Technical note: Energy dependence of the Gafchromic EBT4 film: Dose-response curves for 70 kV, 6 MV, 6 MV FFF, 10 MV FFF, and 15 MV x-ray beams

BACKGROUND

EBT4 was newly released for radiotherapy quality assurance to improve the signal-to-noise ratio in radiochromic film dosimetry. It is important to know its dose-response characteristics before its use in the clinic.

PURPOSE

This study aims to investigate and compare the dose-response curves of the Gafchromic EBT4 film for megavoltage and kilovoltage x-ray beams with different dose levels, scanning spatial resolutions, and sizes of region of interest (ROI).

METHODS

EBT4 film (Lot#07052201) calibration strips (3.5 × 20 cm2 ) were exposed to a 10×10 cm2 open field at doses of 0, 63, 125, 500, 750, 1000 cGy using 6 MV photon beam. EBT4 film strips from the same lot were then exposed to each x-ray beam (6 MV, 6 MV FFF, 10 MV FFF, 15 MV, and 70 kV) at six dose values (50, 100, 300, 600, 800, 1000 cGy). A full sheet (25 × 20 cm2 ) of EBT4 film was irradiated at each energy with 300 cGy for profile comparison with the treatment planning calculation. At two different spatial resolutions of 72 and 300 dpi, each film piece was scanned three consecutive times in the center of an Epson 10000XL flatbed scanner in 48-bit color. The scanned images were analyzed using FilmQA Pro. For each scanned image, an ROI of 2 × 2 cm2 at the field center was selected to obtain the average pixel value with its standard deviation in the ROI. An additional ROI of 1 cm diameter circle was also used to evaluate the impact of ROI shape and size, especially for FFF beams. The dose value, average dose-response value, and associated uncertainty were determined for each energy and relative responses were analyzed. The Student's t-test was performed to evaluate the statistical significance of the dose-response values with different color channels, ROI shapes, and spatial resolutions.

RESULTS

The dose-response curves for the five x-ray energies were compared in three color channels. Weak energy dependence was found among the megavoltage beams. No significant differences (average ∼1.1%) were observed for all doses in this study among 6 MV, 6 MV FFF, 10 MV FFF, and 15 MV beams, regardless of spatial resolution and color channel. However, a statistically significant difference in dose-response was observed up to 12% between 70 kV and 6 MV beams.

CONCLUSIONS

The dose-response curves for Gafchromic EBT4 films were nearly independent of the energy of the photon beams among 6 MV, 6 MV FFF, 10 MV FFF, and 15 MV. For very low-energy photons (e.g., 70 kV), a separate calibration from the same low-energy x-ray is necessary.

Risk Management of Clinical Reference Dosimetry of a Large Hospital Network Using Statistical Process Control

Managing TG-51 reference dosimetry in a large hospital network can be a challenging task. The objectives of this study are to investigate the effectiveness of using Statistical Process Control (SPC) to manage TG-51 workflow in such a network. All the sites in the network performed the annual reference dosimetry in water according to TG-51. These data were used to cross-calibrate the same ion chambers in plastic phantoms for monthly QA output measurements. An energy-specific dimensionless beam quality cross-calibration factor, kqnSW, was derived to monitor the process across multiple sites. The SPC analysis was then performed to obtain the mean, 〈kqnSW〉, standard deviation, σ_k, the Upper Control Limit (UCL) and Lower Control Limit (LCL) in each beam. This process was first applied to 15 years of historical data at the main campus to assess the effectiveness of the process. A two-year prospective study including all 30 linear accelerators spread over the main campus and seven satellites in the network followed. The ranges of the control limits (±3σ) were found to be in the range of 1.7% – 2.6% and 3.3% – 4.2% for the main campus and the satellite sites respectively. The wider range in the satellite sites was attributed to variations in the workflow. Standardization of workflow was also found to be effective in narrowing the control limits. The SPC is effective in identifying variations in the workflow and was shown to be an effective tool in managing large network reference dosimetry.

Investigation of a Novel Decision Support Metric for Head and Neck Adaptive Radiation Therapy Using a Real-Time In Vivo Portal Dosimetry System

In adaptive radiation therapy of head and neck cancer, any significant anatomical changes observed are used to adapt the treatment plan to maintain target coverage without elevating the risk of xerostomia. However, the additional resources required for adaptive radiation therapy pose a challenge for broad-based implementation. It is hypothesized that a change in transit fluence is associated with volumetric change in the vicinity of the target and therefore can be used as a decision support metric for adaptive radiation therapy. This was evaluated by comparing the fluence with volumetric changes in 12 patients. Transit fluence was measured by an in vivo portal dosimetry system. Weekly cone beam computed tomography was used to determine volume change in the rectangular region of interest from condyloid process to C6. The integrated transit fluence through the region of interest on the day of the cone beam computed tomography scan was calculated with the first treatment as the baseline. The correlation between fluence change and volume change was determined. A logistic regression model was also used to associate the 5% region of interest volume reduction replanning trigger point and the fluence change. The model was assessed by a chi-square test. The area under the receiver-operating characteristic curve was also determined. A total of 46 pairs of measurements were obtained. The correlation between fluence and volumetric changes was found to be -0.776 (P value <.001). The negative correlation is attributed to the increase in the photon fluence transport resulting from the volume reduction. The chi-square of the logistic regression was found to be 17.4 (P value <.001). The area under the receiver-operating characteristic curve was found to be 0.88. Results indicate the change in transit fluence, which can be measured without consuming clinical resources or requiring additional time in the treatment room, can be used as a decision support metric for adaptive therapy.

Commissioning and Evaluation of a Third-Party 6 Degrees-of-Freedom Couch Used in Radiotherapy

Purposes:

The newly released Protura 6 degrees-of-freedom couch (CIVCO) has limited quality assurance protocols and pertinent publications. Herein, we report our experiences of the Protura system acceptance, commissioning, and quality assurance.

Methods:

The Protura system integration was tested with peripheral equipment on the following items: couch movement range limit, 6 degrees-of-freedom movement accuracy, weight test and couch sagging, system connection with Linac, isocentricity of couch and rotation alignment, kV and cone-beam computed tomography imaging of HexaCHECK with MIMI phantom (Standard Imaging), and an in-house custom 6 degrees-of-freedom quality assurance phantom. A couch transmission measurement was also performed.

Results:

The vertical, longitudinal, and lateral ranges of the 6 degrees-of-freedom couch pedestal are 43.9 to 0.0 cm, 24.6 to 149.5 cm, −20.6 to 20.7 cm, respectively. The couch movement accuracy was within 1 mm in all directions. The couch sagging with a 200 lbs (∼91 kg) evenly distributed object is 1.0 cm and 0.4° pitch in the distal end of the couch. The isocentricity of the couch was about 0.5 mm in diameter of all crosshair projections on the couch isocenter level, and the largest couch rotation alignment observed was (0.3°) at the couch angle of 90°. The deviation from the reference position (zero position) of the HexaCHECK phantom, measured by matching the cone-beam computed tomography with the reference planning computed tomography, was found to be below 0.2 mm in the anterior–posterior and right–left dimensions, 0.4 mm in superior–inferior dimension, and 0.1° in roll, pitch, and yaw directions.

Conclusions:

A 6 degrees-of-freedom quality assurance phantom is helpful for the commissioning and routine quality assurance tests. Due to the third-party integration with Linac, the system is prone to “double-correction” errors. A rigorous quality assurance program is the key to a successful clinical implementation of the Protura system.

Intraoperative implantation of a mesh of directional palladium sources (CivaSheet): Dosimetry verification, clinical commissioning, dose specification, and preliminary experience

PURPOSE

To present the clinical commissioning of a novel ¹⁰³Pd directional brachytherapy device (CivaSheet) for intraoperative radiation therapy.

METHODS AND MATERIALS

Clinical commissioning for the CivaSheet consisted of establishing: (1) source strength calibration capabilities, (2) experimental verification of TG-43 dosimetry parameters, (3) treatment planning system validation, and (4) departmental practice for dose specification and source ordering. Experimental verification was performed in water with radiochromic film calibrated with a 37 kVp X-ray beam. Percentage difference ([measurements - calculation]/calculation) and distance to agreement (difference between film-to-source distance and distance that minimized the percentage difference) were calculated. Nomogram values (in U/100 Gy) for all configurations (up to 20 × 20 sources) were calculated for source ordering. Clinical commissioning was used on patients enrolled in an ongoing Institutional Review Board-approved protocol.

RESULTS

A source calibration procedure was established, and the treatment planning system was commissioned within standard clinical uncertainties. Percentage dose differences (distances to agreement) between measured and calculated doses were 8.6% (-0.12 mm), 0.6% (-0.01 mm), -6.4% (0.22 mm), and -10.0% (0.44 mm) at depths of 2.3, 5.1, 8.0, and 11.1 mm, respectively. All differences were within the experimental uncertainties. Nomogram values depended on sheet size and spatial extent. A value of 2.4U/100 Gy per CivaDot was found to satisfy most cases, ranging from 2.3 to 3.3U/100 Gy. Nomogram results depended on elongation of the treatment area with a higher variation observed for smaller treatment areas. Postimplantation dose evaluation was feasible.

CONCLUSIONS

Commissioning and clinical deployment of CivaSheet was feasible using BrachyVision for postoperative dose evaluation. Experimental verification confirmed that the available TG-43 dosimetry parameters are accurate for clinical use.

Survival Benefit of Early Cancer Detection Through Regular Endoscopic Screening for De Novo Gastric and Colorectal Cancers in Korean Liver Transplant Recipients

BACKGROUND

De novo malignancy is not uncommon after liver transplantation (LT). Gastric cancer is one of the most common malignancies in both the Korean general population and LT recipients, and colorectal cancer prevalence is gradually increasing.

METHODS

Among 3690 adult recipients who underwent LT from January 1999 and December 2013, the screening patterns and prognosis of 26 cases of gastric cancer and 22 cases of colorectal cancer were analyzed.

RESULTS

For gastric cancer, the mean patient age was 54.6 ± 6.2 years at LT and 59.5 ± 6.7 years at cancer diagnosis, with a post-transplant interval of 60.2 ± 29.8 months. Patients were divided into regular (n = 18) and non-regular (n = 8) screening groups, with early cancer found in 14 and 0 patients; their 2-year survival rates after cancer diagnosis were 93.1% and 33.3% (P = .006), respectively. Endoscopic resection was successfully performed in 8 patients, all in the regular screening group. For colorectal cancer, the mean patient age was 53.3 ± 6.1 years at LT and 58.1 ± 6.7 years at cancer diagnosis, with a post-transplant interval of 54.3 ± 38.0 months. Patients were divided into regular (n = 19) and non-regular (n = 3) screening groups, with early cancer found in 12 and 0 patients; their 2-year survival rates after cancer diagnosis of 92.3% and 33.3% (P = .003), respectively. Endoscopic resection was successfully performed in 6 patients, all in the regular screening group.

CONCLUSIONS

LT recipients are strongly advised to undergo regular screening studies for various de novo malignancies, especially cancers common in the general population. Regular endoscopic screening contributes to the timely detection of gastric and colorectal cancers, improving post-treatment survival outcomes.

The psychometric properties of the Quantitative-Checklist for Autism in Toddlers (Q-CHAT) as a measure of autistic traits in a community sample of Singaporean infants and toddlers

Background

There is growing research evidence that subclinical autistic traits are elevated in relatives of individuals with autism spectrum disorder (ASD), continuously distributed in the general population and likely to share common etiology with ASD. A number of measures have been developed to assess autistic traits quantitatively in unselected samples. So far, the Quantitative-Checklist for Autism in Toddlers (Q-CHAT) is one of very few measures developed for use with toddlers as young as 18 months, but little is known about its measurement properties and factor structure.

Methods

The present study examined internal consistency, factor structure, test-retest stability, and convergent validity of the Q-CHAT in a sample of toddlers in Singapore whose caregivers completed the Q-CHAT at 18 (n = 368) and 24 months (n = 396).

Results

Three factors were derived accounting for 38.1 % of the variance: social/communication traits, non-social/behavioral traits, and a speech/language factor. Internal consistency was suboptimal for the total and speech/language scores, but acceptable for the social/communication and non-social/behavioral factor scores. Scores were generally stable between 18 and 24 months. Convergent validity was found with the Pervasive Developmental Disorders subscale of the Child Behavior Checklist (CBCL) completed by caregivers when their children were 24 months. Q-CHAT total scores in this sample were higher than those reported in other unselected samples from the UK.

Conclusions

The Q-CHAT was found to have a three-factor structure, acceptable internal consistency for its two main factor scores (social/communication and non-social/behavioral), normally distributed scores in an unselected sample, and similar structure and measurement properties as those reported in other published studies. Findings are discussed in relation to existing literature and future directions for the validation of the Q-CHAT.

Childhood intermittent exotropia from a different angle: does severity affect quality of life?

BACKGROUND

Few studies have explored the relationship between health-related quality of life (HRQOL) and clinical severity of childhood intermittent exotropia (IXT) measured by angle of deviation, control and stereoacuity.

METHODS

Sixty-eight consecutive children aged 5-17 years with childhood IXT who attended the paediatric eye clinic were recruited. One accompanying parent was recruited concurrently. Child, parent and proxy (parent about the child) HRQOL was measured using the IXT questionnaire (IXTQ). Angle of deviation, control and stereoacuity of the children were measured and correlated with IXTQ scores using Spearman's correlation coefficient and paired t test for differences in child and proxy IXTQ mean scores.

RESULTS

The mean age of the children was 9.0±2.6 years. Child HRQOL was not correlated to any strabismus measurements. Poorer parent HRQOL was correlated with poorer distance control (surgery subscale, r=-0.24 p=0.049), poorer near control (surgery subscale, r=-0.30, p=0.013), poorer office near control (mean, r=-0.24, p=0.047; psychological subscale, r=-0.27, p=0.025; surgery subscale, r=-0.28, p=0.020) and larger angle of deviation (psychological subscale, r=-0.30, p=0.013). Poorer proxy HRQOL was correlated with poorer home control (r=-0.28, p=0.022) and larger angle of deviation (r=0.33, p=0.0061).

CONCLUSIONS

It is difficult to predict child HRQOL based on clinical measurements. However, parent HRQOL tends to be worse with poorer control and larger angle of deviation. Perhaps HRQOL should be routinely assessed in clinic alongside clinical measurements in order to tailor management appropriately.

Synchronous gastric cancer in primary sporadic colorectal cancer patients in Korea

BACKGROUND AND AIMS

Colorectal cancer has been reported to be the malignancy most frequently associated with gastric cancer in Korea. The aim of this study was to define the frequency and clinical characteristics of synchronous gastric cancer detected at preoperative esophagogastroduodenoscopy (EGD) in colorectal cancer patients.

MATERIALS AND METHODS

This prospective study analyzed the EGD results from 1,542 consecutive colorectal cancer patients who underwent surgery from January 2003 to December 2005 at the Center for Colorectal Cancer, National Cancer Center, Korea.

RESULTS

Of the 1,542 cases, 1,155 (74.9%) underwent EGD at our center and 387 underwent EGD at other hospitals within 6 months before surgery. Of the 1,542 cases, synchronous gastric cancers were detected in 31 cases (2.0%). Of these 31 cases, 26 had early gastric cancer (EGC; 83.9%) and 5 had advanced gastric cancer. Ten (38.5%) of the 26 EGC cases were managed using endoscopic mucosal resection. Compared to colorectal cancer patients without synchronous gastric cancer, the group of patients with synchronous gastric cancer was older (65.5+/-9.6 vs 58.4+/-11.3 years, p=0.001) and had a greater proportion of males (77.4 vs 59.4%, p=0.043).

CONCLUSION

This study found that 2% of Korean sporadic colorectal cancer patients had synchronous gastric cancer. A preoperative EGD for colorectal cancer patients is likely to greatly assist in the diagnosis of synchronous gastric cancer at an early stage and the implementation of appropriate minimally invasive treatment.

Knockdown of polypyrimidine tract-binding protein suppresses ovarian tumor cell growth and invasiveness in vitro

Polypyrimidine tract-binding protein (PTB) is an RNA-binding protein with multiple functions in the regulation of RNA processing and IRES-mediated translation. We report here overexpression of PTB in a majority of epithelial ovarian tumors revealed by immunoblotting and tissue microarray (TMA) staining. By western blotting, we found that PTB was overexpressed in 17 out of 19 ovarian tumor specimens compared to their matched-normal tissues. By TMA staining, we found PTB expression in 38 out of 44 ovarian cancer cases but only in two out of nine normal adjacent tissues. PTB is also overexpressed in SV40 large T-antigen immortalized ovarian epithelial cells compared to normal human ovarian epithelial cells. Using doxycycline-inducible small interfering RNA technology, we found that knockdown of PTB expression in the ovarian tumor cell line A2780 substantially impaired tumor cell proliferation, anchorage-independent growth and in vitro invasiveness. These results suggest that overexpression of PTB is an important component of the multistep process of tumorigenesis, and might be required for the development and maintenance of epithelial ovarian tumors. Moreover, because of its novel role in tumor cell growth and invasiveness, shown here for the first time, PTB may be a novel therapeutic target in the treatment of ovarian cancer.

Universal newborn hearing screening in Singapore: the need, implementation and challenges

With about 1 in 1000 born with severe to profound hearing loss and about 5 in 1000 with lesser degrees of loss, congenital deafness is the commonest major birth defect. It is the recommended standard that hearing loss in newborns be detected by 3 months of age and intervention implemented by 6 months of age. Delayed detection and intervention may affect speech, language and psychosocial development, resulting in poor academic achievements. Universal newborn hearing screening (UNHS) is the only effective way of detecting all babies with hearing loss, within the recommended time frame. A survey in Singapore revealed that traditional childhood hearing screening programmes resulted in late detection (mean age, 20.8 months; range, 0 to 86 months) and late intervention (mean age, 42.4 months; range, 1 to 120 months). Increasingly, UNHS is becoming standard medical care in developed countries. In Singapore, UNHS has been implemented in all hospitals with obstetric services. Although a screening rate of more than 99% has been achieved in public hospitals, private hospitals have a screening rate of only about 77%. Parents' awareness and acceptance of early detection is still lacking, and this needs to be addressed by appropriate public education. Support from obstetricians and paediatricians will significantly contribute towards this objective. Effective programme management is essential; this includes the use of data management systems, the maintenance of a team of experienced screeners, and efficient coordination between screening and diagnostic services. Early detection of childhood deafness, together with early and effective intervention, maximises the chances of successful integration into mainstream education and society.

Long-term follow-up and outcome of extremely-low-birth-weight (ELBW) infants

INTRODUCTION

Modern day obstetric and neonatal care has dramatically increased the survival of the extremely-low-birth-weight (ELBW) neonates. As the limits of viability decrease, it is of paramount importance to have reliable data on long-term morbidity. Long-term follow-up of these high-risk survivors is thus becoming an integral part of neonatal intensive care units.

METHODS

Detailed Medline search and review of leading journal articles were done to assess the current data on long-term outcome of ELBW infants.

RESULTS

The developmental outcome of the ELBW infant is determined by a complex interaction of medical and environmental factors acting on a developmentally vulnerable premature brain. In early childhood, 13% to 37% of ELBW survivors have a significant delay in cognitive function while 7% to 17% have neurosensory impairment viz. cerebral palsy. Advances have been made in measuring functional outcome to assess the impact of ELBW births on long-term quality of life and skills for independent living. Measuring school age outcome is an important landmark in the longitudinal follow-up of ELBW infants and most reports show high rates of cognitive impairment as well as increased incidence of learning disability and school difficulties as well as behavioural problems. The ELBW adolescent and young adult continue to lag behind in academic achievement and cognitive score. However, more than half of the ELBW survivors function within the normal range of variability and their self-reported quality of life in adolescence continues to be comparable to that of their peers.

CONCLUSION

In managing ELBW infants, a holistic, systematic approach is needed to assess the degree and impact of impairment on their daily function and issues related to quality of life.

Eight-year outcome of very-low-birth-weight infants born in KK hospital

AIM

To determine the education, neurodevelopmental outcome and educational achievement of babies weighing < 1500 g at 8 years of age.

MATERIALS AND METHODS

This prospective study involved 171 of 202 survivors from KK Women's and Children's Hospital (KKWCH). Cognitive function was assessed using the Weschler Intelligence Scale for Children--version III (WISC-III).

RESULTS

Of these, 90.1% were in mainstream education and 1.2% were in home or religious schools. Special education programmes were recommended for 11.1% of children [24.4% of 56 extremely-low-birth-weight (ELBW) babies < 1000 g and 9.6% of 115 larger babies weighing 1000 to 1499 g]. Of these, only 7.8% eventually enrolled and 1.2% were not in any programme. In 136 children who had psychological assessments, the mean full-scale, verbal and performance intelligence scores were 87.0 +/- 17.7, 86.6 +/- 17.0 and 90.1 +/- 21.8 in ELBWs and 96.1 +/- 18.3, 93.3 +/- 15.7 and 100.0 +/- 17.5 in larger children, with the former having significantly lower scores than the latter (full scale: P = 0.02, 95% CI -18.23, -4.18; verbal: P = 0.04, 95% CI -13.8, -1.95; performance: P = 0.004, 95% CI -17.67, -3.35). 33.8% of the cohort, 49.0% of ELBWs and 25.3% of larger children had neurodevelopmental impairment (full scale score < 85 or in need of special education). Logistic regression analysis showed that birth weight < 1000 g, female sex, Chinese race, a non-intact family structure and bronchopulmonary dysplasia (BPD) were significant risk factors associated with neurodevelopmental impairment. 72.7% of children scored > or = 50% of total marks for English, Mathematics and second language. 14.1% had Band 4 (< 50% of total marks) in all 3 subjects. Logistic regression analysis showed that the only significant risk factors associated with adverse school performance in any of these three subjects were hypoglycaemia in the newborn period and impaired cognitive function.

CONCLUSION

The outcome of ELBWs is a major cause of concern. BPD and hypoglycaemia were the only perinatal factors that still exerted an influence on outcome at 8 years. Better methods of prediction of academic difficulty are critical for this high-risk group of children.

Effect of the mannose-binding Artocarpus integer lectin on the cellular proliferation of murine lymphocytes

The effect of the mannose-binding champedak (Artocarpus integer) lectin-M on the cellular proliferation of murine lymphocytes was investigated in this study. Our data demonstrated that the lectin was the main mitogenic component in the crude extract of the champedak seeds. It stimulated the proliferation of murine T cells at an optimal concentration of 2.5 microg/ml in a 3 day culture. Lectin-M appeared to be a T-cell mitogen as it does not induce significant DNA synthesis when cultured with spleen cells from the nude mouse. In the absence of T cells, the lectin was incapable of inducing resting B cells to differentiate into immunoglobulin secreting plasma cells.

Isolation of a mannose-binding and IgE- and IgM-reactive lectin from the seeds of Artocarpus integer

A mannose-binding lectin, termed champedak lectin-M, was isolated from an extract of the crude seeds of champedak (Artocarpus integer). On gel filtration chromatography, the lectin eluted in a single peak at elution volumes corresponding to 64 kDa. SDS-PAGE showed the mannose-binding lectin to be composed of 16.8 kDa polypeptides with some of the polypeptides being disulphide-linked to give dimers. When tested with all isotypes of immunoglobulins, champedak lectin-M demonstrated a selective strong interaction with human IgE and IgM, and a weak interaction with IgA2. The binding interactions of lectin-M were metal ion independent. The lectin was also shown to interact with horseradish peroxidase, ovalbumin, porcine thyroglobulin, human alpha1-acid glycoprotein, transferrin and alpha1-antitrypsin. It demonstrated a binding preference to Man alpha 1-3Man ligands in comparison to Man alpha 1-6Man or Man alpha 1-2Man.

Outcome of infants weighing 500-999 grams at birth in a Singapore hospital (1990-1993)

Over a 4-year period (1990-1993) 126 babies weighing 500-999 grams (0.39% of 32,362 livebirths) were born in the hospital that provides tertiary care. Seventy-eight babies (61.9%) were discharged alive. Survival rate (79.4% or 50/63) was higher in the larger babies (800-999 gm) than in the smaller babies (28/63 of the 500-799 gm or 44.4%, p = 0.0001). Survival rates among the 2 periods, 1990-91 (period 1) and 1992-93 (period 2) have also improved, from 44/74 or 59.5% to 34/52 or 65.4%, p = 0.62 (NS). Surfactant replacement therapy (SRT) has an impact on decreasing the mortality for babies < 1,000 gm. Only 35.3% (6/17) babies had SRT in 1993. Other perinatal factors are also contributing to a better outcome of these high risk babies. Neurodevelopmental outcome at 2 years of age of the 39 babies (50%) born in period 1 has been determined. Thirty-five percent (5/14) of the smaller babies and 28% (7/25) of the larger babies had MDI (Bayley Mental Developmental Index) of < 69. For cerebral palsy, it was 14% and 8% respectively; and for neurosensory disorder, 7% and 4% respectively. Some babies had a combination of 2 or 3 major impairments. It is estimated that 33% of babies who weighed less than 1,000 gm at birth had a disability. It was found that severe intraventricular haemorrhage (IVH) of grade III and IV correlated significantly with MDI of < 69 (p < 0.05). Severe IVH in period 2 (17.2%) did not differ significantly from that of period 1 (29.4%, p = 0.55).(ABSTRACT TRUNCATED AT 250 WORDS)

Aetiology of diarrhoea in Singapore

Stools from acute diarrhoea were investigated for bacterial and viral pathogens. In one study involving 63 young children in a paediatric ward, 70% of the stools were positive for the pathogens looked for of which 37% contained bacteria, 22% viruses and 11% mixed cultures of bacteria and viruses. In another study in which 130 watery stools from routine specimens of patients of all ages were investigated, 36% were positive for pathogens with 11% bacteria, 18% viruses and 7% mixed pathogens. The high incidence of bacterial diarrhoea in young children was attributed to gastroenteritis caused by Salmonella species. Salmonella and rotavirus were found the most common pathogens in bacterial and viral diarrhoeas, and the most susceptible age group was under 5 years-old.

Bronchopulmonary dysplasia in very low birthweight infants

Twenty-four (6%) of 375 infants with birthweights less than or equal to 1500g developed bronchopulmonary dysplasia (BPD); 16 (15%) of 107 in those less than or equal to 100g and 8 (3%) of 268 in those greater than 1000g. The incidence was 10% in those who required assisted ventilation. Perinatal asphyxia, significant respiratory distress, pulmonary interstitial emphysema and patent ductus arteriosus were statistically more common in BPD infants compared with the remaining 351 very low birthweight infants. Hyaline membrane disease was the primary respiratory disease in 54% of BPD infants. The mean durations of oxygen and ventilatory therapy were 68 days and 37 days respectively. Twenty-nine percent did not require more than 60% oxygen for over 24 hours. Only 38% required a peak airway pressure of over 30 cmH2O. Early postnatal growth was satisfactory on parenteral nutrition support. No perinatal factor was found to be predictive of death from BPD. The prolonged duration of hospital treatment has obvious implications to the psychosocial and economic costs of BPD.

Growth and development of very low birthweight infants recovering from bronchopulmonary dysplasia

Twenty four infants with birthweights less than or equal to 1500 g had bronchopulmonary dysplasia (BPD). Four died in the neonatal period and four in the postneonatal period-one had been discharged and was aged one year. Sixteen (67%) survived long term and were followed up until they were two years old. Common medical conditions included respiratory illnesses in 14 (88%) children and otitis media in 8 (50%). Eleven (69%) required hospital admission for an average of 5 times; total days in hospital averaged 27 days. The most common reasons for admission were bronchiolitis and bronchopneumonia. At two years 37% were below the 10th centile for weight, as were 25% for height: head circumferences were normal. Two children had cerebral palsy, two had developmental delay, two had multiple disabilities, and one had sensorineural deafness. Of the 24 BPD infants, 8 (33%) died, 7 (29%) survived with a disability (severe in one), and 9 (38%) had a normal neurodevelopmental outcome. From the available perinatal data it was not possible to predict late disabilities in BPD survivors.