Search PubMed⌕ Search

Biomedical subjects

I Shah

Publications and source records attributed to I Shah.

At least 19 recordsLinked to original sources
PubMed2000

Primary pancreatic lymphoma: a case report, literature review, and proposal for nomenclature.

Primary neoplasms of the pancreas are most often adenocarcinoma. Non-Hodgkin's lymphoma (NHL) involving the pancreas is less common but well documented; the pancreas as the primary site of NHL is rare. The majority of patients with pancreatic cancer, whether it is adenocarcinoma or lymphoma, present with a mass in the head of the gland. Pancreatic lymphoma is often described as a large homogeneous mass with extra-pancreatic extension, with or without associated lymphadenopathy. Less common presentations are masses in the body or tail, or more rarely diffuse involvement of the pancreas. We present a case of diffuse pancreatic lymphoma with extra-pancreatic dissemination to the spleen and lymph nodes, and review the literature on pancreatic lymphoma. Because the definition of pancreatic lymphoma and primary pancreatic lymphoma varies, we also propose a nomenclature system to make future studies of pancreatic lymphoma more comparable.

Diagnosis, Differential↗
PubMed2000

Visual management of large scale data mining projects.

This paper describes a unified framework for visualizing the preparations for, and results of, hundreds of machine learning experiments. These experiments were designed to improve the accuracy of enzyme functional predictions from sequence, and in many cases were successful. Our system provides graphical user interfaces for defining and exploring training datasets and various representational alternatives, for inspecting the hypotheses induced by various types of learning algorithms, for visualizing the global results, and for inspecting in detail results for specific training sets (functions) and examples (proteins). The visualization tools serve as a navigational aid through a large amount of sequence data and induced knowledge. They provided significant help in understanding both the significance and the underlying biological explanations of our successes and failures. Using these visualizations it was possible to efficiently identify weaknesses of the modular sequence representations and induction algorithms which suggest better learning strategies. The context in which our data mining visualization toolkit was developed was the problem of accurately predicting enzyme function from protein sequence data. Previous work demonstrated that approximately 6% of enzyme protein sequences are likely to be assigned incorrect functions on the basis of sequence similarity alone. In order to test the hypothesis that more detailed sequence analysis using machine learning techniques and modular domain representations could address many of these failures, we designed a series of more than 250 experiments using information-theoretic decision tree induction and naive Bayesian learning on local sequence domain representations of problematic enzyme function classes. In more than half of these cases, our methods were able to perfectly discriminate among various possible functions of similar sequences. We developed and tested our visualization techniques on this application.

Alcohol Dehydrogenase↗
PubMed1998

Visualization based on the Enzyme Commission nomenclature.

We developed a tool for visualizing data related to protein function, based on the nomenclature defined by the International Enzyme Commission. The method represents the 1327 specific reaction types and three additional levels of abstract classifications in the nomenclature as an interactive graph. Each node and link in the graph can have associated with it stored or computed data values of various types, each of which can be assigned to any of a set of visualization methods, including color, size, various chart types and text. Visualizations can then be interactively created for single nodes, groups of nodes or the entire graph. This visualization tool is particularly useful for exploring the distribution of quantitative attributes across protein function classes. As a test of this tool, we developed a visualization of data measuring the effectiveness of sequence similarity for prediction of EC class. Using this tool, it was possible to rapidly scan hundreds of functional classes, and to correlate predictability from sequence with other attributes, facilitating the generation of hypotheses about the causes of predictive failure.

Amino Acid Sequence↗
PubMed1998

Identification of divergent functions in homologous proteins by induction over conserved modules.

Homologous proteins do not necessarily exhibit identical biochemical function. Despite this fact, local or global sequence similarity is widely used as an indication of functional identity. Of the 1327 Enzyme Commission defined functional classes with more than one annotated example in the sequence databases, similarity scores alone are inadequate in 251 (19%) of the cases. We test the hypothesis that conserved domains, as defined in the ProDom database, can be used to discriminate between alternative functions for homologous proteins in these cases. Using machine learning methods, we were able to induce correct discriminators for more than half of these 251 challenging functional classes. These results show that the combination of modular representations of proteins with sequence similarity improves the ability to infer function from sequence over similarity scores alone.

Alcohol Dehydrogenase↗
PubMed1997

Chloroquine resistance in Pakistan and the upsurge of falciparum malaria in Pakistani and Afghan refugee populations.

Surveys conducted in Pakistan during the last decade show that falciparum malaria has become resistant to chloroquine in Pakistani and Afghan refugee populations throughout the country. Although RI resistance is common everywhere (with a frequency of 30%-84%), RII is rarer (2%-36%), and RIII resistance has yet to be detected. The national policy is to prescribe chloroquine as first-line treatment of malaria. A repeated in-vivo survey in a sentinel village indicated that prescription of chloroquine can lead to a 15% increase in the frequency of resistance in a single year, and similar trends were observed in other districts. Coinciding with the spread of resistance is a 6-fold increase in the number of falciparum cases recorded nationally between 1982 and 1992 and a parallel, 5-fold increase in the number of cases recorded in the Afghan refugee population. Resistance contributes to this trend in various ways. Firstly, patients with resistant malaria make repeated visits to health centres. In the sentinel village, for example, where resistance was measured at 71%, recrudescent infections inflated by 66% the genuine incidence of new infections recorded at the health centre. Secondly, owing to ineffective treatment, resistant infections are often still patent during the post-transmission season. This may enlarge the 'overwintering' parasite reservoir, leading to a surge of new cases when transmission resumes. Other factors potentially contributing to the upsurge in falciparum include the decrease availability of insecticide for indoor spraying. Despite the problems posed by resistance for case management, the evidence from the vector-control programme among the refugees is that malaria control through well-targeted campaigns of insecticide spraying is still able to reduce the incidence of falciparum malaria to a level that existed before the advent of resistance.

Afghanistan↗
PubMed1997

Fertility and contraception in Europe: the case of low fertility in southern Europe.

Demographic trends in Europe can be summarized in terms of a declining proportion of its population in the world total, low fertility, and a slow population growth. Fertility in Western Europe was already below the replacement level in 1970-75 and has remained low. Fertility has substantially declined in Eastern and Southern Europe, with Italy and Spain recording one of the lowest levels (1.2 children per woman) in 1994. Some explanations of the dramatic fertility decline in Southern Europe are: (1) The emancipation of women and their increased participation in the labor force; (2) Economic aspects such as costs for child care and education; and (3) The couple's motivation for low fertility because of the expanded choices for travel and leisure and their concerns for improving their standard of living. Social pressures on childbearing outside marriage remain quite strong; cohabitation and extramarital births is Southern Europe are not as prevalent as in other European regions and there is a trend toward delaying the birth of the first child rather than foregoing childbearing.

Adult↗
PubMed1997

Predicting enzyme function from sequence: a systematic appraisal.

Gapped and ungapped sequence alignment were tested as possible methods to classify proteins into the functional classes defined by the International Enzyme Commission (EC). We exhaustively tested all 15,208 proteins labeled with any EC class in a recent release of the SwissProt database, evaluating all 1,327 relevant EC classes. We effectively tested all possible similarity thresholds that could be used for this assignment through the use of the ROC statistic. Approximately 60% of Enzyme Commission classes containing two or more proteins could not be perfectly discriminated by sequence similarity at any threshold. An analysis of the errors indicates that false positive matches dominate, and that various error mechanisms can be identified, including the multidomain nature of many proteins and polyproteins, convergent evolution, variation in enzyme specificity, and other factors. Many of the putatively false positives are in fact biologically relevant. This work strongly suggests that functional assignment of enzymes should attempt to delimit functionally significant subregions, or domains, before matching to EC classes.

Databases, Factual↗
PubMed1991

Knowledge and perceptions about AIDS among married women in Bangkok.

People's knowledge and perceptions about AIDS are critical in efforts to combat the further spread of this disease. Using data from a study on "Determinants and Consequences of Contraceptive Use Patterns in Thailand", this paper investigates the knowledge and perceptions about AIDS among ever-married women in Bangkok Metropolis. Differentials in knowledge and perceptions are investigated by socio-economic subgroups. The results indicate the need to inform and educate people about AIDS, especially those in low-income groups or with lower levels of education.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Thermogravimetric analysis of urinary stones.

Routine thermogravimetric (TG) analysis of 501 upper urinary calculi from the State of Jammu and Kashmir is described. The technique is simple, rapid and quantitative, and the equipment is easily maintained. The technique was found to be helpful in 95.4% of urinary stones and it is suggested that TG analysis may be employed as a technique of first choice in the routine quantitative analysis of all urinary calculi.

Calcium Oxalate↗
PubMed1988

The AI/RHEUM knowledge-based computer consultant system in rheumatology. Performance in the diagnosis of 59 connective tissue disease patients from Japan.

AI/RHEUM is a knowledge-based computer consultant system for the diagnosis of rheumatic diseases. Its diagnostic accuracy was evaluated using information that was supplied by Japanese rheumatologists on 59 patients with connective tissue diseases. The diagnoses of the AI/RHEUM model were in full or partial agreement with those of the Japanese rheumatologists in 54 of 59 cases (92%). Preliminary evaluation of the criteria tissue disease showed a sensitivity of 90% and a specificity of 96%.

Artificial Intelligence↗
PubMed1984

Pharmacokinetics and tolerance of intravenous and intramuscular recombinant alpha 2 interferon in patients with malignancies.

Fifteen patients with advanced hematopoietic and other malignancies were treated with recombinant DNA produced Alpha 2 Interferon (IFN) (Schering) by intravenous (IV) and intramuscular (IM) routes at weekly intervals in escalating doses from 1 X 10(6) IU to 100 X 10(6) IU in order to determine the tolerance and pharmacokinetics. The most common side effects included fever, chills, myalgia, and arthralgia. At doses of 60 X 10(6) or above, severe but reversible hypotension was observed in five patients receiving interferon by intravenous route. Patients receiving interferon by intramuscular route had fever, chills, and myalgias but did not develop hypotension at the same dosage. Two patients with non-Hodgkin lymphoma showed objective evidence of regression. Our data suggest a biphasic pattern of elimination with terminal half-life ranging from 1.9 to 2.9 hours and peak titer of 16,000 units and under for IV interferon, and terminal half-life of 6 hours with peak titers of 600 units for intramuscular interferon. However, interpatient variability precludes a definite conclusion. Although the areas under the serum concentration vs time curves were similar, the intravenous route provided higher but unsustained levels of interferon than the intramuscular route.

Adolescent↗
PubMed1984

Sickle cell anemia and epidural extramedullary hematopoiesis.

Acute flaccid paralysis due to epidural extramedullary hematopoiesis developed in a 43-year-old man with sickle cell anemia. The patient showed no response to emergency decompressive laminectomy, radiotherapy, or exchange transfusion, and his neurologic deficit persisted unimproved. This is the first reported case of acute or irreversible spinal cord compression due to epidural extramedullary hematopoiesis in a patient with sickle cell anemia.

Adult↗
PubMed1984

Acute basophilic leukemia.

Acute basophilic leukemia was diagnosed in a 61-year-old black woman on the basis of 85 to 90 percent basophils in the peripheral blood as well as bone marrow and very high serum histamine level (more than 10,000 ng/ml). These complications occurred as a transformation from essential thrombocythemia. Accompanying this transformation, there was also cytogenetic change from 46XX karyotype to 46XX 2p+ in 66 to 90 percent of cells in the bone marrow. This may be the first reported occurrence of transformation of essential thrombocythemia into acute basophilic leukemia.

Acute Disease↗
PubMed1984

Diagnostic morphometry of the adult respiratory distress syndrome (shock lung).

In the pathogenesis of "shock lung", the morphometric analysis allows us to determine the "point of no return" when the exudative alveolitis turns into the life-threatening sclerosing form. In addition, we found that this "point of no return" is reached much earlier in septic than in traumatic shock. Our studies confirm that the term "shock lung" should not be simply substituted for "respiratory lung". Based on our morphometric methods, we conclude that shock-induced pulmonary fibrosis differs with regard to its functional pathogenesis from the non-shock-induced type of fibrosis.

Epithelium↗
PubMed1984

Role of sialyltransferase in hypercupraemia of non-Hodgkin's lymphoma.

Copper, ceruloplasmin and sialyltransferase activity were measured in serum of 25 patients with lymphoreticular malignancies, in an attempt to study the sialyltransferase activity and correlation if any with the activity of the disease and ceruloplasmin. All 3 parameters were elevated in active disease but no definite correlation between sialyltransferase activity and copper or ceruloplasmin could be found. We conclude that plasma sialyltransferase activity is increased in lymphomas.

Adult↗