Undernutrition in young children with congenital heart disease undergoing cardiac surgery in a low-income environment

BACKGROUND

Malnutrition (undernutrition) in children with congenital disease (CHD) is a notable concern, with preoperative and persistent growth failure post-cardiac surgery contributing to poorer outcomes. Poor growth in children with CHD in low-income environments is exacerbated by feeding difficulties, poverty, delayed diagnosis, and late corrective surgery. This study describes and compares the growth of young children with CHD undergoing cardiac surgery in central South Africa from before to 6-months after cardiac surgery.

METHODS

Children 30 months and younger, with their mothers, were included in this prospective observational descriptive study. Weight- height-, and head circumference-for-age z-scores were used to identify children who were underweight, stunted and microcephalic. Z-scores for growth indices were compared from baseline to 3-months and 6-months post-cardiac surgery. Changes in growth over time were calculated using a 95% confidence interval on the difference between means. Linear regression was used to determine the association between growth and development, health-related quality of life and parenting stress respectively.

RESULTS

Forty mother-child pairs were included at baseline. Most children (n = 30) had moderate disease severity, with eight children having cyanotic defects. A quarter of the children had Down syndrome (DS). Twenty-eight children underwent corrective cardiac surgery at a median age of 7.4 months. Most children (n = 27) were underweight before cardiac surgery [mean z-score - 2.5 (±1.5)], and many (n = 18) were stunted [mean z-score - 2.2 (±2.5)]. A quarter (n = 10) of the children had feeding difficulties. By 6-months post-cardiac surgery there were significant improvements in weight (p = 0.04) and head circumference (p = 0.02), but complete catch-up growth had not yet occurred. Malnutrition (undernutrition) was strongly associated (p = 0.04) with poorer motor development [Mean Bayley-III motor score 79.5 (±17.5)] before cardiac surgery. Growth in children with cyanotic and acyanotic defects, and those with and without DS were comparable.

CONCLUSION

Malnutrition (undernutrition) is common in children with CHD in central South Africa, a low-income environment, both before and after cardiac surgery, and is associated with poor motor development before cardiac surgery. A diagnosis of CHD warrants regular growth monitoring and assessment of feeding ability. Early referral for nutritional support and speech therapy will improve growth outcomes.

Macroscopic electrical propagation in the guinea pig urinary bladder

There is little knowledge about macroscopic electrical propagation in the wall of the urinary bladder. Recording simultaneously from a large number of extracellular electrodes is one technology that could be used to study the patterns of macroscopic electrical propagations. The urinary bladders from 14 guinea pigs were isolated and placed in an organ bath. A 16 × 4-electrode array was positioned at various sites on the serosal bladder surface, and recordings were performed at different intravesical volumes. In four experiments, carbachol (CCH; 10(-6) M), nifedipine (10 mM), or tetrodotoxin (TTX; 10(-6) M) was added to the superfusing fluid. After the experiments, the extracellular signals were analyzed and propagation maps were constructed. Electrical waves were detected at all sites on the bladder surface and propagated for a limited distance before terminating spontaneously. The majority of waves (>90%) propagated in the axial direction (i.e., from dome to base or vice versa). An increase in vesicle volume significantly decreased the conduction velocity (from 4.9 ± 1.5 to 2.7 ± 0.7 cm/s; P < 0.05). CCH increased, nifedipine decreased, while TTX had little effect on electrical activities. In addition, a new electrical phenomenon, termed a "patch," was discovered whereby a simultaneous electrical deflection was detected across an area of the bladder surface. Two types of electrical activities were detected on the bladder surface: 1) electrical waves propagating preferentially in the axial direction and 2) electrical patches. The propagating electrical waves could form the basis for local spontaneous contractions in the bladder during the filling phase.

Aberrations in the epidermal growth factor receptor gene in 958 patients with diverse advanced tumors: implications for therapy

BACKGROUND

Epidermal growth factor receptor (EGFR) mutations are associated with the response to EGFR inhibitors in patients with non-small-cell lung cancer (NSCLC). We sought to investigate EGFR aberrations in patients with diverse advanced cancers.

PATIENTS AND METHODS

Patients referred to the phase I clinic were evaluated for the presence of EGFR mutations and response to therapy.

RESULTS

EGFR aberrations were detected in 34 of 958 patients (3.5%). Though EGFR mutations were most frequent in NSCLC (21 of 131, 16%), they were also present in a variety of other solid tumors (13 of 827 patients, 1.6%) including adrenocortical (1/10 patients), skin (1/24), breast (1/55), carcinoid (1/8), cholangiocarcinoma (1/20), head and neck (1/61), ovarian (1/84), parathyroid (1/1), salivary gland (1/20), renal (1/17), sarcoma (2/38), and thymic carcinomas (1/7). Of the 13 EGFR aberration-positive non-NSCLC patients (median number of prior systemic therapies = 3), 6 had treatment with an EGFR inhibitor. Two patients (diagnosis = parathyroid tumor and basal cell carcinoma) achieved stable disease (SD), lasting 6 and 7 months, respectively.

CONCLUSION

We found EGFR aberrations in 1.6% of a large group of patients with diverse tumors other than NSCLC, and treatment with an EGFR inhibitor could be associated with prolonged SD.

Risk of serious toxicity in 1181 patients treated in phase I clinical trials of predominantly targeted anticancer drugs: the M. D. Anderson Cancer Center experience

BACKGROUND

This study assessed toxicity in advanced cancer patients treated in a phase I clinic that focuses on targeted agents.

PATIENTS AND METHODS

An analysis of database records of 1181 consecutive patients with advanced cancer who were treated in the phase I program starting 1 January 2006 was carried out.

RESULTS

All patients were treated on at least 1 of the 82 phase I clinical trials. Overall, 56 trials (68.3%) had only targeted agents, 13 (15.9%) only cytotoxics, and 13 (15.9%) targeted and cytotoxic agents. Rates of grade 3 and 4 toxicity that were at least possibly drug related were 7.1% and 3.2%, respectively, and 5 of the 1181 patients (0.4%) died from toxicity that was at least possibly drug related. The most common grade 3 or more toxic effects were neutropenia, thrombocytopenia, anemia, dehydration, infection, altered mental status, bleeding, vomiting, nausea, and diarrhea. Eastern Cooperative Oncology Group (ECOG) performance status greater than zero and use of a cytotoxic agent were selected as independent factors associated with serious toxicity.

CONCLUSION

Phase I trials of primarily targeted agents showed low rates of toxicity, with 10.3% of patients experiencing grade 3 or 4 toxicity and a 0.4% rate of death, at least possibly drug related.

Functional reentry and circus movement arrhythmias in the small intestine of normal and diabetic rats

In a few recent studies, the presence of arrhythmias based on reentry and circus movement of the slow wave have been shown to occur in normal and diseased stomachs. To date, however, reentry has not been demonstrated before in any other part of the gastrointestinal system. No animals had to be killed for this study. Use was made of materials obtained during the course of another study in which 11 rats were treated with streptozotocin and housed with age-matched controls. After 3 and 7 mo, segments of duodenum, jejunum, and ileum were isolated and positioned in a tissue bath. Slow wave propagation was recorded with 121 extracellular electrodes. After the experiment, the propagation of the slow waves was reconstructed. In 10 of a total of 66 intestinal segments (15%), a circus movement of the slow wave was detected. These reentries were seen in control (n = 2) as well as in 3-mo (n = 2) and 7-mo (n = 6) diabetic rats. Local conduction velocities and beat-to-beat intervals during the reentries were measured (0.42 ± 0.15 and 3.03 ± 0.67 cm/s, respectively) leading to a wavelength of 1.3 ± 0.5 cm and a circuit diameter of 4.1 ± 1.5 mm. This is the first demonstration of a reentrant arrhythmia in the small intestine of control and diabetic rats. Calculations of the size of the circuits indicate that they are small enough to fit inside the intestinal wall. Extrapolation based on measured velocities and rates indicate that reentrant arrhythmias are also possible in the distal small intestine of larger animals including humans.

Slow wave propagation and plasticity of interstitial cells of Cajal in the small intestine of diabetic rats

The number of myenteric interstitial cells of Cajal (ICC-MY), responsible for the generation and propagation of the slow wave in the small intestine, has been shown to decrease in diabetes, suggesting impairment of slow-wave (SW) propagation and related motility. To date, however, this expected decrease in SW propagation has neither been recorded nor analysed. Eleven rats were treated with streptozotocin and housed in pairs with 11 age-matched control animals. After 3 or 7 months, segments of duodenum, jejunum and ileum were isolated and divided into two parts. One part was processed for immediate freezing, cryosectioning and immunoprobing using anti-c-Kit antibody to quantify ICC-MY. The second part was superfused in a tissue bath, and SW propagation was recorded with 121 extracellular electrodes. In addition, a cellular automaton was developed to study the effects of increasing the number of inactive cells on overall propagation. The number of ICC-MY was significantly reduced after 3 months of diabetes, but rebounded to control levels after 7 months of diabetes. Slow-wave frequencies, velocities and extracellular amplitudes were unchanged at any stage of diabetes. The cellular automaton showed that SW velocity was not linearly related to the number of inactive cells. The depletion of ICC-MY is not as severe as is often assumed and in fact may rebound after some time. In addition, at least in the streptozotocin model, the initial reduction in ICC-MY is not enough to affect SW propagation. Diabetic intestinal dysfunction may therefore be more affected by impairments of other systems, such as the enteric system or the muscle cells.

Patterns of electrical propagation in the intact pregnant guinea pig uterus

Previous studies have reported on propagation of individual spikes in isolated segments of the pregnant uterus, but there is no information on patterns of spike propagation in the intact organ. There is also no information on propagation of myometrial burst. The aim of this study was to record, at high resolution, patterns of propagation of electrical activities in the pregnant uterus. Sixteen timed-pregnant guinea pigs were euthanized at term, and their uteruses isolated. Fetuses were removed and replaced by an equal amount of Tyrode. A 240-electrode array was positioned at various locations along the organ, all signals were recorded simultaneously, and the electrical propagations were reconstructed. In the intact pregnant uterus at term, spikes propagated with high velocity in longitudinal (6.8 +/- 2.4 cm/s) and slower velocity in circular direction (2.8 +/- 1.0 cm/s; P < 0.01). Direction of propagation and frequency of activity were highly variable but showed similar patterns at the ovary or cervical end and along the anterior, posterior, and antimesometrial borders. Along mesometrium, spike propagation was sparse and fractionated. Migration of burst (0.6 +/- 0.4 cm/s) was significantly much slower than that of individual spikes (P < 0.001). Initial burst activity was located at variable locations along the ovarial end of the antimesometrial border, while the latest excitation occurred at the cervical end (1.2 +/- 0.9 min). In conclusion, high resolution electrical mapping of the intact pregnant uterus reveals fundamental properties in spatial and temporal patterns of spike and burst propagation that determine the contraction of the organ.

Spatial determination of successive spikes in the isolated cat duodenum

In seven isolated segments of the feline duodenum, the timings of all spikes and the locations of all spike patches that occurred after 12-16 successive slow waves were analysed. Simultaneous recordings were performed during 1-min periods using 240 extracellular electrodes (24 x 10 array; interelectrode distance 2 mm) positioned onto the serosal surface. In all seven preparations, spikes always occurred during the first half of the slow wave cycle. From preparation to preparation, and within 1-min periods in each preparation, there was limited variation in the spike-spike intervals, in the times between the spikes and the preceding slow wave and in the number of spikes at each electrode site. In contrast, the number of electrode sites that recorded spikes and the number of spike patches both showed great variability between preparations and sometimes within a single preparation. In addition, the location of spikes and spike patches was not random but was significantly concentrated in certain areas, often located along the anti-mesenteric border, while other sites showed little or no spike activity. In conclusion, spikes and spike patches tend to occur significantly in some areas and not in others. This spatial heterogeneity will play a role in intestinal motility.

Anisotropic propagation in the small intestine

Abstract Measuring propagation anisotropy may help in determining the tissue layers involved in the propagation of electrical impulses in the intestine. We used 240 extracellular electrograms recorded from the isolated feline duodenum. The conduction velocities of slow waves and of individual spikes were measured from their site of origin into all directions. Both slow waves and spikes propagate anisotropically in the small intestine but in different directions and to a different degree. Slow waves propagated anisotropically faster in the circumferential (1.7 +/- 0.8 cm s(-1)) than in the axial direction (1.3 +/- 0.5 cm s(-1); P < 0.001). Spikes, on the other hand, propagated faster in the longitudinal direction (7.8 +/- 4.5 cm s(-1)) than in the circumferential direction (3.3 +/- 4.3 cm s(-1); P < 0.001). Furthermore, the average conduction velocity of spikes (6.3 +/- 4.5 cm s(-1)) was significantly higher than that of slow waves (1.5 +/- 1.1 cm s(-1); P < 0.001). The anisotropic propagation of spikes supports the argument that these propagate in the longitudinal muscle layer. The anisotropic propagation of slow waves may be the result of the interaction between the myenteric layer of interstitial cells of Cajal and their electrotonic connection to both the longitudinal and the circular muscle layer.

Two-dimensional high-resolution motility mapping in the isolated feline duodenum: methodology and initial results

Several types of electrical events occur in the small intestine but their spatial and temporal contributions to overall motility are not clear. In order to quantify local motility in greater detail, a new technique of recording and analysing movements at multiple sites was developed. Use was made of isolated segments of feline duodenum superfused in a tissue bath. Multiple marker dots (20-75) were placed on the serosal surface by applying fine spots of candle soot in rectangular arrays (1-2 mm dot separation). A digital video camera was used to record spontaneous movements of the dots for periods of 10-30 min. After each experiment, 4-6 periods (10-60 s each) of video frames were transferred to a computer (25 fps, 720 x 576 pixels) and the movements of the dots was tracked every 40 ms using custom-made software. Initial results (eight experiments) show that spontaneous motility is remarkably variable, both in space and time. Three types of movement could be discerned: (i) periodic, rolling or pendular movements, with a frequency of approximately 15 min-1 occurring predominantly in the longitudinal direction; (ii) twitches, wherein a subset of dots were suddenly displaced longitudinally; and (iii) drifts of most of the dots in a circular or oblique direction. All three types of movement occurred throughout every recording session although their relative magnitudes differed greatly from moment to moment. Occasionally, it was possible to detect propagated 'contractions' with an apparent velocity of 10 mm s(-1). Immobilizing the preparation at one point by inserting a needle through the middle of the array of markers had a negligible effect on the displacements, whereas application of verapamil (10(-5) mol L(-1)) reduced or abolished motility. In summary, we present a new technique to map in detail two-dimensional motility at the surface of the intestine. Initial results seem to suggest that motility at the serosal surface is not uniform and highly anisotropic.

The spatial behaviour of spike patches in the feline gastroduodenal junction in vitro

In the isolated feline gastroduodenal region, the spatial propagation of slow waves and of individual spikes was reconstructed. Recordings were performed simultaneously from 240 extracellular electrodes positioned on the serosal surface across the junction. Results from nine experiments (22 slow waves) showed that the slow wave never propagated across the gastroduodenal region and that this block was due to the presence of a zone of quiescence caudal to the pylorus. In contrast, spikes (n=155) were able to propagate into the quiescent zone, either from the antrum (15.4%) or from the duodenum (34.0%) and occasionally, were able to propagate from one organ to the other (10.9%). However, in all cases, spike conduction was self-limited and activated a local area termed a 'patch'. The length of the patches located in the gastroduodenal region was significantly longer than in the rest of the duodenum (20.2 mm +/- 9. 7 vs. 9.5 mm +/- 3.2; P < 0.001) indicating a possible enhancement of spike propagation in this region. In conclusion, in spite of the total conduction block for slow waves, individual spikes are able to propagate across the gastroduodenal region, albeit in self-limited areas or 'patches'. These spike patches could form the building blocks for gastroduodenal coordination.

Noninvasive estimation of pulmonary artery diastolic pressure in patients with tricuspid regurgitation by Doppler echocardiography

OBJECTIVES

The purpose of this study was to determine whether Doppler echocardiographic assessment of right ventricular pressure at the time of pulmonary valve opening could predict pulmonary artery diastolic pressure.

BACKGROUND

Doppler echocardiography has been used to estimate right ventricular systolic pressure noninvasively. Because right ventricular and pulmonary artery diastolic pressure are equal at the time of pulmonary valve opening, Doppler echocardiographic estimation of right ventricular pressure at this point might provide an estimate of pulmonary artery diastolic pressure.

METHODS

We studied 31 patients who underwent right heart catheterization and had tricuspid regurgitation. Pulmonary flow velocity was recorded by pulsed wave Doppler echocardiography, and tricuspid regurgitant velocity was recorded by continuous wave Doppler echocardiography. The time of pulmonary valve opening was determined as the onset of systolic flow in the pulmonary artery. Tricuspid velocity at the time of pulmonary valve opening was measured by superimposing the interval between the onset of the QRS complex on the ECG and the onset of pulmonary flow on the tricuspid regurgitant envelope. The tricuspid gradient at this instant was calculated from the measured tricuspid velocity using the Bernoulli equation. This gradient was compared to the pulmonary artery diastolic pressure obtained by right heart catheterization.

MEASUREMENTS AND RESULTS

The pressure gradient between the right atrium and right ventricle obtained at the time of pulmonary valve opening ranged from 9 to 31 mm Hg (mean, 19+/-5) and correlated closely with invasively measured pulmonary artery diastolic pressure (range, 9 to 36 mm Hg; mean, 21+/-7 mm Hg; r = 0.92; SEE, 1.9 mm Hg).

CONCLUSION

Doppler echocardiographic measurement of right ventricular pressure at the time of pulmonary valve opening is a reliable noninvasive method for estimating pulmonary diastolic pressure.

The effects of oxytocin on the pattern of electrical propagation in the isolated pregnant uterus of the rat

In the isolated pregnant myometrium of the rat, the pattern of propagation was investigated by recording simultaneously from 240 different extracellular sites while the contraction of the tissue was recorded isometrically. Analysis of all recorded electrograms allowed the two-dimensional spread of activity in the myometrium to be reconstructed. From these activation maps, the conduction velocities were measured in the longitudinal, oblique and transversal directions. At low concentrations (10(-9 )and 5x10(-9) M), oxytocin significantly increased the frequency and duration of electrical bursts and the average spike intervals, without affecting the homogeneity of action potential propagation, concomitant with a significant increase in the amplitude of contractions. At high concentrations (10(-8) and 5x10(-8) M), oxytocin induced conduction blocks and the size of inexcitable areas was increased, concomitantly with an increase in muscle contractures. In contrast, the conduction velocities in the longitudinal, oblique and circular directions were not influenced by oxytocin at any concentrations.

The slow wave does not propagate across the gastroduodenal junction in the isolated feline preparation

Detailed spatial analysis of the propagation of individual slow waves was performed in the isolated gastroduodenal preparation of the cat. Use was made of a system that allowed the simultaneous recordings from 240 extracellular electrodes, which were positioned across the gastroduodenal region. Reconstructions of the spread of propagation (n = 31) revealed that (a) the antral slow wave never propagated into the duodenum but was blocked at the pyloric ring, (b) the duodenal slow wave did not activate the antral tissue, and (c) a quiescent zone in which no slow waves could be recorded was always present at the most proximal part of the duodenum immediately distal to the pyloric ring. Furthermore, phase density distributions of duodenal cycles revealed that antral activity had no influence on the rate of discharge of duodenal pacemakers. Light microscopic study of sections of the duodenum close to the pyloric ring and further away did not show any structural differences between the quiescent zone and the active areas. In conclusion, slow waves do not propagate across the gastroduodenal junction in the isolated feline preparation and therefore do not seem to play a role in the electro-mechanical integration between the stomach and the duodenum.

Studies of resistance to anticoccidials in Eimeria field isolates and pure Eimeria strains

Ten Eimeria field isolates from North Germany were studied in battery tests for sensitivity to selected anticoccidials. A high percentage of the Eimeria field isolates (9 out of 10) showed resistance to anticoccidials, mostly multiple resistance. Partial or complete resistance to maduramicin was found in 7 field isolates, to monensin in 6, to salinomycin in 5, to nicarbazin in 8, to halofuginone in 7, to robenidine and toltrazuril in 1, and to diclazuril in 2 field isolates. Multiple resistance had developed in 7 of the 10 isolates. Cross-resistance between maduramicin, monensin, and salinomycin occurred in 5 Eimeria isolates. One isolate showed cross-resistance between diclazuril and toltrazuril. From the resistant isolates 15 pure E. acerculina and 5 pure E. brunetti strains were obtained by single oocyst infections. Seven of the E. acerculina and 4 of the E. brunetti strains showed resistance or partial resistance that was also present in the original isolate. Ten of 11 resistant strains were multiply resistant.

High resolution electrical mapping in the gastrointestinal system: initial results

High resolution electrical mapping in the gastrointestinal system entails recording from a large number of extracellular electrodes simultaneously. It allows the collection of signals from 240 individual sites which are then amplified, filtered, digitized, multiplexed and stored on tape. After recording, periods of interest can be analysed and the original sequence of activity reconstructed. This technology, originally developed to study normal rhythms and abnormal dysrhythmias in the heart, has been modified to allow recordings from the gastrointestinal tract. In this report, initial results are presented describing the origin and propagation of the slow wave in the isolated stomach and the isolated duodenum in the cat. These results show that in both organs it not uncommon to have more than one focus active during a single cycle. The conduction of slow waves from such a multiple pacemaker environment can become quite complex, and this may play a role in determining the contractile pattern in these organs.