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At least 685 records · Page 38Linked to original sources
PubMed1994

Subtiligase: a tool for semisynthesis of proteins.

A variant of subtilisin BPN', which we call subtiligase, has been used to ligate esterified peptides site-specifically onto the N termini of proteins or peptides in aqueous solution and in high yield. We have produced biotinylated or heavy-atom derivatives of methionyl-extended human growth hormone (Met-hGH) by ligating it onto synthetic peptides containing biotin or mercury. Polyethylene glycol (PEG)-modified atrial natriuretic peptide (ANP) was produced by ligating ANP onto peptides containing sites for PEG modification. We have established the N-terminal sequence requirements for efficient ligation onto proteins, using either synthetic substrates or pools of filamentous phage containing Met-hGH with random N-terminal sequences (substrate phage). To facilitate ligations involving proteins with highly structured or buried N termini, a more stable subtiligase was designed that effectively ligates peptides onto Met-hGH even in 4 M guanidine hydrochloride. The use of subtiligase should expand the possibilities for protein semisynthesis and rational protein design.

Amino Acid Sequence↗
PubMed2001

Differential requirement for Rho family GTPases in an oncogenic insulin-like growth factor-I receptor-induced cell transformation.

Insulin-like growth factor I receptor (IGFR) plays an important role in cell growth and transformation. We dissected the downstream signaling pathways of an oncogenic variant of IGFR, Gag-IGFR, called NM1. Loss of function mutants of NM1, Phe-1136 and dS2, that retain kinase activity but are attenuated in their transforming ability were used to identify signaling pathways that are important for transformation of NIH 3T3 cells. MAPK, phospholipase C gamma, and Stat3 were activated to the same extent by NM1 and its two mutants, suggesting that activation of these pathways, individually or in combination, was not sufficient for NM1-induced cell transformation. The mutant dS2 has decreased IRS-1 phosphorylation levels and IRS-1-associated phosphatidylinositol 3'-kinase activity, suggesting that this impairment may be in part responsible for the defectiveness of dS2. We show that Rho family members, RhoA, Rac1, and Cdc42 are activated by NM1, and this activation, particularly RhoA and Cdc42, is attenuated in both mutants of NM1. Dominant negative mutants of Rho, Rac, and Cdc42 inhibited NM1-induced cell transformation, as measured by focus and colony forming ability. Dominant negative Rho most potently inhibited the focus forming activity, whereas Cdc42 was most effective in inhibiting the colony forming ability of NM1-expressing cells. Conversely, constitutively activated (ca) Rho is more effective than ca Rac or ca Cdc42 in rescuing the focus forming ability of the mutants. By contrast, ca Cdc42 is most effective in rescuing the colony forming ability of both mutants.

3T3 Cells↗
PubMed1990

Molecular basis of polymorphisms of human complement component C3.

C3 exhibits two common allotypic variants that may be separated by gel electrophoresis and are called C3 fast (C3 F) and C3 slow (C3 S). C3 F, the less common variant, occurs at appreciable frequencies only in Caucasoid populations (gene frequency = 0.20). An increased prevalence of the C3 F allele has been reported in patients with partial lipodystrophy, IgA nephropathy, and Indian childhood hepatic cirrhosis. Studies of the genomic organization of the human C3 gene led to the identification of a single change (C to G) between C3 S and C3 F at nucleotide 364 in exon 3. This leads, at the translation level, to the substitution of an arginine residue (positively charged) in C3 S for a glycine residue (neutral) in C3 F. This substitution results in a polymorphic restriction site for the enzyme HhaI. The resulting restriction fragment length polymorphism (RFLP) was investigated using genomic DNA, amplified using the polymerase chain reaction; there was absolute concordance between the genomic polymorphism and the distribution of C3 S and C3 F in 50 normal subjects. The molecular basis of a second structural polymorphism, defined by the monoclonal antibody HAV 4-1, was also characterized. The polymorphic determinant was identified at codon 314 in the exon 9 of the beta chain where a leucine residue (HAV 4-1+) is substituted for a proline residue (HAV 4-1-). Identification of the amino acid sequences of these polymorphic variants will facilitate characterization of possible functional differences between different allotypes of C3. Three RFLPs (BamHI, EcoRI, and SstI) were located to introns in the C3 gene. There was no allelic association between these three RFLPs, or between the RFLPs and the C3 F/S polymorphic site. Genetic equilibration of these polymorphisms has occurred within a gene of 41 kb.

Antibodies, Monoclonal↗
PubMed1998

Automating the identification of DNA variations using quality-based fluorescence re-sequencing: analysis of the human mitochondrial genome.

Diagnostic re-sequencing plays a central role in medical and evolutionary genetics. In this report we describe a process that applies fluorescence-based re-sequencing and an integrated set of analysis tools to automate and simplify the identification of DNA variations using the human mitochondrial genome as a model system. Two programs used in genome sequence analysis (Phred, a base-caller, and Phrap, a sequence assembler) are applied to assess the quality of each base call across the sequence. Potential DNA variants are automatically identified and 'tagged' by comparing the assembled sequence with a reference sequence. We also show that employing the Consed program to display a set of highly annotated reference sequences greatly simplifies data analysis by providing a visual database containing information on the location of the PCR primers, coding and regulatory sequences and previously known DNA variants. Among the 12 genomes sequenced 378 variants including 29 new variants were identified along with two heteroplasmic sites, automatically detected by the PolyPhred program. Overall we document the ease and speed of performing high quality and accurate fluorescence-based re-sequencing on long tracts of DNA as well as the application of new approaches to automatically find and view DNA variants among these sequences.

Base Sequence↗
PubMed1997

Intravascularly disseminated angiosarcoma: true neoplastic angioendotheliomatosis? Report of two cases.

Although vascular invasion is common in many malignant tumors, disseminated intravascular anaplastic neoplasms with occult primary tumor are rare occurrences. Intravascular malignant lymphoma, also called angiotropic lymphoma, is a rare variant of large cell lymphoma predominantly involving vessels in multiple organs, and usually without significant nodal involvement. Although initially misinterpreted as an endothelial neoplasm-angioendotheliomatosis-immunohistochemical studies subsequently proved it to represent a peculiar form of malignant lymphoma. In this report, we describe two patients with extensive intravascular dissemination of angiosarcoma initially without clinically obvious primary tumor. These may be interpreted as examples of true angioendotheliomatosis. In each case the immunohistochemical studies ruled out the most common intravascular malignant neoplasms. The diagnosis of intravascular angiosarcoma was confirmed by the immunoreactivity of the tumor cells to several markers of endothelial lineage in both cases. Thus, angiosarcoma may present with intravascular dissemination and occult primary tumor and closely resemble metastatic carcinoma, melanoma, or angiotropic lymphoma. Immunohistochemical studies are crucial in ruling out these possibilities and in confirming the endothelial origin of the neoplastic cells.

Adult↗
PubMed2000

Mouse Zac1, a transcriptional coactivator and repressor for nuclear receptors.

Transcriptional activation by nuclear hormone receptors is mediated by the 160-kDa family of nuclear receptor coactivators. These coactivators associate with DNA-bound nuclear receptors and transmit activating signals to the transcription machinery through two activation domains. In screening for mammalian proteins that bind the C-terminal activation domain of the nuclear receptor coactivator GRIP1, we identified a new variant of mouse Zac1 which we call mZac1b. Zac1 was previously discovered as a putative transcriptional activator involved in regulation of apoptosis and the cell cycle. In yeast two-hybrid assays and in vitro, mZac1b bound to GRIP1, to CREB-binding protein (CBP) and p300 (which are coactivators for nuclear receptors and other transcriptional activators), and to nuclear receptors themselves in a hormone-independent manner. In transient-transfection assays mZac1b exhibited a transcriptional activation activity when fused with the Gal4 DNA binding domain, and it enhanced transcriptional activation by the Gal4 DNA binding domain fused to GRIP1 or CBP fragments. More importantly, mZac1b was a powerful coactivator for the hormone-dependent activity of nuclear receptors, including androgen, estrogen, glucocorticoid, and thyroid hormone receptors. However, with some reporter genes and in some cell lines mZac1b acted as a repressor rather than a coactivator of nuclear receptor activity. Thus, mZac1b can interact with nuclear receptors and their coactivators and play both positive and negative roles in regulating nuclear receptor function.

Animals↗
PubMed1995

Advances in human immunoglobulin allotypes.

Monoclonal anti-Rh's and monoclonal anti-Gm's are now available, permitting a more precise serological determination of the human allotypes. Several Gm allotypes can be determined at the gene level, without resort to serological reagents. PCR, subclass-specific amplification and allele-specific probes are used. Many RFLPs of the human IgH C- and V-region genes have now been defined. More than 10(6) variant haplotypes of the so-called constant part of the Ig chain are possible because more than 20 polymorphic sites are known. A schematic physical map of the human IgHC gene cluster is presented.

Animals↗
PubMed1990

Structure and expression of the mouse Oct2a and Oct2b, two differentially spliced products of the same gene.

A large family of tissue-specific nuclear proteins interact with the octamer motif ATTTGCAT, a transcriptional regulatory element found in the promoter and enhancer sequences of many genes. As a step towards elucidating the mechanism of this regulation, cDNA clones of the mouse Oct2 protein were isolated. One, called here Oct2b, encodes a larger variant of the previously described Oct2a proteins. The Oct2b cDNA has an insertion of 74 bp close to the 3' end which creates an open reading frame distinct from Oct2a. As a result, the Oct2b protein has a carboxy end which is similar to that of the ubiquitous octamer-binding protein Oct1. Analysis of the Oct2 gene shows that Oct2a and Oct2b are differentially spliced products of the same gene. The insertion in the Oct2b cDNA results from the inclusion of an additional exon in the mRNA which would otherwise reside in an intron sequence of the Oct2a transcript. RNA analysis demonstrates that both Oct2a and 2b mRNAs are most abundant in B-cells but they are also expressed in a variety of tissues including brain, intestine, testis, kidney, as well as in embryos. Interestingly, the ratio of Oct2a and 2b varies among tissues. In situ hybridization studies during mouse embryogenesis show that the Oct2 gene is widely expressed in the developing nervous system. In contrast, expression in the adult brain is confined to very specific areas which include the suprachiasmatic and medial mammillary nuclei, hippocampus, olfactory tract and the olfactory bulb. Oct2 proteins are present in both neuronal and oligodendroglial cells, although they are more abundant in glial cells.

Amino Acid Sequence↗
PubMed2005

Long-range trends in adult mortality: models and projection methods.

In the study reported here, I had two objectives: (1) to test a new version of the logistic model for the pattern of change over time in age-specific adult mortality rates and (2) to develop a new method for projecting future trends in adult mortality. A test of the goodness of fit of the logistic model for the force of mortality indicated that its slope parameter is nearly constant over time. This finding suggests a variant of the model that is called the shifting logistic model. A new projection method, based on the shifting mortality model, is proposed and compared with the widely used Lee-Carter procedure.

Adult↗
PubMed1995

The predicted structure of chick lens CP49 and a variant thereof, CP49ins, the first vertebrate cytoplasmic intermediate filament protein with a lamin-like insertion in helix 1B.

The full length cDNA sequence for the lens-specific intermediate filament protein, CP49, from chicken is presented. The sequence contains features typical of the other intermediate filament proteins, including two major alpha-helical regions, helix I and II and appropriate linker regions. CP49 lacks a C-terminal non-alpha-helical domain and is only the second intermediate filament protein to be described missing this feature. Comparison to the bovine CP49 shows significant homology in all domains except the N-terminal non-alpha-helical domain. Besides bovine CP49, the other protein most homologous to chicken CP49 in the database was keratin 18, a type I keratin. A variant of CP49 is also described, called CP49ins. Of the 61 positive clones identified in the library, two encoded CP49ins, one of these being a full-length clone. The sequence differed to CP49 by the insertion of 49 amino acids in helix IB. This is the first chordate cytoplasmic intermediate filament protein sequence to be identified with an archetypal lamin-like insertion in this helical subdomain and represents a key discovery in tracing the evolutionary pathway of intermediate filament protein family.

Amino Acid Sequence↗
PubMed2000

[Molecular biological and clinical-morphological studies of gastric tumors associated with Epstein-Barr virus].

The paper presents the results of the studies of gastric cancer (GC) associated with Epstein-Barr virus (EBV) among the patients residing in 4 geographical regions. In situ hybridization (ISH) techniques revealed that 49(11.4%) of the 430 examinees were EBV positive (EBV+), the virus-specific marker mRNA-1 of EBV, EBER-1) was found to be present in 80-100) of tumor cells. The proportion of EBV(+)-associated GC cases in different geographic regions ranged from 7.3 to 15%. These tumors were predominant in males (15%) as opposite to females (5.5%). Histological types most common among EBV+ tumors and their location in the stomach are also described. Serological findings indicated that the increased anti-EDV antibody response in 70% of GC cases coincided with the presence of the viral genetic information detected by ISH. In contrast to a humoral response to EBV, a humoral response to Helicobacter pylori was equal both in patients with EBV(+)- and EBV(-)-associated gastric tumors. Further molecular biological analysis of EBV isolates from virus positive and virus negative GC may answer the question whether there are really the so-called tumor and non-tumor variants of EBV.

Adenocarcinoma↗
PubMed2003

Functional and molecular properties of Na+:HCO-3 cotransporters (NBC).

The sodium bicarbonate cotransporter (NBC) is located on the basolateral membrane of the kidney proximal tubule and is responsible for the reabsorption of the majority of filtered bicarbonate. In secretory epithelia (such as pancreatic duct) NBC is responsible for the transport of bicarbonate from the blood to the cell for the eventual secretion at the apical membrane. As such and due to its versatility, NBC can function in 2 distinct modes of bicarbonate reabsorption or secretion depending on the epithelia. NBC is also present in a wide variety of non-epithelial tissues where it is mainly involved with cell pH regulation. Recent molecular cloning experiments have identified the existence of 4 NBC isoforms (NBC1, 2, 3 and 4) and 2 NBC-related proteins AE4 and NCBE (anion exchanger 4 and sodium-dependent chloride-bicarbonate exchanger). Except for AE4 which does not transport Na, all are presumed to mediate the cotransport of Na+ and HCO(3)-. NBC isoforms show significant homology to each other and to the AE (anion exchange) family. NBC1 shows a limited tissue expression pattern, is electrogenic and plays an important role in bicarbonate reabsorption in kidney proximal tubule. A variant of NBC1 is expressed in pancreatic duct and gastrointestinal tract, and plays an important role in HCO(3)- secretion. NBC2 and NBC3 have a wider tissue distribution than NBC1, are electroneutral, and are involved with cell pH regulation. The electrogenecity of NBC4 may be variant-specific. An NBC related protein called NCBE mediates Na-dependent, Cl-/bicarbonate ex-change. The purpose of this review is to summarize functional and molecular properties of NBC isoforms and related proteins, and discuss their role and regulation in pathophysiologic states.

Acid-Base Imbalance↗
PubMed2004

ERCC2 genotypes and a corresponding haplotype are linked with breast cancer risk in a German population.

The polygenic concept of breast cancer susceptibility calls for the identification of genetic variants that contribute to breast cancer risk. Reduced DNA repair proficiencies in women with breast cancer pointed to a possible role of DNA repair enzymes in the risk to develop the disease. The nucleotide excision repair enzyme encoded by the excision repair cross-complementing group 2 gene ERCC2 (formerly XPD) known to cause skin cancer by germ line mutations has multiple regulatory cellular functions, including nucleotide excision repair, basal transcription, cell cycle control, and apoptosis. ERCC2 polymorphisms ERCC2_6540_G>A (Asp(312)Asn) and ERCC2_18880_A>C (Lys(751)Gln) within the coding region of this evolutionarily highly conserved gene have been of functional relevance and therefore are potential candidates to confer breast cancer susceptibility. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, we analyzed genotype frequencies in constitutional DNA of study participants of a German case-control study that included 688 cases of incident breast cancer and 724 population-based, age-matched controls. We identified ERCC2_6540_GG (Asp(312)Asp) as an at-risk genotype [odds ratio (OR), 2.06; 95% confidence interval (95% CI), 1.39-3.07]. The ERCC2_6540_GG-associated breast cancer risk was even higher in women who were also carriers of the ERCC2_18880_CC (Gln(751)Gln) genotype (OR, 3.69; 95% CI, 1.76-7.74). We identified ERCC2_6540_G/ERCC2_18880_C (Asp(312)/Gln(751)) as the most potent risk-conferring haplotype (OR, 3.49; 95% CI, 2.30-5.28). To our knowledge, this is the first study assigning breast cancer risk to both the ERCC2 genotype encoding Asp(312)Asp and the haplotype encoding Asp(312)/Gln(751).

Adult↗
PubMed1991

[Clinical differentiation and prognosis of acute hallucinatory conditions in schizophrenia].

Altogether 61 patients with schizophrenia manifesting for the first time by hallucinatory disorders, playing the leading part in the psychosis picture were examined. 3 typological varieties of acute hallucinatory conditions were described, their comparative characteristics were provided. It has been demonstrated that acute hallucinosis occurred during the disease in different clinical forms: so-called schizophrenic reactions in latent disease (variant I), phases and attacks within the framework of a well-defined attack-like (shift-like) and similar to a recurrent (variant and an attack-like progredient course, approximating to a continuous one (variant III). Problems of a comparative assessment of the further disease course manifesting by different conditions of acute hallucinosis and adequacy of the use of the elaborated typology thereof for prediction and choice of therapy are discussed.

Acute Disease↗
PubMed1975

[The so-called amaurotic idiocies. Clinical, morphological and biochemical findings as a basis for modern classification].

First of all seven of our own thoroughly investigated cases of so-called amaurotic idiocies are presented, they are two infantile, two juvenile, two late infantile one, as well as one adult case. The two infantile cases represent the typ of a GM2-gangliosidosis: with cerebral symptoms and cherry-red spot in the macula they correspond clinically to the typical picture of Tay-Sachs disease. Lightmicroscopically they show neuronal storage, electronmicroscopically a deposition of "membranous cytoplasmic bodies" and biochemically a strong increase in ganglioside GM2. The two juvenile cases correspond in their symptoms and findings to the so-called ceroid-lipofuscinoses or "Myoclonic variant of amaurotic idiocy", respectively. Clinically most remarkable is the deterioration of vision caused by retinitis-pigmentosa-like changes of the fundus, which sets in at the beginning of the disease and precedes the cerebral symptoms by years. The extinguished electroretinogramm corresponds in the histological retina findings to a severe lesion of the layer of rods and cones in the sense of a tapeto-retinal degeneration. Neuropathologically finegranular, Sudan-Black-B- and PAS-positive material is mainly but not exclusively stored in the neurons. The electronmicroscope shows them to be lipofuscin-like inclusions, as well as "curvilinear" or "fingerprint-bodies". Depositions are also to be found in astrocytes and in the cells of the vascular walls. The ganglioside pattern is normal in the brain tissue of the biochemically investigated case. Of the two late infantile cases the first represents a GM2-gangliosidosis, the second one corresponds to the ceroid-lipofuscinosis. The adult patient, who suffered from an ill-defined psychiatric disease and died at the age of 51 presents a diagnostically problematic case, showing a relatively slight, regionally rather differently accentuated intraneuronal storage of granular material and biochemically a slight increase in ganglioside GM2. On discussing our own findings and commenting on the relevant literature various aspects of amaurotic idiocies are considered, such as genetics, neuropsychiatry, ophthalmology, pathomorphology and biochemistry. In this respect special attention is paid to the pathomorphological substrate documented, as localization, degree and kind of tissue changes determine the clinical picture. This is also the case for the correlation between the findings of the different fields, so e.g. concerning the ophthalmological findings it is shown, that in gangliosidoses with preserved ERG histologically a storage in the nerve cells of the ganglion cell-layer only is to be found, where as the ceroid-lipofuscinoses with early onset of deterioration of vision and extinguished ERG in the histological picture of the retina show an additional severe lesion of the layer of rods and cones...

Adolescent↗
PubMed1980

Segmental necrotizing granulomatous neuritis of leprosy.

In leprosy, the occurrence of necrotizing nodular lesions in peripheral nerves is a relatively uncommon complication. Despite clinical and gross similarities, there are microscopical differences among groups of such cases, indicating that in all probability different pathogenetic mechanisms are operative. Furthermore, the vast majority of such cases are not true abscesses but are characterized by caseous necrosis and granulomatous inflammation. The traditional collective name "nerve abscess" is therefore inappropriate. Presented herein is an analytic study of 30 cases of the commonest variant, which we suggest should be called segmental necrotizing granulomatous neuritis of leprosy (SNGN). This lesion commonly affects the right ulnar nerve just above the elbow and occurs most often in those with the borderline tuberculoid form of leprosy. It appears to represent the result of a hypersensitivity phenomenon marked by a preponderance of epithelioid cells rather than a reaction of immunity in which lymphocytes predominate. Acid fast bacilli were demonstrable in the lesion in 77% of cases.

Adolescent↗
PubMed1980

[Features of the clinical picture and course of schizoaffective psychoses in adolescents].

The clinical follow-up study of 181 adolescent patients, suffering from so-called schizoaffective psychoses allowed 3 main variants to be singled out on the basis of the clinical symptoms and features of the disease course: in the first variant the clinical picture and disease course were very similar to those of the manic-depressive syndrome; in the second one the clinical symptomatology was characterized from the disease onset by the presence of the depressive-paranoid syndrome, and the third variant was characterized by delusional symptomatology in a bipolar circular disease course.

Adolescent↗
PubMed1997

[Pigmented fibrosarcomatous dermatofibrosarcoma protuberans (Bednar tumor). 3 case reports, analogy with the "conventional" type and review of the literature].

BACKGROUND: The so-called Bednar tumor represents a pigmented variant of dermatofibrosarcoma protuberans (DFSP) and is characterized by a usually scant (1-5% of cells) population of dendritic melanocytes within an otherwise typical DFSP. This pigmented variant accounts for up to 5% of all DFSPs. Other variants of DFSP include cases showing features (in the primary or recurrence) of either giant cell fibroblastoma or fibrosarcoma. Less than 5% of DFSPs are associated with metastases and many of these show either a fibrosarcomatous component or, much more rarely, an "MFH"-like appearance. Only one previous case has been reported which showed combined features of the pigmented and fibrosarcomatous variants. MATERIALS: We present herein 3 cases of fibrosarcomatous Bednar tumor, all occurring in males, 2 aged 75 and 1 aged 23; two patients were white and one black. The tumors were located on the trunk or shoulder and two had been present for many years with recent rapid growth. One patient developed local recurrence and metastases to bone and lung and died within 1 year. The other two patients are disease free at 3 and 5 years follow-up respectively. All three cases showed typical histological features and in two tumors the pigment was evident macroscopically. CONCLUSIONS: A through literature review, including all cases of fibrosarcomatous DFSP and metastasizing fibrosarcomatous DFSP (whether or not pigmented), confirms that the fibrosarcomatous variant of DFSP (including its pigmented counterpart) is significantly more aggressive than usual DFSP, thus underlining the importance of its accurate recognition.

Adult↗