Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Origin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

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

Primitive and definitive blood share a common origin in Xenopus: a comparison of lineage techniques used to construct fate maps.

Primitive blood constitutes the ventralmost mesoderm in amphibians, and its cleavage-stage origin reveals important clues about the orientation of the dorsal/ventral axis in the embryo. In recent years, investigators employing various lineage-labeling strategies have reported disparate results for the origin of primitive blood in Xenopus [W. D. Tracey, Jr., M. E. Pepling, G. H. Thomsen, and J. P. Gergen (1998). Development 125, 1371-1380; M. C. Lane W. C. Smith (1999). Development 126, 423-434; K. R. Mills, D. Kruep, and M. S. Saha (1999). Dev. Biol. 209, 352-368; A. Ciau-Uitz, M. Walmsley, and R. Patient (2000). Cell 102, 787-796]. These discrepancies must be resolved in order to elucidate early embryonic patterning mechanisms in vivo. We directly compared two of the techniques used to determine the origin of the ventral blood islands and primitive blood, injection of either beta-galactosidase mRNA or conjugated dextrans, by coinjecting both tracers simultaneously into individual blastomeres in cleavage-stage embryos. We find that dextrans label progeny efficiently, while beta-galactosidase activity is not present in many of the progeny of an injected blastomere, suggesting that mRNA fails to diffuse throughout a blastomere. This result demonstrates that beta-galactosidase mRNA fails to meet the criterion for a true lineage label, namely efficient detection of the progeny of a blastomere, and raises questions about interpretations based on mapping the ventral blood islands using Lac Z mRNA as a tracer. We examined the origins of the ventral blood islands and primitive blood from the vegetal region of the marginal zone in regularly cleaving embryos by coinjecting both reporters into C-tier blastomeres. Our results demonstrate that both the ventral blood islands and primitive blood routinely arise from all C-tier blastomeres. Our data, in combination with published mapping results for the dorsal aorta, demonstrate that primitive and definitive blood do not have separate origins at the 32-cell stage in Xenopus. In addition, these results support a proposal to align the dorsal/ventral axis of the mesendoderm with the animal/vegetal axis in pregastrula Xenopus.

Animals↗
PubMed2002

The origin of mesoderm in phoronids.

Descriptive studies of phoronid development have concluded that the mesoderm of these animals originates from the endoderm during gastrulation. This interpretation has been tested by labeling one blastomere of 4- through 16-cell embryos and examining the position and germ layers occupied by the labeled clones of cells in the larva. No 2 injections gave rise to identical clones of cells, suggesting that the cleavage program does not generate cells of unique identity and that cell fates are established at later developmental time points. In many cases, a relatively large sector composed of ectodermal cells was labeled. When these labeled cells were adjacent to the mouth or anus of the larva, muscle and mesenchyme cells originated from the labeled clones. Under these circumstances, nerve cells also originated from these labeled sectors. These labeling studies also showed that endodermal cells can give rise to mesodermal and neural cells. These results suggest that nerve and muscle cells are induced to form at ectodermal-endodermal boundaries from both germ layers. These marking experiments also confirmed the observation that nerve cells originate both from the apical organ and the trunk region and show for the first time that the intestine originates by ingression of posterior ectoderm.

Animals↗
PubMed1993

Conformation of the origin of P1 plasmid replication. Initiator protein induced wrapping and intrinsic unstacking.

The origin of plasmid DNA replication in bacteriophage P1 has five 19 base-pair sites that bind the plasmid-encoded initiator, RepA. Here we show, using a DNA band retardation assay, that RepA can bend DNA that carries one or more of the RepA binding sites. RepA binding to supercoiled DNA carrying the five sites, directly repeated and phased two turns of B-DNA apart, absorbs about one positive superhelical turn of DNA as determined by two-dimensional gel electrophoresis. This indicates that the DNA is wrapped around RepA as a consequence of in-phase bending at the individual binding sites. The RepA-DNA complexes did not show elevated sensitivity to KMnO4, a reagent specific for pyrimidine bases (T >> C) in unstacked DNA. The wrapping of the DNA around RepA, therefore, does not lead to significant unwinding of the double helix. Extensive unwinding, suitable for the initiation of DNA replication, most likely requires participation of factors other than RepA. We also noted that the thymine bases of the sequence 5'-ATC-3', of which there are 20 in the origin, all reacted to KMnO4 strongly whether or not RepA was present. The preferential reactivity of ATC sequences was specific to the origin region, as thymine residues including those in the ATC sequences did not display elevated sensitivity to KMnO4 in a DNA fragment from pBR322. On one of two strands of the origin the selective reactivity at the ATC sequences was supercoiling dependent. These results indicate that the origin includes unstacked DNA bases, the significance of which remains to be determined.

Bacterial Proteins↗
PubMed2000

Guided selection of a pan carcinoma specific antibody reveals similar binding characteristics yet structural divergence between the original murine antibody and its human equivalent.

Antibody engineering provides an excellent tool for the generation of human immunotherapeutics for the targeted treatment of solid tumours. We have engineered and selected a completely human antibody to epithelial glycoprotein-2 (EGP-2), a transmembrane glycoprotein present on virtually all human simple epithelia and abundantly expressed on a variety of human carcinomas. We chose to use the procedure of "guided selection" to rebuild a high-affinity murine antibody into a human antibody, using two consecutive rounds of variable domain shuffling and phage library selection. As a starting antibody, the murine antibody MOC-31 was used. After the first round of guided selection, where the V(H) of MOC-31 was combined in Fab format with a human V(L)C(L) library, a small panel of human light chains was identified, originating from a segment of the VkappaIII family, whereas the MOC-31 V(L) is more homologous to the VkappaII family. Nevertheless, one of the chimaeric Fabs, C3, displayed an off-rate similar to MOC-31 scFv. Combining the V(L) of C3 with a human V(H) library, while retaining the V(H) CDR3 of MOC-31, clones were selected using human V(H) genes originating from the rarely used V(H)7 family. The best clone, 9E, shows over 13 amino acid mutations from the germline sequence, has an off-rate comparable to the original antibody and specifically binds to the "MOC-31"-epitope on EGP-2 in specificity and competition ELISA, FACS analysis and immunohistochemistry. In both V(L) and V(H) of antibody 9E, three germline mutations were found creating the MOC-31 homologue residue. Structural modelling of both murine and human antibodies reveals that one of the germline mutations, 53Y in V(H) CDR2, is likely to be involved in antigen binding. We conclude that, although they may bind the same epitope and have similar binding affinity to the antigen as the original murine antibody, human antibodies derived by guided selection unlike CDR-grafted antibodies, may retain only some of the original key elements of the binding site chemistry. The selected human anti-EGP-2 antibody will be a suitable reagent for tumour targeting.

Amino Acid Sequence↗
PubMed1998

Reflections on the origin of the genetic code: a hypothesis.

The origin of the organisation of the genetic code reflects both the biosynthetic relationships between amino acids and the physicochemical interactions between these and anticodons; moreover, these two forces do not act independently. It must therefore be explained why it is simultaneously true that the anticodons of product amino acids were assigned prior to their biosynthetic appearance and that physicochemical correlations must exist between anticodons and amino acids. This gives rise to difficulties of interpretation, even of a more general nature, in the theories that have been proposed to explain the origin of the genetic code; a hypothesis is thus presented in this manuscript. In particular, the hypothesis suggests that RNA hairpin structures, the ancestors of tRNAs, housing anticodon-like nucleotides in the stem were charged with precursor amino acids. As the precursor amino acids gradually developed into product amino acids, a coevolution came into being between the development of amino acids and that of anticodons, with a concomitant formation of the complete tRNA molecule thought direct duplication of the hairpin structures. All this led to the definition of the genetic code organisation. Furthermore, this made it possible for the evolving anticodons to select the emerging product amino acids, which the hypothesis therefore considers to be unspecified in the initial phase of genetic code evolution but which were selected also because of their ability to interact with anticodons. In this way the main obstacle to interpretation is removed. Fossils of these events can now be observed in some amino acid-modified nucleosides specifically located in the tRNA anticodon loops. This is all presented in the framework of a general discussion of the ideas and data in favour of a late origin of the genetic code, as opposed to an early origin in the context of the theories proposed to explain the origin of the genetic code organisation.

Amino Acids↗
PubMed1999

The non-monophyletic origin of the tRNA molecule.

The hypothesis that the tRNA molecule may have originated from the assembly of two similar RNA hairpin structures is utilised to understand the evolutionary period in which this molecule originated. Consistent with the exon theory of genes is the observation that the introns in tRNA genes are found almost exclusively in the anticodon loop and "stitched together" the two halves of the molecule, which originally may have been simply two hairpin structures and which can still be observed in the three-dimensional structure of tRNAs. This theory therefore considers these hairpin structures as minigenes on which complex protein synthesis may have been achieved. This in turn leads to the belief that the organisation of the genetic code may have been determined by use of the hairpin structures but not the complete tRNA molecule. In view of this, it can be conjectured that tRNA molecules might have been assembled only after the establishment of the main phyletic lines. If this is all true, then the origin of the tRNA molecule might have been non-monophyletic, i.e. a tRNA specific for a certain amino acid might have been assembled in different phyletic lines with a second and different hairpin structure. This leads to the belief that tRNAs specific for different amino acids but belonging to the same phyletic line might have been more similar to one another than to tRNAs specific for the same amino acid but belonging to different phyletic lines. This prediction seems to be supported by phylogenetic analysis making major use of the bootstrap technique performed on the tRNA sequences and by analysis already existing in the literature which supports the non-monophyletic origin of the tRNA molecule. The main conclusion of this paper is that if the tRNA molecule was assembled in the main phyletic lines this would imply a still rapidly evolving translation apparatus which, in turn, seems to imply that the last universal common ancestor was a progenote.

Amino Acids↗
PubMed1999

Different models, different trees: the geographic origin of PTLV-I.

Using nucleotide sequences from three genomic regions of the human and simian T-cell lymphotropic virus type I (HTLV-I/STLV-I)-consisting of 69 sequences from a 140-bp segment of the pol region, 98 sequences from a 503-bp segment of the LTR, and 154 sequences from a 386-bp segment of the env region-we tested two hypotheses concerning the geographic origin and evolution of STLV-I and HTLV-I. First, we tested the assumption of equal rates of evolution along STLV-I and HTLV-I lineages using a likelihood ratio test to ascertain whether current levels of genomic diversity can be used to determine ancestry. We demonstrated that unequal rates of evolution along HTLV-I and STLV-I lineages have occurred throughout evolutionary time, thus calling into question the use of pairwise distances to assign ancestry. Second, we constructed phylogenetic trees using multiple phylogenetic techniques to test for the geographic origin of STLV-I and HTLV-I. Using the principle of likelihood, we chose a statistically justified model of evolution for each data set. We demonstrated the utility of the likelihood ratio test to determine which model of evolution should be chosen for phylogenetic analyses, revealing that using different models of evolution produces conflicting results, and neither the hypothesis of an African origin nor the hypothesis of an Asian origin can be rejected statistically. Our best estimates of phylogenetic relationships, however, support an African origin of PTLV for each gene region.

Animals↗
PubMed2001

The left-end and right-end origins of minute virus of mice DNA differ in their capacity to direct episomal amplification and integration in vivo.

Previously it was shown that a 53-nucleotide viral replication origin, derived from the left-end (3') telomere of minute virus of mice (MVM) DNA, directed integration of infecting MVM genomes into an Epstein-Barr virus (EBV)-based episome in cell culture. Integration depended upon the presence, in the episome, of a functional origin sequence which could be nicked by NS1, the viral initiator protein. Here we extend our studies to the genomic right-end (5') origin and report that three 131- to 135-nucleotide right-end origin sequences failed to target MVM episomal integration even though the same sequences were functional in NS1-driven DNA replication assays in vitro. Additionally, we observed amplification of episomal DNA in response to MVM infection in cell lines harboring episomes which directed integration, but not in cell lines containing episomes which did not direct integration, including those with inserts of the MVM right-end origin.

5' Untranslated Regions↗
PubMed1995

Excess of deletions of maternal origin in the DiGeorge/velo-cardio-facial syndromes. A study of 22 new patients and review of the literature.

We have determined the parental origin of the deleted chromosome 22 in 29 cases of DiGeorge syndrome (DGS) using a CA-repeat mapping within the commonly deleted region, and in one other case by using a chromosome 22 short arm heteromorphism. The CA-repeat was informative in 21 out of 29 families studied and the deleted chromosome was of maternal origin in 16 cases (72%). When these data are pooled with recent results from the literature, 24 de novo DGS, velo-cardio-facial syndrome (VCFS) and isolated conotruncal cardiac disease deletions are found to be of maternal origin and 8 of paternal origin, yielding a chi 2 of 8 with a probability level lower than 0.01. These data, and review of the literature on familial DGS/VCFS and isolated conotruncal cardiopathies suggest that there is a strong tendency for the 22q11.2 deletions to be of maternal origin.

Chromosome Deletion↗
PubMed1981

Nucleotide sequence of a cloned cDNA copy of TMV (cowpea strain) RNA, including the assembly origin, the coat protein cistron, and the 3' non-coding region.

The cloned cDNA derived from the 3' end of cowpea strain (Cc) RNA of tobacco mosaic virus (TMV) has been sequenced. Substantial sequence information of 1,060 nucleotides from the 3' end of the RNA reveals some interesting features: (1) the coat protein cistron corresponds to residues 210-701 from the 3' end. Some errors in the amino acid sequence previously reported have been corrected and the revised total length of the coat protein is 162 amino acid residues. The capping site of the coat protein mRNA is at residue 711 from the 3' end of genome RNA. (2) The assembly origin of reconstitution is positioned within the coat protein cistron at residue 369-461 which can be formed into a highly base-paired hairpin loop structure. The sequence, GAXGUUG, in the loop region and a triplet-repeated purine base tract surrounding the loop are found. These structural features are common to assembly origins of both Cc and vulgare strains. (3) We find the sequence highly homologous to, but distinct from, the genuine assembly origin. It will be called the pseudo-assembly origin, which is located in the corresponding region to the assembly origin of the vulgare strain, outside the coat protein cistron. There is also the sequence, GAXGUUG, in the middle of the region. (4) In the 5' flanking region of the coat protein cistron, a long reading frame, probably of 30 K protein, is found. The coding region is terminated in the coat protein cistron and thus the 30 K protein and the coat protein cistrons overlap. (5) The 3' non-coding region is 209 residues long and can be folded into a possible tRNA-like structure. Surprisingly, we find that the 3' terminal sequence of Cc RNA is not very similar to that of vulgare RNA but extensively homologous to that of turnip yellow mosaic virus (TYMV) RNA.

Amino Acid Sequence↗
PubMed1981

Characterization of cells of amniotic fluids by immunological identification of intermediate-sized filaments: presence of cells of different tissue origin.

Antibodies against intermediate-sized filaments, of the prekeratin or vimentin type, were used to investigate the presence of these filaments by indirect immunofluorescence microscopy in cultured and non-cultured amniotic fluid cells, in frozen sections of the placenta and in isolated cells of the amniotic epithelium. Two major classes of cells can be cultured from amniotic fluids, namely cells of epithelial origin containing filaments of the prekeratin type and cells of different origin which contain filaments of the vimentin type but are negative when tested with antibodies to epidermal prekeratin. The presence of prekeratin type filaments correlates with the morphology of colonies of amniotic fluid cell cultures in vitro as classified by Hoehn et al. (1974). Cells of E-type colonies are shown to be of epithelial origin. In contrast our data indicate a different origin of almost all cells of F-type colonies and of the large majority of cells of AF-type colonies. Cells of epithelial origin and positively stained with antibodies to epidermal prekeratin are occasionally scattered in F-type colonies and in variable percentages (up to 30%) in AF-type colonies. Surprisingly, cryostat sections of the amniotic epithelium and isolated groups of amniotic cells showed positive reactions with both antibodies to vimentin and prekeratin. The possibility that amniotic cells may be different from other epithelial cells in that they contain both types of filaments simultaneously already in situ is presently under investigation.

Adult↗
PubMed1981

Nucleotide sequence of the region of the origin of replication of the broad host range plasmid RK2.

A DNA sequence consisting of 617 base pairs (bp) from the region of the origin of replication of the broad-host range plasmid RK2 has been determined. Included within this sequence is a 393 bp HpaII restriction fragment that provides a functional origin or replication when other essential RK2 specified functions are provided in trans. Also contained in this sequence is a region, distinguished functionally from the replication origin, which is involved in the expression of inc2 incompatibility, i.e., the ability of derivatives of RK2 to eliminate a resident RK2 plasmid. The 617 bp sequence includes eight 17 base pair direct repeats with 5 located within the region required for a functional replication origin and 3 within the region involved in inc2 incompatibility. In addition, a 40 bp region rich in A-T followed by a 60 bp stretch having a high G + C content is present. Deletion evidence indicates that the A-T rich and possibly the G + C regions are required for a functional replication origin. Based on the evidence contained in this and the preceding paper (Thomas et al. 1980 b) a model will be presented for the involvement of these specific sequences in the initiation of RK2 DNA replication, plasmid maintenance and plasmid incompatibility.

Base Sequence↗
PubMed1993

Yeast pre-meiotic DNA replication utilizes mitotic origin ARS1 independently of CDC7 function.

In budding yeast, mitotic DNA replication initiates at sequence-specific replication origins, the prototype for which is ARS1. Initiation serves as the primary control point for mitotic DNA replication, and is catalyzed by the Cdc7 protein kinase. In contrast, premeiotic DNA replication apparently does not require Cdc7, and the existence and nature of specific replication origins in the meiotic division cycle have not been previously reported. We have begun to investigate the mechanism of premeiotic DNA synthesis by determining whether or not ARS1 functions as a DNA replication origin in meiosis. We have taken advantage of the fact that transcription through ARS1 disrupts its ability to function as an origin to show that ARS1 is required for premeiotic DNA replication of a plasmid bearing this element. Further, premeiotic replication from ARS1 still occurs in a cdc7 mutant strain held at conditions non-permissive for Cdc7 protein kinase activity. These findings reveal that premeiotic DNA replication can initiate from origins also used in mitosis, and is not regulated by Cdc7. Taken together with previous findings implicating Cdc7 in meiotic DNA recombination and induced mutagenesis, these findings prompt us to postulate that the Cdc7 protein kinase regulates some step common to several DNA metabolic processes such as local disassembly of chromatin or activation of a key component of the DNA metabolic machinery.

Cell Cycle Proteins↗
PubMed1995

Variations of the origin of the artery of the sinoatrial node in normal human hearts.

The artery of the sino-atrial node was studied in 100 normal human hearts after injection of each coronary artery with coloured gelatine containing a radiopaque substance. The hearts belonged to 69 males and 31 females, being 64 Caucasians and 36 non-Caucasians (Negroes and Mulattoes) whose age ranged from 7 to 80 years. Since the individuals had committed suicide or were victims of accidents, their hearts, after pathologists' evaluation, were considered normal. The sinoatrial node of the normal human heart is supplied by the right coronary artery more frequently (58% +/- 4.9% of the cases) than by the left (42% +/- 4.9). The right anterior medial atrial artery, originating from the right coronary at the level of the medial third of the right anterior quadrant of the atrial dome, is most frequently (50% +/- 5) responsible for the blood supply of the sinoatrial node. Among the branches of the left coronary artery, the left anterior medial atrial artery, originating at the level of the medial third of the left. anterior quadrant of the atrial cupola, was the most frequent blood supplier (25% +/- 4.3) of the sinoatrial node. The origin of the artery of the sinoatrial node from the proximal portion or trunk of the left coronary artery was less frequent (12% +/- 3.2) than the origin from the circumflex artery (30% +/- 4.5). Neither sex nor race influenced the variations of the origin of the sino-atrial node.

Adolescent↗
PubMed1992

Identification and mapping of origins of DNA replication within the DNA sequences of the genome of insect iridescent virus type 6.

The origins of DNA replication of the genome (209 kbp) of Chilo iridescent virus (CIV), which is circularly permuted and terminally redundant, were identified. The defined genomic library of CIV, which represents 100% of DNA sequences of the viral genome (e.g., all 32 EcoRI CIV DNA fragments), was used for transfection of Choristoneura fumiferana insect cell cultures (CF-124) that were previously infected with CIV. The plasmid rescue experiments were carried out to select those recombinant plasmids that were amplified during viral replication in CIV-infected cell cultures. It was found that six recombinant plasmids harboring the EcoRI DNA fragments C [13.5 kbp, 0.909-0.974 map units (m.u.)], H (9.8 kbp, 0.535-0.582 m.u.), M (7.25 kbp, 0.310-0.345 m.u.), O (6.5 kbp, 0.196-0.228 m.u.), Q (5.9 kbp, 0.603-0.631 m.u.), and Y (2.0 kbp, 0.381-0.391 m.u.) were able to be amplified under the conditions used. This indicates that the CIV genome possesses six DNA replication origins. Subclones of the EcoRI CIV DNA fragments C and H were screened under the same conditions. It was found that DNA sequences within the EcoRI DNA fragments C and H at the genome coordinates 0.924-0.930 and 0.535-0.548, respectively, contain origins of viral DNA replication. The DNA nucleotide sequences of the EcoRI CIV DNA fragment Y (1986 bp) were determined for identifying the DNA sequence of the corresponding origin of DNA replication. The computer-aided analysis revealed the presence of a 15-mer inverted repeat at nucleotide positions 661-675 and 677-691 (661-TAAATTTAATGAGAA-G-TTCTCATTAAATTTA-692). The analysis of the DNA sequence of the EcoRI DNA fragment H corresponding to the particular region at the genome coordinates 0.535-0.548 (1) showed that this region contains a 16-mer inverted repeat at the nucleotide positions 1315 and 1332 (1315-TAAATTTTAATGGTTA-A-TAACCATTAAAATTTA-1347), which is very similar to the inverted repetition found within the EcoRI DNA fragment Y. The successful recognition and amplification of the single-stranded synthetic DNA sequences of both strands of CIV-ori-Y (nucleotide position 661-691) using phage M13 system in CIV-infected cells is strong evidence that the CIV-ori-Y is bidirectionally active, and this DNA sequence is considered to be the origin of DNA replication within the EcoRI CIV DNA fragment Y.

Base Sequence↗
PubMed1996

Origin of the anterior spinal artery.

This investigation was designed to extend our present knowledge of the origin of the anterior spinal a. and is based on 80 brains of human cadavers. The anterior spinal a. is usually formed rostrally by the union of the anterior spinal branches from the intracranial segments of the vertebral aa. In this study, we observed three different locations of the origin of the anterior spinal a. Each type has different characteristics. A bilateral origin (type I) was present in 60 specimens (75%). This type could be further subdivided according to the caliber of the arteries, into the following subtypes: "balanced" (type Ia 42.5%), right-dominated (type Ib 17.5%), and left-dominated (type Ic 15%). A unilateral origin (type II) was found in 9 specimens (11.3%), and an origin in an intervertebral transverse anastomosis was demonstrated in 11 (13.8%). In all cases, the anterior spinal a. had an average caliber of 1.145 +/- 0.12 mm.

Adult↗
PubMed2005

[Differences between Eastern European immigrants of German origin and the rest of the German population in health status, health care use and health behaviour: a comparative study using data from the KORA-Survey 2000].

UNLABELLED: Differences between Eastern European immigrants of German origin and the rest of the German population in health status, health care use and health behaviour: a comparative study using data from the KORA-Survey 2000 OBJECTIVES: To identify differences in health status, health care use and health behaviour between Eastern European immigrants of German origin and the rest of the German population in order to develop new concepts for preventive programs. METHODS: Using data from the KORA-Survey 2000 (Cooperative Health Research in the Region of Augsburg), immigrants of German origin were compared to the rest of the German population with multiple regression models controlling for sex, age, living with partner, years of education and occupation. Tests of trend were performed for the groups classified according to the year of immigration. RESULTS: Compared to other Germans, immigrants of German origin consider their health status more often as poor. They were more likely to be obese (OR = 1.95) and have hyperlipidemia (total-cholesterol/HDL-C > 4: OR = 1.71). They were less likely to use cancer screening (OR = 0.41) or to perform sport activities (OR = 0.47). All these differences decrease with the length of residence in Germany. CONCLUSIONS: Concerning their health status, Eastern European immigrants of German origin were identified as a high risk group. They should be considered for specific preventive programs and health care interventions, especially during the first years of immigration.

Adult↗
PubMed2005

[Vestibular evoked muscle potentials dependency on neural origin and the location of an acoustic neuroma].

INTRODUCTION: Most acoustic neuromas (AN) originate from the inferior vestibular nerve (IVN). Vestibular evoked myogenic potentials (VEMP) are accepted as the only unilateral test for the function of the sacculus and the IVN. METHODS: The influence of the origin from the IVN and superior vestibular nerve (SVN), and the position of the AN in relation to the internal auditory canal on VEMPs was investigated. A total of 39 patients (aged: 30-67 years, mean: 53 years) were examined. The VEMPs were recorded on the activated sternocleidomastoid muscle and averaged over 200 stimuli. Tone bursts (95 dB nHL; 500 Hz; stimulation rate 5 Hz) were used to generate the VEMPs. RESULTS: The exact origin of the AN from the SVN or the IVN could be determined intraoperatively and correlated using VEMP in 28 patients. CONCLUSION: The origin of the AN has only a marginal influence on the results of VEMP measurements. The position of the AN in relation to the internal auditory canal seems to have more influence than the origin.

Acoustic Stimulation↗