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Showing papers by "National University of Singapore published in 1969"


Journal ArticleDOI
16 Aug 1969-Nature
TL;DR: The removal of prostaglandins by the lung restricts their activities to the organs from which they are released and between their organ of origin and the site in the pulmonary circulation where they are inactivated.
Abstract: STIMULATION of the splenic nerves releases prostaglandins from the spleen to give concentrations of as much as 0.2 µg/ml. in splenic venous blood1. The release of prostaglandins might influence organs remote from the site of release, for prostaglandins can exert potent actions on smooth muscle2. The lung has recently been shown to determine the fate of many vasoactive substances; some are activated—conversion of angiotensin I to angiotensin II (ref. 3)—and some inactivated. The degree of inactivation seems to be specific for a given substance, ranging from almost complete (bradykinin4, 5-hydroxytryptamine5, prostaglandins E1 E2 and F2α (ref. 1)), to minor (noradrenaline6), to allowance of their free passage (adrenaline6 and angiotensin II (ref. 7)). The removal of prostaglandins by the lung restricts their activities to the organs from which they are released and between their organ of origin and the site in the pulmonary circulation where they are inactivated1. A prostaglandin which passed through the lungs after its release from an organ could be considered a circulating hormone, as long as it is not rapidly degraded in the blood. Ferreira and Vane1 reported that prostaglandins E1 E2 and F2α were stable in blood, though rapidly inactivated by the lung. Removal of prostaglandins A1 and A2 by the lung was not determined because the assay organs are insensitive to them. Vascular smooth muscle, however, unlike other smooth muscle, is reactive to low concentrations of prostaglandins A1 and A2 (refs. 8–10) and the renal vasculature is probably most sensitive to prostaglandins A1 and A2 (refs. 10 and 11). Because the renal vasculature is also sensitive to prostaglandins E1 and E2 (ref. 12), it has been used as an index of the fate of prostaglandins infused into the venous and arterial circulations.

226 citations


Journal ArticleDOI
TL;DR: This two-year study of the breeding and moulting cycles of a small bird was made on Singapore Island, which is near the equator and has a very uniform climate, and seasonal changes in the weight of the flight muscles indicate a cycle in the protein level of the body.
Abstract: This two-year study of the breeding and moulting cycles of a small bird, Pycnonotus goiavier, was made on Singapore Island, which is near the equator and has a very uniform climate. There are well-marked breeding and moulting seasons in the population, and it is suggested that these protein-demanding processes are timed to occur within the period of increased insect abundance in the first half of the year. Seasonal changes in the weight of the flight muscles indicate a cycle in the protein level of the body. This cycle might serve as an internal regulator of the reproductive cycle.

141 citations




Journal ArticleDOI
26 Apr 1969-Nature
TL;DR: Hb-Chiapas is not unstable and its presence does not lead to clinical or haematological symptoms, and two new haemoglobin variants of this type are observed which are also not associated with marked molecular instability.
Abstract: AN abnormal haemoglobin with a substitution involving a proline residue might be expected to be either unstable or functionally abnormal because of the inevitable conformational changes which occur. This has been borne out in the cases of haemoglobins Genova, Dhofar, Bibba and Santa Ana, all of which are unstable and associated with Heinz body anaemia1. Replacements involving proline residues do not, however, invariably result in these changes. Thus Hb-Chiapas2,3 is not unstable and its presence does not lead to clinical or haematological symptoms. We have recently observed two new haemoglobin variants of this type which are also not associated with marked molecular instability.

46 citations


Journal ArticleDOI
TL;DR: The CMC of cetomacrogol 1000 was practically unaffected by the addition of salt and the extent of interfacial tension reduction with respect to salt concentration was small when compared to corresponding systems containing ionic surfactants.

37 citations


Journal ArticleDOI
TL;DR: In Sesarma (Geosesarma) perracae Nobili, 1903 the ovigerous females live in burrows containing fresh-water into which the young are released and the larval stages live entirely on stored yolk.
Abstract: In Sesarma (Geosesarma) perracae Nobili, 1903 the ovigerous females live in burrows containing fresh-water into which the young are released. The larval life is greatly abbreviated and the larval stages live entirely on stored yolk. The megalopa stage is almost unrecognizable.

32 citations



Journal ArticleDOI
TL;DR: The paediatric aspect of this interesting condition and with the factors influencing fetal survival gained from the experience of abdominal pregnancy in the Kandang Kerbau Maternity Hospital, Singapore are dealt with.

29 citations


Journal ArticleDOI
01 Jan 1969-Analysis

24 citations


Journal ArticleDOI
11 Jan 1969-Nature
TL;DR: The effect on the generation of angiotensin of interrupting conduction in the vagus nerve is studied, which suggests that it is brought about by reflex activation of the nerves.
Abstract: HAEMORRHAGE causes an increase of the concentration of renin1–4 and of angiotensin5–8 in blood; when the blood volume of anaesthetized dogs is reduced this rise in concentration of renin4 and of angiotensin7 can be prevented by local anaesthesia of the renal nerves, which suggests that it is brought about by reflex activation of the nerves. The changes of angiotensin concentration correlate not with changes of arterial pressure but with changes of central venous pressure7. Changes of central venous pressure are usually accompanied by changes of pressure in the atria and the pulmonary circulation; these areas are plentifully supplied by vagal afferent fibres and so it seemed possible that the vagus nerve might form the afferent limb of the reflex. We have therefore studied the effect on the generation of angiotensin of interrupting conduction in the vagus nerve.

Journal ArticleDOI
07 Jun 1969-Nature
TL;DR: The induction of delayed hypersensitivity reactions in the footpads of mice is described and resistance to isografts of chemically induced tumours in mice may also be a form of cell mediated immunity.
Abstract: ALLOGRAFT rejection is usually grouped with delayed hypersensitivity, acquired cellular resistance to infection and some types of auto-immune disease as a form of cell-mediated immunity, implying that all these phenomena may share a common immunological mechanism. The rejection of skin allografts is generally accompanied by the development of delayed-type hypersensitivity to graft antigens. Reactions having the time-course and macroscopic and microscopic features of skin reactions in delayed-type hypersensitivity have been elicited by injecting donor antigen (in the form of lymphoid cells or extracts thereof) into sensitized humans, guinea-pigs, hamsters, dogs and rats1–3. Similar reactions could not be elicited in mice1. Here we describe the induction of delayed hypersensitivity reactions in the footpads of mice. Because resistance to isografts of chemically induced tumours in mice may also be a form of cell mediated immunity4, we have also tested whether similar reactions can be elicited after tumour isografting in mice.


Journal ArticleDOI
TL;DR: A detailed investigation of Singapore women suffering from antepartum haemorrhage was undertaken as part of a wider study of the folate status of patients attending the Kandang Kerbau Hospital, Singapore.


Journal ArticleDOI
TL;DR: Evidence that the glucuronyl transferase in homogenate, measured by this procedure reflects its activity in the microsomes is presented, and it is suggested that the reaction velocity increased linearly with the weight of liver used in the incubation medium.


Journal ArticleDOI
TL;DR: The presence of the resin implants seems to lessen the contour changes occurring over the period of observation both on the labial and palatal surfaces as compared with the control sites.
Abstract: Summary A continuing report of the effect of acrylic resin root implants on the preservation of the alveolar process or the prevention of its loss subsequent to tooth extractions was presented. This report was made 20 months after the insertion of the acrylic resin root implants and the contour changes both labially and palatally were presented together with radiographs of the implants with the bony changes observed. The presence of the resin implants seems to lessen the contour changes occurring over the period of observation both on the labial and palatal surfaces as compared with the control sites. The radiographs suggest the implants are now “sealed” within a bony framework. The absence of clinical manifestations of pathology at any stage of the 20 month period seems to indicate a favorable acceptance of the implants by the tissues.

Journal ArticleDOI
TL;DR: This study established the effectiveness and safety of vacuum aspiration in the treatment of incomplete abortion by treating all cases of abortion over a three months period from November, 1967, to January, 1968.


Journal ArticleDOI
TL;DR: Elephantopus scaber has been found to contain epifriedelinol, lupeol, stigmasterol, potassium chloride, and a mixture of triacontan-1-ol and dotriacontans 1-ol.



Journal ArticleDOI
TL;DR: The Allan-Robinson method has been used to synthesize several naturally occurring flavones, such as 3.4, 4.7, 7-trihydroxy-3methoxyflavone (3methylfisetin), 4.5-dihydroxy-4.7-dimethyl ether (kumatakenin) and 3.

Journal ArticleDOI
TL;DR: It is evident that patent infections can be produced in a natural host by using artificial puncture wounds, and this method of infection, perhaps with certain modifications, will probably be of value in subsequent studies on development and distribution of filarial nematodes in the vertebrate host.
Abstract: The use of artificially produced puncture wounds as a route whereby Brugia pahangi larvae could be administered to a vertebrate host was tested in mice. Approximately 50% of the larvae administered were recovered in the tissues. This method of infection was then compared with that commonly used in experimental infections, namely inoculation with a syringe and needle. The differences in infections produced by these two procedures are too small and the number of observations too few to make any generalizations on the relative effectiveness of the two methods, but it is evident that patent infections can be produced in a natural host by using artificial puncture wounds, and this method of infection, perhaps with certain modifications, will probably be of value in subsequent studies on development and distribution of filarial nematodes in the vertebrate host.

Journal ArticleDOI
TL;DR: Soil and root surface support slightly different mycoflora, and a notable feature in this study is the absence of Penicillium spp.
Abstract: A preliminary study on soil and root-surface fungi is reported. Soil and root surface support slightly different mycoflora. Fungi encountered on the root surfaces of gramineous members also differ slightly from those on the root surface of a legume.Paecilomyces fusisporus appears to predominate in soil, andFusarium oxysporum on root surfaces. A notable feature in this study is the absence ofPenicillium spp. from both soil and root surface.


Journal ArticleDOI
TL;DR: A series of gallates of varying alkyl chain length was used to study the effect of antioxidants on the oxidation of benzaldehyde and p-methylbenzaldehyde dispersed in aqueous solutions of cetomacrogol at 25° in the presence of cupric sulfate.

Journal ArticleDOI
TL;DR: The multi-modal evaluation of an assessment system is feasible and provides thorough and diagnostic information and utility of the assessment system could be further improved by modifying the psychometrically inappropriate assessment items.
Abstract: Objective: To evaluate assessment system of the ‘Research Methodology Course’ using utility criteria (i.e. validity, reliability, acceptability, educational impact, and cost-effectiveness). This study demonstrates comprehensive evaluation of assessment system and suggests a framework for similar courses. Methods: Qualitative and quantitative methods used for evaluation of the course assessment components (50 MCQ, 3 Short Answer Questions (SAQ) and research project) using the utility criteria. Results of multiple evaluation methods for all the assessment components were collected and interpreted together to arrive at holistic judgments, rather than judgments based on individual methods or individual assessment. Results: Face validity, evaluated using a self-administered questionnaire (response rate-88.7%) disclosed that the students perceived that there was an imbalance in the contents covered by the assessment. This was confirmed by the assessment blueprint. Construct validity was affected by the low correlation between MCQ and SAQ scores (r=0.326). There was a higher correlation between the project and MCQ (r=0.466)/SAQ (r=0.463) scores. Construct validity was also affected by the presence of recall type of MCQs (70%; 35/50), item construction flaws and non-functioning distractors. High discriminating indices ( > 0.35) were found in MCQs with moderate difficulty indices (0.3-0.7). Reliability of the MCQs was 0.75 which could be improved up to 0.8 by increasing the number of MCQs to at least 70. A positive educational impact was found in the form of the research project assessment driving students to present/publish their work in conferences/ peer reviewed journals. Cost per student to complete the course was US$164.50. Conclusions: The multi-modal evaluation of an assessment system is feasible and provides thorough and diagnostic information. Utility of the assessment system could be further improved by modifying the psychometrically inappropriate assessment items.

Journal ArticleDOI
TL;DR: In this paper, a series of psychobiological experiments bearing on just this sort of question were carried out, and the results revealed some of the limitations of ordinary language philosophy, which might contribute to our philosophical understanding of pleasure.
Abstract: About the time Professor Ryle was telling us in the Tarner Lectures that pleasure is not a sensation because, inter alia, it is not separable from its source, a cause or effect, dockable or locatable or describable the way pains are, there began a series of psychobiological experiments bearing on just this sort of question. Taking these into account might therefore contribute to our philosophical understanding of pleasure. It might also reveal some of the limitations of ordinary language philosophy.