Papers Published by Academic Staff
Department of Anatomy
Faculty of Medicine, University of Colombo, Sri Lanka.
Adolescent Growth in Stature among Sinhalese Males: Preliminary Results of a Cross Sectional Study - Rohan Jayasekera, Jane Lasswell-Hoff, Charles Garner, Gina Kristl and Charles Hoff.
Abstract - Cross-sectional stature growth profiles are presented for pre-adolescent, adolescent and young adult Sinhalese males of middle and upper socio-economic status from Colombo, Sri Lanka. Sinhalese males are compared to cross-sectional standards for adolescent male stature developed by the National Centre for Health Statistics(NCHS) of the U.S.A. While the shapes of the NCHS and Sinhalese cross-sectional growth curves are similar, the majority Sinhalese adolescent males(>80%) fall below the NCHS 50th percentile for stature at a given age.
Human Biology: Volume 60, No 6, December, 1988, pp 825-831.
Acceptance of Genetic Services: A Study of Physicians in Colombo, Sri Lanka - Rohan Jayasekera, Gina Barrett Kristl and Wladimir Wertelcki.
Summary - A survey of 302 physicians from Colombo, Sri Lanka, reveals a strong overall acceptance of genetic counselling, prenatal diagnosis of genetic disorders and therapeutic abortion. Demographic and experimental factors, especially being older and having children, were associated with acceptance of genetic services. There was little support for prenatal diagnosis in order to satisfy curiosity about the sex of the fetus. The results of this analysis were compared to those from a study of physicians in Arizona, USA.
Journal of Biosocial Science: Volume 20, 1988, pp 1-7.
Genetic Polymorphism of Orosomucoid(ORM) in Populations of the United Kingdom, Indian Subcontinent, and Cambodia - S.S. Mastana, R. Jayasekera, P.Fisher, R.J. Sokol and S.S. Papiha.
Summary - The genetic variation of the human serum orosomucoid(ORM) was investigated by isoelectric focusing (IEF) followed by immunofixation in 15 different populations from East Midlands(United Kingdom), India, Sri Lanka, and Cambodia. Statistically significant differences were observed between various Asiatic and British populations, however differences within Asiatic and European populations were minor. The distribution of ORM1 alleles in populations investigated to date suggests an interesting east-west geographical cline. There is a suggestion that present day wide polymorphism at the ORM1 locus may be influenced by selection.
Japan Journal of Human Genetics 38, 289-296, 1993.
Key words - polymorphism, orosomucoid, ethnic groups, United Kingdom, India, Cambodia and Sri Lanka.
Distribution of Group specific component(GC) and Transferrin(TF) subtypes in populations of Sri Lanka - R. Jayasekera, S.S. Mastana, S.S.Papiha.
Summary - A random sample of 503 individuals from five endogamous groups of Sri Lanka was studied for the genetic polymorphism of the group specific component(GC) and transferin(TF) using isoelectric focusing. Both systems showed statistically significant heterogeneity among the five main populations of the island. The GC allele frequencies of Malays are significantly different from those of the other four populations (Sinhalese, Tamils, Moors and Burghers). However, the TF system shows less variation, since only the Moors show a significant heterogeneity compared to Tamils and Burghers. The frequencies found in the present study are very different from those reported for the populations of the Indian mainland.
Gene Geography: Volume 8, 1994, pp 151-156.
Deletion Screening of Sri Lankan Duchenne muscular dystrophy patients using the polymerase chain reaction - Jayantha Welihinda, E.H. Karunanayake, R Jayasekera, J.B.Pieris, Ulf Petterson & Claes Wadelius.
Summary - Duchenne muscular dystrophy (DMD) is an X-chromosome-linked myopathy caused by a defect in the DMD gene. Intragenic deletions appear to be the most common gene defect leading to DMD, and the deletion frequency has been estimated to be 66%. Results of this study using a group of 24 DMD patients of Sri Lankan origin employing technique of multiplex DNA amplification using the polymerase chain reaction indicated a deletion frequency of 62.5%. Eighty percent of those deletions were localized in a region of the DMD gene regarded as a `hot spot' for DMD deletions. Our results are in agreement with the results of other studies carried out on Caucasian populations.
Annals of Tropical Paediatrics: Volume 13, 1993, pp 83-86.
Parental Age and Parity in Dyslexic Boys - R. Jayasekera and J.Street.
Summary - The influence of parental age at birth, and parity, was studied in a series of 48 dyslexic boys. It was concluded that both increased paternal and maternal age contributes to a greater incidence of the condition. The similarity to the age distributions of chromosomal aberrations and some mutation defects suggests some genetic implication. The findings thus favour a biological rather than environmental element in the aetiology.
Journal of Biosocial Science:Volume10, 1978, pp 255-261..
The Attitude of Doctors and Students Towards a Genetic Service in an Asian Country : Sri Lanka - Rohan W. Jayasekera.
Abstract - A study comparing the views on the acceptance of a genetic service of 302 doctors and 143 final year medical students from Colombo, Sri Lanka, showed both groups have strong positive views on the provision and use of genetic counselling, prenatal diagnosis of genetic disorders and therapeutic abortion. The students responded with greater restraint possibly due to being a younger cohort with less clinical experience. Both groups, however, showed little support for the use of prenatal diagnosis purely to determine fetal sex.
Key words: genetic counselling, prenatal diagnosis, therapeutic abortion, genetic service.
Asia-Oceania Journal of Obstetrics and Gynaecology: Volume 15, No.3, September, 1989, pp 267-270.
Screening for Turner Syndrome: how useful is the buccal smear test? - Tara de Mel, Rohan Jayasekera, Narda Warnasooriya.
Summary - The buccal smear test was used to screen for Turner syndrome in a sample of girls with severe short stature who did not have any other clinical features of the condition. The majority of the girls did not show X chromatin bodies in the buccal mucosal cells. None of those who qualified for chromosomal analysis showed an XO chromosomal pattern either. We conclude that reliability of the buccal smear test as a screening method for Turner syndrome remains doubtful.
The Ceylon Medical Journal: Volume 37, 1992, pp 83-84.
Genetic Diversity in Sri Lanka : Some Implications in Paternity and Forensic testing - S.S. Mastana, R. Jayasekera, S.S.Papiha.
Introduction - In the Indian Subcontinent a vast number of subpopulations exist, originating from different racial stocks and their diversity is dynamically maintained by linguistic, cultural, religious and geographical barriers. The genetic markers that are polymorphic in the populations of this region, show extensive magnitude of variation in allele frequency among subpopulations in different regions (Papiha et al 1982, Mastana and Papiha 1994). In the countries of the Indian subcontinent, pooling of genetic information from different populations for medico-legal problems will lead to spurious results. The necessity to study the genetic composition of various subpopulations for paternity and forensic testing has recently been advocated by Lewontin and Hartl (1991) and others. We have studied five main endogamous groups of Sri Lanka and have seen a considerable variation in their individual allele frequencies for several genetic systems. The aim of this paper is to examine how these allele frequency differences influence parameters like PE (Power of Exclusion), PM (Probability of Match), and DP (Discriminant Probability) in each of the five endogamous subpopulations.
Advances in Forensic Haemogenetics - 15th Congress of the International Society for Forensic Haemogenetics, Venezia, 13-15 October 1993.
Studies on the morphology and vascular patterns of human placentae in relation to birth defects in Sri Lanka - S. Satchithananthan.
Abstract - Placentae were studied, after dissection, using enzyme digestion (Crawford, 1955), gelatine injection (Tompsett, 1972), resin injection (Tompsett, 1973) and radiological techniques using barium sulphate and micropaque. Statistical analysis of maternal, foetal and placental data established morphological norms, interrelations between individual parameters and variability within each group. There was no significant difference between the data for foetuses with and foetuses without birth defects.
The normal growth parameters of the placentae (weight, volume, surface area, thickness, and cord length) were interrelated with those of normal and abnormal foetuses (weight and length), and both parameters were found to be highly correlated to the period of gestation. This natural interrelationship was established for both groups of foetueses.
The vascular tree with Hyrtl's anastomosis, dispersion, magistral and atypical arterial patterns with dichotomus branching to the level of the tertiary branches was basically maintained in both groups of placentae and was uninfluenced by maternal, foetal or placental factors. The attribution of foetal malformations solely to deviations of the vascular pattern was thus not justified.
There is no direct evidence that morphological abnormalities of the placenta or cord produce birth defects.
Fifth International Conference on Birth Defects : Montreal, Quebec, Canada, 21-27 August, 1977.