			Home About us Contact

Independent Entities (independent + entity)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

New directions: a South Asian perspective

INTERNATIONAL SOCIAL SCIENCE JOURNAL, Issue 167 2001
Gamini Lakshman Peiris
The central challenge facing countries of the developing world such as Sri Lanka is how to reconcile ethnic and cultural diversity with the concept of mature and cohesive nationhood. This is especially so where a federation is created not by the traditional pattern of independent entities coming together, but by devolution from a unitary state to one involving power sharing. In such situations there arealways fears that federalism is a precursor of dismemberment or disintegration. What is needed is to reconcile competing objectives for a strong and effective centre and for recognition of cultural and ethnic diversity. This may require hybrid or quasi-federal structures that do not fit neatly into unitary or federal categories. In attempting to achieve this reconciliation practicalities may require asymmetrical devolution, but this in turn may provoke emotional resistance to special or disparate treatment of particular minorities. Nor is devolution by itself sufficient. To be viable there must be suitable mechanisms to resolve intergovernmental disputes. Particularly important if confrontation and polarisation are to be minimised isemphasis upon compromise and proportionality and a public respect for pluralism, secularism, and representative democracy. [source]

Multiple diverse ligands binding at a single protein site: A matter of pre-existing populations

PROTEIN SCIENCE, Issue 2 2002
Buyong Ma
Abstract Here, we comment on the steadily increasing body of data showing that proteins with specificity actually bind ligands of diverse shapes, sizes, and composition. Such a phenomenon is not surprising when one considers that binding is a dynamic process with populations in equilibrium and that the shape of the binding site is strongly influenced by the molecular partner. It derives implicitly from the concept of populations. All proteins, specific and nonspecific, exist in ensembles of substates. If the library of ligands in solution is large enough, favorably matching ligands with altered shapes and sizes can be expected to bind, with a redistribution of the protein populations. Point mutations at spatially distant sites may exert large conformational rearrangements and hinge effects, consistent with mutations away from the binding site leading to population shifts and (cross-)drug resistance. A similar effect is observed in protein superfamilies, in which different sequences with similar topologies display similar large-scale dynamic motions. The hinges are frequently at analogous sites, yet with different substrate specificity. Similar topologies yield similar conformational isomers, although with different distributions of population times, owing to the change in the conditions, that is, the change in the sequences. In turn, different distributions relate to binding of different sizes and shapes. Hence, the binding site shape and size are defined by the ligand. They are not independent entities of fixed proportions and cannot be analyzed independently of the binding partner. Such a proposition derives from viewing proteins as dynamic distributions, presenting to the incoming ligands a range of binding site shapes. It illustrates how presumably specific binding molecules can bind multiple ligands. In terms of drug design, the ability of a single receptor to recognize many dissimilar ligands shows the need to consider more diverse molecules. It provides a rationale for higher affinity inhibitors that are not derived from substrates at their transition states and indicates flexible docking schemes. [source]

A case of small-cell gastric carcinoma with an adenocarcinoma component and hepatic metastases: treatment with systemic and intra-hepatic chemotherapy

EUROPEAN JOURNAL OF CANCER CARE, Issue 5 2007
T. CIOPPA md
Primary small-cell carcinoma (SmCC) of the stomach is a rare neoplasm with a poor prognosis and unclear histogenesis: to date, only 50 cases, including ours, have been reported in the literature. In the World Health Organization gastrointestinal tumours' classification, SmCC of the stomach has been recognized as an ,independent entity affecting the stomach'. In this paper, the authors present a clinical case and the surgical treatment of an adult with a SmCC of the stomach associated with gastric adenocarcinoma. After laparotomy, a large neoplasm with locoregional extension and multiple liver metastases were found. A palliative resection, subtotal gastrectomy, was performed, followed by systemic and intra-hepatic chemotherapy: computed tomography scan demonstrated a marked response, but the patient died 15 months after the operation. A review of the literature showed that the diagnosis of gastric SmCC is based on immunohistochemical findings. Our experience confirmed the high aggressiveness of this neoplasm, which is generally diagnosed in advanced stage and is unresponsive to chemotherapy, but the combined use of systemic and intra-hepatic chemotherapy shows an acceptable result in a palliative care perspective. [source]

Signet-ring cell carcinoma of the breast

PATHOLOGY INTERNATIONAL, Issue 1 2000
Shian-Min Liu
Primary signet-ring cell carcinoma of the breast is a very rare tumor and is not recognized as an independent entity of the World Health Organization classification of breast tumor. Primary signet-ring cell carcinoma of the breast is usually considered as a variant of mucinous carcinoma or lobular carcinoma and usually originates from the lobular epithelium. A case of primary signet-ring cell carcinoma of the breast in a 68-year-old woman is presented. Histologically, the majority of neoplastic cells had an intracytoplasmic mucin collection. The histological presence of ductal carcinoma in situ, absence of lobular lesion and immunoreactivity for estrogen and progesterone receptors implicated the tumor cells arising from ductal epithelium. The papillary or organoid growth pattern is characteristic in this case. The patient underwent a modified radical mastectomy and was subsequently followed up for 6 months. [source]