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At least 1,045 records · Page 58Linked to original sources
PubMed2003

DNA microarrays in lymphoid malignancies.

Gene expression profiling using cDNA microarrays has the potential to improve current lymphoma classification schemes by establishing a molecular diagnosis of these malignancies. The use of this technology led to the discovery of biologically and clinically distinct subtypes of diffuse large B-cell lymphoma (DLBCL). Gene expression data can also be used to formulate powerful mathematical algorithms that predict the clinical outcome in patients with DLBCL and mantle cell lymphoma. In B-cell chronic lymphocytic leukemia, gene expression profiling identified ZAP70, an important prognostic marker whose expression correlates with the mutational status of the immunoglobulin heavy chain gene and, therefore, with survival in these patients. These examples illustrate that gene expression profiling may pave the way for detailed molecular characterization of lymphoid malignancies that will ultimately lead to tailored, disease-specific therapies.

Gene Expression Profiling↗
PubMed2005

[Rickettsioses].

Rickettsioses can present with protean manifestations. Recent progress in molecular biology allows a better classification of the array of pathogens involved. Rickettsial tick-borne diseases are of emerging importance given nowadays increased in international travellers. Because of substantial morbidity and mortality associated with a delay in diagnosing and treating these infections, awareness of both their geographical distribution and their clinical presentations is important, and the empirical administration of appropriate antibiotic is often justified. Travellers to endemic areas should be encouraged to use personal protective measures.

Animals↗
PubMedDate not supplied

[Evolution of the classification of acute and chronic transplant rejection].

In the last twenty years, several systems have been proposed to codify renal allograft rejection. The Banff classification for kidney allograft pathology, introduced in 1993, started a new era in the standardization of criteria for rejection and for allowing uniform reporting. This consensus on allograft grading proposed a scheme to guide therapy in transplant patients and to help establish an objective rejection end point in clinical trials. This scheme, modified during 1993-1997 to address many of the criticisms, was substantially improved. Another important system of classification of allograft renal biopsies was the Cooperative Clinical Trials in Transplantation (CCTT) classification which was published in 1997. The aim of this system was to develop a schema that would be practical to implement, easy to describe to unfamiliar personnel, reproducible, with high rates of sensitivity and specificity and clinically informative (predictive of course and/or response to therapy). In March 1997, a fundamental revision of the Banff classification for acute rejection was achieved by a consensus conference for incorporating many of the strengths of the CCTT system. Some of these were the importance of vascular damage (endoarteritis, endothelial activation, fibrinoid necrosis) and interstitial hemorrhage, but not the interstitial infiltrate or tubulitis, which correlated with response to anti-rejection therapy and/or 1 year clinical outcome. The most recent modification concerns the addition of C4d-positive acute humoral rejection and the emphasis on differences between cell-mediated and antibody-mediated rejections. Future refinements of these classifications and findings of new molecular markers of allograft rejection, such as fas-ligand or granzyme-B, will help to improve diagnosis and therapy in renal transplant patients.

Acute Disease↗
PubMed2006

[Application of modern molecular biology techniques to study micro-ecosystem in the rumen].

The microbial community inhabiting in the rumen is characterized by its high population density, wide diversity and interactive complexity. However, until recently our knowledge of rumen microbiology was primarily based on classical culture based techniques (isolation, enumeration and nutritional characterization) which probably only account for 10% to 20% of the rumen microbial population. Modem molecular biology techniques provide effective methods to study the micro-ecosystem in the rumen. The use of molecular techniques based on nucleic acid probes is likely to revolutionize the approach to microbial ecology in the rumen and provide, not simply a refinement or increased understanding but a complete description of rumen community for the first time. Modem molecular techniques based on sequence comparisons of nucleic acids may be used to explore molecular characterization and provide a classification scheme which predicts natural evolutionary relationships. Genetic fingerprinting techniques that provide a pattern or profile of genetic diversity have been applied in a variety of environmental studies for the analysis of microbial communities. Whole-cell hybridization is a powerful technique which may be used to study the structure and function of microbial communities in situ and describe the expression of key enzymes. Real-time quantitative PCR technique may be conducted to accurately quantify the target microorganisms in the rumen. Development of these procedures and techniques will result in greater insights into community structure and activity of rumen microbial communities in relation to functional interactions, spatial and temporal relationships between different microorganisms and between microorganisms and feed particles. The successful development and application of these methods promise to provide the first opportunity to link distribution and identity of rumen microbes in their natural environment with their genetic potential and in situ activities.

Animals↗
PubMed1995

What can be learned from intermediate filament gene regulation in the mouse embryo.

In recent years, intermediate filaments (IFs) have attracted much interest, largely because their constitutive polypeptide units are specifically expressed in various cell types and thus represent excellent differentiation markers. Data obtained through biochemical studies and molecular cloning have allowed the classification of IFs into five types according to their protein structure. The expression of most IF types is characteristic of a given cell type: cytokeratins (IF types I and II) are produced in epithelia, neurofilaments and alpha-internexin (type IV) in neurons and nestin (type IV) in neuroblast and myoblast. On the other hand the four type III IFs are highly related proteins which are expressed in different cell types. Thus the study of type III IF gene regulation provides an excellent approach towards the analysis of cell-specific transcription. This review focuses on type III IF gene regulation during mouse embryogenesis and describes the latest data obtained through the combination of both in vitro (in cell lines) and in vivo (in transgenic mice) approaches. It appears that, while intragenic sequences play a major role in the regulation of the expression of the genes encoding other types of IFs, a major contribution to the transcriptional regulation of type III IF genes is brought by 5' upstream sequences. However, recent evidence obtained through the use of transgenic mice indicate that upstream sequences must cooperate with intragenic elements to establish the complex and dynamic expression pattern characteristic of type III IF genes. The very high similarity between the coding sequences of type III IF genes raises the question of the significance of the occurrence of four members of this class. We propose a model for the amplification of this small gene family based on the increasing complexity of expression patterns in higher organisms. This could have led first to the requirement for a highly sophisticated control region in an ancestral type III IF gene, followed by two successive gene duplications, thus leading to the appearance of four different regulatory regions directing the cell-specific transcription of nearly identical genes in different cell types.

Animals↗
PubMed1997

[Adrenergic receptors and alpha 2 agonists--1) Molecular biological study of adrenoceptors].

Molecular biological studies have established classification of adrenergic receptors 40 years after Prof Ahlquist first classified them into alpha and beta. They are now classified into 9 subtypes consisting of 400 to 480 amino acids. They belong to a super-family of G-protein coupled receptors. Based on the amino acid sequence, the topography of adrenoceptors is depicted as a snake model twisting itself back and forth through the membrane 7 times.

Animals↗
PubMed1998

[Idiopathic hypercalciuria in childhood].

This review describes the supposed mechanisms leading to idiopathic hypercalciuria (IHU) in childhood, further the diagnostic criteria and the proposed treatment modalities are discussed. IHU is not only one of the main causes of renal stone disease in children but it's also at the origin of the postglomerular haematuria and the frequency-dysuria syndrome. Its role in the development of osteoporosis in adults is also documented. The diagnosis of raised calcium excretion is based on age specific values during early infancy. In older children and adults a urinary calcium/creatinine ratio exceeding 0.6 mmol/mmol is regarded as elevated. Dietary calcium restriction can no longer be recommended for the treatment of IHU because it results in secondary hyperoxaluria and on the long-term causes decreased bone mineral density. Patients should be kept on dietary sodium restriction and high fluid intake. In cases IHU associated with recurrent episodes of macroscopic haematuria or recurrent stone disease a therapeutic trial with hydrochlorothiazide in the dose of 0.5-1 mg/kg/day with potassium-citrate supplementation and possibly magnesium citrate should be started. In some special forms of hypercalciuria such as the X-linked recessive nephrolithiasis syndrome or Bartter syndrome the localization and in some cases even the molecular mechanism of the events leading to increased calcium excretion are elucidated. In IHU enhanced Ca(++)-ATPase, and Na-Li countertransport activity and decreased Na+/K+ ATPase activity were described in the erythrocyte membrane model. It is expected that with the molecular genetic development the clinical classification of the hypercalciuric syndromes will become a rational genome-based one.

Adolescent↗
PubMed2004

[Classification of von Willebrand disease].

Von Willebrand disease (VWD) is known for its marked heterogeneity which was already recognized by von Willebrand in 1926. The basis of phenotypic differentiation are quantitative and qualitative or functional differences between the different types and subtypes of VWD. One of the most important tools in the classification of VWD is multimer analysis that visualizes many of the structural abnormalities of mutant VWF. The introduction of multimer analysis was followed by the identification of an increasing number of different VWD phenotypes that were first reviewed in 1987 by Ruggeri and Zimmerman, thus forming a first classification of the disease. However, the detection of additional phenotypes required a revision of the nomenclature at a time point when only a few types of VWD had already been analyzed on the molecular level. Consequently, the molecular data only played a minor role in the revised classification published by Sadler in 1994. The advent of molecular techniques provided the opportunity for genotype/phenotype studies which recently helped not only to elucidate or confirm important functions of VWF and its steps of post-translational processing but also many disease causing defects. The reproducible correlation between certain phenotypes and particular mutations can now be used for a molecular approach towards a soundly based classification of VWD, equally useful for the clinician and for research requirements.

Humans↗
PubMed2003

Genetic disorders of the skeleton: a developmental approach.

Although disorders of the skeleton are individually rare, they are of clinical relevance because of their overall frequency. Many attempts have been made in the past to identify disease groups in order to facilitate diagnosis and to draw conclusions about possible underlying pathomechanisms. Traditionally, skeletal disorders have been subdivided into dysostoses, defined as malformations of individual bones or groups of bones, and osteochondrodysplasias, defined as developmental disorders of chondro-osseous tissue. In light of the recent advances in molecular genetics, however, many phenotypically similar skeletal diseases comprising the classical categories turned out not to be based on defects in common genes or physiological pathways. In this article, we present a classification based on a combination of molecular pathology and embryology, taking into account the importance of development for the understanding of bone diseases.

Animals↗
PubMed1994

Vascular receptors for 5-hydroxytryptamine: distribution, function and classification.

The complex actions of 5-hydroxytryptamine (5-HT) on blood vessels result from interactions with a multiplicity of specific 5-HT receptors. Dramatic advances recently have been made in defining the receptor subtypes involved in terms of their pharmacology and biochemistry, as well as their molecular biology, provoking an evolution of the criteria used for classifying and naming them. This article reviews the distribution and function of different 5-HT receptor types present on vascular smooth muscle, endothelium and perivascular neurones, and considers ways in which they can be positively defined and differentiated using traditional pharmacological approaches. The characteristics of each receptor type are also considered in terms of current biochemical and molecular perspectives on 5-HT receptor classification.

Animals↗
PubMed1998

The molecular and functional characterization of an Opaque2 homologue gene from Coix and a new classification of plant bZIP proteins.

The seed storage proteins of Coix, sorghum and maize are codified by homologous genes which are coordinately expressed in the endosperm in a temporal-specific fashion. Opaque2 (O2), a bZIP protein originally isolated from maize, has been described as a transcription activator of alpha- and beta-prolamin genes. The isolation and characterization of cDNA and genomic clones encoding the Opaque2 homologue from Coix are reported here. The coding region of the Coix O2 gene is interrupted by five introns and codifies a polypeptide of 408 amino acids. Comparison of the deduced amino acid sequence with two different sequences of maize O2 protein showed that the Coix O2 protein is similar to the maize O2 isolated from W22 maize inbred line. The Coix O2 protein has the same binding specificity and expression pattern of the maize O2. The O2 proteins together with OHP1, OsBZIPPA, SPA, CPRF2 and RITA1 were assigned to one of the five bZIP plant families in an updated classification of plant bZIP according to bZIP domain similarity.

Amino Acid Sequence↗
PubMed2004

Molecular characterization of uterine clear cell carcinoma.

Clinicopathological studies support a broad classification of endometrial carcinoma into two major types, designated as type I and type II, which correlate with their biological behavior. More recently, molecular studies have provided further insights into this classification scheme by elucidating the genetic events involved in the development and progression of endometrial carcinoma. Microsatellite instability and mutations in the PTEN gene have been widely associated with type I (endometrioid) endometrial carcinoma, while p53 mutations have been identified in the majority of type II endometrial carcinoma, of which uterine serous carcinoma is the prototype. Uterine clear cell carcinoma (UCC) is an uncommon variant of endometrial carcinoma, and clinicopathological studies have produced conflicting results regarding its biological behavior with 5-year survival ranging from 21 to 75%. The molecular characteristics of endometrioid and serous carcinoma have been studied extensively; however, there have been few molecular genetic studies of the clear cell subtype. In this study, we evaluated 16 UCCs (11 pure and 5 mixed) for mutations in the p53 gene, PTEN gene and for microsatellite instability. Although we found that these alterations were uncommon in pure clear cell carcinomas, all three were identified. In addition, two cases of mixed serous and clear cell carcinoma showed an identical mutation of the p53 gene in the histologically distinct components and one case of mixed clear cell and endometrioid carcinoma had identical mutations in the PTEN and p53 genes, and microsatellite instability in both components. Our data suggest that UCC represent a heterogeneous group of tumors that arise via different pathogenetic pathways. Additional molecular studies of pure clear cell carcinoma are required to further elucidate the genetic pathways involved in its development and progression.

Adenocarcinoma, Clear Cell↗
PubMed1998

Cellular and molecular pathology of gastric carcinoma and precursor lesions: A critical review.

The cellular and molecular pathology of gastric cancer and its precursors are reviewed and discussed. Gastric carcinogenesis is a multistep phenomenon, beginning with precancerous conditions. Among these, adenoma is a direct precursor, because of the dysplastic nature of its cells. However, gastric adenoma is relatively rare. Chronic atrophic gastritis (CAG) is the most common precancerous condition, in which intestinal metaplasia often occurs. Carcinoma develops in CAG through stages of hyperplasia and dysplasia involving both metaplastic and non-metaplastic glands. Molecular alterations, including replication error and p53 and APC gene mutation and aneuploidy have been found in some of these conditions, confirming their role in carcinogenesis. Carcinomas of the stomach are heterogeneous in cellular composition. Both intestinal and gastric types of cells are found in all types of tumors, indicating the unique characteristics of gastric cancer. Many molecular lesions have been found in gastric carcinomas. Basic changes involve replication errors, telomerase activity, and aberrant CD44 transcripts. Many other changes often show differences in the frequency of their occurrence between the two major histological types of gastric carcinoma: well differentiated versus poorly differentiated, or intestinal type versus diffuse type. The timing and frequency of these changes in the stomach differ from the timing and frequency in colonic carcinogeneis. Pathological evaluation remains reliable and meaningful, in basic research as well as clinical management. To obtain correlation with molecular alterations, the need for detailed pathologic classification of gastric carcinoma is recognized, taking into account its biologic behavior and grades of cell differentiation.The cellular and molecular pathology of gastric cancer and its precursors are reviewed and discussed. Gastric carcinomas are unique in their heterogeneity in both cellular composition and molecular changes.

Journal Article↗
PubMed1996

Karyotype variability in Trypanosoma rangeli.

The molecular karyotypes of several different protozoan parasites show high intra-species variation, including different kinetoplastids such as Trypanosoma brucei, Trypanosoma cruzi and Leishmania ssp. In this study, the molecular karyotype of Trypanosoma rangeli was examined. To evaluate potential intra-species molecular karyotype variations, 16 different samples were studied by pulsed field gel electrophoresis (PFGE) followed by ethidium bromide staining and hybridizations with 6 different probes. The result showed that different T. rangeli populations are highly polymorphic regarding the molecular karyotype, and thus suggests that PFGE analysis can be used for classification of different T. rangeli isolates. In addition, the molecular karyotype of T. rangeli was compared to molecular karyotypes of other kinetoplastids, and was shown to be distinctly different from that of T. cruzi, but shows some similarities with the karyotype described for T. brucei. Among the probes used one was identified as highly polymorphic, and thus informative for studies of different T. rangeli populations, and another was useful for differentiation between T. rangeli and T. cruzi.

Animals↗
PubMed2005

Gene expression profiling in acute myeloid leukemia.

Over the last decades, significant advances have been made in the knowledge and treatment of acute myeloid leukemia (AML). The WHO has recognized this new information by incorporating into its classification morphologic, immunophenotypic, genetic, and clinical features in an attempt to define biologically and clinically relevant entities. Nevertheless, well-defined cytogenetic subgroups exhibit considerable heterogeneity, and in many AML subtypes the pathogenic event is still not known. A classification system based on the underlying molecular pathogenetic abnormalities would be ideal, but such detailed knowledge is not yet available. Novel approaches in genomics, such as surveying the expression levels of thousands of genes in parallel using DNA microarray technology, open possibilities to further refine the studies on AML. Today, gene expression profiling in AML is becoming well established and has already been proven to be valuable in diagnosing different cytogenetic subtypes, discovering novel AML subclasses, and predicting clinical outcome. Recently, gene expression profiling studies in AML showed a remarkable level of concordance in findings, which may ultimately lead to an increasingly refined molecular taxonomy. While many challenges remain to be overcome, a combination of gene expression profiling with other microarray-based applications, high-throughput mutational analyses and proteomic approaches will not only significantly contribute to the classification and therapeutic decision making of AML, but also give important insights into the true pathobiologic nature of this type of leukemia.

Cytogenetic Analysis↗
PubMed2001

New developments in the pathology of skull base tumors.

As an anatomical interface between various tissues, the skull base harbors an exceptionally broad variety of neoplasms, some of which pose a major challenge for surgical pathology. The characterization of distinct immunohistochemical expression profiles and the identification of molecular genetic alterations associated with different tumor entities have significantly advanced this field. The new World Health Organization (WHO) classification of tumors of the nervous system lists 15 histopathological variants of meningioma. Of clinical importance are those entities that carry an increased risk of recurrence and a poor prognosis, i.e., the atypical meningioma (WHO grade II), clear-cell meningioma (WHO grade II), chordoid meningioma (WHO grade II), rhabdoid meningioma (WHO grade III), papillary meningioma (WHO grade III), and anaplastic meningioma (WHO grade III). Diagnostic criteria for atypical and anaplastic meningioma variants have now been stringently defined. The differential diagnosis of meningiomas includes hemangiopericytoma, hemangioblastoma, solitary fibrous tumor, sarcomas, and chordoid neoplasms. Recent data highlight the importance of distinguishing chordoma and chondrosarcoma of the skull base since chondrosarcomas show a significantly better clinical outcome. Among the less common, aggressive tumor entities in this anatomical region, infiltrating pituitary adenoma/pituitary carcinoma, superficial malignant gliomas, rhabdomyosarcoma, olfactory neuroblastoma, various sarcomas, and malignant lymphoma must be considered. Profiles of molecular genetic alterations have been established for several of these neoplasms and may facilitate the differential diagnosis. This review summarizes recent developments in the histopathological characterization, classification, and molecular pathology of neoplasms arising at the skull base.

Biomarkers, Tumor↗
PubMed1988

Classification of chronic granulomatous disease.

Chronic granulomatous disease is a heterogeneous disorder caused by at least three, and possibly four, types of mutations. Based on recent biochemical and molecular genetic data on this disease, a classification scheme and summary of the various forms of the disease are presented.

Cytochrome b Group↗
PubMed2006

Hodgkin's lymphoma: molecular targets and novel treatment strategies.

The WHO classification of Hodgkin's lymphoma (HL) distinguishes between two major subtypes, classical and nodular lymphocyte predominant HL. Approximately 95% of patients with HL will have the classical HL histology, which is characterized by the presence of rare malignant Hodgkin's and Reed-Sternberg cells among an overwhelming number of benign reactive cells. In recent years, new studies have shed more light on the biological and molecular features of Hodgkin's and Reed-Sternberg cells, providing hope that new targeted therapy may be developed to enhance the cure rate and to reduce treatment-related toxicity. In this review, the current understanding of the pathology and biology of HL will be discussed, as well as the current treatment approaches for patients with classical HL. Future treatment strategies will also be discussed based on our understanding of HL biology.

Hodgkin Disease↗