Search Results - (Author, Cooperation:S. H. Tan)

2018-06-15

BMJ Publishing

2044-6055

Medicine

Open access, Qualitative research

2013-12-07

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; *Autocrine Communication ; Axin Protein/genetics/metabolism ; Cell Differentiation ; Cell Lineage ; Cell Proliferation ; Cells, Cultured ; Epidermis/*cytology/injuries/metabolism ; Epithelial Cells/cytology/metabolism ; Gene Expression ; Homeostasis ; Humans ; Intercellular Signaling Peptides and Proteins/metabolism ; Keratinocytes/cytology/metabolism ; Mice ; Regeneration ; Skin/injuries ; Stem Cell Niche ; Stem Cells/cytology/*physiology ; Wnt Proteins/metabolism ; *Wnt Signaling Pathway ; Wound Healing ; beta Catenin/genetics/metabolism

2018-01-20

Cold Spring Harbor Laboratory Press

0890-9369

Biology

2018-04-14

The American Association for Cancer Research (AACR)

1078-0432

1557-3265

Medicine

2018-11-02

The American Association for Cancer Research (AACR)

1078-0432

1557-3265

Medicine

1365-2230

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

This prospective study investigated patients with a clinical diagnosis of bullous pemphigoid (BP) who presented to a tertiary dermatology referral centre in Singapore. All patients had blood samples and skin biopsies taken for histology, immunofluorescence (IF) and immunoblot analysis prior to initiation of treatment. We analysed 23 new cases of BP during the 1-year study period. Seventeen of 22 biopsy specimens showed subepidermal blister formation, and 12 of the 17 (71%) had a predominance of eosinophils (〉 50%) in the blister cavity. The dermal inflammatory infiltrate of 22 biopsy specimens was predominantly lymphocytic in nine (41%) and eosinophilic in eight (36%). The histological picture was highly suggestive of BP in 15 of 22 patients (68%), suggestive in two (9%) and poorly suggestive in five (23%). Twenty-one of 23 (91%) patients had linear deposits of IgG and C3 along the dermo-epidermal junction. Serum indirect IF was positive in 22 of 23 (96%) patients, all showing antibody binding to the roof of the induced blister on salt-split skin. All of the 23 serum samples demonstrated positive immunoblot reactivity to BP180 and/or BP230 from epidermal extracts of normal human skin. Immunoblot reactivity with BP180 and BP230 was 78% (n = 18) and 52% (n = 12), respectively. The BP180 NC16A antibody could be detected in 22 of 23 (96%) sera using the enzyme-linked immunosorbent assay (ELISA) technique. The sensitivity of traditional diagnostic techniques, i.e. direct IF (91%) and indirect IF (96%), was comparable with that of the newer techniques, i.e. immunoblot analysis (100%) and ELISA (96%). ELISA in combination with routine indirect IF may be a useful diagnostic tool in patients with suspected BP who refuse a skin biopsy but consent to give a serum sample.

Electronic Resource

1365-2230

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We describe a 26-year-old Indian man who presented with chickenpox and subsequently developed pemphigus vulgaris 17 days after initial resolution of lesions. The mechanism of progression from one disease to the other is postulated to be that of epitope spreading or molecular mimicry.

Electronic Resource

1365-2230

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Scleroderma is a systemic disease with a myriad of cutaneous manifestations. Pigmentary disturbances have been described in scleroderma. While diffuse generalized hyperpigmentation and localized hypopigmentation with perifollicular hyper-pigmentation are well recognized, a vascular induced hyperpigmentation has only been recently described. In this paper, we report another unrecognized pigmentary abnormality in a 48-year-old patient who presented with a reticulate hyper-pigmentation affecting the trunk, upper and lower limbs. To our knowledge, cutaneous hyperpigmented reticulate scleroderma has not been reported previously.

Electronic Resource

1365-2230

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Sarcoidosis is a systemic noncaseating granulomatous disorder of unknown origin involving multiple organ systems. There has been no report so far to describe the epidemiological pattern of cutaneous involvement in sarcoidosis in South-East Asia with diverse ethnic groups. A retrospective study examining the clinicopathological features of all patients diagnosed with sarcoidosis at a tertiary dermatology centre in Singapore from 1980 to 2003 was conducted. Cutaneous sarcoidosis was diagnosed in 25 patients: 13 were Indian, 11 were Chinese and one was Eurasian. Cutaneous manifestations included papules, nodules, plaques and scarring alopecia. Extracutaneous involvement of lymph nodes (four patients), lungs (eight patients) and eyes (two patients) was seen. Eight patients had abnormal chest radiographic findings. Histopathological examination of skin lesions revealed noncaseating, epithelioid granulomatous infiltration in the dermis without evidence of mycobacterial infection, deep fungal infection or polarizable birefringent material. Treatment modalities included corticosteroids, hydroxychloroquine, isotretinoin, methotrexate and surgical excision. Five patients had complete resolution of the cutaneous lesions. Cutaneous sarcoidosis is rare in Asia and indeed in Singapore. Extracutaneous involvement is not uncommon and a thorough clinical evaluation should be undertaken.

Electronic Resource

1365-2230

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The chemical environment is one aspect of the oral environment, which could have an appreciable influence on the in vivo degradation of composite restoratives. The effects of chemical media on surface hardness of four composite restoratives (Silux [SX], Z100 [ZO], Ariston [AR] and Surefil [SF]) were investigated. The relationship between hardness and the thickness of the degradation layer was also studied. Thirty six specimens (3 × 4 × 2 mm) were made for each material. Following polymerization, the specimens were stored in artificial saliva at 37 °C for 24 h. The specimens were then randomly divided into six groups of six, subjected to microhardness testing (load = 500 gf, dwell time = 15 s) and stored in the following chemicals for 1 week at 37 °C: artificial saliva (S), distilled water (W), 0˙02 N citric acid (C), 0˙02 N lactic acid (L), heptane (H) and 75–25% ethanol–water solution (E). After conditioning, the specimens were again subjected to hardness testing and sectioned. Change in hardness (DH) was computed and the thickness of the degradation layer (DL) was measured using a computerized image analysis system at 600× magnification. Results of statistical analysis (ANOVA/Scheffe’s [P 〈 0˙05]) of DH based on materials were as follows: SX – E 〉 all other mediums; ZO – W 〉 C; and AR – S, W, E 〉 H (〉 indicates significantly greater hardness change). No significant difference in DH was observed between the different chemicals for SF. The effects of chemical media on DH were found to be material dependent. A significant but weak positive correlation (Pearson’s correlation [P 〈 0˙05]) exists between change in hardness and thickness of the degradation layer.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1432-0568

Monkey ; Bilateral superior cervical ganglionectomy ; Axon terminals ; Pinealocytes ; Synapses

Springer Online Journal Archives 1860-2000

Medicine

Summary The distribution of axon terminals in the pineal gland of monkeys was studied by electron microscopy. Numerous terminals bearing small pleomorphic agranular and dense-cored vesicles were localized in the perivascular space and among the pinealocytes in the parenchyma in normal monkeys. Following bilateral superior cervical ganglionectomy, they underwent degenerative changes, including the accumulation of glycogen masses, appearance of dense residual bodies and the displacement of synaptic vesicles. Some of these degenerating terminals showed synaptic contacts with the cell bodies of pinealocytes. At the synaptic junction the postsynaptic membrane was thickened asymmetrically. Examples of synaptic contacts were most frequently observed in 5 and 7 days postoperative animals. In the longer surviving (30 days) monkey, most of the axon terminals showed round agranular vesicles, and they were mainly presynaptic to the intrapineal ganglion cells with some of the pinealocytes. They remained structurally unchanged following the resection of both the superior cervical ganglia. A few axon terminals containing small dense-cored vesicles appeared to have survived the initial insult, but some of their vesicles appeared swollen 30 days after the operation. It is concluded from this study that some of the pinealocytes are under the influence by the postganglionic neurons in the superior cervical ganglia through direct synaptic contacts. The intrapineal ganglion cells are postsynaptic to fibres originating exclusively from the central nervous system. Some of these fibres, however, may be presynaptic directly to pinealocytes.

Electronic Resource

1432-0568

Monkey ; Ultrastructure ; Pinealocytes ; Axon terminals ; Synapses

Springer Online Journal Archives 1860-2000

Medicine

Summary The present study described the normal ultrastructure of the monkey pineal gland. The gland was composed of the principal pinealocytes, intramural neurons and glial cells. The nucleus of the pinealocytes was deeply infolded with evenly distributed chromatin materials. The abundant cytoplasm was rich in organelles including the well-developed Golgi apparatuses, multivesicular bodies, dense-cored vesicles and widely scattered free and polyribosomes. A variety of axon terminals was observed and the majority of them contained pleomorphic agranular vesicles with a few large dense-cored vesicles. A few terminals showed flattened vesicles or small dense cored vesicles. Some of the axon terminals formed synaptic contacts with the cell bodies of pinealocytes. These synapses were mainly concentrated in the posterior third of the gland. The occasional intramural neurons observed were postsynaptic to axon terminals containing round agranular vesicles. The sources of the nerve fibres and terminals forming synaptic junctions with pinealocytes and intramural neurons were discussed.

Electronic Resource

1432-8798

Springer Online Journal Archives 1860-2000

Medicine

Summary.  The genome of the Y strain of kyuri green mottle mosaic virus (KGMMV-Y) has been completely sequenced. Its genomic structure and sequence show it to be a typical tobamovirus, that is closest to, but distinct from, that of cucumber green mottle mosaic tobamovirus (CGMMV). The genomic sequence of KGMMV-Y was compared in detail with that of the SH strain of CGMMV. The sequences of their 5′- and 3′-untranslated regions were 74% and 63% identical. The amino acid sequences of the shorter and longer (read through) RNA replicase components, movement protein (MP) and coat protein (CP) were 58, 58. 60 and 46% identical, respectively. The KGMMV-Y genome sequence was also compared partly to that of another strain of KGMMV, KGMMV-C. The CP sequences of KGMMV-Y and KGMMV-C differed by 20 amino acid residues, suggesting that their relationship is more distant than the relationship between CGMMV-SH and CGMMV-W whose CP sequences are identical. The MPs of KGMMV-Y and KGMMV-C, however, differ only by one amino acid residue, although three amino acid substitutions are present in the MPs between CGMMV-SH and CGMMV-W. Two long stretches, one in the RNA replicase and the other in the MP, were highly conserved in KGMMV and CGMMV.

Electronic Resource

1573-1561

Choristoneura pinus pinus ; jack pine budworm ; Lepidoptera ; Tortricidae ; (E,Z)-11-tetradecenyl acetate ; (E,Z)-11-tetradecen-1-ol ; sex pheromone ; sex attractant

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Abstract Chemical identification and field-trapping experiments have shown that a blend of 85∶15 (E,Z)-11-tetradecenyl acetates and 85∶15 (E,Z)-11-tetradecen-1-ols (in a 9∶1 ratio) are female sex pheromone components for jack pine budworm,Choristoneura pinus pinus. This blend of chemicals, formulated in PVC (0.1 %, w/w) sources is as effective a trap bait as virgin females. Preliminary wind tunnel observations have indicated that this blend, effective as a trap bait, is not equivalent to females.

Electronic Resource

1573-1561

Fatty acid analysis ; double-bond location ; dimethyl disulfide adducts ; mass spectrometry ; pheromone ; Choristoneura fumiferana ; C. occidentalis ; C. pinus pinus ; Plusia chalcites ; Lepidoptera ; Tortricidae ; Noctuidae

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Abstract A rapid analytical procedure for the determination of the position of double bonds in mixtures of monounsaturated fatty acid methyl esters has been developed. The method is based on direct capillary GC-MS-EI analysis of dimethyl disulfide adducts. The procedure was applied to mixtures of monounsaturated fatty esters from pheromone gland extracts of three tortricids from theChoristoneura genus,C. fumiferana, C. occidentalis, andC. pinus pinus, and one noctuid from the Plusiinae subfamily,Plusia chalcites. A correlation was found between the known major pheromone components in the four species with the corresponding fatty acids. Some of the additional fatty acids may be precursors to as yet unidentified minor pheromone components, present in extremely small quantities, in these species.

Electronic Resource

1573-1561

Kairomone ; biological control ; cabbage ; wheat ; Diuraphis noxia ; Brevicoryne brassicae ; olfactometer ; infochemical ; preference ; host plants

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Abstract Diaeretiella rapae (M'Intosh) (Hymenoptera: Aphidiidae) is a parasitoid of several aphid species, including the Russian wheat aphid (RWA),Diuraphis noxia (Mordvilko), and the cabbage aphid (CA).Brevicoryne brassicae (L.). The response of matedD. rapae females to odors from wheat, cabbage, and plant-host complexes was investigated using a four-choice olfactometer. Experienced parasitoids, but not inexperienced females, responded positively to odors of the wheat-RWA complex in a no-choice test. In choice tests, experienced parasitoids did not respond to odors of uninfested cabbage and wheat leaves, but did respond positively to aphid-infested plants and to aphids alone. The response ofD. rapae to the cabbage-CA complex and to CA alone was significantly greater than to the wheat-RWA complex and RWA alone, suggesting an innate odor preference for crucifer-feeding aphids.

Electronic Resource

1573-1561

Choristoneura occidentalis ; western spruce budworm ; Lepidoptera ; Tortricidae ; pheromone chemistry ; Choristoneura fumiferana ; capillary GC-MS ; (E/Z)-11-tetradecenal

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Abstract SCOT capillary Chromatographic and SCOT capillary chromatographic-mass spectrometic analyses of gland washes and effluvia of virgin femaleChoristoneura occidentalis Free, have been conducted with both a diapausing and nondiapausing strain of this insect. The following compounds were identified in gland washes and effluvia in both strains:E andZ11–14∶Ald,E andZ11–14∶Ac,E andZ11–14∶OH and 14∶Ald, 14∶Ac, and 14∶OH. The average aldehyde: acetate: alcohol ratio found by analysis of single glands by virgin females (nondiapausing strain) was 1∶7∶0.73. Analysis of virgin female effluvia gave this ratio as 10∶3∶8 (diapausing strain: %Z=8, 11, 15, respectively) and 10∶3∶6 (nondiapausing strain: %Z=8, 11, 12, respectively). The saturated components were generally 1–2% of theE isomer in each case. Comparisons of EAG responses of bothC. occidentalis andC. fumiferana toE11–14∶Ald,E11–14∶Ac andE11–14∶OH were made. Correlations with both laboratory and field data previously published were also made betweenC. fumiferana andC. occidentalis.

Electronic Resource

1573-4803

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract Nanosized silicon carbide powders of high purity and low oxygen content have been prepared by thermal chemical vapour deposition (CVD) of dimethyldichlorosilane at pyrolytic temperatures, 1100–1400 °C. The nanosized silicon carbide particles prepared at 1400 °C consist of small crystallites of β-SiC arranged randomly in the particles. At pyrolytic temperature below 1300 °C, the particles consist of amorphous phase and β-type SiC crystallites. The average particle size changed from 70 nm to 40 nm and the average size of the β-SiC crystallite changed from 7.3 nm to 1.8 nm depending on the pyrolysis conditions. The C/Si molar ratios of the product powders changed from 0.5 to 1.07 with the CVD conditions. The near theoretical values of C/Si molar ratio of the product powders within 0.95–1.05 can be controlled by CVD conditions such as pyrolytic temperature and reactant concentration. Finally, the product powders were characterized by chemical analysis, X-ray diffraction, electron microscopy, and infrared spectroscopy.

Electronic Resource