Showing papers by "University of Malaya published in 1978"
TL;DR: The occurrence of apomixis in some other rain forest trees is reported, consistent with the view that these species are outbreeders in which predominantly short-range pollen and fruit dispersal are accompanied by short- range heterogeneity in gene frequencies.
Abstract: THE exceptional species diversity of tropical rain forests is well known; of these the lowland forests of the Malay Peninsula are among the richest1. This, and the size of the trees, pose obvious difficulties for the maintenance of pan-mixis, and tempt speculation on the processes by which such diversity has evolved and may now be favoured. Fedorov2 suggested that natural selection is low and self-pollination prevalent, favouring random genetic drift. Prevalence of random drift, or apomixis—agamospermy—would contradict Ashton's3 view that, given a stable environment, evolution proceeds through ecotypic differentiation while diversity accrues through ever increasing niche specialisation; for this view to be correct, maintenance of genetic variability within breeding groups would be essential. Solid evidence has been meagre but there is evidence4 that genetic polymorphism, and hence heterozygosity, is common in the emergent tree Shorea leprosula Miq., and Xerospermum intermedium Radlk., an undeirstorey species. The pattern of spatial variation is consistent with the view that these species are outbreeders in which predominantly short-range pollen and fruit dispersal are accompanied by short-range heterogeneity in gene frequencies. However, both are common trees with minimal spatial isolation. We now report the occurrence of apomixis in some other rain forest trees.
109 citations
TL;DR: It is demonstrated that mice injected intravenously with 1 × 109 sheep red blood cells (SRBC) produce cells which suppress delayed‐type hypersensitivity (DTH), and these suppressor cells are inhibitable by cyclophosphamide (CY).
Abstract: A previous study (Eur. J. Immunol. 1977. 7: 714) has shown that mice injected intravenously (i.v.) with 4 x10(9) sheep red blood cells (SRBC) produce cells which suppress delayed-type hypersensitivity (DTH). These suppressor cells are theta-positive, antigen-specific and act via a soluble factor which does not bear immunoglobulin determinants (Eur. J. Immunol. 1978. 8: 168). The present paper demonstrates that these suppressor cells are inhibitable by cyclophosphamide (CY). Mice injected with graded amounts of CY two days prior to SRBC injection, showed maximum augmentation of DTH at 200 mg/kg body weight, a dose which completely suppressed the appearance of splenic plaque-forming cells (PFC) to SRBC. In contrast, lower doses of CY enhanced both DTH and PFC responses. Time course studies showed that CY inhibited the precursors of suppressor cells and had little or no effect on suppressor cells which have already encountered antigens. This was further confirmed by passive transfer studies which showed tha- suppressor cells were inhibited if CY was administered at the same time or 2 days before SRBC injection, but were not affected if CY was given after antigen stimulation. Direct evidence for the effect of CY on suppressor cells was obtained by cell fractination with a Ficoll density gradient. The denser suppressor cell population was absent from the spleens of mice treated with 200 mg/kg of CY 2 days before i.v. injection with 1 x 10(9) SRBC.
94 citations
56 citations
TL;DR: Magnetic remanence of Jurassic radiolarian chert from the southwest arm of Sulawesi (Celebes) yields a palaeomagnetic pole at 55°N,32°E, indicating rotation of about 35° anticlockwise since the late Mesozoic.
44 citations
TL;DR: Light and electron microscopic studies and feeding experiments have confirmed the presence of two species of Sarcocystis in the water buffalo Bubalus bubalis as mentioned in this paper, one of which is the already known species with large macroscopic sarcocysts.
Abstract: Light and electron microscopic studies and feeding experiments have confirmed the presence of two species of Sarcocystis in the water buffalo Bubalus bubalis. One is the already known species with large macroscopic sarcocysts, Sarcocystis fusiformis (Railliet, 1897) Bernard and Bauche, 1912 and the other is S. levinei n. sp. which is being described in detail. The sarcocysts of S. levinei are 0.9×0.1 mm and the zoites in them 17.8×4.2 μm. Ultrastructurally, the primary cyst wall shows sloping villi with irregular wavy outlines. Within the villi are coarse granules and annulated fibrils. Trabeculae are present. The sexual stages of S. levinei occur in the subepithelial tissue of the small intestine of the dog and sporocysts shed by this definitive host are 15–16 by 10 μm.
36 citations
TL;DR: Sera from 243 donors belonging to the four main ethnic groups in West Malaysia were tested, using the indirect fluorescent antibody technique for the prevalence of antibodies to Sarcocystis, finding that prevalence was highest in the Orang Asli and lowest in Chinese.
Abstract: Sera from 243 donors belonging to the four main ethnic groups in West Malaysia (Orang Asli, Malays, Chinese and Indians) were tested, using the indirect fluorescent antibody technique for the prevalence of antibodies to Sarcocystis . Almost 20% reacted positively at dilutions of 1:64 or higher and eight among the Orang Asli and Malays gave the highest titres of 1:256. Prevalence was highest in the Orang Asli and lowest in Chinese. 22 sera also reacted positively to Toxoplasma , whether due to polyparasitism or cross-reactions is, as yet, unknown.
32 citations
TL;DR: The Darvel Bay ophiolite as mentioned in this paper consists of a conformable sequence of mantle harzburgite, a gabbro layer of about 2 km thickness, a basalt layer and associated chert-spilite association of Late Cretaceous to Eocene age and overlying Miocene melange and olistostrome deposits.
28 citations
TL;DR: The effects of trialkyltin compounds on the colchicine‐binding activity and the in vitro polymerisation of rat brain tubulin have been investigated and both the effects were found to be concentration dependent.
Abstract: The effects of trialkyltin compounds on the colchicine-binding activity and the in vitro polymerisation of rat brain tubulin have been investigated. Trialkyltins at concentrations between 10 and 100 μM inhibited the colchicine-binding activity of purified tubulin preparations derived from rat brain. Viscometric studies have shown that the same concentrations of trialkyltins also inhibited the in vitro polymerisation of tubulin. Both the effects were found to be concentration dependent. However, trialkyltins did not interfere with the in vitro preassembled microtubules. The reasons which are believed to explain the inhibitory effects of these compounds are discussed.
28 citations
TL;DR: The optimum storage and ripening temperature for the two cultivars was approximately 20°C as mentioned in this paper, and the nutritional value of ripe papayas decreased rapidly with prolonged storage in an atmosphere devoid of C 2 H 4 but containing 5% (v/v) CO 2 and with a high relative humidity.
28 citations
TL;DR: The experimental results suggest that these sea snake toxins exert a lethal effect via a mechanism of action different from that of the phospholipase A2 fraction.
27 citations
TL;DR: An antigen‐specific suppressor factor for delayed‐type hypersensitivity (DTH) to sheep red blood cells (SRBC) in mice is described and seems to act across the H‐2 barrier.
Abstract: An antigen-specific suppressor factor for delayed-type hypersensitivity (DTH) to sheep red blood cells (SRBC) in mice is described. Lymph node cells and spleen cells from mice injected intravenously with 1 x 10(9) SRBC 4 days previously were incubated in vitro for 48 h in culture medium. Supernatant obtained from the culture inhibited the induction of DTH to SRBC in normal mice. It also suppressed the expression of DTH in presensitized mice. The suppression is specific as the suppressor factor had no effect on the DTH to noncross-reacting antigen, chicken red blood cells. Treatment of the spleen cells with anti-theta serum and complement prevented the production of the suppressor factor, whereas treatment with anti-Ig serum and complement had no effect. Suppressor factor produced by H-2k mice suppressed the DTH in H-2b mice. The factor thus seems to act across the H-2 barrier. The suppressor factor was not removed by adsorption with goat anti-mouse immunoglobulin immunoadsorbent, but could be adsorbed by SRBC. It was stable at 56 degrees C for 1 h, but was partially inactivated by freezing and thawing. The factor has a molecular weight of less than 35 000 daltons.
TL;DR: A review of this problem and a study of the plants as they occur in Malaysia, Singapore, and Ceylon, has revealed that in fact only one species is involved and that the ‘large’ and the "small’ forms hitherto referred to the two species are merely growth phases of the one.
Abstract: A cultivated, usually sterile species ofPandanus, found rather widely in Malesia (especially in W. Indonesia, Malaya, and the Philippines, but also known in Ceylon), commonly used in cooking, e.g., to flavour rice and jellies, has been called in the past by several different scientific names, and indeed two distinct species were thought to exist. A review of this problem and a study of the plants as they occur in Malaysia, Singapore, and Ceylon, has revealed that in fact only one species is involved; that the ‘large’ and the ‘small’ forms hitherto referred to the two species are merely growth phases of the one; and that the correct botanical name for the plant isPandanus amaryllifolius Roxb. Notes on morphology, nomenclature, and uses of the plant are appended.
TL;DR: A case of mediastinal granuloma due to Rhizopus species is described, and comparisons are made with other infections of similar histologic appearance.
Abstract: Phycomycosis is seen most frequently in association with states of immunologic disturbance or hormonal imbalance. Several characteristic sites of infection with Phycomycetes are recognized, but mediastinal involvement has not been previously reported. A case of mediastinal granuloma due to Rhizopus species is described, and comparisons are made with other infections of similar histologic appearance.
TL;DR: In this paper, the authors show that upper Triassic shale from central Seram gives a direction of magnetization (D=82, I=23) which (assuming, as seems probable, that it was acquired before folding, and during a period of reversed magnetization) indicates Seram lay in 12±7°S latitude and has rotated anticlockwise 98° since the late Triassic.
Abstract: Upper Triassic shale from central Seram gives a direction of magnetization (D=82, I=23) which (assuming, as seems probable, that it was acquired before folding, and during a period of reversed magnetization) indicates Seram lay in 12±7°S latitude and has rotated anticlockwise 98° since the late Triassic. The equivalent (south) palaeomagnetic pole is at 8°N, 207°E. Pillow basalt of late Miocene age, from Kelang Island, west Seram has a magnetic vector D=106, I=9, indicating extrusion in 5°S latitude, and anticlockwise rotation of 74°. The equivalent (south) palaeomagnetic pole is at 16°S, 214°E. These results, although only of a reconnaissance nature, are consistent with the postulations of various authors that Seram has rotated anticlockwise in late Cainozoic.
TL;DR: Two rye populations with a B chromosome polymorphism were subject to a range of environmental stress conditions, by varying the sowing density, to assess the relative fitness of individuals with and without B chromosomes.
Abstract: Two rye populations with a B chromosome polymorphism were subject to a range of environmental stress conditions, by varying the sowing density, to assess the relative fitness of individuals with and without B chromosomes. In the Experimental population, characterised by a wide range and high frequency of B numbers, the B chromosome individuals were found to compete and survive less well than their 0 B counterparts throughout die range of densities used. Much of the reduced fitness in this population was due to the presence of odd-numbered and high-numbered B combinations. Progenies derived from plants surviving to maturity, however, were found to have significantly higher B frequencies, and a greater range of B numbers, than their parent plants. The Korean population, with a much lower B frequency, and composed mainly of 0 B and 2 B types, showed a more complex relationship between B frequency and plant density. At low densities plants with Bs had a selective advantage over those without. They also responded more favourably, in terms of survival, at very high rather than at intermediate densities. In this variety there were no significant differences in mean B frequency between the standard population from which the seed sample originated, the parent plants subjected to density stress and suffering a high mortality rate, and the seed progenies derived from these parents.
TL;DR: The two species ofSarcocystis—S.
Abstract: The two species ofSarcocystis—S. levinei andS. fusiformis from the water buffalo,Bubalus bubalis, show some ultrastructural similarities in their cyst wall and zoites. The zoites of both species are of about the same size, banana-shaped and have 22 subpellicular microtubules, numerous micronemes, eight rhoptries, a micropore in the region of the micronemes, an elongated mitochondrion, and a nucleus.S. levinei has 200–300 micronemes andS. fusiformis has about 400. The sarcocysts of both species are trabeculated and their cyst walls have cytophaneres containing annulated fibrils and coarse, electron dense granules. The cytophaneres ofS. levinei are sloping, with irregular, wavy outlines, whereasS. fusiformis has the cauliflower-type of cytophaneres. This difference in the appearance of the cytophaneres, together with the difference in size of the sarcocysts and their definitive hosts, further confirms thatS. levinei andS. fusiformis are two distinct species in the water buffalo.
TL;DR: A detailed petrological study of the Banda Arc volcanism, documented by extensive microprobe whole-rock and mineral analysis, shows that the apparent geographical eastwards continuity of the Sunda Arc conceals a major geochemical discontinuity adjacent to the southern end of the Weber Deep beneath Serua as discussed by the authors.
Abstract: A detailed petrological study of the Banda Arc volcanism, documented by extensive microprobe whole-rock and mineral analysis, shows that the apparent geographical eastwards continuity of the Sunda Arc conceals a major geochemical discontinuity adjacent to the southern end of the Weber Deep beneath Serua. The alkali contents and Sr isotope ratios suggest that Nila, Teun and Damar form one volcanic group distinct from Banda and Manuk, and Serua is in the border discontinuity, reflected in its widely fluctuating Fe/Mg partitioning between mineral phases and its variable Sr isotope ratios.
TL;DR: In this paper, a comparison was made between Scatchard's and Pitzer's interpretations of mixed-electrolyte solutions for HCl+NiCl2+H2O at 298.15°K at constant total ionic strengths of 0.1, 0.5, 1.0, 2.0 moles-kg−1 have been determined by an emf method.
Abstract: Activity coefficients for CHl in the system HCl+NiCl2+H2O at 298.15°K at constant total ionic strengths of 0.1, 0.5, 1.0, 2.0, and 3.0 moles-kg−1 have been determined by an emf method. A comparison was made between Scatchard's and Pitzer's interpretations of mixed-electrolyte solutions for this system and six related systems. Preference can be given to Pitzer's method provided cognizance is taken of the effects of higher-order electrostatic terms beyond the Debye-Huckel approximation on the thermodynamic properties of asymmetrical mixtures.
TL;DR: The results indicate that blocking antibody could be involved in the survival of 1 year old established larvae and experiments with 1 month old larvae were inconclusive.
Abstract: An attempt was made to determine if blocking antibody is involved in protecting cysticerci of Taenia taeniaeformis against a host immune response. Immunoflourescence microscopy confirmed that host antibody is present on the parasite surface within the capsule. To test if the larvae can still survive after such a coat of blocking antibody is removed, the larvae were trypsinised and then implanted into recipients. The results indicate that blocking antibody could be involved in the survival of 1 year old established larvae. Untrypsinised larvae were normal 14 days after implantation into control or immunised rats. Trypsinised larvae implanted in control rats were alive but showed on intense cell adherence on their surface. On the other hand, trypsinised larvae implanted into immunised rats were dead and completely encapsulated. However, experiments with 1 month old larvae were inconclusive.
TL;DR: The three major tin granitoid belts are, from west to east:a) Western: From Phuket to Tenasserim, the tin deposits are associated with high-level Cretaceous adamellite, granite and pegmatite as mentioned in this paper.
Abstract: The three major tin granitoid belts are, from west to east:a) Western: From Phuket to Tenasserim. The tin deposits are associated with highlevel Cretaceous adamellite, granite and pegmatite. The mineralization extends over a wide vertical extent.b) Main Range: From Bangka to South Thailand. The tin deposits are associated with deep-seated large-microcline granite and adamellite of late Carboniferous and late Triassic age. The mineralization is confined to the roof zones of the batholith.c) Eastern: From Billiton to Pahang-Trengganu. The tin-tungsten deposits are associated with adamellite to granite of Permian to mid Triassic high-level plutons. Mineralization extends over a wide vertical extent and there is an important Fe-Sn association.Only the Eastern Belt can be classified as Circum-Pacific type. It represents an epizonal volcano-plutonic arc characterized by plutonic rocks ranging from gabbro, through tonalite, granodiotite, adamellite to granite. Rhyolitic ignimbritic volcanic rocks are important.The Western Belt has some of the Eastern Belt characteristics, but lacks the range of plutonic rocks, and volcanic rocks are absent. However, the Tertiary opening of the Andaman Sea requires that the Burmese-Indonesian volcanic arc formerly was adjacent to the adamellite-granite belt.The Main Range Belt is interpreted as resulting from crustal anatexis of the leading edge of the western craton as it attempted to subduct beneath the Eastern volcano-plutonic arc following the late Triassic closure of the central marginal basin.
01 Jan 1978
TL;DR: Four species of Uca each inhabiting a distinct zone within the mangrove were studied to determine whether they differed in their behavioural and physiological responses to temperature, and each species was relatively independent of temperature over the thermal range most commonly experienced in its particular habitat.
Abstract: Mud surface temperatures in open mangrove habitats in Malaysia reach 44°C which is above the thermal tolerance of resident fiddler crabs Four species of Uca each inhabiting a distinct zone within the mangrove were studied to determine whether they differed in their behavioural and physiological responses to temperature The species were similar in their pattern of daily activity Despite zonal variations in ambient temperature, fiddler crab burrows in all parts of the mangrove attained a thermal equilibrium of between 28° and 30°C at about 10 cm depth Body temperatures were regulated in part by a burrow-retreat response in which the frequency of burrow visits by active crabs increased with environmental temperature Measured upper thermal tolerances of the four Uca species differed only slightly; LD 50 varied from 13 to 15 minutes at 43°C Interspecific differences were evident in the metabolic response of Uca to temperature In relation to their zonation on the shore the species showed a decrease in respiratory rate with increasing tidal position In addition, the rate of each species was relatively independent of temperature over the thermal range most commonly experienced in its particular habitat From these findings, the probable influence of temperature on the intertidal distribution of mangrove fiddler crabs is discussed
TL;DR: This is the tenth case of schistosomiasis reported from aborigines in Malaysia and a sylvatic source of infection is suggested.
Abstract: The first living patient with a Schistosoma japonicum-type infection who presented with the nephrotic syndrome is reported in detail. It is not clear whether the nephrotic syndrome was due to the schistosome infection or to the deposition of hepatitis B antigen and antibody complexes. This is the tenth case of schistosomiasis reported from aborigines in Malaysia and a sylvatic source of infection is suggested.
TL;DR: The conclusion is that the Adrenaline/Cocaine mixture has no advantage and its potentially dangerous interaction makes it unnecessary and unjustified.
Abstract: Topic adrenaline with cocaine has been used commonly for intranasal vasoconstriction to facilitate surgery and to control haemorrhage. Pharmacologically the drug combination is known to be a potentially dangerous interaction. This investigation studied whether either drug could be used separately rather than in combination, to achieve the same purposes. One hundred cases were randomized into four groups using 1:1000 Adrenaline, 5% Cocaine, 10% Cocaine and 5% Cocaine/1:1000 Adrenaline as the topical vasoconstriction regimes. The results showed that the vasoconstrictor effect was not significantly different within the four groups; topical 1:1000 Adrenaline resulted in more haemorrhage compared to the other three regimes; comparing the other three regimes the blood loss was not significantly different. The conclusion is that the Adrenaline/Cocaine mixture has no advantage and its potentially dangerous interaction makes it unnecessary and unjustified. Topical 5% Cocaine is recommended because it achieves the aims with the least side-effects.
TL;DR: The radiographic features include expansion of cortical bone, resorption of roots of teeth, the presence of lace-like bony septa and a spotty calcification within the tumor.
TL;DR: Across all five cultures, greater courtship participation, less religiosity, greater physical attractiveness, and spending less time with one's family were associated with greater permissiveness, and students from high-status backgrounds were generally more permissive.
Abstract: Our purpose was to investigate, cross-culturally, university students' premarital sexual standards. A number of predictions were derived from the work of Christensen, Reiss, and Burr. Data were collected via self-administered questionnaires from over 1100 English-speaking respondents in five “cultures” (four countries). These cultural contexts had a strong effect on the attitudes and behavior of individual respondents. As predicted, the difference in the standards held by males and females was small in highly permissive societies. Negative consequences of premarital intercourse (i.e., guilt) were reported by the highest proportion of sexually experienced respondents in the most restrictive society. An unsuccessful effort was made to predict how the correlation between permissiveness and such variables as religiosity would change in different cultures. Across all five cultures, greater courtship participation, less religiosity, greater physical attractiveness, and spending less time with one's family were associated with greater permissiveness. Finally, students from high-status backgrounds were generally more permissive.
TL;DR: A new metronidazole derivative, Tiberal (Ro-07-0207, Roche Laboratories), was evaluated in 22 children with Giardia lamblia infection and confirms the findings of other authors that a mucosal imprint method is more reliable than examination of stools, duodenal juice or jejunal biopsy material for the detection of G. lamblian infection.
Abstract: A new metronidazole derivative, Tiberal (Ro-07-0207, Roche Laboratories), was evaluated in 22 children with Giardia lamblia infection. Seven patients received an oral dose of 1 g twice daily for one day; the remaining 15 patients received a single dose of 50 mg/kg. Parasitological cure was noted in all 22 patients. Significant side effects were observed only in those children who received the drug at the higher dosage regime. The present study also confirms the findings of other authors that a mucosal imprint method is more reliable than examination of stools, duodenal juice or jejunal biopsy material for the detection of G. lamblia infection.
TL;DR: Oxantel-pyrantel treatment was associated with more cures, and a marginally greater reduction in ovum excretion than mebendazole but the differences were not statistically significant.
Abstract: In a pilot study in 17 children, oxantel-pyrantel as one single dose of 10 to 20mg/kg of each, gave good results in ascariasis but poor cure rates in both trichuriasis and necatoriasis. However in the latter groups the infection was extremely heavy. In a controlled trial in 51 children, using oxantel-pyrantel at the same dose, but given daily for 3 consecutive days, or mebendazole 100mg twice daily for 3 days, the drugs gave similar response rates. Both gave 100% cure rates, as assessed by the absence of ova by both Beaver and brine-flotation techniques, in Ascaris lumbricoides infection. The percentage cures and egg reduction rates were 66.7 and 94.5 in trichuriasis and 53 and 93.6 in necatoriasis respectively. Those for mebendazole were 52 and 91.2 in trichuriasis and 37.5 and 89.7 in necatoriasis. Oxante-pyrantel treatment was associated with more cures, and a marginally greater reduction in ovum excretion than mebendazole but the differences were not statistically significant. No side-effects were seen with either treatment.
TL;DR: In this article, isothermal dehydrations of the pentahydrate and trihydrate of copper sulfate are studied in the temperature ranges of 47-63°C and of 70.5-86°C respectively.
TL;DR: This report contains new biological information, and confirmation of earlier reports on Toxorhynchites splendens that are presented, and some of the observations contrast with previous studies.
Abstract: Biological observations of Toxorhynchites splendens are presented. Material for the study was obtained from an established laboratory colony. This report contains new biological information, and confirmation of earlier reports. Some of our observations contrast with previous studies.