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Biomedical subjects

K L Lam

Publications and source records attributed to K L Lam.

At least 55 records · Page 3Linked to original sources
PubMed1978

Neonatal tetanus treated with high dosage diazepam.

The combination of continuous intravenous infusion of diazepam (20--40 mg/kg per day) and intragastric phenobarbitone (10--15 mg/kg per day in 4 divided doses) was used to treat 19 cases of neonatal tetanus. Mortality was 2/19 (11%). This regimen was considered to have reduced the mortality and the need for artificial ventilation. The main side effects encountered were severe drowsiness, coma, and apnoeic episodes which were reversible when the level of diazepam was reduced.

Diazepam↗
PubMed1975

Respiratory virus disease in Malaysian children: a serological study.

Paired sera from 101 Malaysian children aged up to 10 years and suffering from respiratory illnesses were examined serologically for evidence of respiratory viral infections. Of these children, 32.6% showed rising antibody titres for one or more of the test agents. Respiratory syncytial virus appeared to be the main respiratory pathogen involved, followed by Mycoplasma pneumoniae, parainfluenza viruses, adenoviruses, and influenza A virus. These findings are generally similar to those reported by others in temperate and tropical countries.

Antibodies, Viral↗
PubMedDate not supplied

Effect of soy protein on the small bowel mucosa of young infants recovering from acute gastroenteritis.

The effect of soy protein on the small bowel mucosa of 18 infants with acute gastroenteritis was studied. The infants were maintained on a protein hydrolysate formula for 6-8 weeks, following which they were readmitted for soy protein challenge studies. Jejunal biopsy was performed before and 24 h after challenge. On the basis of the clinical and histological reaction to soy protein challenge, three groups were identified. Group 1 consisted of three infants who had clinical and histological reaction. There was associated depletion of mucosal enzymes, lactase, sucrase, malatase, alkaline phosphatase, and blood xylose levels. Group 2 consisted of seven infants who had histological reaction but no clinical symptoms. Two of these seven infants, however, developed clinical reaction when rechallenged with soy protein 2 and 90 days later. Following challenge, mucosal enzymes and blood xylose levels were depressed in five of the seven infants tested. Group 3 consisted of eight infants who did not have either a clinical or a histological reaction. The mucosal enzymes and blood xylose levels were not depressed in four infants tested. The present study shows that the small bowel mucosa of some young infants recovering from acute gastroenteritis remains sensitive to soy protein for a variable period of time. The feeding of soy protein to these infants may result in the persistence of mucosal damage and perpetuation of diarrhea.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMedDate not supplied

Severity and extent of upper small bowel mucosal damage in cow's milk protein-sensitive enteropathy.

A series of 31 infants, 28 with cow's milk protein sensitive enteropathy (CMPSE) and 3 controls, was studied for severity and extent of mucosal damage of the upper small bowel in relation to the development of clinical symptoms. Following challenge with the offending cow's milk, 18 infants (Group 1) developed severe mucosal changes at both the proximal and distal small bowel mucosa and all of these infants presented with clinical symptoms. The other 10 infants (Group 2) who did not develop clinical symptoms following the challenge had less severe damage to the distal small bowel mucosa as compared to the proximal region. The histological score of both the proximal and distal postchallenge biopsies were significantly lower in Group 2 as compared to Group 1 infants. The mucosal disaccharidase and alkaline phosphatase levels were depleted in both the proximal and distal biopsies following challenge but the depletion was greater in the proximal than the distal biopsies. It is suggested that the extent and severity of mucosal damage to the proximal duodenum and jejunum have a critical bearing on the development of clinical symptoms.

Alkaline Phosphatase↗
PubMedDate not supplied

Causative effect of cow's milk protein and soy protein on progressive small bowel mucosal damage.

Some infants intolerant to cow's milk protein (CMP) are often also intolerant to other food proteins including soy protein (SP). The effect of CMP and SP in infants recovering from diarrhoeal disease was studied in 22 infants who were maintained on an hypo-allergenic formula for 4-6 weeks. The infants were then challenged successively, initially with SP, followed 24 h later with CMP and then rechallenged with SP 24 h after CMP provocation. Three groups were recognized on the basis of clinical symptoms and mucosal changes following SP challenge. Group 1 comprised four infants who developed clinical and histological reactions on SP challenge. The subsequent CMP challenge, 24 h after the initial SP challenge, resulted in clinical symptoms in three of the four infants, and they developed increased mucosal injury. Rechallenge with SP in the three infants caused development of severe clinical symptoms. Group 2 comprised 12 infants who developed histological reaction but had no clinical symptoms to initial SP challenge. The subsequent CMP challenge caused further progression in mucosal pathology in 11 of the 12 infants and six also had associated clinical symptoms. Rechallenge with SP in the latter six infants resulted in development of clinical symptoms in three and tolerance to SP in three infants. Group 3 comprised six infants who tolerated SP and CMP but one of these infants developed mild histological changes to CMP. The progression of mucosal injury following SP and CMP challenge was associated with a significant decrease in mucosal disaccharidases, alkaline phosphatase levels and presence of reducing sugar in the stools. The 1 h blood xylose level continued to decrease significantly following the pre-SP, post-SP, and post-CMP challenge. It appears that the small bowel mucosa of young infants recovering from diarrhoeal disease remains sensitive not only to CMP but also to SP. The feeding of these proteins in rapid successive sequence to infants with mucosal damage might result in further progression of the mucosal injury. Thus, the exclusion for a variable period of time of antigenic food proteins like CMP and SP from the diet of young infants recovering from diarrhoea might reduce the risk of inducing mucosal sensitivity to these proteins in susceptible infants.

Diarrhea, Infantile↗
PubMedDate not supplied

Optical image processing with liquid-crystal display for image intensifier/television systems.

We have studied the effect of real-time optical image processing (OIP) in an image intensifier/television (II-TV) radiographic imaging system by using a liquid-crystal display (LCD) placed between the II and the TV camera. The LCD compresses the dynamic range of the transmitted image by modulating the spatial distribution of the light intensity of the image from the output phosphor of the II. The degree of dynamic-range compression can be designed so that the dependence of the signal-to-noise ratio (SNR) of the LCD-TV system on x-ray intensity matches that of the quantum noise. We measured the physical properties of an LCD and evaluated its capability for OIP. Our experimental results demonstrate that it is feasible to use an LCD to compress the dynamic range and to improve the SNR of the image. The advantages of implementing OIP with an LCD in image acquisition systems in which a TV camera is used are discussed.

Humans↗
PubMedDate not supplied

Studies of performance of antiscatter grids in digital radiography: effect on signal-to-noise ratio.

We developed a theoretical model which describes the improvement of signal-to-noise ratio (SNR) by a grid in digital radiography. The model takes into account the effects of spatial variations in the scatter-to-primary ratio and in the large-area contrast over an image with structured background on quantum noise, and the effects of noise in the imaging system such as electronic noise and digitization noise. Based on the theoretical model, we analyzed the effects of these factors on the SNR when a grid is employed. We performed experimental measurements to evaluate the improvement in the SNR by a grid when quantum noise is the dominant noise source. It was found that the measured SNR improvement factor due to quantum noise agreed closely with that determined from the measured transmission values of a grid, as predicted from our theoretical model. In order to evaluate the relative performance of grids with various geometric design parameters for digital radiographic systems, we employed Monte Carlo calculations and determined the transmission values of a number of grids under various scatter conditions. The calculated SNR improvement factor, due to quantum noise, correlated well with the measured improvement of the SNR by the grids. Our model predicts that the SNR improvement factor depends strongly on the local contrast ratio and also on the scatter-to-primary ratio. The SNR improvement factor is higher in the underpenetrated regions than in the well-penetrated regions of an image.

Models, Theoretical↗
PubMedDate not supplied

Effects of x-ray beam equalization on mammographic imaging.

We employed an elastic reservoir filled with tissue-equivalent fluid as an x-ray beam filter for exposure equalization. The filter is designed to be placed between the upper compression plate and the breast. During compression, it will conform to the shape of the peripheral region of the breast and fill the space between the upper and lower compression plates, thereby reducing the variation in x-ray penetration between the thick and thin regions of the breast and compressing the dynamic range of the breast image. Results of a phantom study showed that the visibility of low-contrast features was improved in the peripheral region of the equalized breast phantom image. Experimental measurements indicated that the filter reduced scattered radiation in the peripheral region. This result was confirmed by a Monte Carlo simulation study. The radiation contrast, with the effect of beam hardening included, was also improved when equalization was employed.

Computer Simulation↗
PubMedDate not supplied

Improvement of precision in spatial localization of radio-opaque markers using the two-film technique.

Radio-opaque markers implanted inside or placed on the skin of patients can be used to detect set-up errors and patient motion. The effects of imaging geometry accuracy for standard radiotherapy equipment on the precision of calculating the positions of radio-opaque spherical markers using two orthogonal radiographic film projections is investigated. Inaccuracies in the imaging geometry are computed from the manually digitized positions of the marker images on each film pair. Actual marker locations are calculated with a precision limited only by the variance in manual digitization by incorporating those imaging geometry inaccuracies into their computation. Results of a phantom study using a grid of markers in a plastic block indicate that submillimeter precision can be obtained for the spatial coordinates of individual markers, and that the precision is not sensitive to the small inaccuracies in imaging geometry present within the mechanical tolerances of modern radiotherapy treatment machines and simulators.

Humans↗