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PubMed2000

Foliage echoes: a probe into the ecological acoustics of bat echolocation.

The research reported here aims at understanding the biosonar system of bats based on the properties of its natural inputs (ecological acoustics). Echoes from foliages are studied as examples of ubiquitous, natural targets. The echo properties and their qualitative relationship to plant architecture are described. The echoes were found to be profoundly stochastic and in general neither Gaussian nor stationary. Consequently, features useful for discrimination of such target classes will be confined to estimated random process parameters. Several such statistical signal features which are sufficiently invariant to allow a classification of the used example plants were identified: the characteristic exponent and the dispersion of an alpha-stable model for the amplitude distribution, a crest factor defined as the ratio of maximum squared amplitude and signal energy, the dispersion of the first threshold passage distribution, the structure of the correlation matrix, and a nonstationarity in sound channel gain. Discrimination error probability could be reduced by combining features pairwise. The best combination was the crest factor and the correlation coefficient of a log-linear model of the time-variant sound channel gain; it yielded an estimated Bayes risk of 6.9% for data pooled from different views.

Acoustics↗
PubMed1997

The molecular biology and ocular distribution of prostanoid receptors.

Enormous progress has been made in the characterization of prostanoid receptors during the past five years. Molecular biological studies have enabled structural identification of all the human prostanoid receptors that had been proposed according to pharmacological criteria. The pharmacological classification proposed different receptor subtypes for prostaglandins D2, E2, F2 alpha, I2 and thromboxane A2 which were termed DP, EP, FP, IP and TP, respectively. Further subdivision for only the EP receptor has been reported and EP1, EP2, EP3, and EP4 subtypes have been unequivocally identified. The molecular structure of all prostanoid receptors is typical of that for G protein-coupled receptors and consists of seven alpha-helical transmembrane domains, three extracellular loops and an amino terminus, and three intracellular loops and a carboxyl terminus. Interestingly, mRNA alternative splice variants of the carboxyl termini have been found to determine G protein interactions for the EP3 receptor. Application of molecular biological techniques is beginning to make an impact in ocular research, where precise localization of receptors is difficult by more traditional methods because of the diminutive size of most ocular tissues. In situ hybridization and immunohistochemical studies using antibodies against the cloned human FP receptor have already suggested an unexpectedly wide distribution in the monkey eye. Transgenic studies involving FP receptor knock-out animals may provide future insight into the role of this receptor in glaucoma. However, since prostaglandins are extraordinarily effective in reducing intraocular pressure, it follows that traditional physiological and pharmacological studies retain a key role in glaucoma research. Studies in perfused human anterior segment organ culture have revealed that although prostaglandin F2 alpha does not facilitate trabecular aqueous humor outflow, prostaglandin E1 does increase trabecular outflow. Thus, different prostanoids may lower intraocular pressure by distinctly different mechanisms of action. Recent studies also indicate that prostanoids may exert a beneficial effect on retinal blood perfusion and may even act as neuroprotective agents.

Animals↗
PubMed1986

Alterations in relative proportions of microheterogenous forms of human alpha 1-acid glycoprotein in liver disease.

To determine whether liver damage correlates with typical changes in alpha 1-acid glycoprotein (alpha 1-AGP) carbohydrate branching, we selected patients with liver disease determined by histological liver findings. The severity of their illness was assessed by a clinical classification depending on the presence singly or together of four clinical complications (jaundice, ascites, hepatic encephalopathy and weight loss). An alpha 1-AGP crossed immunoelectrophoresis with Concanavalin A, an easy-to-perform method, revealed 3 or 4 subpopulations, the areas of which were calculated. A ratio R was determined as the most anodic peak area relative to the other ones. In our experimental conditions a ratio R value exceeding 1 correlated with the presence of one or more clinical complications. These results, evidencing fluctuations in the proportion of the carbohydrate variants of alpha 1-AGP, lead us to propose such a ratio as an index for grading liver damage. The sensitivity of this test was 86% and its specificity was 83%.

Clinical Laboratory Techniques↗
PubMed1987

Genetic relatedness of corriparta serogroup viruses.

Eight viruses of the Corriparta serogroup (Reoviridae: Orbivirus) that were known to be heterogeneous on the basis of serology and polyacrylamide gel electrophoresis were examined by reciprocal RNA-RNA blot hybridization of genomic RNA. Conserved and variant genes were identified by the degree of hybridization between cognate genes of different isolates. The eight viruses were divided into three subsets on the basis of the number of shared genes. Four of the viruses, isolated in Australia, formed one subset of related isolates and shared five conserved genes. Another isolate, Acado, was variant in all 10 genes and was considered to be a second subset. The remaining three isolates formed a third subset and shared four conserved genes. Genes 1, 3 and 10 were the most variable among the Corriparta serogroup isolates. Subsets of isolates within a serogroup which are highly related in the majority of the 10 genes and less related to serogroup viruses in another subset have not been reported previously. The phylogenetic relationship of Corriparta serogroup members suggested by the blot hybridization data is not apparent in the current taxonomic classification of these viruses which is based primarily upon serological data. The hybridization data on the Corriparta serogroup viruses are discussed and contrasted with other Orbivirus serogroups which have been examined similarly.

Animals↗
PubMed2004

Falcon: neural fuzzy control and decision systems using FKP and PFKP clustering algorithms.

Neural fuzzy networks proposed in the literature can be broadly classified into two groups. The first group is essentially fuzzy systems with self-tuning capabilities and requires an initial rule base to be specified prior to training. The second group of neural fuzzy networks, on the other hand, is able to automatically formulate the fuzzy rules from the numerical training data. Examples are the Falcon-ART, and the POPFNN family of networks. A cluster analysis is first performed on the training data and the fuzzy rules are subsequently derived through the proper connections of these computed clusters. This correspondence proposes two new networks: Falcon-FKP and Falcon-PFKP. They are extensions of the Falcon-ART network, and aimed to overcome the shortcomings faced by the Falcon-ART network itself, i.e., poor classification ability when the classes of input data are very similar to each other, termination of training cycle depends heavily on a preset error parameter, the fuzzy rule base of the Falcon-ART network may not be consistent Nauck, there is no control over the number of fuzzy rules generated, and learning efficiency may deteriorate by using complementarily coded training data. These deficiencies are essentially inherent to the fuzzy ART, clustering technique employed by the Falcon-ART network. Hence, two clustering techniques--Fuzzy Kohonen Partitioning (FKP) and its pseudo variant PFKP, are synthesized with the basic Falcon structure to compute the fuzzy sets and to automatically derive the fuzzy rules from the training data. The resultant neural fuzzy networks are Falcon-FKP and Falcon-PFKP, respectively. These two proposed networks have a lean and efficient training algorithm and consistent fuzzy rule bases. Extensive simulations are conducted using the two networks and their performances are encouraging when benchmarked against other neural and neural fuzzy systems.

Journal Article↗
PubMed1994

Methotrexate revisited: effects of long-term treatment in psoriasis.

In the past 22 years, 113 patients with severe psoriasis have been treated with low-dose methotrexate (MTX) in our department. The maximum weekly dosage was 15 mg (Weinstein schedule), the estimated mean cumulative dose was 4803 mg, and the estimated mean duration of therapy was 8 years and 11 months. In 81% of the patients, prolonged clearance or near clearance was achieved, indicating the potent and sustained potential of MTX in the treatment of both the pustular and erythematosquamous variants of psoriasis. Eighty-three patients (73%) had side-effects, most frequently abnormal liver function tests, nausea and gastric complaints. Apart from hair loss in seven patients, there were no mucocutaneous side-effects, probably because of the low-dose treatment schedule. In 71 patients MTX therapy was discontinued; in 33 patients because of side-effects. In 55 patients one or more liver biopsies were performed. Fibrosis was seen in seven of these patients (13%) and cirrhosis in two (4%). There was no relation between liver biopsy classification and cumulative dosage or duration of MTX therapy, nor was there any relation between liver histology and abnormal liver function tests. During this 22-year period, there were no deaths or life-threatening side-effects attributable to MTX treatment. We conclude that low-dose MTX (< or = 15 mg/week) is a relatively safe therapy for severe psoriasis, if patients are carefully selected beforehand, and regular monitoring for side-effects and drug interactions is performed during therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2004

Gene expression phenotypes of atherosclerosis.

OBJECTIVE: Fulfilling the promise of personalized medicine by developing individualized diagnostic and therapeutic strategies for atherosclerosis will depend on a detailed understanding of the genes and gene variants that contribute to disease susceptibility and progression. To that end, our group has developed a nonbiased approach congruent with the multigenic concept of complex diseases by identifying gene expression patterns highly associated with disease states in human target tissues. METHODS AND RESULTS: We have analyzed a collection of human aorta samples with varying degrees of atherosclerosis to identify gene expression patterns that predict a disease state or potential susceptibility. We find gene expression signatures that relate to each of these disease measures and are reliable and robust in predicting the classification for new samples with >93% in each analysis. The genes that provide the predictive power include many previously suspected to play a role in atherosclerosis and additional genes without prior association with atherosclerosis. CONCLUSIONS: Hence, we are reporting a novel method for generating a molecular phenotype of disease and then identifying genes whose discriminatory capability strongly implicates their potential roles in human atherosclerosis.

Aorta, Thoracic↗
PubMed2002

Significance of chromosomal markers in the diagnosis of mantle cell lymphoma (MCL).

According to the REAL/WHO classification, the diagnosis of mantle cell lymphoma (MCL) should be based on clinical, histopathological, immunological and cytogenetic or molecular data. This study is based on 13 cases, which were initially diagnosed as MCL with the use of conventional cytogenetic method and fluorescent in situ hybridization (FISH). MCL is associated with a specific cytogenetic aberration t(11;14)(q13;q32). The chromosomal analyses confirmed the MCL diagnosis in four cases. A neartetraploid cell line and two copies of t(11;14) were observed in three cases. These results correspond with a blastoid variant of MCL, accompanied by aggressive course and poor prognosis. The presence of karyotype with t(11;14) as the sole anomaly predicts an intermediate clinical outcome. Six patients had normal karyotypes, which is characteristic for the typical form of MCL, associated with a better prognosis. In this study we show that detection of chromosomal abnormalities is useful in diagnosis of MCL and has some prognostic significance.

Chromosomes, Human, Pair 11↗
PubMed1993

Absence of rheumatoid arthritis in a rural Nigerian population.

A 2-stage population screening survey of 2,000 inhabitants of 2 rural townships in southern Nigeria was undertaken. No case of rheumatoid arthritis (RA) was discovered in those responding, although 3 cases of inflammatory polyarthritis were found. One of these individuals satisfied the modification of the American College of Rheumatology classification tree criteria that allows for missing radiographic data. Simultaneous monitoring, during a 4-month period, of the local health clinic serving the townships also failed to reveal a case of RA. Three (5.5%) of 55 individuals tested were positive for rheumatoid factor, a rate lower than in previous surveys of rural West African populations. Further immunogenetic investigation of that subsample from this population, using HLA oligonucleotide typing, suggested that HLA-DR4 was rare (1/55). Further, although HLA-DR1 was present in 7 (13%), 6 had the DRB1*0102 variant seen in black populations and not thought to be associated with RA. Our study confirmed the findings of others that rural African groups have extremely low rates of RA. In addition HLA genes containing the RA associated "shared epitope" are also relatively infrequent and might explain this reduction in RA prevalence.

Adolescent↗
PubMed1981

[Neurogenic sarcoma of the head and neck with contact to the skull base (author's transl)].

The neurogenic sarcoma is a neoplasm found seldom. It descends from the sheaths of peripheric nerves. If this tumor develops from a solitary or multiple neurofibroma, it might also be called a neurofibrosarcoma. All other synonyms, especially that of the malignant schwannoma, should better be abandoned for histogenetic reasons. Today the classification of all tumors of the peripheral nervous system is based on a suggestion of the WHO from 1969. The tabular summary of the literature shows that only a little more than a hundred cases of neurogenic sarcoma of the head and neck were reported during the last 50 years. Differential diagnosis of this malignant tumor includes nearly all other malignant neoplasms of soft tissue, sometimes even anaplastic carcinoma. Histopathology, including electron microscopy, is described in general and also in detail with regard to three cases. Three forms of micro-morphological variants are dealt with, too. For diagnosis histological examination will be absolutely successful only in cases of neurofibromatosis or in cases where the nerve from which the tumor originates may be identified. Otherwise, conventional and computerized X-ray tomography may be helpful. Finally, some therapeutic and prognostic principles are discussed.

Adolescent↗
PubMed1989

The analysis of five carbenicillin-hydrolysing enzymes by electrophoretic methods.

Five carbenicillin-hydrolysing enzymes (carbenicillinases, or CARB), PSE-4 (CARB-1), PSE-1 (CARB-2), CARB-3, CARB-4 and CARB-5, and the beta-lactamase PSE-2 were compared by analysing their isoelectric points (pI), electrophoretic mobilities (mR) and titration curves (pH gradient electrophoresis). The pI determined by isoelectric focusing were 4.3 (CARB-4), 5.3 (PSE-4/CARB-1), 5.7 (PSE-1/CARB-2), 5.75 (CARB-3), 6.1 (PSE-2) and 6.35 (CARB-5). Their mR were estimated by zone electrophoresis as congruent to 26 for PSE-1 (CARB-2), CARB-3 and CARB-5, congruent to 30 for PSE-2, congruent to 33 for PSE-4 (CARB-1) and congruent to 61 for CARB-4. Titration curve analyses indicated that (1) PSE-4 (CARB-1), PSE-1 (CARB-2), CARB-3 and CARB-5 are closely related variants differing by a few amino acid substitutions; (2) the qualitative titration curve of CARB-4 is different from those of PSE-4 (CARB-1), PSE-1 (CARB-2), CARB-3 and CARB-5, although their patterns are somewhat similar; and (3) PSE-2 has no structural relationship with any of the other carbenicillin-hydrolysing enzymes or carbenicillinases (CARB) studied. Electrophoretic methods, and in particular titration curve determination combined with other physicochemical and enzymatic data, allowed a rapid comparison of the molecular structures of the beta-lactamases, and hence their classification.

Acinetobacter↗
PubMed1989

Morphometric analysis of chronic B-cell leukemias--an aid to the classification of lymphoid cell types.

In order to evaluate the ultrastructural features which may be of relevance in distinguishing cells from the various chronic B-cell leukemias, a morphometric analysis was performed on a large number of cells from each disease group. The parameters selected were: cell size, nucleo: cytoplasmic ratio, chromatin condensation, size of the nucleolus and degree of irregularity of both the nucleus and the cytoplasmic outlines. The mean values obtained for each parameter for each disease group were compared statistically. In disorders in which the cells have villous cytoplasmic projections, the quantitative analysis of the cellular features was helpful to characterise the different types of B cells involved. Thus, cells from cases of splenic lymphoma were found to be different from those of hairy cell leukemia, and a variant form of HCL was also identified by its distinct ultrastructural features. Similarly cells from chronic lymphocytic, prolymphocytic leukemia and an intermediate group CLL/PL were identified by the size of the nucleolus and the degree of chromatin condensation. The morphometric findings provided an objective morphological basis for the differential diagnosis between these closely related B-cell leukemias which was further supported by differences in the cells immunophenotype.

Cell Nucleolus↗
PubMed1996

Beet soil-borne virus RNA 3--a further example of the heterogeneity of the gene content of furovirus genomes and of triple gene block-carrying RNAs.

The complete nucleotide sequence of RNA 3 of the Ahlum isolate of beet soil-borne virus (BSBV) was determined from cDNAs obtained with immunocaptured virus particles and denatured preparations of dsRNA. BSBV RNA 3 is unique among the plant virus RNAs studied so far in containing apparently only the coding sequences of a triple gene block (TGB). The derived amino acid sequences of the three putative TGB-encoded proteins showed the highest level of sequence similarities with those of the corresponding proteins of potato mop top furovirus (PMTV) followed by those of peanut clump furovirus and barley stripe mosaic hordeivirus. Progressively fewer similarities were found with the TGB-encoded proteins of beet necrotic yellow vein virus (uncertain classification), potato X potexvirus, and potato M carlavirus. The 3'-terminal 78 nucleotides of BSBV RNA 3 can be folded into a tRNA-like structure and a high degree of sequence similarity exists between the 122 3'-terminal nucleotides of BSBV RNA 3 and PMTV RNA 2. In other regions, however, no pronounced sequence similarities were found between the two RNAs, and PMTV RNA 2 contains an additional putative gene for a cysteine-rich protein downstream of the TGB. The two viruses are unrelated serologically. BSBV RNA 3 adds a further variant to the heterogeneity of the gene content of furovirus genomes and of triple gene block-carrying RNAs.

Amino Acid Sequence↗
PubMed2006

t(8;21) (q22;q22) acute myelogenous leukemia in Mexico: a single institution experience.

We analyze the prevalence and clinical features of a group of patients with t(8;21) (q22;q22) acute myeloblastic leukemia, identified in a single institution in México over a 10-year period. Fifteen patients presented at the Centro de Hematología y Medicina Interna de Puebla from February 1995 to August 2005; only nine were treated and followed in the institution. Median age was 24 years, (range 7-49); there was only one male. According to the French-American-British (FAB) morphological classification of leukemia, the morphology was M2 in four cases, M4 in three cases, M3 in one case and M0 in one. In addition to the myeloid markers, lymphoid markers were identified in 6 patients. Patients were induced to remission with combined chemotherapy and three subsequently underwent bone marrow transplantation (BMT). The median overall and disease-free survival has not been reached, being above 3390 days, the probability of survival at this time was 73%. In this single-center experience in México, we found that the t(8;21) (q22;q22) variant of leukemia was more frequent than in Caucasian populations, that the co-expression of lymphoid markers in the blast cells is very frequent and that this malignancy is associated with a relatively good prognosis.

Acute Disease↗
PubMed1997

Animal lectins.

Protein and lipid glycosylation is no longer considered as a topic whose appeal is restricted to a limited number of analytical experts perseveringly pursuing the comprehensive cataloguing of structural variants. It is in fact arousing curiosity in various areas of basic and applied bioscience. Well founded by the conspicuous coding potential of the sugar part of cellular glycoconjugates which surpasses the storage capacity of oligonucleotide- or oligopeptide-based code systems, recognition of distinct oligosaccharide ligands by endogenous receptors, i.e. lectins and sugar-binding enzymes or antibodies, is increasingly being discovered to play salient roles in animal physiology. Having inevitably started with a descriptive stage, research on animal lectins has now undubitably reached maturity. Besides listing the current categories for lectin classification and providing presentations of the individual families and their presently delineated physiological significance, this review places special emphasis on tracing common structural and functional themes which appear to reverberate in nominally separated lectin and animal categories as well as lines of research which may come to fruition for medical sciences.

Animals↗
PubMed2004

Unusual uptake of radioiodine in the chest in a patient with thyroid carcinoma.

A wide spectrum of potentially misleading artefacts can arise in 131I whole body scans from various anatomical variants and physiological processes as well as several unrelated non-thyroidal disease processes. A proper understanding of the causes of false positive 131I scans is essential for accurate interpretation of the images and to obviate diagnostic errors which may lead to administration of unnecessary therapy doses. The authors, in this article, present a case which had 131I uptake in the mediastinum persisting after surgical excision of mediastinal nodes, which was subsequently found to be due to accumulation of radioiodine in a hugely dilated oesophagus in secondary to achalasia. A comprehensive and rational classification of the various false positive 131I scintigraphic patterns based on the knowledge of the existing literature is reviewed.

Artifacts↗
PubMed2003

Complete coding sequences of dengue-1 viruses from Paraguay and Argentina.

We have determined the complete coding sequences of six dengue-1 (DEN-1) viruses isolated from Paraguay and Argentina in 2000 from patients with dengue fever. Sequences of strains 259par00, 280par00, 295arg00, 297arg00 and 301arg00 can encode a polyprotein of 3392 amino acids. Strain 293arg00 circulated as a "wild type+deletion mutant" quasispecies, with a subpopulation characterized by a 3-nucleotide deletion in the NS4A region. This variant, which would encode a three amino acid change in the NS4A protein, was found as a minority population in one additional partially-sequenced isolate from the same outbreak. These six South American strains group into two different clades of the "American-African" DEN-1 genotype-one clade is most closely related to strains isolated from Brazil in 1997, the other to a Peruvian strain isolated in 1991 for which only partial sequence information is available. DEN-1 viruses isolated worldwide comprise at least four different genotypes according to previously defined classification criteria.

Amino Acid Sequence↗
PubMed2001

Antigenic and genetic divergence of rabies viruses from bat species indigenous to Canada.

Antigenic characterisation of over 350 chiropteran rabies viruses of the Americas, especially from species reported rabid in Canada, distinguished 13 viral types. In close accord with this classification, nucleotide sequencing of representative isolates, at both the N and G loci, identified four principal phylogenetic groups (I-IV), sub-groups of which circulated in particular bat species. Amongst the North American bat viruses, there was a notable division between group I specimens associated with colonial, non-migratory bats (Myotis sp. and Eptesicus fuscus) and those of group II harbored by solitary, migratory species (Lasiurus sp. and Lasionycteris noctivagans). Certain species of Myotis were clearly identified as rabies reservoirs, an observation often obscured previously by their frequent infection by viral variants of other chiroptera. An additional group (III) apparently circulates in E. fuscus, whilst viruses harbored by both insectivorous and haematophagus bats of Latin America clustered to a separate clade (group IV). Comparison of the predicted N and G proteins of these viruses with those of strains of terrestrial mammals indicated a similarity in structural organisation regardless of host species lifestyle. Finally, these sequences permitted examination of the evolutionary relationship of American bat rabies viruses within the Lyssavirus genus.

Animals↗