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At least 901 records · Page 50Linked to original sources
PubMed2002

Molecular characterization of multiresistant d-tartrate-positive Salmonella enterica serovar paratyphi B isolates.

Since 1996, the National Salmonella Reference Laboratory of Germany has received an increasing number of Salmonella enterica subsp. enterica serovar Paratyphi B isolates. Nearly all of these belonged to the dextrorotatory tartrate-positive variant (S. enterica subsp. enterica serovar Paratyphi B dT(+)), formerly called S. enterica subsp. enterica serovar Java. A total of 55 selected contemporary and older S. enterica subsp. enterica serovar Paratyphi B dT(+) isolates were analyzed by plasmid profiling, antimicrobial resistance testing, pulsed-field gel electrophoresis, IS200 profiling, and PCR-based detection of integrons. The results showed a high genetic heterogeneity among 10 old strains obtained from 1960 to 1993. In the following years, however, new distinct multiresistant S. enterica subsp. enterica serovar Paratyphi B dT(+) clones emerged, and one clonal lineage successfully displaced the older ones. Since 1994, 88% of the isolates investigated were multiple drug resistant. Today, a particular clone predominates in some German poultry production lines, poultry products, and various other sources. It was also detected in contemporary isolates from two neighboring countries as well.

Animals↗
PubMed2005

Successful multiresistant community-associated methicillin-resistant Staphylococcus aureus lineage from Taipei, Taiwan, that carries either the novel Staphylococcal chromosome cassette mec (SCCmec) type VT or SCCmec type IV.

Methicillin-resistant Staphylococcus aureus (MRSA) isolates carry the methicillin resistance gene (mecA) on a horizontally transferred genetic element called the staphylococcal chromosome cassette mec (SCCmec). Community-acquired MRSA (CAMRSA) isolates usually carry SCCmec type IV. We previously reported that 76% of 17 CAMRSA isolates (multilocus sequence type 59) obtained from pediatric patients with skin and soft tissue infections (SSTI) from Taipei did not carry SCCmec types I to IV. We used DNA sequence analysis to determine that the element harbored by these nontypeable isolates is a novel subtype of SCCmec V called SCCmec V(T.) It contains a ccrC recombinase gene variant (ccrC2) and mec complex C2. One SSTI isolate contained molecular features of SCCmec IV but also contained ccrC2 (a feature of SCCmec V(T)), suggesting that it may harbor a composite SCCmec element. The genes lukS-PV and lukF-PV encoding the Panton-Valentine leukocidin (PVL) were present in all CAMRSA SSTI isolates whether they contained SCCmec type IV or V(T). SCCmec V(T) was also present in 5 of 34 (14.7%) CAMRSA colonization isolates collected from healthy children from Taipei who lacked MRSA risk factors. Four (80%) of the these isolates contained lukS-PV and lukF-PV, as did 1 of 27 (3.7%) SCCmec IV-containing colonization isolates. A total of 63% (10 of 16) of the SSTI isolates and 61.7% (21 of 34) of the colonization isolates tested were resistant to at least four classes of non-beta-lactam antimicrobials. SCCmec V(T) is a novel SCCmec variant that is found in multiply resistant CAMRSA strains with sequence type 59 in Taipei in association with the PVL leukotoxin genes.

Anti-Bacterial Agents↗
PubMed2000

Genetic heterogeneity of hypervariable region 1 of the hepatitis C virus (HCV) genome and sensitivity of HCV to alpha interferon therapy.

Hepatitis C virus (HCV) populations persist in vivo as a mixture of heterogeneous viruses called quasispecies. The relationship between the genetic heterogeneity of these variants and their responses to antiviral treatment remains to be elucidated. We have studied 26 virus strains to determine the influence of hypervariable region 1 (HVR-1) of the HCV genome on the effectiveness of alpha interferon (IFN-alpha) therapy. Following PCR amplification, we cloned and sequenced HVR-1. Pretreatment serum samples from 13 individuals with chronic hepatitis C whose virus was subsequently eradicated by treatment were compared with samples from 13 nonresponders matched according to the major factors known to influence the response, i.e., sex, genotype, and pretreatment serum HCV RNA concentration. The degree of virus variation was assessed by analyzing 20 clones per sample and by calculating nucleotide sequence entropy (complexity) and genetic distances (diversity). Types of mutational changes were also determined by calculating nonsynonymous substitutions per nonsynonymous site (K(a)) and synonymous substitutions per synonymous site (K(s)). The paired-comparison analysis of the nucleotide sequence entropy and genetic distance showed no statistical differences between responders and nonresponders. By contrast, nonsynonymous substitutions were more frequent than synonymous substitutions (P </= 0.05) in responders, but there was no significant difference in nonresponders. Nonsynonymous substitutions tended to be more frequent than synonymous substitutions in women (P = 0.06) but not in men. Nucleotide entropy and genetic distances were significantly related to serum RNA concentration (P </= 0.01). Our findings suggest that after controlling for the major determinants of interferon response, neither complexity nor diversity of the HVR-1 region is associated per se with virus eradication. Because a higher proportion of nonsynonymous substitutions than synonymous substitutions was found only in responders, host anti-HCV-specific immune response rather than viral factors may be playing an important role in the interferon response.

Adult↗
PubMed1995

Functional activation of the cystic fibrosis trafficking mutant delta F508-CFTR by overexpression.

The most common mutation in the gene associated with cystic fibrosis (CF) causes deletion of phenylalanine at residue 508 (delta F508) of the gene product called CFTR. This mutation results in the synthesis of a variant CFTR protein that is defective in its ability to traffic to the plasma membrane. Because earlier studies showed delta F508-CFTR retains significant phosphorylation-regulated chloride (Cl-) channel activity, processes capable of restoring the mislocalized delta F508-CFTR to the correct cellular destination may have therapeutic benefit. Here we report one such process that involves overexpression of the mutant protein and appears to result in the escape of a small amount of delta F508-CFTR to the plasma membrane. In recombinant cells where expression of delta F508-CFTR is controlled by the metallothionein promoter, this effect can be brought about by treatment with sodium butyrate. Although cAMP-activated Cl- channel activity could also be detected in immortalized human airway epithelial cells homozygous for the delta F508 mutation at the single cell level, treatment with butyrate did not generate a measurable cAMP-stimulated Cl- current in polarized monolayers of primary CF airway epithelia. However, the observation that overexpression can effect the presence of recombinant delta F508-CFTR at the plasma membrane suggests that perhaps other butyrate-like compounds that are more potent and more specific for the promoter of the CF gene may be efficacious in alleviating the Cl- channel defect associated with CF.

Animals↗
PubMed2005

Hürthle (oncocytic) cell tumors of thyroid: etiopathogenesis, diagnosis and clinical significance.

The etiopathogenesis and the classification of oncocytic (Hürthle cell) tumors of the thyroid is reviewed with an emphasis on the role played by mitochondrial and nuclear genetic abnormalities that interfere with mitochondrial function. Oxyphilia is classified into primary or secondary and the so-called Hürthle cell carcinoma is divided into oncocytic (Hürthle cell) variants of papillary and follicular carcinoma.

Adenoma, Oxyphilic↗
PubMed2025

Quantifying prevalence and risk factors of HIV multiple infection in Uganda from population-based deep-sequence data.

People living with HIV can acquire secondary infections through a process called superinfection, giving rise to simultaneous infection with genetically distinct variants (multiple infection). Multiple infection provides the necessary conditions for the generation of novel recombinant forms of HIV and may worsen clinical outcomes and increase the rate of transmission to HIV seronegative sexual partners. To date, studies of HIV multiple infection have relied on insensitive bulk-sequencing, labor intensive single genome amplification protocols, or deep-sequencing of short genome regions. Here, we identified multiple infections in whole-genome or near whole-genome HIV RNA deep-sequence data generated from plasma samples of 2,029 people living with viremic HIV who participated in the population-based Rakai Community Cohort Study (RCCS). We estimated individual- and population-level probabilities of being multiply infected and assessed epidemiological risk factors using the novel Bayesian deep-phylogenetic multiple infection model (deep&#xa0;-&#xa0;phyloMI) which accounts for bias due to partial sequencing success and false-negative and false-positive detection rates. We estimated that between 2010 and 2020, 4.09% (95% highest posterior density interval (HPD) 2.95%-5.45%) of RCCS participants with viremic HIV multiple infection at time of sampling. Participants living in high-HIV prevalence communities along Lake Victoria were 2.33-fold (95% HPD 1.3-3.7) more likely to harbor a multiple infection compared to individuals in lower prevalence neighboring communities. This work introduces a high-throughput surveillance framework for identifying people with multiple HIV infections and quantifying population-level prevalence and risk factors of multiple infection for clinical and epidemiological investigations.

Humans↗
PubMed2006

Optimization of sample size in controlled experiments: the CLAST rule.

Sequential rules are explored in the context of null hypothesis significance testing. Several studies have demonstrated that the fixed-sample stopping rule, in which the sample size used by researchers is determined in advance, is less practical and less efficient than sequential stopping rules. It is proposed that a sequential stopping rule called CLAST (composite limited adaptive sequential test) is a superior variant of COAST (composite open adaptive sequential test), a sequential rule proposed by Frick (1998). Simulation studies are conducted to test the efficiency of the proposed rule in terms of sample size and power. Two statistical tests are used: the one-tailed t test of mean differences with two matched samples, and the chi-square independence test for twofold contingency tables. The results show that the CLAST rule is more efficient than the COAST rule and reflects more realistically the practice of experimental psychology researchers.

Behavioral Research↗
PubMedDate not supplied

[Typing of STR locus in biological objects with pronounced degeneration: analysis of DNA in exhumed remains of victims of war actions].

The authors describe some specific features of enzymatic amplification typing of DNA preparations obtained from degraded tissues of remains of humans, which were brought from regions of war actions in the Chechen Republic. Special attention is paid to the specific artefact of polymerase chain reaction, for the first time detected by the authors in examinations of the above-mentioned objects. This so-called "ladder" effect manifesting by simultaneous nonspecific amplification of many variants of allele fragments of the STR locus on the individual DNA matrix, which can be erroneously interpreted as an evidence of mixed DNA preparation, is apparently characteristic of individual objects with pronounced degradation of biological material. Such phenomena were observed in typing of STR locuses in biological tissues subjected to biological, thermal, and physicohemical degradation. The phenomenon was studied in detail.

Bone and Bones↗
PubMed2001

Henry Friesen Award Lecture. Work, the clinician-scientist and human biochemical genetics.

The pursuit of human biochemical genetics has allowed us to understand better how the person with the (genetic) disease differs from the disease the person has and to develop the concept that genetics belongs in all aspects of health care. It is a perspective that comes quite readily to the clinician-scientist, and the restoration of that "species" in the era of functional genomics is strongly recommended. Garrod, the initial founder of human "biochemical genetics" belonged to the clinician-scientist community. Archibald Edward Garrod introduced a paradigm, new for its day, in medicine: biochemistry is dynamic and different from the static nature of organic chemistry. It led him to think about metabolic pathways and to recognize that variation in Mendelian heredity could explain an "inborn error of metabolism." At the time, Garrod had no idea about the nature of a gene. Genes are now well understood; genomes are being described for one organism after another (including Homo sapiens) and it is understood that genomes "speak biochemistry (not phenotype)." Accordingly, in the era of genomics, biochemistry and physiology become the bases of functional genomics, and it is possible to appreciate why "nothing in biology makes sense without evolution" (and nothing in medicine will make sense without biology). Mendelian, biochemical and molecular genetics together have revealed what lies behind the 4 canonical inborn errors described by Garrod (albinisn, alkaptonuria, cystinuria and pentosuria). Both older and newer ideas in genetics, new tools for applying them (and renewed respect for the clinician-scientist) will enhance our understanding of the human biological variation that accounts for variant states of health and overt disease. A so-called monogenic phenotype (phenylketonuria) is used to illustrate, in some detail, that all disease phenotypes are, in one way or another, likely to be complex in nature. What can be known and what ought to be done, with knowledge about human genetics, to benefit individuals, families and communities (society), is both opportunity and challenge.

Animals↗
PubMed2002

Differential palmitoylation directs the AMPA receptor-binding protein ABP to spines or to intracellular clusters.

Long-term changes in excitatory synapse strength are thought to reflect changes in synaptic abundance of AMPA receptors mediated by receptor trafficking. AMPA receptor-binding protein (ABP) and glutamate receptor-interacting protein (GRIP) are two similar PDZ (postsynaptic density 95/Discs large/zona occludens 1) proteins that interact with glutamate receptors 2 and 3 (GluR2 and GluR3) subunits. Both proteins have proposed roles during long-term potentiation and long-term depression in the delivery and anchorage of AMPA receptors at synapses. Here we report a variant of ABP-L (seven PDZ form of ABP) called pABP-L that is palmitoylated at a cysteine residue at position 11 within a novel 18 amino acid N-terminal leader sequence encoded through differential splicing. In cultured hippocampal neurons, nonpalmitoylated ABP-L localizes with internal GluR2 pools expressed from a Sindbis virus vector, whereas pABP-L is membrane targeted and associates with surface-localized GluR2 receptors at the plasma membrane in spines. Mutation of Cys-11 to alanine blocks the palmitoylation of pABP-L and targets the protein to intracellular clusters, confirming that targeting the protein to spines is dependent on palmitoylation. Non-palmitoylated GRIP is primarily intracellular, but a chimera with the pABP-L N-terminal palmitoylation sequence linked to the body of the GRIP protein is targeted to spines. We suggest that pABP-L and ABP-L provide, respectively, synaptic and intracellular sites for the anchorage of AMPA receptors during receptor trafficking to and from the synapse.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Bovine aortic arch variant in humans: clarification of a common misnomer.

The term "bovine arch" is widely used to describe a common anatomic variant of the human aortic arch branching. This so-called bovine aortic arch has no resemblance to the bovine aortic arch. We describe the most common human aortic arch branching patterns and compare these with the bovine aortic arch.

Anatomy, Comparative↗
PubMed1989

Human transthyretin (prealbumin) gene and molecular genetics of familial amyloidotic polyneuropathy.

Transthyretin (TTR, also called prealbumin) is a plasma protein produced in liver. The variant types of TTR are known to be closely associated with familial amyloidotic polyneuropathy (FAP), an autosomal dominant genetic disorder. This article summarizes, together with some new data, our current knowledge on FAP from the view point of molecular genetics. As an initial step towards understanding the disease at the DNA level, the complete nucleotide sequence of the human TTR gene (-7 kb to 7 kb; 1 kb = 10(3) bases) was determined and analyzed. The gene is located on chromosome 18 q12.1 and consists of four exons. Homology search revealed that there exist several possible regulatory signals in the 5' flanking region of the gene, including the binding sites for liver-specific nuclear factors HNF-1, 3, 4 and C/E BP, which have been previously identified in mouse TTR gene. Sequence analysis enabled us to identify all the mutations related to various types of FAP. The mutations were shown to be almost completely linked to FAP and it has become possible to diagnose FAP even at presymptomatic (prenatal) stages by recombinant DNA technology, with a high reliability. Haplotype analysis of FAP families using DNA polymorphic markers in the TTR locus suggested that the Val30----Met mutation closely related to type I FAP, the most common type of FAP, has frequently recurred in the human population to generate FAP families of independent origin. Although the primary cause of FAP has become clear, extensive screening of FAP families in various locations suggested that the expression of FAP is a complicated process and affected by some unknown factors (other than TTR).(ABSTRACT TRUNCATED AT 250 WORDS)

Amyloidosis↗
PubMed1985

["Cupid's bow" contour of the lumbar vertebrae].

The cortical margin of the inferior end plate of lumbar vertebral bodies, in the frontal projection, frequently simulates the curvature of a bow, aimed cephalad. On lateral view, the two concavities are superimposed and lie in the posterior portion of the vertebral body. The aspect, called "Cupid's bow" must be considered a normal anatomic variant and should not be confused with diseases affecting the spine. The incidence and degree of the finding are discussed.

Adult↗
PubMed1980

[Classification of follicular cysts: epidermal cysts including Günther sebocystomatosis, steatocystoma multiplex and trichilemmal cysts].

The clinical and histopathological nomenclature of various follicle-derived cysts is confusing. A uniform terminology, based on histopathological criteria is proposed. Cysts may develop from vellus follicles, sebaceous follicles, and terminal hair follicles. The various sections from each follicle may give rise to various types of cysts: 1. the infundibulum to epidermal cysts (e.g. epidermal cysts, comedones, milia, and scrotal cysts); 2. the sebaceous ducts and sebaceous acini to steatocystoma multiplex; 3. the infraglandular portion of the infrainfundibulum to trichilemmal cysts (atheromas). A clinical variant of epidermal cysts, the scrotal cysts, at times incorrectly called sebocystomatosis Günther, is described in 10 patients. For all types of cysts clinical and histopathological guidelines are offered.

Cysts↗
PubMed1978

[The lupus erythematosus (LE) phenomenon. Status in 1978].

The results of 835 studies of LE cells carried out over 8 years in 563 clinical cases of various nature are reported. The LE phenomenon--i.e. LE cells, LE globs and rosettes--was encountered exclusively in patients with LES, whereas tart-cells, nucleophagocytosis A and nucleophagocytosis B, although present in initial LES, and particularly in regressing LES, were very frequent in many other conditions. It is therefore held that true LE phenomenon is pathognomonic of LES since so-called AR with LE cells can be considered a clinical variant of LES, whereas lupoid hepatitis remains a vague, uncertain syndrome.

Arthritis, Rheumatoid↗
PubMed1995

[Disorders of sphingolipid activator proteins].

Small-molecular nonenzymatic glycoproteins are necessary for degradation of sphingolipids in lysosomes. GM2 activator encoded by a gene on chromosome 5 is essential for hydrolysis of ganglioside GM2 and its asialo derivative. Mutations of this gene cause Tay-Sachs disease-like clinical phenotype (GM2-gangliosidosis AB variant). Another gene on chromosome 10 codes for a protein called prosaposin, which is then processed to four related but independent activator proteins; saposin A, B, C, and D. These five proteins show different molecular functions, and their mutations cause diseases with prosaposin deficiency (clinically similar to Gaucher disease type 2), and saposin C deficiency (clinically similar to Gaucher disease type 3). They are rare genetic disorders, but provide information about molecular events between the enzyme and substrate in lysosomes.

G(M2) Ganglioside↗
PubMed1997

[Deep multilayer plastic repair in inguinal hernias].

The article presents the authors' variant of a surgical technique of hernioplasty, the so-called deep multi-layer hernioplasty. This type of hernioplasty is thought by the authors to give best results in patients with recurrent and so-called difficult inguinal hernias when there are true anatomic defects of the musculo-aponeurotic and fascial structures. Long-term results of 35 operations were followed-up. Neither recurrences nor complications were noted.

Adult↗
PubMed1986

Proposal for the nomenclature of human plasminogen (PLG) polymorphism.

Since its discovery, human plasminogen (PLG) polymorphism has received widespread acceptance in population genetics and forensic haematology. Due to the large number of variant alleles described, a PLG reference typing and Plasminogen Symposium was held, at which a nomenclature proposal was inaugurated. The technology of comparing PLG variants was based on isoelectric focusing and subsequent detection by caseinolytic overlay and 'Western' blotting. Typing results permitted comparison of so far described variant designations and resulted in a new nomenclature proposal for PLG polymorphism. It is recommended that the two most common alleles found in all investigated races be called: PLG*A (previously also PLG*1) and PLG*B (previously also PLG*2), the known variants with acidic pI: PLG*A1 to *A3, intermediate variants: PLG*M1 to *M5, PLG*M5 being functionally inactive, and basic variants: PLG*B1 to *B3. For future classification of newly discovered variants, samples should be compared at any of the laboratories participating in the reference typing.

Collodion↗