PubMed Health⌕ Search

Biomedical subjects

D Sohn

Publications and source records attributed to D Sohn.

At least 19 recordsLinked to original sources
PubMed2006

Prognostic significance of beta-catenin in colorectal cancer with liver metastasis.

AIMS: A decreased expression of beta-catenin has been known to be associated with tumour metastasis. The prognostic value of beta-catenin expression in colorectal cancer (CRC) patients with liver metastasis was evaluated. MATERIALS AND METHODS: Seventy patients who underwent curative resection for CRC with liver metastasis were included. Tissue samples from normal colon mucosa, primary CRC and metastatic liver lesions were prepared in tissue microarrays, and were stained by immunohistochemistry with beta-catenin antibody. The beta-catenin expression of primary CRC tissues and metastatic liver tissues was analysed. RESULTS: A high expression of beta-catenin (score > 6) was observed in 42.0% and 21.9% of primary colorectal tissues and metastatic liver tissues, respectively. The beta-catenin expression in metastatic liver tissues was significantly lower than in primary CRC tissues (P = 0.022). The patients were classified into two groups according to the difference in the beta-catenin expression score between the primary CRC and the liver metastasis. Group A was defined as patients showing a remarkably decreased expression of beta-catenin in their metastatic liver tissue and group B was defined as patients showing a maintained or increased beta-catenin expression in their metastatic liver tissue in comparison with their primary CRC. The overall survival and disease-free survival rates were better in group B than in group A, and this was statistically significant (P = 0.02, P = 0.002). CONCLUSION: The decreased expression of beta-catenin in a metastatic liver lesion may be a poor prognostic marker in CRC with liver metastasis and further investigation is necessary.

Adult↗
PubMed2000

Effect of hypercholesterolemia on the sequential changes of apoptosis and proliferation after balloon injury to rabbit iliac artery.

To evaluate the effect of hypercholesterolemia on apoptosis and proliferation after vascular injury, iliac arteries of hypercholesterolemic (HC) and normocholesterolemic (NC) rabbits were examined after balloon injury using TUNEL, immunohistochemical staining of PCNA, macrophages, smooth muscle actin and p53. In media, apoptosis occurred massively early after injury and then decreased. HC did not affect this early post-injury apoptosis but significantly increased apoptosis 14 days later (D14). Immediate apoptosis in media was followed by active proliferation. HC sustained a high activity of proliferation until D14. The changes of immunoreactivity to p53 over the same 14 day period parallel that of apoptosis. In intima, where cells were scarce initially, proliferative activity reached a peak at D7 and then decreased. HC significantly enhanced proliferation at D14. In intima proliferation was accompanied by a later low-level apoptosis. HC significantly enhanced this low-level apoptosis at D14. These effects of HC resulted in significantly increased areas of intima and media. The fundamental difference between HC and NC was the infiltration of macrophages in HC. In conclusion, balloon injury induces early massive p53-associated apoptosis followed by proliferation in media, whereas in intima, it induces active proliferation followed by a low-level apoptosis. Hypercholesterolemia does not affect the early post-injury apoptosis but enhances proliferation and low-level apoptosis at a later stage, which in turn results in intimal and medial hyperplasia.

Actins↗
PubMed1999

Radiosynthesis and autoradiographic evaluation of [11C]NAD-299, a radioligand for visualization of the 5-HT1A receptor.

The selective 5-HT1A receptor antagonist NAD-299 ([R]-3-N,N-dicyclobutylamino-8-fluoro-3,4- dihydro-2H-1-benzopyran-5-carboxamide) was labeled with the positron-emitting radionuclide carbon-11. The radioligand was synthesized from NAD-195 ([R]-3-N,N-dicyclobutylamino-8-fluoro-5-trifluoromethylsulfonyl oxy-3,4- dihydro-2H-1-benzopyran) in two radiochemical steps. A palladium-catalyzed reaction of NAD-195 and [11C]cyanide was followed by hydrolysis of the carbon-11-labeled nitrile intermediate with basic hydrogen peroxide. The total radiochemical yield, based on [11C]CO2 and corrected for decay, was 20-40%. The specific radioactivity was 24 GBq/mumol (900 Ci/mmol) at end of synthesis, with a radiochemical purity better than 99% and a total synthesis time of 40-45 min. Autoradiographic examination of [11C]NAD-299 binding in human brain postmortem demonstrated high binding in hippocampus, raphe nuclei, and neocortex. The binding in the hippocampus was higher than in the neocortex. Within the hippocampus, the densest binding was observed in the CA1 region. [11C]NAD-299 binding was inhibited by addition of the 5-HT1A receptor ligands WAY-100635, pindolol, (+/-)-8-OH-DPAT, 5-HT, and buspirone, leaving a low background of nonspecific binding. The results indicate that [11C]NAD-299 binds specifically to 5-HT1A receptors in the human brain in vitro and is a potential radioligand for positron emission tomography (PET) examination of 5-HT1A receptors in vivo.

Autoradiography↗
PubMed1997

Questions for meta-analysis.

In spite of an abundance of data, the empirical evidence as yet does not make clear whether meta-analysis will bring about progress in psychological science. Therefore, it is still useful and desirable to engage in rational analysis of the methodology. Such analysis is done in the present essay by posing five questions that go to the logical and conceptual foundation of meta-analysis. The questions are (a) What are the grounds for believing that the review of the literature, even a quantitative one, will bring about scientific discovery? (b) Why is the individual study devalued when the history of successful science seems largely the story of the success of the individual study? (c) What is the rationale for believing that data analysis by itself can markedly improve the fortunes of psychological science? (d) Is there a basis for claims made on behalf of meta-analysis that it is more accurate than either the traditional literature review or the individual study? (e) Is there justification for the claim that de facto meta-analysis has been used effectively in physical science?

Humans↗
PubMed1997

The pharmacological characterization of a novel selective 5-hydroxytryptamine1A receptor antagonist, NAD-299.

The pharmacological properties of a novel selective 5-hydroxytryptamine1A (5-HT1A) receptor antagonist, NAD-299 [(R)-3-N,N-dicyclobutylamino-8-fluoro-3,4-dihydro-2H-1-benzopyran-5-carboxamide hydrogen (2R,3R)-tartrate monohydrate] were examined in vitro and in vivo and compared with the reference 5-HT1A receptor antagonist, WAY-100635 [N-(2-(1-(4-(2-methoxyphenyl)piperazin-yl))ethyl)-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride]. The new compound had high affinity for 5-HT1A receptors in vitro with a Ki value of 0.6 nM. The only other receptors for which NAD-299 had affinity less than 1 microM were alpha-1 and beta adrenoceptors with Ki values of 260 and 340 nM, respectively. Thus, the selectivity of NAD-299 for 5-HT1A receptors was more than 400 times. WAY-100635 had considerably higher affinity than NAD-299 for alpha-1 adrenoceptors (Ki = 45 nM) and dopamine D2 and D3 receptors (Ki = 79 and 67 nM, respectively). Like WAY-100635, NAD-299 competitively blocked 5-HT-induced inhibition of vasoactive intestinal peptide-stimulated cAMP production in GH4ZD10 cells and had no intrinsic activity. Both compounds were therefore 5-HT1A receptor antagonists in vitro and also behaved as such in in vivo experiments. Thus, they competitively antagonized the 8-hydroxy-2-(di-n-propylamino)tetralin-induced 5-HT behavioral effects, hypothermia, corticosterone secretion and inhibition of passive avoidance behavior without causing any actions of their own. The effective dose of NAD-299 varied between 0.03 and 0.35 micromol/kg s.c., depending on the test and the dose of 8-hydroxy-2-(di-n-propylamino)tetralin.

5-Hydroxytryptophan↗
PubMed1996

Light Scattering Study of Magnetic Latex Particles and Their Interaction with Polyelectrolytes.

Commercially available latex particles with superparamagnetic inclusions have been characterized by polarized and depolarized dynamic light scattering. The particles are spherical, but the larger ones (R(g) approximately 0.1 µm) with many magnetic inclusions behave in dynamic light scattering experiments like symmetric tops while the smaller particles do not. The as-received materials had a broad size distribution, but more narrowly distributed particles were prepared by selective filtration for use in probe diffusion and stability studies. The interaction of these negatively charged particles with a linear polyelectrolyte, negatively charged sodium polystyrene sulfonate, was studied by static and dynamic light scattering. Depolarized dynamic light scattering is particularly sensitive to changes in the stability of the colloids or interaction with the polyelectrolyte. The polyelectrolyte can prevent or reverse salt-induced aggregation of the superparamagnetic latex particles. Fluorescence photobleaching recovery experiments to monitor the mobility of fluorescently labeled polyelectrolyte suggest that it is not bound to the latex particles; apparently, a mechanism other than steric stabilization is involved. The dependence of the diffusion of the superparamagnetic latex particles upon added salt is discussed in terms of the ion atmosphere surrounding the polyelectrolyte.

Journal Article↗
PubMed1980

Multiple keratoacanthomas associated with steatocystoma multiplex and rheumatoid arthritis. A case report.

Keratoacanthomas have been associated with multiple carcinomas, discoid lupus erythematosus, and multiple sebaceous gland tumors with colonic and gastric carcinoma. Steatocystoma multiplex has been associated with ichthyosis and koilonychia, pachyonychia congenita, multiple hairs and acrokeratosis verruciformis of Hopf, hypertrophic lichen planus, hypohidrosis, hypothyroidism, hidradenitis suppurativa, and hypotrichosis. We report a case of multiple keratoacanthoma associated with steatocystoma multiplex and rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1976

Two concepts of adaptation: Darwin's and psychology's.

The paper takes issue with the traditional view of Darwin's influence on psychology; namely, that it is he who passed on to psychology the concept of individual adaptation. Three arguments are presented: a) that Darwin, qua scientist, was only interested in species adaptation, an entirely different concept from that of individual adaptation, b) that Darwin's writings on individual adaptation are so unexceptional that it is inconceivable that psychologists should have been influenced by them and c) that the two concepts are logically incompatible since species adaptation presupposes a strict hereditary determinism, while individual adaptation conceives of the organism either as free and undetermined or else as determined by the environment.

Adaptation, Biological↗
PubMed1975

The first year of the toxicology program.

The CAP Toxicology Survey Program's initial year is reviewed. Four series of samples, each consisting of five specimens with approximately 12 different drugs, were sent to almost 200 participants and as many as seven referees. They reported the presence or absence of more than 16 different compounds, and identified specific barbiturates when present. In each series, two serum samples were for qualitative identification and quantitative analysis. The remainder were urine samples for qualitative analysis. The aim of the survey is to enhance the "current state of the art" among participants. Drug-abuse toxicology and therapeutic monitoring of drugs were given priority. Clinically relevant samples reflecting current drug abuse, especially mixed-drug abuse, were provided, including serum for quantitative determination as is required in treatment of barbiturate overdose and for therapeutic drug monitoring. The Committee has interacted with participants by critiques of surveys, by questionnaires, and by responding to queries from participants.

Amphetamine↗