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Biomedical subjects

S Brenner

Publications and source records attributed to S Brenner.

At least 19 recordsLinked to original sources
PubMed2006

Uneven evolutionary rates of bradykinin B1 and B2 receptors in vertebrate lineages.

Bradykinin acts through two receptor subtypes in mammals and generates a variety of responses including pain, inflammation and hypotension. The evolutionary history of the bradykinin system has been unclear due to shortage of information outside mammals. We describe here two receptor subtypes and the bradykinin precursor in three species of bony fish (the zebrafish Danio rerio, the Japanese pufferfish Takifugu rubripes, and the green spotted pufferfish Tetraodon nigroviridis) and chicken and analyze the relationships to mammals by a combination of phylogeny, conserved synteny and exon-intron organization. All of these species have two receptor genes located close to each other in a tandem formation, with the B2 gene 5' to the B1 gene, in chromosomal regions displaying conserved synteny between the species (albeit conservation of synteny in zebrafish is still unclear due to poor genome assembly). The evolutionary rate differs between the two genes as well as between lineages leading to differing pharmacological properties for both B1 and B2 across vertebrate classes. Also the bradykinin precursor gene was identified in all of these species in a chromosome region with conserved synteny. The tissue distribution of mRNA in T. rubripes is similar for B1 and B2, suggesting more similar regulation for the two genes than in mammals. In conclusion, the receptor tandem duplication predates the divergence of ray-finned fish and tetrapods and no additional duplicates of the receptors or bradykinin seem to have survived the ray-finned fish tetraploidization.

Animals↗
PubMed2006

A Faraday effect position sensor for interventional magnetic resonance imaging.

An optical sensor is presented which determines the position and one degree of orientation within a magnetic resonance tomograph. The sensor utilizes the Faraday effect to measure the local magnetic field, which is modulated by switching additional linear magnetic fields, the gradients. Existing methods for instrument localization during an interventional MR procedure often use electrically conducting structures at the instruments that can heat up excessively during MRI and are thus a significant danger for the patient. The proposed optical Faraday effect position sensor consists of non-magnetic and electrically non-conducting components only so that heating is avoided and the sensor could be applied safely even within the human body. With a non-magnetic prototype set-up, experiments were performed to demonstrate the possibility of measuring both the localization and the orientation in a magnetic resonance tomograph. In a 30 mT m(-1) gradient field, a localization uncertainty of 1.5 cm could be achieved.

Equipment Design↗
PubMed2006

Minocycline-induced cutaneous hyperpigmentation: confocal laser scanning microscope analysis.

BACKGROUND: Minocycline has a characteristic yellow-green fluorescent emission. This fluorescence has been previously demonstrated only in type 1 minocycline-induced skin hyperpigmentation. OBJECTIVE: To investigate whether the fluorescence can be detected in other types of minocycline-induced cutaneous hyperpigmentation, and to study the possible mechanisms. METHODS: Biopsies of pigmented and nonpigmented skin from 3 patients with different types of skin hyperpigmentation induced by minocycline were analysed by light microscopy and Confocal Laser Scanning Microscope (CLSM). RESULTS: A yellow-green fluorescence was observed in the hyperpigmented skin of two patients with type 2, and one patient with type 4 minocycline-induced cutaneous hyperpigmentation. No fluorescence was detected in the non-pigmented skin. CONCLUSION: Minocycline can possibly serve as a fluorescent probe in the diagnosis of all types of minocycline-induced cutaneous hyperpigmentation.

Adolescent↗
PubMed2005

Nocardia elegans sp. nov., a member of the Nocardia vaccinii clade isolated from sputum.

Two bacterial isolates from the sputa of a patient with a pulmonary infection were subjected to a polyphasic taxonomic study. Chemotaxonomic investigations revealed the presence of cell-wall chemotype IV and mycolic acids consistent with the profile for the genus Nocardia. Comparative 16S rRNA gene sequencing showed that these isolates constitute a distinct subline within the genus Nocardia, displaying 99.6-95.5% sequence similarities with established species. However, DNA-DNA hybridization studies demonstrated unambiguously that the isolates are genealogically distinct from closely related species, namely Nocardia veterana and Nocardia africana, which show high levels of 16S rRNA sequence similarity (99.2 and 99.6% sequence similarity, respectively). On the basis of both phenotypic and phylogenetic evidence, it is proposed that these isolates be classified as a novel species of the genus Nocardia, for which the name Nocardia elegans sp. nov. is proposed. The type strain is IMMIB N-402(T) (=CCUG 50200(T)=CIP 108553(T)).

Bacterial Typing Techniques↗
PubMed2004

Common ancestral origin of pemphigus vulgaris in Jews and Spaniards: a study using microsatellite markers.

Pemphigus is a group of autoimmune blistering diseases of the skin and mucous membranes. The association of pemphigus with human leukocyte antigen (HLA) is widely accepted. It was described in many ethnic groups and in most countries of the world. Studies showed that the associated HLA haplotype in Jewish pemphigus vulgaris (PV) patients is HLA-B38, DRB1*0402, and DQB1*0302; or HLA-B35, DRB1*0402, and DQB1*0302. Similar associations with class II genes were found in Spanish non-Jewish PV patients. As Jews lived in Spain for hundreds of years and many converted to Christianity, the presence of the same HLA haplotype in the Jewish and Spanish PV suggests that they may share the same founder. Microsatellite markers which span the entire major histocompatibility complex (MHC) locus were used as genetic probes. They were utilized to dissect the MHC region in the search for possible common haplotypes, besides HLA, which may provide an answer to this question. It was found that in both cohorts, in addition to HLA class II genes, there are probably genes in the class I region which are associated with PV. Alleles belonging to the associated markers were used to construct haplotypes and to estimate genetic distances. The distance between the two PV cohorts is relatively short, but the distance between the Jewish patients and the Jewish controls is greater compared to the distance between Spanish patients and Spanish controls. In both PV populations, the same microsatellite haplotypes in addition to a common class II haplotype were found, suggesting that both patient populations originated from the same genetic stock and, therefore, share the same ancestral disease gene.

Alleles↗
PubMed2003

Neurone-specific expression and regulation of the pufferfish isotocin and vasotocin genes in transgenic mice.

We used comparative genetics to investigate the location, structure and evolution of the oxytocin and vasopressin gene regulatory regions. The pufferfish, Fugu rubripes, is an attractive vertebrate model for comparison because of its maximal evolutionary distance from mammals and short intergenic regions. To determine whether regulatory DNA is conserved between oxytocin and vasopressin, and their Fugu homologs, isotocin and vasotocin, we generated transgenic mice bearing overlapping Fugu cosmids that contained the isotocin and/or vasotocin genes as well as short isotocin (5 kb) and vasotocin (9 kb) constructs. Our study shows that the Fugu isotocin and vasotocin genes express specifically in the mouse oxytocinergic and vasopressinergic neurones, respectively, and that the cis-regulatory elements which mediate neurone-specific expression are located within the short transgene constructs tested. Thus, the neurone-specific expression of the oxytocin and vasopressin gene families, and the mechanisms mediating the cell-specificity, evolved before the divergence of the fish and mammalian lineages. Salt-loading of transgenic mice induced an increase in abundance of isotocin, but not vasotocin mRNA in the cognate neurones. It appears that either the vasotocin gene does not respond to osmotic perturbations or the vasotocin transgene construct tested lacks osmotic response elements. Comparisons of homologous flanking sequences of the Fugu and mouse genes identified several short matching sequences, which are candidate regulatory elements.

Animals↗
PubMed2003

Pemphigus can be induced by topical phenol as well as by foods and drugs that contain phenols or thiols.

Pemphigus is an autoimmune disease that results from the interaction between predisposing genetic factors and exogenous factors, the most common environmental factors being drugs and food. Topical phenol has induced pemphigus in one patient. Drugs and foods that induce pemphigus are divided into three main groups according to their chemical structure: thiols (containing a sulfhydryl group), phenol, nonthiol nonphenol. Thiol and phenol compounds can induce acantholysis in tissue cultures in vitro. The suggested mechanisms for thiol acantholysis include direct biochemical impairment of cell adhesion, protease activation and immunological reaction with the formation of a neoantigen. Possible mechanisms of phenol-induced pemphigus include the induction of IL-1alpha and TNF-alpha release by keratinocytes. These cytokines have been shown to be relevant in the regulation and synthesis of complement and proteases, like plasminogen activator, which has been implicated in the pathogenesis of acantholysis in pemphigus vulgaris. Avoiding exposure of genetically predisposed individuals to these factors is important in treating and preventing this disease.

Journal Article↗
PubMed2002

Pemphigus vulgaris: a review of treatment over a 19-year period.

BACKGROUND: Pemphigus vulgaris is an autoimmune blistering disease of the skin and mucous membranes with a high mortality if left untreated. OBJECTIVE: We present a retrospective analysis of 159 patients with pemphigus vulgaris and pemphigus vegetans who were admitted to the Department of Dermatology and Venereology, Zagreb University Hospital Center (Zagreb, Croatia) from 1980 to 1998. RESULTS: Female to male ratio was approximately 2:1. The mean age was 53 years. During the war years in Croatia (1991-95) we noticed a low incidence of pemphigus vulgaris, and from 1996 to 1998 the incidence almost doubled. Diagnosis was based on histopathology [showing typical pemphigus vulgaris changes in 156 (98%) patients], indirect immunofluorescence [positive in 122 (77%) patients], direct immunofluorescence [positive in 141 (89%) patients], and blister smear cytology (Tzanck test) [positive in 115 (72%) patients]. High dosages of prednisone (100-150 mg) were given to 129 patients, which was combined with azathioprine. Patients with refractory pemphigus vulgaris were treated with intramuscular gold (14 patients) and plasmapheresis (five patients). All patients were treated with local ointments. The prolonged use of high doses of corticosteroids and immunosuppressants caused several complications, in particular, steroid diabetes (37 patients), skin infections (26 patients), arterial hypertension (23 patients), cardiorespiratory diseases (22 patients), sepsis (nine patients), etc. During the hospital treatment, 14 patients died, 10 during 1980-89 and only four during the 1990-98 period. The main causes of death were cardiorespiratory failure (six patients) and sepsis (five patients). CONCLUSIONS: Although pemphigus vulgaris is still a life-threatening disease, today it can be successfully treated with a combination of immunosuppressive agents. Early diagnosis and treatment of pemphigus vulgaris allow a better prognosis with lower mortality rates.

Adrenal Cortex Hormones↗
PubMed2001

Molecular synapomorphies resolve evolutionary relationships of extant jawed vertebrates.

The evolutionary relationships of gnathostomes (jawed vertebrates), which comprise chondrichthyans (cartilaginous fishes), lobe-finned fishes (coelacanths and lungfishes), tetrapods, and actinopterygians (ray-finned fishes), have been debated for almost a century. Phylogenetic analyses based on fossils, morphology, and molecular sequences have generated different models of relationships that remain unresolved. We identified 13 derived shared molecular markers (synapomorphies) that define clades in the vertebrate lineage and used them to resolve the phylogenetic relationships of extant jawed vertebrates. Our markers include the presence or absence of insertions and deletions in coding sequences, nuclear introns, and alternatively spliced transcripts. The synapomorphies identified by us are congruent with each other and give rise to a single phylogenetic tree. This tree confirms that chondrichthyans are basal to all living gnathostomes, that lungfishes (Dipnoi) are the closest living relatives of tetrapods, and that bichirs (Cladistia) are the living members of the most ancient family of ray-finned fishes. Our study also provides molecular evidence to support the monophyly of living tetrapods and teleosts.

Amino Acid Sequence↗
PubMed2001

Conserved synteny between the Fugu and human PTEN locus and the evolutionary conservation of vertebrate PTEN function.

Mutations of PTEN, which encodes a protein-tyrosine and lipid phosphatase, are prevalent in a variety of human cancers. The human genome 'draft' sequence still lacks organization and much of the PTEN and adjacent loci remain undefined. The pufferfish, Fugu rubripes, by virtue of having a compact genome represents an excellent template for rapid vertebrate gene discovery. Sequencing of 56 kb from the Fugu pten (fpten) locus identified four complete genes and one partial gene homologous to human genes. Genes neighboring fpten include a PAPS synthase (fpapss2) differentially expressed between non-metastatic/metastatic human carcinoma cell lines, an inositol phosphatase (fminpp1) and an omega class glutathione-S-transferase (fgsto). We have determined the order of human BAC clones at the hPTEN locus and that the locus contains hPAPSS2 and hMINPP1 genes oriented as are their Fugu orthologs. Although the human genes span 500 kb, the Fugu genes lie within only 22 kb due to the compressed intronic and intergenic regions that typify this genome. Interestingly, and providing striking evidence of regulatory element conservation between widely divergent vertebrate species, the compact 2.1 kb fpten promoter is active in human cells. Also, like hPTEN, fpten has a growth and tumor suppressor activity in human glioblastoma cells, demonstrating conservation of protein function.

Amino Acid Sequence↗
PubMed2001

Molecular cloning and genomic structure of a gene encoding interferon regulatory factor in the pufferfish (Fugu rubripes).

Interferon regulatory factors (IRFs) are a large family of transcription factors involved in regulating the transcriptional response of vertebrates to interferons and viral infection. In this report we describe the cloning and genomic organization of an IRF gene from the pufferfish (Fugu rubripes). The fugu IRF gene spans 2.7 kb from the transcription start site to the polyadenylation signal. It consists of 10 exons and 9 introns and encodes a protein of 296 amino acids. The overall amino acid sequence of fugu IRF displays 55% identity to flounder IRF and approximately 44% identity to avian and mammalian IRF-1 and IRF-2. On the basis of the genomic structure and the absence of a transcriptional repression domain, we conclude that the fugu IRF is a member of the IRF-1 family. The fugu IRF gene is expressed in a wide range of tissues. While a single transcript of 1.4 kb was detected in most tissues, several larger transcripts generated using alternative polyadenylation signals were found in the gills.

Journal Article↗
PubMed2001

Adolescent-onset ichthyosiform-like erythroderma with lichenoid tissue reaction: a new entity?

A patient with severe ichthyosiform erythroderma and lichenoid histological changes is presented. We discuss the clinical and histological differential diagnosis, including lupus erythematosus, lichenoid drug eruption, lichen planus, graft-versus-host disease, lymphoma, keratosis lichenoides chronica, Netherton's syndrome and ichthyosiform erythroderma. None of these is consistent with the features in our case, which may represent either a hitherto unreported form of ichthyosiform erythroderma or possibly a new entity.

Adolescent↗
PubMed2001

Pemphigus vulgaris: environmental factors. Occupational, behavioral, medical, and qualitative food frequency questionnaire.

BACKGROUND: There have been reports suggesting the involvement of environmental factors in the disease process of pemphigus. Factors suggested include exposure to pesticides or certain drugs. OBJECTIVE: To analyze the association of pemphigus with environmental exposure to various agents, including smoking, recreational and occupational insults, drugs, and food. DESIGN AND SETTING: In-person interviews of pemphigus patients and control subjects were conducted by trained medical investigators using a structured questionnaire. Questions included occupational, behavioral, medical, and qualitative food frequency details. The multicenter study was conducted at outpatient services of teaching hospitals in Bulgaria, Brazil, India, Israel, Italy, Spain, and the USA. PARTICIPANTS: A total of 126 pemphigus patients (55 men, 71 women; age, 54 +/- 17 years) and 173 healthy controls (87 men, 86 women; age 50 +/- 19 years) were interviewed in the period between October 1, 1999 and March 31, 2000. The diagnosis of pemphigus was based on clinical, histologic, immunohistologic, and immunohistochemical criteria. The disease duration was 2-27 years (8.4 +/- 7.2 years). Individuals with skin diseases other than pemphigus were selected as control subjects. MAIN OUTCOME MEASURE: Information on drugs, foods, and occupational, environmental, constitutional, and other possible risk factors was analyzed by t-tests and chi-squared tests as applicable. A multivariate logistic regression model was applied to the data to study simultaneously the independent relationship between each risk factor and pemphigus vulgaris. RESULTS: The risk for pemphigus vulgaris was lower for ex-smokers and current smokers than for patients who had never smoked. Exposure to pesticides and occupational exposure to metal vapor were associated with an increased risk of pemphigus. Pemphigus patients had more pregnancies than controls. There were differences in environmental factors between countries, with exposure to gardening materials and pesticides being highest among patients from Bulgaria, followed by Israel. Disease characteristics also exhibited differences between countries. Bulgarian patients less frequently had oral mucous membrane lesions: 66% compared to 92% for Israeli patients and 83% for Italians. The distribution of the disease in skin and mucous membranes was similar among patients from all countries. Exclusive skin involvement was seen in 50% of patients, mucous membranes alone in 23% of patients, and both skin and mucous membranes in 27% of patients. CONCLUSIONS: The beneficial effect of smoking on pemphigus might be explained by its effect on the immune system. In addition, smoking has an antiestrogenic effect, while pesticides have an estrogenic effect. The lower numbers of smokers among patients, the higher exposure rates to pesticides, and the higher number of female patients who had been pregnant may point to the contribution of estrogens to the disease process. It remains to be determined whether measures, such as avoiding exposure to pesticides or metal vapor, may be beneficial in the clinical context. As the present study was a survey, more definitive studies should be conducted to validate the results.

Agriculture↗