Biomedical subjects

M Song

Publications and source records attributed to M Song.

At least 109 records · Page 6Linked to original sources

PubMed1997

Bombesin-induced gastrin release from canine G cells is stimulated by Ca2+ but not by protein kinase C, and is enhanced by disruption of rho/cytoskeletal pathways.

Isolated canine G cells in primary culture have been used to study calcium, protein kinase C (PKC), and rho/cytoskeletal-dependent intracellular pathways involved in bombesin- stimulated gastrin release. A method to obtain highly purified G cells by culture (64% G cells) after flow cytometry on elutriated fractions of cells from digested canine gastric antral mucosa has been developed. Pretreatment of G cells with thapsigargin (10(-8)-10(-6) M) and release experiments in Ca2+-containing or -depleted media showed that influx of Ca2+ into the cells and not acute release from intracellular stores plays an important role in bombesin-stimulated gastrin release. Inhibition of PKC by the specific inhibitor GF 109 203X did not affect bombesin-stimulated release. Rho, a small GTP-binding protein that regulates the actin cytoskeleton, is specifically antagonized by Clostridium botulinum C3 exoenzyme. C3 (10 microg/ml) enhanced basal and bombesin-stimulated gastrin release by 315 and 266%, respectively. The importance of the cytoskeleton for regulation of gastrin release was emphasized by a more pronounced release of gastrin when the organization of the actin cytoskeleton was disrupted by cytochalasin D (5 x 10(-)7 and 10(-)6 M). Wortmannin, a potent inhibitor of phosphoinositide-3-kinase, did not alter bombesin-stimulated gastrin release. Thus, it is concluded that bombesin-induced gastrin release from canine G cells is stimulated by Ca2+ but not by PKC, and is enhanced by disruption of rho/cytoskeletal pathways.

ADP Ribose Transferases↗

PubMed1997

Conformational change of cytochrome P450 1A2 induced by phospholipids and detergents.

Recently, it was reported that the activity of rabbit P450 1A2 is markedly increased at elevated salt concentration (Yun, C-H., Song, M., Ahn, T., and Kim, H. (1996) J. Biol. Chem. 271, 31312-31316). The activity increase of P450 1A2 coincides with the raised alpha-helix content and decreased beta-sheet content. The presence of phospholipid magnified this effect. Here, possible structural change of rabbit P450 1A2 accompanying the phospholipid-induced increase in its enzyme activity was investigated by circular dichroism, fluorescence spectroscopy, and absorption spectroscopy. Studies with the reconstituted system supported by cumene hydroperoxide or NADPH showed that the P450 1A2 activities were found to be dependent on the head group and hydrocarbon chain length of phospholipid. Phosphatidylcholines having short hydrocarbon chains with a carbon number of 8-12 were very efficient for reconstitution of the P450-catalyzed reactions supported by both cumene hydroperoxide and NADPH. It was found that the phospholipid increased the alpha-helix content and lowered the beta-sheet content of P450. Intrinsic fluorescence intensity is also increased in the presence of phospholipid. The low spin iron configuration of P450 1A2 shifted toward the high spin configuration by most of the phospholipids in the endoplasmic reticulum. Some synthetic phospholipids having short hydrocarbon chains with a carbon number of 10-12 caused a shift in the spin equilibrium of P450 1A2 toward low spin. The effect of detergents on the activity and conformation of P450 1A2 was also studied. It was found that the addition of detergents to P450 1A2 solution increased the enzyme activity of P450 1A2. Detergents also increased the alpha-helix content and lowered the beta-sheet content of P450 1A2. Intrinsic fluorescence emissions also increased with the presence of detergents. Octyl glucoside and deoxycholate caused a shift toward high spin. On the other hand, cholate caused a shift toward low spin. It was found that the activity increase of rabbit P450 1A2 coincides with the conformational change including raised alpha-helix content. It is proposed that the interaction with the phospholipid molecules surrounding P450 1A2 in the endoplasmic reticulum is important for a functional conformation of P450 1A2 in a monooxygenase system including NADPH-P450 reductase.

Animals↗

PubMed1997

Molecular constituents of maxi KCa channels in human coronary smooth muscle: predominant alpha + beta subunit complexes.

1. Human large-conductance voltage- and calcium-sensitive K+ (maxi KCa) channels are composed of at least two subunits: the pore-forming subunit, alpha, and a modulatory subunit, beta. Expression of the beta subunit induces dramatic changes in alpha subunit function. It increases the apparent Ca2+ sensitivity and it allows dehydrosoyasaponin I (DHS-I) to upregulate the channel. 2. The functional coupling of maxi KCa channel alpha and beta subunits in freshly dissociated human coronary smooth muscle cells was assessed. To distinguish maxi KCa currents modulated by the beta subunit, we examined (a) their apparent Ca2+ sensitivity, as judged from the voltage necessary to half-activate the channel (V1/2), and (b) their activation by DHS-I. 3. In patches with unitary currents, the majority of channels were half-activated near -85 mV at 18 microM Ca2+, a value similar to that obtained when the human KCa channel alpha (HSLO) and beta (HKV,Ca beta) subunits are co-expressed. A small number of channels half-activated around 0 mV, suggesting the activity of the alpha subunit alone. 4. The properties of macroscopic currents were consistent with the view that most pore-forming alpha subunits were coupled to beta subunits, since the majority of currents had values for V1/2 near to -90 mV, and currents were potentiated by DHS-I. 5. We conclude that in human coronary artery smooth muscle cells, most maxi KCa channels are composed of alpha and beta subunits. The higher Ca2+ sensitivity of maxi KCa channels, resulting from their coupling to beta subunits, suggests an important role of this channel in regulating coronary tone. Their massive activation by micromolar Ca2+ concentrations may lead to a large hyperpolarization causing profound changes in coronary blood flow and cardiac function.

Adolescent↗

PubMed1997

Stability and solvent accessibility of SecA protein of Escherichia coli.

It has been shown that many proteins, when converted into partially unfolded structures, interact strongly with a lipid bilayer. SecA protein of Escherichia coli is an unusual water-soluble protein which, in the native form, can readily penetrate the membrane and lipid bilayer. In order to see whether the native SecA exhibits partially unfolded characteristics, the stability and solvent accessibility of SecA were studied using various spectroscopic and hydrogen-exchange methods. The results are compared with the reported data for native and molten globule forms of alpha-lactalbumin (alpha-LA), as well as those for apocytochrome c. The exposure of hydrophobic residues of SecA, as monitored by 8-anilinonaphthalene-1-sulfonic acid (ANS) binding, and the extent of amide hydrogen exchange were comparable to those of native alpha-LA. On the other hand, equilibrium unfolding experiments showed that SecA is less stable than native alpha-LA. The results of tryptic digestion and the change of endogenous ATPase activity induced by guanidine hydrochloride were suggestive of the C-terminal half of SecA being more flexible than the rest of the protein. The overall conclusion is that the SecA as a whole has a somewhat open structure due to a relatively unstable C-domain which may facilitate its penetration into a lipid bilayer.

Adenosine Triphosphatases↗

PubMed1997

Pulse steroid therapy for children's severe alopecia areata?

Seven children with severe, rapidly evolving alopecia areata (AA) were treated with pulse steroid therapy (PST). AA had been present for 3-44 weeks and involved more than 30% of the scalp. One patient had alopecia totalis. Intravenous methylprednisolone (5 mg/kg twice a day) was administered for 3 days. No serious side effects were noted. At the 12-month follow-up, complete regrowth had occurred in 5 patients (71%). The patient with alopecia totalis had no regrowth. PST appears to be a promising and safe treatment for extensive, recent-onset AA in children. No response is to be expected in alopecia totalis or long-standing AA.

Adolescent↗

PubMed1997

Tufted angioma, a particular form of angioma.

Tufted angioma is a rare acquired cutaneous angiomatous proliferation characterized by slowly spreading erythematous macules and plaques, sometimes surmounted by nodular formations. Synonyms are progressive capillary hemangioma and Nakagawa's angioblastoma. Tufted angioma appears to be benign since follow-up studies did not report malignant transformation. This lesion must be distinguished from other vascular tumors, especially from Kaposi's sarcoma. If this lesion appears in an older patient, angiosarcoma should be excluded.

Child, Preschool↗

PubMed1997

Docetaxel-induced subungual hemorrhage.

Docetaxel (RP 56976 or Taxotere), a semisynthetic drug belonging to the family of taxoids, is a new chemotherapeutic agent used in phase II trials for breast, ovarian and lung cancer. We report 2 cases of subungual hemorrhages, which, to our knowledge, have yet to be cited in association with the use of docetaxel. Although not incapacitating, the patient should be made aware of the potential risk of this drug reaction.

Adult↗

PubMed1997

Baboon syndrome.

An 18-month-old patient developed Baboon syndrome after oral treatment with erythromycin syrup for a sore throat. The lymphoblastic transformation test was positive for erythromycin. Prick tests were negative although the intradermal test was positive at a concentration of erythromycin of 1:10,000. The biopsy showed a perivascular lymphocytic dermatitis. Local treatment with a potent corticoid improved the lesions after 3 days. The Baboon syndrome is uncommon among children. It has a pattern similar to systemic contact dermatitis with particular features (erythema in flexural areas). In our case, the role of erythromycin was documented. However, this antibiotic remains a relatively rare allergen.

Anti-Bacterial Agents↗

PubMed1997

[The effect of alkalinity of methylation reagent on isomerization and degradation of polyunsaturated fatty acids with pyrolysis gas chromatography].

Simultaneous pyrolysis and methylation gas chromatography (SPM-GC) is a fast analytical method which was developed in recent years. However, the strong alkalinity of tetramethylammonium hydroxide (TMAH) may result in the isomerization and degradation of polyunsaturated fatty acids in oils and fats during analysis. This paper describes the application of SPM-GC to polyunsaturated fatty acids in soybean oil and the isomerization and degradation may be prevented by choosing the optimum proportion of TMAH to methanol which is 1:50 (pH 8.8). With this chosen optimum proportion there were no detectable isomerized and degraded peaks in the chromatograms. Pyrograms were obtained by interfacing a Curie-point pyrolyser to a Shimadzu GC-14A gas chromatograph equipped with a flame ionisation detector. A capillary column (FFAP) was used. All of the pyrolysis products were identified by mass spectrometry which was carried out with a Varian 3400 gas chromatograph interfaced to a Finnigan SSQ 710 mass spectrometer using electron impact ionisation (70 eV). This method is simpler and more convenient than both the methods "neutralization of acid" and "simultaneous injection of the sample and a short chain fatty acid methylester" reported in the previous papers.

Chromatography, Gas↗

PubMed1997

Diagnosis of fulminant pulmonary embolism by transthoracic echocardiography.

When pulmonary embolism is severe enough to produce acute cor pulmonale, transthoracic 2-dimensional echocardiography can promptly yield findings highly suggestive of this condition while ruling out competing diagnoses. We present a case diagnosed by transthoracic echocardiography and successfully treated despite a prolonged refractory cardiac arrest.

Echocardiography↗

PubMed1997

Infected total knee arthroplasty. Two-stage reimplantation with a gastrocnemius rotational flap.

This study reviews a consecutive series of 21 patients undergoing two-stage reimplantation total knee arthroplasty for late chronic infection. All 21 patients had late chronic infections, and 20 of 21 patients were compromised hosts. Seven different organisms were isolated at the time of prosthetic resection. Staphylococcus coagulase negative species was the most frequently isolated organism. At the time of reimplantation, a medial gastrocnemius rotational flap was rotated over the proximal tibia and knee for wound closure. The average explantation time was 25 weeks (range, 7-76 weeks), and no methylmethacrylate spacers were used. At an average 17-month followup (range, 5.1-33.1 months) all reimplanted total knee replacements remained in place with one patient having recurrent infection. At reimplantation, 11 patients had positive bacterial cultures from tissue specimens. Sixteen of the 33 (40%) positive cultures were from specimens taken from the medullary canal. At followup, the average Knee Society Score was 77.4 (range, 40-100). The lack of a methylmethacrylate spacer and a long explantation time were considered important factors in diminishing functional performance and determining the need for a gastrocnemius flap. A medial gastrocnemius rotational flap should be considered at the time of reimplantation total knee arthroplasty if the soft tissue envelope about the knee is compromised and cannot be closed without undue tension.

Adult↗

PubMed1997

[Clinical aspects of leg ulcers].

Clinical aspects of leg ulcers are reviewed. Among the most important factors to be kept in mind are: localisation, features of the ulcers and surrounding skin, clinical history and general physical examination. Leg ulcers are most frequently caused by vascular diseases.

Humans↗

PubMed1997

[Particular aspects of ulcers in children].

Leg ulcers of juvenile onset are uncommon. The infectious origin is fairly frequent but the presence of leg ulcers in children should prompt an investigation into possible underlying causes especially hemangioma, vasculitis, inborn errors of metabolism (i.e. prolidase deficiency), hemoglobinopathies, occult spinal dysraphism and immunodeficiencies. Bacteriological investigations are essential and a skin biopsy specimen may be able to differentiate some of these disorders.

Age Distribution↗

PubMed1996

Conformational change of cytochrome P450 1A2 induced by sodium chloride.

Recently, it was reported that the activity of rabbit P450 1A2 is markedly increased at elevated sodium phosphate concentration. Here, the possible structural change of rabbit P450 1A2 accompanying the NaCl-induced increase in its enzyme activity is investigated by fluorescence spectroscopy, circular dichroism, and absorption spectroscopy. It was found that NaCl increased alpha-helix content and lowered beta-sheet content of P450 1A2 in the presence as well as in the absence of a phospholipid. Intrinsic fluorescence emissions also increased with increasing NaCl concentration. The low spin iron configuration of P450 1A2 shifted toward the high spin configuration in response to the increased salt concentration. The effect of increased potassium phosphate and NaCl on the P450 1A2 activity was also studied. It was found that the activity increase of rabbit P450 1A2 occurs concomitantly with the conformational change including raised alpha-helix content.

Animals↗

PubMed1996

Transgenic model for the discovery of novel human secretory non-pancreatic phospholipase A2 inhibitors.

Transgenic mice were created which overexpress human secretory non-pancreatic phospholipase A2 (sPLA2) pansomatically as a potential disease and drug-testing model. The mice were produced using a DNA construct in which the inducible mouse metallothionein gene promoter drives expression of a human sPLA2 minigene. High levels of sPLA2 were detected in several tissues by immunofluorescence localization. Expression in the testes caused hypospermia and male infertility. Circulating catalytically active sPLA2 could be induced to levels observed in patients undergoing a systemic inflammatory response but had no detectable effect on the mice. Therefore, these results suggest that sPLA2 hyperphospholipasemia alone may have only limited pathophysiological consequences. We further show that 3-[3-acetamide-1-benzyl-2-ethylindolyl-5-oxy]propane phosphonic acid LY311727), a potent new inhibitor of phospholipase A2 catalysis developed by our group, dramatically suppresses the circulating enzyme activity in these animals whereas 3-[3-acetamide-1-benzyl-2-propylindolyl-5-oxy]propane phosphonic acid (LY314024), a substantially less potent LY311727 analog, is without effect. These later results thus motivate the further development of this compound as a potential new therapeutic agent and valuable research tool.

Animals↗

PubMed1996

Prospective trial of combined hyperfractionated radiotherapy and bronchial arterial infusion of chemotherapy for locally advanced nonsmall cell lung cancer.

PURPOSE: This article is a prospective trial of hyperfractional radiotherapy with bronchial arterial infusion of anticancer drugs to treat locally advanced bronchogenic cancer. The treatment results, the complications of bronchial arterial infusion, the failure patterns, the relationship of technical aspects of delivery of radiotherapy, and the protocol of anticancer drugs are presented. METHODS AND MATERIALS: One hundred and twenty-six patients with locally advanced bronchogenic cancer, treated from January 1988 to January 1990, were divided randomly into four groups in our hospital. Group 1: combination of hyperfractional radiotherapy with bronchial arterial infusion of anticancer drugs (30 cases); Group 2: combination of conventional radiotherapy with bronchial arterial infusion of anticancer (33 cases); Group 3: combination of systemic chemotherapy and split-course radiotherapy (33 cases); Group 4: conventional radiotherapy only (30 cases). RESULTS: All the patients were followed for 3 years. The 1-year survival rates for Groups 1, 2, 3, and 4 are 80, 63.6, 48.5, and 30%, respectively. The 2-year survival rates for Groups 1, 2, 3, and 4 are 23.3, 15.15, 9.1, and 6.6%, respectively. The 3-year survival rates for Groups 1, 2, 3, and 4 are 10, 3.3, 0, and 0%, respectively. CONCLUSION: This study demonstrated that the combination of hyperfractional radiotherapy with bronchial arterial infusion anticancer drugs can be performed safely and effectively for locally advanced bronchogenic carcinoma.

Adenocarcinoma↗

PubMed1996

Development of a functional capacity model for the elderly.

This study is based on the belief that the amount of nursing care each elderly client requires is determined more by his/or her functional capacity than by diagnosis of medical problems. A functional capacity theoretical model was developed, based on an ecological framework. Environment and personal competence (sensory competence) were hypothesized as predictor constructs, depression as a mediator, and functional capacity as an outcome variable in this model. The model was tested for fit with data from 209 female outpatients of two eye clinics in Seoul, Korea. The results indicated that the hypothesized model fit with the data. Environmental subconcepts showed an indirect effect on functional capacity through depression. This mediating effect of depression was not shown between sensory competence and functional capacity.

Aged↗

PubMed1996

Partial trisomy 6p due to maternal t(1;6) translocation.

Partial trisomy 6p with duplications ranging from 6p21 to 6p25 is emerging as an established syndrome. A case of duplication of segment p22-p25 of the short arm of chromosome 6 as the result of a maternal t (1;6)(q44;p22.2) translocation in a mentally retarded girl with congenital anomalies is reported here. The associated phenotypic anomalies are compared with other reported cases of duplication 6p involving adjacent regions.

Adult↗