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D L Daniels

Publications and source records attributed to D L Daniels.

At least 73 records · Page 4Linked to original sources
PubMed1988

Q-mediated late gene transcription of bacteriophage lambda: RNA start point and RNase III processing sites in vivo.

The location of the RNA start point of in vivo Q-activated late gene RNA of bacteriophage lambda has been determined to be identical to the start point of in vitro 6 S RNA. The 6 S RNA is made early in infection and is efficiently antiterminated by Q. Two RNase III cut sites are located within Q-dependent RNA sequences, 209 and 270 bp from the beginning of the late transcript, and lie on the stem of an inverted repeat which has features in common with previously described RNase III processing sites. This is the third example of RNase III cut sites immediately downstream of transcription termination points in lambda, the others being antiterminated N gene mRNA and int gene mRNA.

Bacteriophage lambda↗
PubMed1988

Cervical spine anatomy and pathologic processes. Applications of new MR imaging techniques.

Important information regarding the MR appearance of the cervical spine can be obtained using spin-echo and gradient-pulse sequences with motion reduction techniques and intravenous gadolinium-DTPA. In this article the normal MR appearance of the cervical spine is presented, using these newer techniques. Some artifacts and pathologic conditions that may alter the normal appearance of the cervical spine are illustrated.

Cervical Vertebrae↗
PubMed1987

Hippocampal formation and related structures of the limbic lobe: anatomic-MR correlation. Part I. Surface features and coronal sections.

Correlation of magnetic resonance (MR) images with cryomicrotome sections and formalin-fixed sections of human brain documents that spin-echo MR imaging with short repetition time/short echo time pulse sequences can display the surface gyri of the inferomedial temporal lobe, including the temporal pole, the parahippocampal gyrus, the isthmus of the cingulate gyrus, the lateral and medial occipitotemporal gyri, and the inferior temporal gyrus; the associated sulci including the rhinal and collateral sulci, the occipitotemporal sulcus, and the anterior calcarine sulcus; the components and fiber tracts of the hippocampal formation including the pes hippocampi, the hippocampus, the subiculum, the dentate gyrus, the subsplenial gyri, the alveus, the fimbria, and the fornix; the fissures and sulci associated with the hippocampal formation, including the hippocampal fissure, dentatofimbrial fissure, and the choroidal fissure; the continuity between the cingulate gyrus and the parahippocampal gyrus through the isthmus of the cingulate gyrus; and the continuity between the callosal sulcus and the hippocampal fissure.

Hippocampus↗
PubMed1987

Hippocampal formation and related structures of the limbic lobe: anatomic-MR correlation. Part II. Sagittal sections.

Magnetic resonance (MR) images in the sagittal plane display the lengths of the parahippocampal gyrus, subiculum, dentate gyrus, hippocampus, fimbria, fornix, hippocampal fissure, choroidal fissure, and temporal horn, and the anatomic relationships of these structures to the surrounding brain. Correlation of these images with anatomic specimens provides criteria for identifying these structures confidently on routine clinical MR imaging.

Hippocampus↗
PubMed1987

Benign extraaxial tumors: contrast enhancement with Gd-DTPA.

Meningiomas, acoustic neuromas, and other benign extraaxial tumors have little contrast with adjacent brain tissue on conventional magnetic resonance (MR) images. The contrast enhancement produced by intravenous administration of 0.1 mmol/kg of gadolinium-DTPA in these tumors was measured on T1 MR images. Acoustic neuromas showed the greatest enhancement (average, 310%), meningiomas the next greatest (average, 180%), and neurofibromas, glomus tumors, and pituitary microadenomas the least enhancement. The degree of enhancement was almost always greater at 3 minutes than at 25 or 55 minutes. Contrast between the tumor and adjacent tissue resulted from tumor enhancement in neuromas, meningiomas, and neurofibromas and from enhancement of the surrounding tissue in pituitary microadenomas.

Adenoma↗
PubMed1987

MR detection of tumor in the internal auditory canal.

The MR appearance of 15 tumors within or near the internal auditory canal was analyzed in detail and compared with the subsequent surgical observations. In most cases, nonenhanced MR showed the precise extent of the intracanalicular and extracanalicular tumor despite minor variations in appearance. In a case of facial nerve neurinoma, the extent to which the tumor invaded the canal was underestimated by MR. Gadolinium-DTPA enhancement is expected to eliminate uncertainties in MR imaging of the internal auditory canal.

Cerebellar Neoplasms↗
PubMed1987

Differentiation of intramedullary neoplasms and cysts by MR.

To determine the MR criteria that are effective for differentiating intramedullary neoplasms from syringo- or hydromyelia, we reviewed MR scans made on prototype and commercial imagers of 33 patients with surgically confirmed cord abnormalities, including nine intramedullary neoplasms and 20 cysts (syringo- or hydromyelia). Two radiologists who did not know the clinical and radiologic diagnoses were asked to evaluate the scans with respect to cord expansion, distinctness of the disease margin, homogeneity, and signal intensity. These observations were correlated with the proved diagnoses. The combination of distinct margins and uniform signal intensity equal to that of CSF correlated consistently (88%) with spinal cord cysts. Other combinations were less reliable for diagnosing a cyst or tumor.

Diagnosis, Differential↗
PubMed1987

Computed tomography and magnetic resonance imaging of the orbital apex.

This article describes the CT and MR appearance of the orbital apex and masses in this region. The sectional anatomy by axial, coronal, and sagittal planes as well as the thin-layer technique used to accomplish this is detailed first. Then the application of these techniques to the presence of tumors is illustrated and discussed.

Humans↗
PubMed1986

Gas in spinal articulations.

The purpose of this review is to illustrate, some for the first time, a variety of gas collections in lumbar facet joints and intervertebral discs and in the sacroiliac joint.

Arthrography↗
PubMed1986

Technical factors in MR image quality.

We studied the subjective rating of MR image quality as field strength, slice thickness, number of acquisitions and matrix size were varied. Matrix and number of acquisitions had the most significant effect on image quality. Therefore, in comparisons of image quality, technique must not be disregarded.

Brain↗
PubMed1986

Comparison of single-photon emission computed tomography with [123I]iodoamphetamine and xenon-enhanced computed tomography for assessing regional cerebral blood flow.

Regional CBF (rCBF) images obtained from xenon-enhanced computed tomography (XeCT) and single-photon emission computed tomography (SPECT) with N-isopropyl-p-[123I]iodoamphetamine (IMP) done with a rotating gamma-camera were compared in nine patients. Both XeCT and SPECT/IMP demonstrated flow abnormalities at all sites of infarction identified by CT, while detecting reduced rCBF in areas normal by CT in eight of the nine patients. All areas that were abnormal on XeCT were abnormal on the comparable SPECT/IMP images. The major advantages of XeCT are its greater resolution and potential for noninvasive quantitation of rCBF, while the major advantage of SPECT/IMP is its visualization of the entire brain on transverse, coronal, and sagittal sections.

Amphetamines↗
PubMed1986

Anterior commissure: anatomic-MR correlation and use as a landmark in three orthogonal planes.

Correlation of cryomicrotomic and myelin-stained sections of human cadaver heads with spin-echo magnetic resonance (MR) images documents that MR imaging routinely displays the anterior commissure in three orthogonal planes as a distinct white-matter tract that resembles bicycle handlebars. The anterior commissure crosses the midline at the upper end of the lamina terminalis, just anterior to the anterior columns of the fornices. To each side of midline, it curves antero-inferolaterally and then postero-inferolaterally through the lateral nucleus of the globus pallidus to course with the white matter of the external and extreme capsules toward the middle and inferior temporal gyri. Because the anterior commissure is easily recognizable in all three planes at differing pulse sequences, the commissure has proved to be a major landmark for identification of the complex anatomy of this region, especially in sagittal sections.

Brain↗
PubMed1986

Trigeminal nerve: anatomic correlation with MR imaging.

Through correlation with cryomicrotic sections, the appearance of the trigeminal nerve and its branches on magnetic resonance images is described in healthy individuals and in patients with tumors involving this nerve. Coronal images are best for defining the different parts of the nerve and for making a side-to-side comparison. Sagittal images are useful to demonstrate tumors involving the gasserian ganglion.

Cavernous Sinus↗
PubMed1986

Cranial tissues: normal MR appearance after intravenous injection of Gd-DTPA.

The effect of intravenously administered gadolinium DTPA on signal intensity of normal intracranial structures was analyzed in 25 patients. Magnetic resonance (MR) image enhancement with Gd-DTPA differs from image enhancement on computed tomography with aqueous iodinated contrast media. Marked contrast enhancement owing to Gd-DTPA was observed in the pituitary gland, infundibulum, cavernous sinus, cranial nerves, choroid plexus, and nasal mucosa. Enhancement was not visible routinely in the falx cerebri, tentorium cerebelli, dura, or rapidly flowing blood. The efficacy of Gd-DTPA in any individual MR study may be assessed by observing the signal intensity of the pituitary gland, pituitary stalk, or nasal mucosa.

Arcuate Nucleus of Hypothalamus↗
PubMed1986

A blinded clinical comparison of MR imaging and CT in neuroradiology.

The sensitivity and specificity of magnetic resonance (MR) imaging and computed tomography (CT) were compared in blinded readings of images of a consecutive series of patients with subsequently proved diagnoses. Overall, MR imaging was less sensitive than CT because of its lower sensitivity in detecting benign tumors. With a similar experimental protocol, the effects of technical refinements or contrast media on the sensitivity of MR imaging can be determined.

Aged↗
PubMed1986

Pituitary and adrenal CT of Cushing syndrome.

Determination of the site of excessive hormone production in Cushing syndrome is possible with biochemical tests in 80% of cases. High-resolution CT of both the pituitary and adrenal glands was used to evaluate eight patients with surgically verified ACTH-secreting pituitary microadenomas and one patient with ectopic Cushing syndrome. Three ACTH-secreting microadenomas were demonstrated by CT. Adrenal CT was normal in six of the eight patients with pituitary tumors. The patient with ectopic ACTH production had mild unilateral adrenal gland enlargement and a normal pituitary CT scan. Normal adrenal or pituitary CT scans do not exclude Cushing syndrome.

Adenocarcinoma↗