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PubMedDate not supplied

[Diagnosis and genetics of congenital dyserythropoietic anemias (CDA)].

The congenital dyserythropoietic anemias (CDA) are hereditary diseases characterized by a lifelong, mostly moderate anemia. CDA can be diagnosed already in early childhood. However, diagnosis is complicated due to poor knowledge of morphological criteria and the large number of differential diagnoses that have to be excluded. CDA type I is characterized by macrocytic anemia with megaloblastic changes in erythropoiesis and chromatin bridges between isolated erythroblasts. Type II shows a normocytic anemia with a positive acidified serum test and increased agglutination with anti-i. Erythroblasts can present with 2 or more nuclei. CDA type III presents with a macrocytic anemia and erythroblasts with up to 12 nuclei, the so called gigantoblasts. Some patients lack the typical morphological abnormalities of type I-III (variants or type IV). Besides light microscopic abnormalities, CDA type-specific changes in electron microscopy are described. The clinical picture of the patients vary between the different forms: signs of hemolysis and ineffective erythropoiesis such as icterus, splenomegaly and gall stones can be present. Most important is the tendency of a part of patients to have an increased iron absorption and iron storage. Patients with and without transfusion dependency are described. Supportive care such as iron chelation can be necessary in some patients. The CDA are inherited in an autosomal recessive manner; in type III an additional autosomal dominant variant exists. Recently, the determination of gene loci for type I, II and III was enabled by linkage analysis on different regions of chromosome 15 and 22. It is considered that CDA I and II are genetically heterogenic. Until now no gene has been identified in either type of CDA. In CDA type II, a glycosylation defect of erythrocyte membrane proteins is present. An international group plans to do further research. Therefore, identification and registration of patients in a registry is necessary. Patients' data and material would enable gene characterization. The results would allow an extended classification according to genotype and prediction of the course of the disease. Additionally, information on the regulation and control of normal and abnormal erythropoiesis could be obtained.

Anemia, Dyserythropoietic, Congenital↗

PubMed2001

Molecular characterization and phylogenetic analysis of a human T cell leukemia virus type 2 strain from French Guiana.

Extensive studies have been carried out on native Amerindian populations living in French Guiana in an attempt to detect human T cell leukemia virus type 2 (HTLV-2). However, the first strain of this virus identified in this region was not detected in these populations, but in a Brazilian woman of Amerindian origin. Comparative analyses of the nucleotide sequences of 589 bp of the gp21 env gene and of 625 bp of the long terminal repeat (LTR) showed that this new HTLV-2 strain (HTLV-2 GUY) was of subtype A. Sequence comparison and phylogenetic analyses demonstrated that HTLV-2 GUY was closely related to a group of distinct variants of HTLV-2 subtype A strains originating mostly from Brazilian inhabitants and formerly called HTLV-2 subtype C. As there is a high level of immigration from Brazil in French Guiana, we carried out a seroepidemiological study of 175 Brazilians, mostly women (obtained from a serum databank) and 72 female Brazilian prostitutes living in French Guiana to determine whether HTLV-2 is likely to become an emerging infection in this area. No HTLV-2 infection was detected, indicating that this virus is unlikely to become prevalent in the near future.

Base Sequence↗

PubMed2000

A new in vivo and in vitro B cell lymphoma model, pi-BCL1.

We report a new variant of the BCL1 syngeneic mouse B-cell lymphoma model, which we have called pi-BCL1. pi-BCL1 can be established as a syngeneic tumor in BALB/c mice. Tumors can be removed, prepared and easily grown in liquid culture and subsequently transferred back successfully as syngeneic tumors. As a syngeneic tumor pi-BCL1 behave more like a lymphoma with solid tumor masses, than a chronic lymphocytic leukaemia of the original BCL1 model. The immunophenotype and the growth characteristics of the pi-BCL1 and BCL1 tumors appear very similar. Cytologically, pi-BCL1 appears to be a transformation from a small lymphocytic lymphoma to a more diffuse large cell centroblast-like higher-grade lymphoma. We are not aware of any previous reports of such transformation events in a syngeneic animal model of B cell lymphoma. We believe pi-BCL1 provides a useful new tool for the study of B cell lymphoma in vitro and in vivo and enables reduced numbers of tumor passage in mice.

Animals↗

PubMed1998

Spindle cell rhabdomyosarcoma (so-called) in adults: report of two cases with emphasis on differential diagnosis.

Spindle cell rhabdomyosarcoma (RMS) is a recently described variant of embryonal RMS that carries a relatively favorable prognosis when compared with other forms of RMS. To date, spindle cell RMS has been described only in children. The authors have identified two unusual cases occurring in adults using the following criteria: tumors composed mainly of fascicular, relatively monomorphic spindle-shaped cells that show unequivocal immunohistochemical and ultrastructural evidence of myogenic differentiation. The tumors were identified in a 38-year-old woman and a 56-year-old man, arising in the cheek and left hemidiaphragm, respectively. Both were treated with surgical resection and chemotherapy. The first patient died of uncontrolled local recurrence of her tumor at 27 months after diagnosis, and the second died of metastatic disease at 13 months follow-up. The tumors were composed mainly of fascicles of spindle cells with palely eosinophilic cytoplasm admixed diffusely with sparse polygonal, rounded, or strap-shaped rhabdomyoblasts with brightly eosinophilic cytoplasm and with cross-striations in the first case only. Immunostaining for muscle-related antigens showed staining for smooth-muscle actin (focal), pan-actin HHF-35, desmin, fast myosin, myoglobin, and MyoD1. Both cases were negative for S-100 protein. On electron microscopy, both cases showed neoplastic rhabdomyoblasts with clear-cut sarcomeric differentiation in many of the tumor cells. Spindle cell RMS poses special problems in differential diagnosis when arising in adults and should be distinguished from leiomyosarcoma, malignant peripheral nerve sheath tumor with heterologous rhabdomyoblastic differentiation (malignant Triton tumor), and fibrosarcoma. In view of the good prognosis afforded children with spindle cell RMS and in light of the chemoresponsive behavior of RMS in general, we feel that it is important to identify tumors that meet the criteria for spindle cell RMS occurring in the adult population. However, based on these two cases, it is possible that spindle cell RMS occurring in adults may not be associated with such a favorable outcome.

Actins↗

PubMed1988

HIV heterogeneity and viral pathogenesis.

HIV research in the past year has elucidated many questions relevant to strategies for treatment and control. For instance, there is a greater understanding of the diversity of HIV isolates as well as the wide range of potential cells sensitive to infection. The search for a safe, effective vaccine now calls for more caution in the light of the discovery of neutralization-resistant variants and antibody-mediated enhancement of infection. Efforts to control HIV must take into account the various mechanisms of virus entry into host cells, and the processes involved in cytopathic effects. Moreover, the role of cells of the mononuclear phagocyte system as reservoirs for HIV particles should be recognized. Together with new information about cytokine induction of HIV, the concept of latent infection of monocytes and macrophages has profound implications for virus persistence and dissemination, especially in the seronegative individual. While many factors about HIV have been uncovered in the past year, several questions remain unanswered and new ones have arisen. For instance, in how many ways does the virus kill in host cell? What causes latency and why does it occur in some but not all hosts? How can virus-filled macrophage vesicles be reached by therapeutic agents or prevented from releasing HIV? What surveillance mechanisms allow some productively infected hosts (cells as well as individuals) to survive beyond expectation? These and other questions should provoke future research on this presently complex and challenging pathogen.

Acquired Immunodeficiency Syndrome↗

PubMed1996

Proposed three-dimensional model for the attachment protein G of respiratory syncytial virus.

Protein G of respiratory syncytial virus (RSV) is an envelope glycoprotein that is structurally very different from its counterparts (haemagglutinin-neuraminidase and haemagglutinin) in other paramyxoviruses. In this study, we put forward a model for this unique viral envelope protein. We propose that protein G of RSV contains several independently folding regions, with the ectodomain consisting of a conserved central hydrophobic region located between two polymeric mucin-like regions. The central conserved region is probably the only relatively fixed and folded part of the ectodomain of RSV-G. This central conserved region contains four conserved cysteine residues which can form two disulphide bridges. Analysis of the proteolytic digestion products of a peptide corresponding to the central conserved region showed that one of the three theoretically possible combinations of disulphide connections could be eliminated. The final disulphide bridge assignment was established by affinity measurements with peptide variants in which different disulphide connections were formed. Additionally, peptide binding studies were used to map the binding site, at the amino acid level, of a monoclonal antibody directed against the central conserved region. These studies indicated the level of surface exposure of the amino acid side-chains. The surface exposure agreed with the structural model. The proteolytic digestion, the peptide binding studies and the affinity measurements with structural peptide variants support a structural model with disulphide connections that correspond to a structural motif called a cystine noose. This model provides a structural explanation for the location and molecular details of important antigenic sites.

Amino Acid Sequence↗

PubMed2006

Isolation of Salmonella enterica subspecies enterica serovar Paratyphi B dT+, or Salmonella Java, from Indonesia and alteration of the d-tartrate fermentation phenotype by disrupting the ORF STM 3356.

Salmonella enterica subspecies enterica serovar Paratyphi B [O1,4,(5),12 : Hb : 1,2] can cause either an enteric fever (paratyphoid fever) or self-limiting gastroenteritis in humans. The d-tartrate non-fermenting variant S. enterica subsp. enterica serovar Paratyphi B dT- (S. Paratyphi B) is the causative agent of paratyphoid fever, and the d-tartrate fermenting variant S. enterica subsp. enterica serovar Paratyphi B dT+ (S. Paratyphi B dT+; formerly called Salmonella Java) causes gastroenteritis. S. Java is currently recognized as an emerging problem worldwide. Twelve dT+ S. Java isolates were collected in Indonesia between 2000 and 2002. One-third of them contained Salmonella genomic island 1 (SGI1), which gives the multidrug-resistant phenotype to the bacteria. In this study, a PCR-based method to detect a single nucleotide difference responsible for the inability to ferment d-tartrate, reported elsewhere, was validated. The d-tartrate fermenting phenotype of S. Java was converted to the non-fermenting phenotype by the disruption of the ORF STM 3356, and the d-tartrate non-fermenting phenotype of the ORF STM 3356-disrupted strain and the dT- reference strain was changed to the dT+ phenotype by complementing ORF STM 3356 in trans. The results show that the dT+ phenotype requires a functional product encoded by STM 3356, and support the use of the PCR-based discrimination method for S. Paratyphi B and S. Java as the standard differentiation method.

Anti-Bacterial Agents↗

PubMed1998

Strategies for mutational analysis of the large multiexon ATM gene using high-density oligonucleotide arrays.

Mutational analysis of large genes with complex genomic structures plays an important role in medical genetics. Technical limitations associated with current mutation screening protocols have placed increased emphasis on the development of new technologies to simplify these procedures. High-density arrays of >90,000-oligonucleotide probes, 25 nucleotides in length, were designed to screen for all possible heterozygous germ-line mutations in the 9.17-kb coding region of the ATM gene. A strategy for rapidly developing multiexon PCR amplification protocols in DNA chip-based hybridization analysis was devised and implemented in preparing target for the 62 ATM coding exons. Improved algorithms for interpreting data from two-color experiments, where reference and test samples are cohybridized to the arrays, were developed. In a blinded study, 17 of 18 distinct heterozygous and 8 of 8 distinct homozygous sequence variants in the assayed region were detected accurately along with five false-positive calls while scanning >200 kb in 22 genomic DNA samples. Of eight heterozygous sequence changes found in more than one sample, six were detected in all cases. Five previously unreported sequence changes, not found by other mutational scanning methodologies on these same samples, were detected that led to either amino acid changes or premature truncation of the ATM protein. DNA chip-based assays should play a valuable role in high throughput sequence analysis of complex genes.

Ataxia Telangiectasia Mutated Proteins↗

PubMed1999

Variation in the composition and pore function of major outer membrane pore protein P2 of Haemophilus influenzae from cystic fibrosis patients.

We investigated the relationship between susceptibility to beta-lactam antibiotics and variation in the major outer membrane protein P2 (OmpP2; also called porin) of persistent nonencapsulated Haemophilus influenzae isolated from cystic fibrosis patients. Nine OmpP2 variants were selected from two distinct H. influenzae strains from two patients extensively treated with beta-lactam antibiotics. The variants differed in their susceptibilities to at least two beta-lactam antibiotics. By detergent extraction and column chromatography, OmpP2 was purified from two variants that were derived from strain 70 and that differed notably in their susceptibilities to beta-lactam antibiotics. The proteins were reconstituted into black lipid membranes for measurement of porin function. OmpP2 from the more resistant isolate (isolate 70b) had a smaller channel conductance than OmpP2 of the more susceptible isolate (isolate 70f). DNA sequencing of ompP2 of these isolates revealed single nonsynonymous base differences; there were changes in the amino acid sequence corresponding to surface-exposed loops 4, 5, 6, and 8. Changes in loops 4, 5, and 6 were previously shown to result in antigenic differences. Beside these mutations, variants of strain 70 showed additional mutations in loop 1 and nonexposed loop 3. Taken together, our results suggest that in variants of strain 70, nonsynonymous point mutations accumulated both in the sequences of ompP2 coding for antigen-variable loops and in other loops, notably, loops 1 and 3. The latter changes are suggested to affect the permeability of the porin channel.

Amino Acid Sequence↗

PubMed1995

Biologic activities of antibodies to the neutral-polysaccharide component of the Pseudomonas aeruginosa lipopolysaccharide are blocked by O side chains and mucoid exopolysaccharide (alginate).

Virulent strains of Pseudomonas aeruginosa are either of a nonmucoid, lipopolysaccharide (LPS)-smooth or mucoid, LPS-rough phenotype, and immunity to these different variants is efficiently mediated by antibodies specific to O antigens or mucoid exopolysaccharide (also called alginate), respectively. In addition to O side chains and core polysaccharide components, the LPS of P. aeruginosa also contains neutral-polysaccharide components that express antigenic determinants common to many clinical isolates. We evaluated antibodies specific to neutral polysaccharides for the ability to mediate opsonic killing and protective immunity. Antibodies to these antigens mediated opsonic killing of poorly virulent nonmucoid LPS-rough isolates but not of isogenic strains with either a LPS-smooth or a mucoid phenotype. Antibodies to neutral-polysaccharide antigens also failed to protect neutropenic mice from challenge with modest doses of LPS-smooth P. aeruginosa strains (< 10(3) CFU per mouse), whereas O-antigen-specific antibodies were highly protective. Antibodies to neutral polysaccharides deposited significantly (P = 0.002) more C3 onto LPS-rough strains than did antibodies to O side chains, but this situation was reversed when isogenic LPS-smooth strains were tested. Given that protective immunity against P. aeruginosa must be directed against either nonmucoid LPS-smooth strains or mucoid LPS-rough strains, it appears that antibodies specific to neutral-polysaccharide antigens do not protect against P. aeruginosa infection. Lack of protection is likely due to the ability of both O side chains and mucoid exopolysaccharide (alginate) to interfere with the opsonic killing activity of neutral-polysaccharide-specific antibodies.

Alginates↗

PubMed2003

The curious genomic path from leaky red cell to nephrotic kidney.

The human red cell has proved to be an invaluable model cell for the study of many aspects of membrane structure and function. It has a series of transport pathways which mediate the movements of the univalent cations Na and K, which are either identical or similar to systems in other human tissues, including the human kidney. The balance between the energy-consuming NaK pump and a 'passive leak' component maintains a net deficit of cations within the cell, which defends the cell volume against osmotic swelling. There exist a series of dominantly inherited human red cell conditions, gathered under the generic title 'hereditary stomatocytoses', in which the so-called 'passive leak' to Na and K is pathologically increased. In the more severe variants this compromises the integrity of the cell and the patients suffer haemolytic anaemia. Some less severe variants present with pseudohyperkalaemia caused by loss of K from red cells on storage of blood at room temperature. The most severe variants show a deficiency in a widely distributed 'raft' protein known as stomatin. The stomatin protein is homologous to the 'podocin' protein, the gene for which is mutated in a recessively inherited form of nephrotic syndrome. Among other possible functions, both proteins could be involved in the trafficking of membrane proteins to and from the plasma membrane.

Anemia, Hemolytic, Congenital↗

PubMed2004

Size and shape determination of proteins in solution by a noninvasive depolarized dynamic light scattering instrument.

Dynamic light scattering (DLS) is a well-known noninvasive technique for investigating interactions of protein molecules in solution. Unfortunately, DLS is not very sensitive to small size changes because covariables, such as temperature, viscosity, and refractive index, are not precisely known, or they vary as functions of an experiment run, making it difficult to resolve subtle size changes of only a few Angstrom. It is usually not possible, if these covariables are not systematically measured and brought into the DLS analysis, to separate monomers from dimers when both are present in solution. We present here measurements with a variant of DLS that determines rotational diffusion as well as translation diffusion. This technique, called depolarized dynamic light scattering (DDLS) is, like DLS, also an old method, but it is rarely used due to enormous practical difficulties. However, we have found that a combination of DLS with DDLS is very promising, because it allows for a rough shape determination of the molecule under study and it is more sensitive to subtle size changes. We built an instrument that overcomes some of the difficulties, and report measurements made with this instrument. One of the samples was Photosystem-I, a membrane protein for photosynthesis. Its dimensions were determined to be 9.6 nm thick and 26 nm in diameter, values that are in good agreement with the dimensions obtained from X-ray diffraction analysis of single crystals.

Biophysics↗

PubMed1997

Creutzfeldt-Jakob disease: therapeutic strategies.

Creutzfeldt-Jakob disease (CJD) is a rare neurodegenerative illness which belongs to the group of transmissible subacute spongiform encephalopathies (TSSE). Today, no treatment is available for TSSE. The appearance of a new variant of CJD, which affects young people and could be linked to so-called ;mad cow disease', has stimulated researchers to develop new therapies against CJD. A few drugs have already been shown to delay the onset of experimental TSSE. They could contribute to the understanding of the pathogenic mechanisms involved in TSSE and, therefore, could be the basis for therapeutic strategies against CJD.

Editorial↗

PubMed2002

[Present perspectives on Creutzfeldt-Jakob disease: pathogenesis, diagnosis and treatment].

In recent years, interest in the group of diseases generically known as "transmissible spongiform encephalopathies" has reemerged, mainly due to the socioeconomic implications of one of its variants: bovine spongiform encephalopathy. Transmissible spongiform encephalopathies seem to be caused by proteinaceous particles called prions, isoforms of a membrane protein which can be found in humans as well as in several animal species. Their precise function is still unknown. Although investigation into transmissible spongiform encephalopathies has clarified some uncertainties about its pathogenesis and epidemiology, many important questions remain. This is especially true or treatment, since no effective curative therapy exists as yet.

Creutzfeldt-Jakob Syndrome↗

PubMed1992

Typing leptospira from the perspective of a reference laboratory.

Leptospirosis is caused by different leptospiral variants. Analysis by cross agglutination absorption tests (CAAT) led to the definition of entities called serovars to distinguish between leptospires on sub-species level, and to the designation of reference strains representing serovars. For decades CAAT has been used to classify leptospires and now approximately 200 serovars have been recognized. In the last few years, it has become increasingly more clear that the serovar concept is no longer fully satisfactory as it may fail to adequately define epidemiologically important entities. In addition, CAAT is too cumbersome and time-consuming for routine typing. Various methods have been developed based on antigenic or genetic analysis with the purpose to supplement or to replace the CAAT. Most of these methods are still in an experimental state. It is to be expected that a typing method based on genomic analysis will eventually become most important. Such a new method should have considerable advantages in order to be acceptable for the development of a new classification system replacing the system based on serovars, which is widely accepted and in many respects still satisfactory. From the new methods, analysis of leptospiral DNA fragment length after digestion with restriction enzymes (REA) has been widely used and proven to be useful for typing. Pending the development of new typing methods that have clear advantages and may lead to a new classification system, it is suggested that the classification system based on serovars is maintained and that REA is added to each description of a new serovar.

DNA↗

PubMed2003

[Fabry disease in 2004].

Fabry disease is a hereditary metabolic disease, with an X-linked transmission, that is due to the deficit of alpha-galactosidase A, a lysosomal enzyme. The enzyme deficiency is responsible for an accumulation of neutral glycosphingolipids in the organism with a consequent disease of overload that is responsible for pain, dermatological, renal, cardiac, gastro-intestinal, cochlear and neurological manifestations. Fabry disease starts during childhood but the diagnosis is often made too late. An early diagnosis is nevertheless essential in order to commence a treatment before the occurrence of morbid cardio or cerebro-vascular accidents, or the development of end-stage chronic renal failure. Some phenotypic variants of Fabry disease are probably under-diagnosed among patients with so-called idiopathic hypertrophic cardiomyopathy on haemodialysis. Treatment by substitution of the enzyme with a recombinant alpha-galactosidase has been recently validated in breakthrough controlled clinical trials. Substitutive enzyme treatment represents a major therapeutic development. At the same time, it raises numerous questions such as the ideal age for initiation of treatment, the dose and the optimal frequency of enzyme administration, the reversibility of certain histopathological lesions and the determination of the best markers for the assessment and follow-up of the efficacy of treatment. Monitoring of the plasma levels of the enzyme substrate and the antibody titre seem to be essential. The documentation of short-term clinical benefits could require the use of sophisticated investigation methods such as the study of the myocardial function by tissue Doppler imaging.

Age Factors↗

PubMed2005

[Recent data on lobular neoplasia of the breast: the pathologist's opinion].

Lobular neoplasia is the new WHO terminology that encompasses the so-called lobular carcinoma in situ and atypical lobular hyperplasia. Besides the classical forms, particular variants have been described, which are mammographically detectable with distinct histologic patterns and behaviour. These variants are characterized by pleomorphic cells, necrosis with calcifications and may be associated to an invasive lobular carcinoma. Their clinical issue looks more like a preinvasive lesion than a marker of increased risk. Thus, their identification on biopsy requires a surgical reexcision. Hybrid forms, sharing a mixed lobular and ductal morphology and phenotype, have also been mentionned. Despite a lack of prognostic evaluation, it seems logical to recommend a subsequent surgical investigation when they are observed. Classical forms are usually managed by simple follow-up, although this attitude does not make a consensus among pathologists. Lobular neoplasia are not all indolent lesions and belong to an heterogeneous group that percutaneous guided biopsies have emphasized. They should be managed in a pluridisciplinar way and correctly diagnosed on percutaneous biopsies as well as surgical specimens.

Biopsy↗

PubMedDate not supplied

Sturge Weber syndrome.

A variant of hemangioma and an uncommon congenital condition, the Sturge Weber syndrome (SWS), also called encephalo trigeminal angiomatosis, is a neurocutaneous disorder with angiomas involving the skin of the face (cutaneous angioma) and pia arachnoid (leptomeningeal angioma). It occurs typically in the ophthalmic and maxillary distributions of the trigeminal nerve (1,2). Here we present a case of a 14 year old girl.

Adolescent↗