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Biomedical subjects

M Song

Publications and source records attributed to M Song.

At least 37 records · Page 2Linked to original sources
PubMed2003

Two cases of cross-sensitivity in subjects allergic to paraphenylenediamine following ingestion of Polaronil.

We report the cases of 2 women presenting allergy to paraphenylenediamine (PPD). Both patients had a history of eczema that worsened following the ingestion of the antihistamine Polaronil (dexamethasone/dexchlorpheniramine). This clinical presentation could be explained by cross-sensitivity to sulfanilic acid (4-aminobenzene sulfonic acid), a metabolite of sunset yellow (FD&C No. 6). Sunset yellow is an azo dye present in this tablet. Indeed, PPD-allergic subjects may suffer from cross-sensitivity to related compounds, especially to those that can be ingested such as azo dyes. Such compounds are used in some instances by the food and pharmaceutical industries, but their presence is often undisclosed.

Adult↗
PubMed2003

[Topical immunosuppressors: new therapeutic approach in atopic dermatitis].

The efficiency of topical immunosuppressors in the treatment of atopic dermatitis is undebatable. These agents induce immunosuppression by inhibiting T cell activation and cytokine production. An intermittent treatment, with two applications per day, and photoprotection is recommended in adults and children aged more than two years. The precise position of the topical immunosuppressors in the treatment strategy of atopic dermatitis remains to be defined. Main side effects are irritative or allergic cutaneous reactions and cutaneous infections, no systemic side effects have been recorded. The consequence of long-term topical immunosuppression and specially the possible development of skin cancers in UV exposed skin, is not well known and necessitates careful monitoring of patients. These treatments are contra-indicated during pregnancy, breast feeding, in erythrodermic states and with any alterations of the cutaneous barrier.

Administration, Topical↗
PubMed2002

Kinetics of KB and HEp-2 cell responses to an invasive, cytolethal distending toxin-producing strain of Actinobacillus actinomycetemcomitans.

The periodontal pathogen Actinobacillus actinomycetemcomitans produces cytolethal distending toxin (CDT), a complex multicomponent toxin that arrests the growth of many types of eukaryotic cell. The kinetics of the effects of CDT-containing extracts, from an invasive strain of this bacterium, were examined on epithelial-like cells routinely used in invasion studies. Both KB and HEp-2 cells were exquisitely sensitive to the effects of the CDT with TD50 of 30 and 300 pg of total bacterial protein, respectively. Initial cell morphology changes were relatively rapid, occurring within the first 13 h of exposure. CDT-treated KB cells increased in size to 4-5 times the size of untreated controls. Cytotoxicity was irreversible when attached cells were incubated, for a minimum of 120 min, with nanogram quantities of CDT-containing extract. As cultures aged, the cells became more resistant to the effects of the CDT-containing extracts. These findings have important implications for understanding the ability of A. actinomycetemcomitans to invade and multiply in epithelial cells.

Adolescent↗
PubMed2002

Allergic contact dermatitis from cosmetics. Retrospective analysis of 819 patch-tested patients.

BACKGROUND: Cosmetics have been used since the oldest known civilisations, and nowadays almost everybody resorts to beauty products. OBJECTIVE: Considering the increasing incidence of contact dermatitis, the aim of the study is to determine the impact of allergy to cosmetics. METHODS: From January 1998 to December 1999, 819 patients were subjected to epicutaneous tests for suspicion of allergic contact dermatitis (ACD). The results were analysed retrospectively in the total population and in that of children under 16: the interest has been focused on cosmetics. RESULTS: 297 patients (36.3%) with ACD to 1 or more cosmetic ingredients have been detected. 34 (48.6%) out of 70 children patch tested showed an ACD: cosmetics represented the first cause. CONCLUSION: For two decades, the incidence of ACD has been rising; two main reasons can be put forward: a rising product consumption and a more exhaustive allergen research in patch testing.

Adolescent↗
PubMed2002

A case of early congenital syphilis.

A case of early congenital syphilis is reported in order to emphasize that syphilis is still present nowadays and that detection of syphilis in pregnant women is primordial for the prevention of this disease.

Female↗
PubMed2002

Multiple HPV-positive basal cell carcinomas on the abdomen in a young pregnant woman.

Basal cell carcinoma (BCC) is the most common malignant skin tumour. In the last few years, the incidence of multiple BCC has also increased in young patients. We describe the clinical case of a young 29-year-old woman who developed 7 BCC on her abdomen during her first pregnancy and 4 other similar tumours 2 years later during her second pregnancy, all located on the abdomen. Polymerase chain reaction revealed the presence of numerous human papillomavirus DNA sequences. To our knowledge, such a clinical presentation has not been previously reported. Different physiopathological considerations are discussed.

Basal Cell Carcinoma↗
PubMed2001

Design and synthesis of new inhibitors of HIV-1 protease dimerization with conformationally constrained templates.

To inhibit the HIV-1 protease dimerization necessary to exhibit enzymatic activity, we synthesized and evaluated a new beta-sheet peptide (compound 1), containing 4-(2-aminoethyl)-6-dibenzofuranpropionic acid as a conformationally restricted linker and a non-peptidic beta-strand mimetic, 2-[3-([2-[(9-fluorenylmethoxy)carbonyl]hydrazino]carbonyl)-4-methoxyanilino]-2-oxoacetic acid (Fmoc-Hao-OH, compound 2). Kinetic analysis showed that compound 1 inhibited the dimerization of HIV-1 protease by a dissociative mechanism with a K(id) value of 5.4 microM at 37 degrees C (pH 5.0). However, compound 2 showed a small shift in the slope of the lines in the Zhang-Poorman plot (K(id)=9.1 microM), suggesting that compound 2 inhibits the dimerization of HIV-1 PR not only through a dissociative mechanism but also through an active-site directed mechanism partly. This is the first study of a non-peptidic inhibitor of HIV-1 protease dimerization.

Dimerization↗
PubMed2001

Angiogenic role for glycodelin in tumorigenesis.

Angiogenesis plays an important role in neovascularization in tumors. Glycodelin, a hormone-responsive protein, has been detected in tumors of reproductive organs and is found in high levels in the plasma of subjects with gynecological malignancies. Glycodelin is also found in the endothelial cells of the umbilical cord and in the blood vessels of tumors. In this study, we tested whether glycodelin-rich amniotic fluid and a synthetic peptide derived from the sequence of glycodelin peptide (Gp) might promote angiogenic response by examining the migration and tube formation in human umbilical cord vein endothelial cells (HUVECs). Increased migration and tube formation of HUVECs were found in the presence of amniotic fluid and Gp, and this increase was blocked by antibody to Gp and by an anti-vascular endothelial growth factor (VEGF) antibody, suggesting that the angiogenic effects of glycodelin might be mediated by VEGF. The results also showed that Gp significantly increased the release of VEGF protein and mRNA expression in HUVECs, RL-95 (human endometrial carcinoma cells), OVCAR-3 (human ovarian adenocarcinoma cells), EM42 (human endometrial epithelial cells), THP-1 (human monocyte), and MCF-7 and MDA-MB-231 (human breast adenocarcinoma cells) cell lines. VEGF receptor Fit-1 mRNA expression in HUVECs was also increased in the presence of Gp. These findings, together with the suggestion from the literature that glycodelin may have immunosuppressive properties, suggest that glycodelin might play an important role in neovascularization during embryogenesis and tumor development.

Amino Acid Sequence↗
PubMed2001

Remodeling of Kv4.3 potassium channel gene expression under the control of sex hormones.

Kv4.3 channels are important molecular components of transient K(+) currents (Ito currents) in brain and heart. They are involved in setting the frequency of neuronal firing and heart pacing. Altered Kv4.3 channel expression has been demonstrated under pathological conditions like heart failure indicating their critical role in heart function. Thyroid hormone studies suggest that their expression in the heart may be hormonally regulated. To explore the possibility that sex hormones control Kv4.3 expression, we investigated whether its expression changes in the pregnant uterus. This organ represents a unique model to study Ito currents, because it possesses this type of K(+) current and undergoes dramatic changes in function and excitability during pregnancy. We cloned Kv4.3 channel from myometrium and found that its protein and transcript expression is greatly diminished during pregnancy. Experiments in ovariectomized rats demonstrate that estrogen is one mechanism responsible for the dramatic reduction in Kv4.3 expression and function prior to parturition. Furthermore, the reduction of plasma membrane Kv4.3 protein is accompanied by a perinuclear localization suggesting that cell trafficking is also controlled by sex hormones. Thus, estrogen remodels the expression of Kv4.3 in myometrium by directly diminishing its transcription and, indirectly, by altering Kv4.3 delivery to the plasma membrane.

Animals↗
PubMed2001

Molten-globule structure and membrane binding of the N-terminal protease-resistant domain (63-193) of the steroidogenic acute regulatory protein (StAR).

The first step in steroidogenesis is the movement of cholesterol from the outer to inner mitochondrial membrane; this movement is facilitated by the steroidogenic acute regulatory protein (StAR). StAR has molten-globule properties at low pH and a protease-resistant N-terminal domain at pH 4 and pH 8 comprising residues 63-193. To explore the mechanism of action of StAR we investigated the structural properties of the bacterially expressed N-terminal domain (63-193 StAR) using CD, limited proteolysis and NMR. Far- and near-UV CD showed that the amount of secondary structure was greater at acidic than at neutral pH, but there was little tertiary structure at any pH. Unlike 63-193 StAR liberated from N-62 StAR by proteolysis, biosynthetic 63-193 StAR was no longer resistant to trypsin or proteinase K at pH 7, or to pepsin at pH 4. Addition of trifluoroethanol and SDS increased secondary structure at pH 7, and dodecylphosphocholine and CHAPS increased secondary structure at pH 2, pH 4 and pH 7. However, none of these conditions induced tertiary structure, as monitored by near-UV CD or NMR. Liposomes of phosphatidylcholine, phosphatidylserine and their mixture increased secondary structure of 63-193 StAR at pH 7, as monitored by far-UV CD, and stable protein-liposome complexes were identified by gel-permeation chromatography. These results provide further evidence that the N-terminal domain of StAR is a molten globule, and provide evidence that this conformation facilitates the interaction of the N-terminal domain of StAR with membranes. We suggest that this interaction is the key to understanding the mechanism of StAR's action.

Gene Products, env↗
PubMed2001

Decreased expression of voltage- and Ca(2+)-activated K(+) channels in coronary smooth muscle during aging.

Aging is the main risk factor for coronary artery disease. One characteristic of aging coronary arteries is their enhanced contractile responses to endothelial vasoconstricting factors, which increase the risk of coronary vasospasm in older people. Because large-conductance voltage- and Ca(2+)-activated K(+) channels (MaxiK) are key regulators of vascular tone, we explored the possibility that this class of channels is diminished with increasing age. Using site-directed antibodies recognizing the pore-forming alpha subunit and electrophysiological methods, we demonstrate that the number of MaxiK channels is dramatically diminished in aged coronary arteries from old F344 rats. Channel density was reduced from 52+/-9 channels/pF (3 months old) to 18+/-5 channels/pF (25 to 30 months old), which represents a 65% reduction in the older population. Pixel intensity of Western blots was also diminished by approximately 50%. Moreover, the age-related decrease in the channel protein expression was also evident in humans, which showed approximately 80% reduction in 61- to 70-year-old subjects compared with 3- to 18-year-old youngsters and approximately 45% reduction compared with 19- to 56-year-old adults. In agreement with a reduction of MaxiK channel numbers in aging coronary arteries, old coronary arteries from F344 rats contract less effectively ( approximately 70% reduction) than young coronary arteries when exposed to the MaxiK channel blocker iberiotoxin. The contraction studies indicate that under physiological conditions, MaxiK channels are tonically active, serving as a hyperpolarizing force that opposes contraction. Thus, reduced expression of MaxiK channels in aged coronary arteries would lead to a decreased vasodilating capacity and increased risk of coronary spasm and myocardial ischemia in older people.

Adolescent↗
PubMed2001

Accuracy of intravascular ultrasound for diameter measurement of phantom arteries.

BACKGROUND: Uniplanar quantitative angiography (QA) is the standard method for measuring vessel diameter during surgical and endovascular procedures. Intravascular ultrasound (IVUS), a relatively new technology, is another means of obtaining this measurement. This study was designed to validate the accuracy of these two modalities by comparing each to direct caliper measurement, the gold standard, using phantom femoral artery segments (PAS). MATERIALS AND METHODS: PAS diameter was measured with a 12.5-MHz mechanically rotating IVUS catheter (Boston Scientific Corp.) and QA (OEC Corp.) was compared to the direct caliper measurement (Mitutoyo Corp.) at 60 different locations within PAS. At each location minimal lumen diameter and perpendicular lumen diameter were measured and their mean was calculated. The intraclass correlation coefficients (ICCC) between direct caliper measurement and IVUS and uniplanar and biplanar angiography were calculated. Fisher's Z transformation was used to compare the correlation coefficients. RESULTS: The ICCC for IVUS was 0.89. The ICCCs for uniplanar and biplanar angiography were 0.73 and 0.82, respectively. IVUS correlated more closely with direct caliper measurement than uniplanar and biplanar angiography (P = 0.00008, 0.02) Biplanar angiography correlated more closely with direct caliper measurement than uniplanar angiography (P = 0.04). CONCLUSIONS: IVUS more accurately measures lumen diameter than uniplanar or biplanar angiography. Diameter measurement with biplanar angiography is more accurate than uniplanar angiography.

Angiography↗
PubMed2001

Rapid and sensitive determination of radiocesium (Cs-135, Cs-137) in the presence of excess barium by electrothermal vaporization-inductively coupled plasma-mass spectrometry (ETV-ICP-MS) with potassium thiocyanate as modifier.

An electrothermal vaporization-inductively coupled plasma-mass spectrometric (ETV-ICP-MS) method based on selective volatilization of cesium with KSCN as modifier has been developed for determination of radiocesium, i.e. 135Cs and 137Cs, in the presence of isobaric barium. A 10,000 times excess of barium, which was volatilized at a temperature of 1,100 degrees C, resulted only in a 1% signal increase in the signal of mass 135 amu. The recommended concentration of KSCN is 0.3 mM, and pretreatment and volatilization temperatures are 400 degrees C and 1,100 degrees C, respectively. A ramp time of 1 s is recommeded for the volatilization step. The achieved limit of detection for 135Cs is 0.2 pg/mL (10 microBq/mL) and 4 fg (0.2 microBq) absolute for a sample volume of 20 microL. This means a limit of detection for 137Cs of 0.2 pg/mL (0.6 Bq/mL) and of 4 fg (0.01 Bq) absolute. Signal variations of 135Cs and 137Cs, respectively, in spiked samples with various matrices were investigated.

Journal Article↗
PubMed2001

Segregation of effector mechanisms in a tumour-specific CD8+ T-cell clone correlates with CD30 expression.

In this study we have analyzed CD30-antigen expression in three melanoma-directed cytotoxic T lymphocyte (CTL) clones with a T helper 0 (Th0)-like cytokine secretion profile (i.e. interleukin (IL)-4, IL-5, and interferon (IFN)-gamma). We show that all CTL clones expressed high levels of CD30 upon contact with the autologous tumour cells. One CTL clone, termed A2 with a monoclonal feature was selected for further analyses and found its CD30 expression dependent on the presence of IL-4. Functionally, a CD30-expressing A2 CTL was capable of producing higher amounts of IFN-gamma (up to 1.5-fold) and IL-4 (up to two-fold) than its CD30- counterpart. Furthermore, CD30-positive A2 CTL displayed an at least three-fold greater proliferative response to the tumour cell stimulation, contrasting with CD30- CTL. However, the antitumour cytotoxic activity of A2 CTL was not modulated by the CD30 expression. These results suggest that CD30 antigen can be inducible on a subset of tumour-directed CD8+ CTL, and that this subset of cells may have profound effector functions, such as cytokine secretion, proliferation, and cytotoxicity.

Cell Line, Transformed↗