Showing papers by "University of Peradeniya published in 1994"

Nutritional assessment of yam (Dioscorea alata) tubers

Abstract: The nutrient and antinutrient components of tubers from seven cultivars ofDioscorea alata were determined. The average crude protein content ofD. alata tubers was 7.4%. Starch (75.6–84.3%) was the predominant fraction of the tuber dry matter. Significant differences in crude protein and starch contents were observed among cultivars. Vitamin C content of the yam tubers ranged from 13.0 to 24.7 mg/100 g fresh weight. The results showed yams to be reasonably good sources of minerals. Phytic acid contents of the yams were low, with values ranging from 58.6 to 198.0 mg/100 g dry matter. Total oxalate levels in yam tubers were found to be in the range of 486–781 mg/100 g dry matter, but may not constitute a nutritional concern since 50–75% of the oxalates were in the water-soluble form. The overall results are suggestive of the nutritional superiority of yams compared to other tropical root crops.

Delayed cerebellar ataxia complicating falciparum malaria: a clinical study of 74 patients.

Abstract: We report the clinical features of 74 patients with delayed cerebellar ataxia (DCA) following falciparum malaria, who were prospectively followed up at two centres. This unusual complication has an acute onset, with signs suggesting a predominantly midline cerebellar lesion without any evidence of cerebral involvement. There was a delay of a median 13 days between the onset of fever and the onset of ataxia. DCA has a good prognosis, with spontaneous and complete recovery within 3 months. In our opinion, it is an example of a post-infective neurological syndrome possibly mediated via an immune mechanism.

Biological activity of some coumarins from Sri Lankan Rutaceae.

Abstract: Twelve coumarins isolated from plants of the Rutaceae collected in Sri Lanka have been subjected to a mechanism-based anticancer bioassay employing DNA repair-deficient and repair-proficient yeasts. Of these, seselin [10] and xanthyletin [11] were found to be active. Seselin also exhibited moderate cytotoxicity.

Survey of mycotic and bacterial keratitis in Sri Lanka.

Abstract: Over a two-year period (1976-1977 and 1980-1981), 66 cases of bacterial and mycotic cases of keratitis were diagnosed in the Eye Clinic of the General Hospital in Kandy, Sri Lanka. The clinical and microbiologic aspects of these cases are described. Noteworthy was the first known human case caused by Paecilomyces farinosus, a geophilic species, commonly encountered as an insect parasite throughout the world. The bacterial and the other fungal etiologic agents isolated and identified were: Pseudomonas aeruginosa, Streptococcus pneumoniae, Aspergillus flavus, A. niger, Fusarium oxysporum, and Lasiodiplodia theobromae. In vitro the fungi showed sensitivity in decreasing order to flucytosine, nystatin, amphotericin B and econazole. Due to the out-patient status of the patients, their in-vivo response to treatment was not assessable.

Postirrigation Breeding Patterns of Surface Water Mosquitoes in the Mahaweli Project, Sri Lanka, and Comparisons with Preceding Developmental Phases

Abstract: A 2-yr (1988–1989) survey of mosquitoes breeding in surface water was done in an area of the Mahaweli Project of Sri Lanka that underwent irrigation development and human settlement during the preceding 3 yr. In total, 78,649 immatures of 42 species were collected during the survey. Species of medical importance in the area were Anopheles annularis van der Wulp, An. culicifacies Giles, An. jamesii Theobald, An. nigerrimus Giles, An. subpictus Grassi, An. vagus Doenitz, An. varuna Iyengar, Mansonia annulifera (Theobald), Ma. uniformis (Theobald), Culex fuscocephala Theobald, Cx. gelidus Theobald, Cx. pseudovishnui Colless, Cx. tritaeniorhynchus Giles, and Cx. vishnui Theobald. These and other species used breeding habitats associated with irrigation development (i.e., canals, reservoirs, seepage pools, and rice fields) as well as natural habitats (i.e., rainwater pools, riverbed pools, streams, and marshes). Trends in the use of breeding habitats that were observed with the onset of irrigated rice cultivation in 1987, continued during the period under stable irrigation in 1988 and 1989. Mosquito species richness declined, but species equitability (as indexed by Shannon–Weaver diversity values) did not change. The overall study showed that ecosystem changes concomitant with irrigation development in the Mahaweli Project resulted in long-term changes in the composition of the mosquito fauna, which was characterized by the increasing dominance of species with the potential to transmit human pathogens.

Haemostatic dysfunction and acute renal failure following envenoming by Merrem's hump-nosed viper (Hypnale hypnale) in Sri Lanka: first authenticated case

Abstract: A five years old boy was bitten by a Merrem's hump-nosed viper (Hypnale hypnale) in Central Province, Sri Lanka. He developed local swelling, incoagulable blood, thrombocytopenia, bleeding into the gastrointestinal tract, and acute renal failure. Treatment with Serum Institute of Indian polyspecific antivenom (specific for venoms of cobra, common krait, Russell's viper and saw-scaled viper) had no effect on the coagulopathy, which persisted for more than a week. The boy recovered after 27 d in hospital, during which he was treated with peritoneal dialysis for renal failure. Laboratory studies demonstrated that the venom of H. hypnale was procoagulant, fibrinolytic and aggregated platelets. This first authenticated case of life-threatening acute renal failure and haemostatic disturbances caused by H. hypnale, a species responsible for 27% of snake bites in Sri Lanka, demonstrates the need for a new antivenom with specific activity against the venom of this species.

Application of present indices of chemical weathering for precambrian metamorphic rocks in Sri Lanka

Abstract: Weathered and fresh samples of Sri Lancan rocks (metamorphic) were collected from various localities and analysed for major elements by XRF method (Rigaku, KG-X System, Japan). The amount of water was found by ignation method.

The influence of potassium supply on nodulation, nitrogenase activity and nitrogen accumulation of soybean (Glycine max L. Merrill) grown in nutrient solution

Abstract: The influence of potassium nutrition on dry matter yield, nodulation, N accumulation and nitrogenase activity of soybean were studied under controlled conditions in hydrophonic and sand culture at 4 levels of K in a nutrient medium (10, 50, 100 and 200 mM) The dry matter yield, nodule parameters (nodule number and fresh weight of nodule per plant, average weight of nodule) and total nitrogen accumulation in the plant increased with increasing K-supply The lowest potassium level, 10 mM was suboptimal for normal growth, nodulation and N -accumulation, whereas 50 mM K was found to be an optimal level for these same parameters However, the nitrogenase activity, which was determined non-destructively, was not affected by an increased supply of K

Reflex epilepsies: experience in Sri Lanka.

Abstract: Reflex epilepsy (RE) is characterised by seizures that are regularly elicited by some specific stimulus or event mediated by neural pathways. In a prospective study of 1287 epileptic patients seen at Peradeniya, 223 (17.3%) were found to have RE, eating being the commonest stimulus (191 patients, 85.7%). Photosensitive epilepsy (PSE) was relatively rare. Intermittent photic stimulation on 874 unselected epileptic patients produced a positive photoconvulsive response in 60 (6.9%). None had photosensitive seizures, but 3 had a higher frequency of seizures while watching television. Eating epilepsy (EE) had the highest prevalence at Peradeniya (148/1000 epileptic patients). This group was male predominant, and the onset of epilepsy in most cases was in the second decade. The majority experienced partial complex seizures. Repetitive and chronic stimulation of the amygdala during eating is suggested as the mechanism underlying EE. Twenty-one patients had seizures evoked by calculation, problem solving or spatial tasks. Juvenile myoclonic epilepsy was the commonest form of seizure disorder in them. Although PSE itself is rare, self-induced epilepsy (SIE) was common. There were 8 patients who self-induced seizures. The majority were photosensitive and they induced seizures by gazing at the sun and waving a hand in front of the eyes. In the management of REs, clobazam produced impressive results. As for possible seizure-inhibitory mechanisms, our studies on a "Sathi" mediator showed definite EEG changes during mediation. Can mediation increase the seizure-threshold and abort or prevent the propagation of the epileptic discharge? The answer, apart from its possible therapeutic applications, may provide insight into the mechanisms of seizure generation.

Viruses Isolated from Mosquitoes Collected in Sri Lanka

Abstract: Attempts to isolate viruses from 178,181 unengorged female mosquitoes collected from different ecologic areas of Sri Lanka yielded 31 isolates: 17 of Japanese encephalitis (JE) virus, nine of Getah virus, three of a Batai-related bunyavirus, and two of Arkonam virus. Culex tritaeniorhynchus and Mansonia uniformis mosquitoes were found to carry JE virus in a dry zone nonepidemic area, and Cx. pseudovishnui was found to carry it in a wet zone nonepidemic area. Japanese encephalitis virus was isolated from Cx. tritaeniorhynchus, Cx. gelidus, Cx. fuscocephala, and Cx. whitmorei during a human epidemic in the dry zone. Getah virus was isolated from Cx. tritaeniorhynchus, Cx. gelidus, and Cx. fuscocephala collected in the vicinity of swine. Isolations of Getah, Arkonam, and Batai-related viruses from Sri Lanka are reported for the first time.

Intestinal parasitoses in the Kandy area, Sri Lanka

Abstract: The prevalence of intestinal protozoa and geohelminths was assessed among two diverse populations in the Kandy area: adults attending medical outpatients clinics at the Teaching Hospital Peradeniya, and pre-school children in low-cost housing areas within the Kandy Municipality. In addition to a brief history and examination, a fresh stool sample was obtained and examined by direct smears in saline and iodine, and by formol-ether concentration. The children's stool samples were also examined for Cryptosporidium by cold Ziehl-Neelsen staining. A total of 192 stool samples from the adult outpatients (101 males, age range 15-82 years, mean 51.4 years) and 354 samples from the pre-school children (age range 1-72 months, mean 30 months) were examined. Entamoeba histolytica was not seen in any of the samples; Giardia cysts and Cryptosporidium oocysts were seen in three and one sample respectively from the pre-school children. The overall prevalence of geohelminth infections was 21.3% among the adults and 24.5% among the children. Ascaris lumbricoides was the predominant species in both populations. Comparison of the rate of intestinal parasite infection among 37 adult patients patients with non-specific abdominal complaints, with the rate among 37 matched controls with no abdominal complaints showed no significant difference (16% and 19% respectively). This suggests that the presence of abdominal pain or diarrhea was unrelated to the presence of intestinal parasites in the adult study population. Although the techniques used were not highly sensitive, the absence of E. histolytic probably reflects a true decline in the prevalence of this parasite in Sri Lanka.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on terpenoids and steroids, 25. complete 1H- and 13C-nmr spectral assignments of salaciquinone, a new 7-oxo-quinonemethide dinortriterpenoid

Abstract: A new 7-oxo-quinonemethide dinortriterpenoid, salaciquinone [1], and a known quinonemethide dinortriterpenoid, isoiguesterin [3], were isolated from the root bark at Salacia reticulata var. β.-diandra (Celastraceae). The structure elucidation of salaciquinone was based on detailed 2D and nOe-difference nmr spectroscopy, leading to the complete assignment of the 1 H- and 13 C-nmr spectra and revision of some 1 H-nmr spectral assignments made previously for the related 7-oxo-quinonemethide nortriterpenoid, dispermoquinone [2]. Complete 1 H- and 13 C-nmr spectral assignments of isoiguesterin were also made, also leading to revision of some 13 C- nmr assignments previously made for this compound

Isolated bilateral recurrent laryngeal nerve paralysis: a delayed complication of organophosphorus poisoning.

Abstract: assess accurately, but clinically the intoxication was severe with pupillary constriction (pin point in 2 patients), tachycardia, excess secretions, and impaired consciousness (2 patients were unconscious and the other was very drowsy on admission). Furthermore, large amounts of atropine were required to treat the cholinergic phase, also indicating severe intoxication. Details of treatment with

Analysis of fully coupled thermomechanical behaviour around a rigid cylindrical heat source buried in clay

Abstract: The problem of fully coupled consolidation and heat flow around a rigid cylindrical heat source buried in clay has been studied. The governing equations of the problem are summarized in the paper and a finite element time-marching scheme to obtain an approximate solution to the governing equations is described. The stress–strain behaviour of the skeleton of the saturated soil has been represented by both a linear elastic model and the modified Cam clay soil model. The results of a limited parametric study are presented with the aim of understanding the major mechanisms of soil behaviour close to buried canisters of hot radioactive waste. A range of soil properties has been included in the study, and the effects of soil disturbance during canister emplacement have also been considered.

Origin of vein graphite in high-grade metamorphic terrains

Abstract: The role of CO2 in the creation of a refractory base of granulite by metamorphism has received increasing attention by geologists investigating sub-crustal phenomena. A voluminous source of mantle-derived CO2 has been postulated for the phenomenon of granulite formation. Recent studies on the granulite terrain of Sri Lanka has clearly shown that it is only an upper crustal section and that it had been subjected to a much smaller influx of CO2 than hitherto envisaged. The close association of graphite with the granulites and the recent discovery of grain-boundary graphite in the lower crust implies graphite as a major source of CO2. Recent reports on the discovery of alluvial diamonds within the granulite belt of the Highland Complex of Sri Lanka where graphite is abundant possibly indicates penetration of the graphite-diamond inversion line.

Malaria eradication as a legacy of colonial discourse: the case of Sri Lanka.

Abstract: Analysis of the history of malaria control in British Ceylon reveals that, besides public health considerations, it was guided by the interests of the colonial powers to expand territory, justify colonial domination, protect the plantation industries and medicalize social misery. The implications of the latter considerations for the choice of a malaria eradication strategy are discussed.

Growth, yield and nodule activity of mungbean intercropped with maize and cassava

Abstract: A field study evaluated the influence of maize (Zea mays) and cassava (Manihot esculenta) on the growth, yield and nodulation parameters of individual plants of mungbean (Vigna radiata), established as an intercrop. The two systems were managed in a similar manner. Germination, establishment and growth of plants, and yield parameters of mungbean within the maize crop were reduced to a greater extent than that of plants grown with cassava. In addition, in both systems, growth and yields of mungbean plants in close promixity to the non-legume were suppressed to a greater degree than in plants in the centre rows. In contrast, nodulation and nodule activity of plants in close promixity to maize or cassava was higher than in that of centre rows. The study revealed that shading of mungbean plants in close proximity to maize and cassava does not reduce nodule activity. While competitive relationships between the non-legume and mungbean could affect the growth and yields of the legume plants in close promixity, the greater utilisation of nitrogen by the non-legume is suggested to be the causal factor for increased nodule activity.

The effect of serum and colostrum immunoglobulins from buffaloes infected with Toxocara vitulorum on T. vitulorum larvae in vitro and in vivo in mice.

Abstract: Serum and colostrum were collected from adult buffalo cows naturally infected with Toxocara vitulorum. When injected into mice, the colostrum reduced the number of larvae of T. vitulorum that migrated in the mice. Injection of particularly the IgG-containing fraction but also the IgM-containing fraction of Sephadex G200-chromatographed colostrum also passively protected mice. When incubated for 6 h in buffalo serum or colostrum or fractions of these from Sephadex G200 and diethylaminoethanol Sephadex, T. vitulorum larvae had their activity in vitro curtailed. When the larvae were then fed to mice, their ability to migrate was markedly inhibited as compared with that of larvae that had been incubated in fetal calf serum or in helminth-free sheep colostrum. Fractions of serum and colostrum containing IgG1 had greater inhibitory effects both on the larvae in vitro and on their subsequent migration in mice than did IgG2-containing fractions. IgM also inhibited the larvae as 2-mercaptoethanol reduction of IgM in the IgM-containing peak eluted from Sephadex G200 reduced the inhibitory activity of this peak, although the activity was not completely abrogated.

Prevalence of hepatitis C virus markers in Sri Lankan patients with alcoholic cirrhosis

Abstract: A high prevalence of antibodies against hepatitis C virus (HCV) has been reported in patients with alcoholic cirrhosis. There are, however, doubts regarding the specificity of the first generation anti-HCV antibody assays used. We prospectively investigated HCV status in 47 Sri Lankan patients with alcoholic cirrhosis. A first generation assay (Ortho HCV enzyme-linked immunosorbent assay [ELISA]) and two second generation tests (Abbott HCV enzyme immunoassay and United Biomedical Incorporated HCV enzyme immunoassay) were used. Positive results were confirmed by the second generation recombinant immunoblot assay (RIBA 2). Of the 47 patients (46 males, mean age 41.7 years), 17 (36.2%) had previously had one or more blood or plasma transfusions. Seven (14.9%) of the samples were positive for anti-HCV antibodies using the Ortho-HCV ELISA, but only one (2.1%) sample was positive when tested with the second generation assays. The positive result was confirmed by RIBA 2. The prevalence of HCV in the patients was low despite many of them being exposed to blood or blood products. Hepatitis C virus, therefore, may not be an important pathogenic factor in alcoholic cirrhosis in Sri Lanka.

Periparturient reduction in buffalo of mitogen-induced lymphocyte proliferation and antibody to Toxocara vitulorum.

Abstract: Lymphocyte and antibody reactivity were examined during the periparturient period in buffalo cows naturally infected withToxocara vitulorum. Titres of antibodies to an extract ofT. vitulorum larvae increased about 3 months before parturition. Antibody titres declined at about the time of parturition and remained low for up to 3 months into lactation. Lowered titres were found in the IgG class and not the IgM class of immunoglobulins. Levels of lymphocyte transformation induced by the mitogens concanavalin A and pokeweed mitogen declined markedly from one to 2 weeks before until one to 2 weeks after parturition. The relationship between this suppressed immunological reactivity and vertical transmission ofT. vitulorum larvae is discussed.

Theory to predict potentially mineralizable nitrogen in soils

Abstract: A new theory, based on the diffusion of NH 4 + ions during incubation, is put forward to predict potentially mineralizable N ( No ) in soils. Its validity is tested using predicted real No , based on the regression analysis of experimental data and also it is compared with the conventional one-pool exponential model of Stanford and Smith (1972). In all soil samples employed for the test, our new model predicted No more accurately than the one-pool model. The procedure to calculate No using our model is also easier than for the one-pool model. It is presumed that the accuracy of prediction of our new model could have been further improved, if an average value for the time-variant diffusion coefficient of NH 4 + ( D ), is used for each of the samples separately, because D could vary with the nature and content of organic matter in soils. Therefore, it is concluded that further studies are needed to establish D for soils with different organic matter contents and under different soil conditions.

Absence of anti-Purkinje cell antibodies in patients with cerebellar ataxia following falciparum malaria

Abstract: Immunological mechanisms have been implicated in the pathogenesis of delayed cerebellar ataxia following falciparum malaria (DCA). We tested serum and CSF samples obtained from 39 Sri Lankan patients with DCA for the presence of antibodies (Ab) directed against cerebellar Purkinje cells by an immunofluorescence (IF) technique and Western blot analysis. For the IF test 7 mu thick frozen sections of histologically normal cerebellum obtained at post mortem were used. Proteins obtained from crude preparations of Purkinje cells isolated from the cerebellum were used for Western blot analysis. Sera obtained from patients known to have antineuronal antibodies associated with cerebellar degenerations and paraneoplastic disorders (anti-Hu and anti-Yo Ab) and sera from normal blood donors served as positive and negative controls, respectively. All serum and CSF samples obtained from patients with DCA were negative for Ab directed against cerebellar Purkinje cells. Humoral mechanisms are, therefore, unlikely to be important in the pathogenesis of this delayed complication of falciparum malaria.