of the internal jugular vein (IJV) in Pakistani adult population with the help of Site Rite II ultrasound machine.

MATERIAL AND METHOD

The right IJV relation to the carotid artery was visualized at four different landmarks (angle of the mandible, thyroid cartilage, cricoid cartilage, and the supraclavicular area). Size of IJV in comparison to carotid artery was also seen.

RESULTS

In 49 cases the IJV was found in aberrant relation to carotid artery at the angle of the mandible (p value < 0.05), 22 at the thyroid cartilage, 20 at the cricoid cartilage, and 46 at the supraclavicular area (p value < 0.05). In 93% of cases the IJV was found to be larger than the carotid artery.

CONCLUSION

Care should be taken while cannulating IJV at the angle of the mandible and supra clavicular area by external landmark guided technique. Ultrasound guided technique should be used in every anticipated difficult case.

Uric acid mediates photodynamic inactivation of caprine alpha-2-macroglobulin

Uric acid (2,6,8 trioxopurine), the end product of purine metabolism in mammalian systems, has shown a wide range of antioxidant properties including scavenging of hydroxyl radical and singlet oxygen. In this study we show that in the presence of visible light, uric acid disrupted caprine alpha-2-macroglobulin (alpha(2) M) structure and antiproteolytic function in vitro. Proteinase cleaves the bait region of caprine inhibitor inducing major conformational changes and entrapping the enzyme within its molecular cage. In contrast to native alpha(2) M, modified antiproteinase lost half of its antiproteolytic potential within 4 hours of uric acid exposure. The changes in uv-absorption spectra of the treated protein suggested possible spatial rearrangement of subunits or conformational change. Analysis of the mechanism by which alpha(2) M was inactivated revealed that the process was dependent on generation of superoxide anion and hydrogen peroxide. Our findings suggest that antiproteolytic activity of caprine alpha(2) M could be compromised via oxidative modification mediated by uric acid. Moreover, low concentrations of alpha(2) M were found to stimulate superoxide production by some unknown mechanism.

Recommendations for water supply in arsenic mitigation: a case study from Bangladesh

Arsenic problems have been observed in several countries around the world. The challenges of arsenic mitigation are more difficult for developing and poor countries due to resource and other limitations. Bangladesh is experiencing the worst arsenic problem in the world, as about 30 million people are possibly drinking arsenic contaminated water. Lack of knowledge has hampered the mitigation initiatives. This paper presents experience gained during an action research on water supply in arsenic mitigation in rural Singair, Bangladesh. The mitigation has been implemented there through integrated research and development of appropriate water supply options and its use through community participation. Political leaders and women played key roles in the success of the mitigation. More than one option for safe water has been developed and/or identified. The main recommendations include: integration of screening of tubewells and supply of safe water, research on technological and social aspects, community, women and local government participation, education and training of all stakeholders, immediate and appropriate use of the available knowledge, links between intermediate/immediate and long term investment, effective coordination and immediate attention by health, nutrition, agriculture, education, and other programs to this arsenic issue.

Complications of endotracheal intubation in mechanically ventilated patients in a general intensive care unit

During a period of one year, 126 patients were prospectively audited to analyse complications of endotracheal intubation in a general intensive care unit setting. A total of 62 complications were observed in 48 patients. The most frequent complications during intubation were hypotension and bradycardia. The blockage of endotracheal tubes significantly increased with the duration of intubation. Sore throat was the commonest (22%) complication following extubation. Other complications like stridor and ulceration of mouth and lips which followed extubation were not related to the duration of intubation.

A crosslinked tetrameric alpha 2M that binds but incompletely entraps trypsin

A crosslinked preparation of alpha-2-macroglobulin was obtained by treatment of the purified human plasma inhibitor with glutaraldehyde at low temperature. The preparation migrated as a 780 KDa polypeptide in SDS-PAGE and with mobility comparable with that of trypsinized native alpha-2-macroglobulin under nondenaturing conditions. Trypsinization of the glutaraldehyde treated alpha-2-macroglobulin further increased its electrophoretic mobility in non-denaturing gels and resulted in the association of the proteinase with the crosslinked inhibitor. Trypsin associated with crosslinked alpha-2-macroglobulin, unlike that associated with native inhibitor was incompletely protected from soybean trypsin inhibition.

Total intravenous anaesthesia with propofol and buprenorphine

A combination of propofol infusion and two bolus doses of buprenorphine, 2.5 or 5.0 micrograms/kg were evaluated in a total intravenous anaesthesia technique in 36 patients of ASA grade 1 or 2 undergoing cholecystectomy. Additional boluses of propofol were given intravenously if needed. Systolic blood pressure after tracheal intubation increased significantly only in those who received the smaller dose of buprenorphine. Patients in both groups remained haemodynamically stable throughout surgery with minimal side effects. Recovery was fast even with prolonged infusions and without major side effects. No patient reported awareness on postoperative questioning.

Effects of nitrofurans on adrenal cortical tissue in chickens

In chicken adrenal glands, aspartate transaminase (AST) activity is concentrated in the adrenal cortical cells. Administration of a bolus dose of furazolidone (200 mg/kg) to the birds produced a decrease in AST activity in the adrenal glands and a general disorganization in the ultrastructure of the adrenal cortical cells. Many adrenal cortical mitochondria appeared to be moribund, being swollen, without cristae or apparently empty. These effects preceded atrophy of the adrenal cortical tissue, which was most marked in the central part of the adrenal glands. The atrophy was still present after 12 weeks, and it is therefore suggested that nitrofurans may be useful in the treatment of Cushing's disease in other animal species. When furazolidone or furaltadone was given in the diet at therapeutic levels, blebs of an electron-dense substance developed in adrenal cortical mitochondria and AST activity in the adrenal glands was reduced. These effects were found to be reversible, and the treatments did not produce atrophy of the adrenal cortical tissue.

Renal and mammary excretion of sulfadimidine in buffaloes

The renal and mammary excretion of sulfadimidine was investigated in 8 lactating buffaloes after intravenous administration. The results showed that sulfadimidine was bound to the proteins in plasma (39--59 per cent) and milk (5.5 per cent). The renal handling of sulfadimidine was influenced by the variations in the urinary pH and the concentration of non-protein-bound drug. From the results it is concluded that glomerular filtration, back diffusion and active tubular secretion are involved in the renal handling of sulfadimidine in buffaloes. The results of mammary excretion showed that sulfadimidine is excreted into milk of buffaloes in concentration lower than in plasma. The ratio between the concentration of sulfadimidine in milk and plasma increases when the pH of milk increases. The results are consistant with the theory that drugs are excreted through the mammary gland by passive diffusion.