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Biomedical subjects

S Sivakumaran

Publications and source records attributed to S Sivakumaran.

At least 19 recordsLinked to original sources
PubMed2006

Outcomes for older patients with hip fractures: the impact of orthopedic and geriatric medicine cocare.

OBJECTIVES: To assess the impact of a specifically designed model of orthopedic-geriatric cocare on hip fracture (HF) outcomes. SETTING: Tertiary teaching hospital (level I trauma center). DESIGN: Prospective observational study with a retrospective (historical) control. Data on 951 consecutive patients 60 years of age or older admitted to the authors' institution with a nonpathologic HF over a 7-year period (1995 to 2002) were analyzed. Between 1995 and 1997, medical problems were managed by a geriatric medicine (GM) consultation-only service (retrospective audit). In 1998, a GM registrar began overseeing daily medical care with weekly geriatrician consultant review (prospective study). Outcomes for 2 time periods were compared: a 3-year period before (no GM; 504 patients) and a 4-year period after (GM; 447 patients) the introduction of GM cocare. MAIN OUTCOME MEASUREMENTS: Postoperative medical complications, mortality, length of stay, discharge destination, use of thromboprophylaxis, and antiosteoporotic treatment. RESULTS: While comparing 2 periods (GM and no GM), significant reductions in postoperative medical complications and comorbid conditions (in total 49.5% vs. 71.0%, P<0.001) and mortality (4.7% vs. 7.7%, P<0.01) occurred and rehospitalization to medical wards within 6 months decreased (28% vs. 7.6%). However, no differences were observed in median length of hospital stay (10.8 vs. 11.0 days) or in discharge destination. Antiosteoporotic treatment (12% to 69%) and specific thromboprophylaxis (63% to 94%) increased in the GM period. CONCLUSIONS: Orthopedic-geriatric cocare for the older patients with HF was associated with significant reductions in morbidity and mortality, and increases in optimal postoperative care. Options for further improvement of orthopedic-GM cocare need to be investigated.

Aged↗
PubMed2004

Green tea flavan-3-ols and oligomeric proanthocyanidins inhibit the motility of infective larvae of Teladorsagia circumcincta and Trichostrongylus colubriformis in vitro.

The effects of a hot water infusion and an aqueous acetone extract of green tea (Camellia sinensis) on the motility of infective larvae of the sheep nematodes Teladorsagia circumcincta and Trichostrongylus colubriformis were investigated under in vitro conditions. The infusion and extract dose-dependently inactivated the infective larvae as assessed by the larval migration inhibition (LMI) assay. To determine the components responsible for the inhibitory activity, the hot water infusion and aqueous acetone extract of green tea were fractionated on Sephadex LH-20 and the green tea extract fractions (GTE-I-VIII) characterised by mass spectrometry. The larvae were exposed to increasing concentrations of these GTE fractions. Fractions containing epigallocatechin gallate (EGCG) and proanthocyanidin oligomers were most effective. GTE fractions were more effective against T. circumcincta than T. colubriformis larvae as assessed by the LMI assay.

Animals↗
PubMed2003

Effect of flavan-3-ols on in vitro egg hatching, larval development and viability of infective larvae of Trichostrongylus colubriformis.

The effects of flavan-3-ols (the monomer units of condensed tannins (CT)) and their galloyl derivatives on the viability of eggs, the development of first stage (L1) larvae, and the viability of the infective larvae of Trichostrongylus colubriformis were investigated under in vitro conditions. Each of the flavan-3-ol gallates showed some inhibition of egg hatching at 100 microg/ml, and 100% inhibition at 1000 microg/ml, with epigallocatechin gallate being the most effective in the egg hatch (EH) assay. In contrast, none of the flavan-3-ols were able to completely inhibit egg hatching. The flavan-3-ols and galloyl derivatives dose-dependently inhibited the development of infective larvae as assessed by the larval development (LD) assay. A larval migration inhibition (LMI) assay was used to assess the effect of flavan-3-ols and their galloyl derivatives on the motility of the infective third-stage (L3) larvae of T. colubriformis. In general, the flavan-3-ol gallates were more effective than the flavan-3-ols at immobilising the infective larvae as evidenced by their ability to inhibit more (P<0.05-0.01) larvae from passing through the LMI sieves. At 500 microg/ml, epigallocatechin gallate inhibited significantly more (P<0.1) larvae from passing through the sieves than did catechin gallate, epicatechin gallate, or gallocatechin gallate. Comparisons were made between the flavan-3-ols and their galloyl derivatives with the in vitro effects of CT extracts from several forage legumes, which have exhibited effects on parasites in vivo. The forage legumes tested at 200-500 microg/ml reduced the proportion of eggs that hatch, with comparable results to those obtained using the flavan-3-ols. The activities may be influenced by the prodelphinidin: procyanidin (PD:PC) ratios: CT extracts from Lotus pendunculatus and sainfoin have PD:PC ratios of 70:30 and 77:23, respectively, whereas the less active CT extract from Lotus corniculatus has a PD:PC ratio of 27:73. The active CT extracts from forage legumes have epigallocatechin as the dominant flavan-3-ol extender unit, and epigallocatechin is the most active flavan-3-ol in both the EH and LD assays.

Animals↗
PubMed2001

Dissecting folliculitis of the scalp with marginal keratitis.

We describe a young man with dissecting folliculitis of the scalp, who subsequently developed marginal keratitis. We are unaware of any previous reports of this association. The aetiology of dissecting folliculitis is thought to relate to abnormal follicular occlusion with subsequent suppuration, although an infective process has never been established. Marginal keratitis is postulated, but not proven, to be caused by an enhanced immune response to Staphylococcus aureus antigens. We suggest that a similar abnormal response to infection may be important in these two conditions. This case also highlights ocular complications which may occur in patients with dissecting folliculitis.

Administration, Topical↗
PubMed1998

Essential thrombocythemia: an uncommon cause of digital gangrene.

We describe a case of essential thrombocythemia (ET), presenting as digital gangrene. ET is a rare myeloproliferative disorder characterised by a persistently elevated platelet count which commonly presents with haemorrhagic manifestations. Thrombosis occurs less frequently and digital gangrene is an uncommon presentation.

Diagnosis, Differential↗
PubMed1997

Identification of soil bacteria expressing a symbiotic plasmid from Rhizobium leguminosarum bv. trofolii.

A hundred strains of non-nodulating, Gram-negative, rod-shaped bacteria were isolated from clover-ryegrass pastures on three different soil types and from a sandy loam under lupins. When crossed with Escherichia coli PN200 containing the cointegrate plasmid pPN1, 11 transconjugants gained the ability to form nodules on the roots of white clover (Trifolium repens cv. Grasslands Huia). A nodA probe indicated that they had gained nodulation genes. The identities of these 11 strains and 4 others derived from earlier work on non-nodulating root nodule bacteria, were determined by ribotyping, DNA-DNA hybridization, and partial 16S rRNA sequencing. Good agreement was obtained between the three methods, and 11 of the strains were identified as Rhizobium leguminosarum (6), Rhizobium loti (2), Rhizobium etli (1), Rhizobium tropici (1), and Sinorhizobium meliloti (1). DNA-DNA hybridization indicated that the remaining four strains were related to the Rhizobium leguminosarum reference strains. The existence of several species of non-nodulating rhizobia in pasture soil, including species for which the normal host plant was absent, is discussed in relation to the fate of symbiotic plasmids from Rhizobium seed inoculants. It is also suggested that new species should be named for the geographical region from which they are first isolated rather than the host plant.

Base Sequence↗
PubMed1996

Health insurance and medical schemes in Papua New Guinea.

Papua New Guinea (PNG) is an independent nation in the Pacific region. It is located due north of Australia. It is made up of a main island and about 100 smaller islands in the Bismark and Solomon Seas, to the north and east of the main island. The population of PNG is about 4.0 million, the total land area approximately 463,840 sq km and population density 8/square km. Only about 15% of the population is urban, average household size is 5.4 and 45.1% literate. Politically and administratively, it is divided into nineteen provinces and a National Capital District. Since 85% of the population lives in rural areas, the provision of services to the rural areas is constrained by difficult terrain, poor infrastructure and geographic dispersion of the rural population. PNG is a developing Pacific nation with an economy largely based on primary and mining industries. According to the 1993 World Bank estimates, more than 30% of the Gross Domestic Product (GDP) is derived from agriculture. The expenditure on health, as a percentage of the GDP, was 2.8% in 1989, (Table 1). This is low compared to developed nations (ranging from 8% to 14%), but very reasonable compared to the rest of the developing world. Indonesia for example expends 2.7% of GDP on health care. All government expenditures declined sharply in the post 1989 period, including health care expenditures. However, by 1989, the expenditure per capita on health was almost back to 1986 levels. PNG has a small population base relative to the other countries in its World Bank peer group. However, its per capita GDP is reasonable at US$850, the third highest amongst its group and higher than Indonesia, for example, which is US$700/head. Like almost all countries in its gorup, it experienced a negative growth rate over the decade 1980-1991 but kept inflation at a reasonable 5.2% for the same period. On most other indicators PNG fares reasonably well, in comparison with other developing nations (Tables 2 & 3).

Adolescent↗
PubMed1993

Intracranial suppuration caused by Micrococcus luteus.

Micrococcus spp. are commensal organisms colonizing the body surfaces of humans. In a few instances these organisms have been reported to colonize ventricular shunts. We report a patient, with no overt evidence of immunosuppression, in whom Micrococcus luteus was responsible for intracranial suppuration at multiple sites.

Adult↗
PubMed1993

Prevalence of sexually transmitted diseases among female drug abusers in Malaysia.

The prevalence of sexually transmitted diseases (STD) among female drug abusers was determined by screening 130 new inmates of a rehabilitation centre. The majority of the subjects (77.7%) were self-confessed sex workers. A high prevalence of syphilis (50.8%), hepatitis B (52.2%), moniliasis (23.8%) and trichomoniasis (19.2%) were noted. Gonorrhoea vaginitis was seen in 8.5%, which was low compared to previous studies. Six subjects were seropositive for human immunodeficiency virus (HIV), with 5 of them admitting to needle sharing and working as prostitutes. More than half of them harboured 2 or more STD. A rich reservoir of STD was seen among the drug abusers. With more evidence now available concerning the ease of HIV transmission associated with ulcerative STD, a stage could be set for greater heterosexual HIV transmission. As part of the rehabilitation process, female drug abusers need a thorough screening for STD followed by aggressive treatment regimens.

Adolescent↗
PubMed1991

A myb gene required for leaf trichome differentiation in Arabidopsis is expressed in stipules.

The GL1 gene is required for the initiation of differentiation of hair cells (trichomes) on the crucifer, Arabidopsis thaliana. This gene has been localized to a 4.5 kb DNA fragment by molecular complementation of gl1 mutants. DNA sequence analysis has shown that the protein encoded by GL1 contains a Myb DNA-binding motif. Southern analysis and subsequence analysis of isolated lambda clones has established that GL1 is a member of an extensive myb gene family in Arabidopsis. The putative GL1 promoter directs the expression of the GUS reporter gene in non-trichome-bearing structures that appear to be stipules. This pattern of expression suggests that GL1 may control the synthesis of a diffusible signal that activates the developmental pathway for trichome differentiation.

Amino Acid Sequence↗
PubMed1991

Parapharyngeal space melioidosis in a diabetic.

Pseudomonas pseudomallei, a gram negative organism causing melioidosis, is found in tropical and subtropical regions. It may manifest as a pulmonary lesion, osteomyelitis, soft tissue abscesses, abscesses in various organs or in septicaemic form. Melioidosis of the parapharyngeal space has not been reported so far. A case of melioidosis of the parapharyngeal space which was successfully treated by drainage and prolonged antibiotic therapy is reported here. Melioidosis should be suspected in severe forms of deep neck space infection, especially if the patient comes from an endemic area.

Adult↗
PubMed1991

A model for cell-type determination and differentiation in plants.

We are using trichome formation on the plant Arabidopsis thaliana as a model for the study of plant cell determination and differentiation. Several of the genes that are required for trichome formation are defined by mutations. Two mutations, ttg and gl1, prevent the initiation of trichome differentiation. Thus, these mutations define products that are involved in the signalling of trichome determination. Other mutations, gl2, gl3, dis1, and dis2, define genes that are involved in trichome maturation. Our immediate goal has been to isolate the genes defined by these mutations and determine the role that they play in trichome formation. Our general goals are (1) to identify counterparts to these genes that are involved in other cell type determination and differentiation processes; (2) to manipulate cell development by altering the normal expression of these genes; and (3) to determine if this information can be used to improve crop plants. Presently, most of our progress has centered on the GL1 gene, which has been isolated and characterized. We have found that GL1 is a myb-related gene that is uniquely required for trichome initiation. As in other plants, Arabidopsis has a family of myb-related genes. We are currently investigating the possibility that some of these other myb-related genes are also uniquely required for other types of cell determination events.

Arabidopsis↗