Search PubMed⌕ Search

Biomedical subjects

N R Miller

Publications and source records attributed to N R Miller.

At least 199 records · Page 11Linked to original sources
PubMed1983

Downbeat nystagmus. A case report of herpetic brain stem encephalitis.

A 35-year-old man with aplastic anemia developed prominent downbeat nystagmus 80 days after receiving an allogeneic bone marrow transplant. A diagnosis of herpes simplex encephalitis was made which was confirmed by positive virus cultures at autopsy 1 week later. Routine pathologic examination of the brain stem revealed no lesions which would explain the downbeat nystagmus. Immunoperoxidase studies, however, revealed virus-infected neurones throughout the brain stem including the nuclei of the basis pontis, the superior olive, and nuclei of the spinal tracts of 5 and 10. The significance of "negative" pathologic brain stem findings in cases of downbeat nystagmus is discussed.

Adult↗
PubMed1983

The detection of JC viral genome in owl monkey tumors.

The JC viral genome is integrated into the cellular DNA of brain tumors from owl monkeys inoculated intracranially with JC virus 16-36 months prior to the development of the tumors. Normal brain tissue of the animals did not contain the viral genome. For at least two tumors, restriction endonuclease analysis of the tumor DNA indicates that there is a complete copy of the viral genome present. Integration of the genome in all but one of the tumors was at only one or only a limited number of sites, indicating a clonal origin for the tumors. In all but one of the tumors, there was tandem, head-to-tail integration of two or more copies of the JC genomes.

Animals↗
PubMed1982

Combined use of neostigmine and ocular motility measurements in the diagnosis of myasthenia gravis.

Forty-four patients with diplopia caused by myasthenia gravis, ocular myopathies, and ocular motor nerve palsies underwent complete orthoptic evaluations before and after intramuscular injection of neostigmine (Prostigmin) methylsulfate. A test score combining the results of binocular and uniocular measurements was developed that allowed correct correct classification of 70% (31) of patients studied.

Diagnosis, Differential↗
PubMed1982

Amodiaquine ocular changes.

A 34-year-old man ingested more then 250 g of amodiaquine hydrochloride (for pain) during one year and was noted to have diffuse conjunctival, corneal, and skin changes and also abnormal results from retinal function tests. Ultrastructural examination of corneal and conjunctival biopsy specimens revealed intralysosomal membranous and amorphous inclusions in corneal epithelial cells, conjunctival epithelial cells, keratocytes, and vascular endothelial cells. Follow-up of more than two years and repeated conjunctival biopsy specimens revealed diminution in both the clinical and electron microscopic abnormalities, but persistence in abnormal results of retinal function tests. These changes are consistent with a drug-induced phospholipidosis.

Adult↗
PubMed1982

Unilateral Duane's retraction syndrome (Type 1).

Duane's retraction syndrome (DRS) is a congenital eye movement disorder characterized by adduction deficiency, abduction limitation, globe retraction, and palpebral fissure narrowing on attempted adduction. In a case of unilateral DRS, the right side of the brainstem, cavernous sinus, and orbit were completely normal. The left abducens nucleus contained no cell bodies from motor neurons, but in its rostral portion, it contained several small cell bodies believed to be compatible with internuclear neurons. The left abducens nerve was absent. The left lateral rectus muscle was partially innervated by branches from the inferior oculomotor nerve.

Abducens Nerve↗
PubMed1982

Sphenoid pneumosinus dilatans. A sign of meningioma originating in the optic canal.

Surgical exploration of three patients who had a radiological diagnosis of sphenoid pneumosinus dilatans disclosed an intracanalicular meningioma of the sheath of the optic nerve (MSON), bilaterally in two patients and unilaterally in the other. Two cases of sphenoid pneumosinus dilatans, previously reported, are reviewed, and a new case is presented. The relationship of sphenoid pneumosinus to MSON is discussed. Sphenoid pneumosinus dilatans may be an early sign of MSON in the optic canals or at the optic foramens.

Adolescent↗
PubMed1982

Three-dimensional osteometric scaling and normative modelling of skeletal segments.

Many analytical biomechanics methods require extensive three-dimensional descriptions of anatomical geometry. In particular, researchers requiring the three-dimensional coordinates of specific boney landmarks (e.g. tendon and ligament attachments) are often forced to extrapolate such measurements from an experimental specimen set to their subject geometry. This work offers an approach to two problems inherent above; accurate extrapolation of specimen landmark locations to subject homologues and statistical accumulation of normative three-dimensional anatomical landmark data bases. A least squares solution for an affine scaling transformation from specimen to subject is used which incorporates both right-left and same hand comparisons. A two stage technique is formulated to consecutively remove landmark location variation and to size a normative specimen from a set of similar specimens. This ability to statistically represent a specimen set will provide better geometric models for other analytical studies and prosthetic design and evaluation.

Anthropometry↗
PubMed1982

Visual following during stimulation of an immobile eye (the open loop condition).

We had the rare opportunity to examine a patient with a unilateral complete ophthalmoplegia in an eye with normal visual acuity. We recorded the movements of the covered, sound eye of the patient during full-field optokinetic stimulation of his seeing, immobile eye (open loop condition). The open loop gain for low velocity stimuli (less than 1 deg/sec) was high (greater than 50) but progressively fell with faster stimuli. This finding is inconsistent with the representation of the optokinetic system as a linear velocity servo. In a second experiment, the patient foveally fixated, with the immobile eye, a head-fixed target during sinusoidal, en block rotation. The vestibular movements of the sound eye were suppressed, even though no retinal image motion occurred in the seeing eye. This suggests that visual attention to a stable retinal image can be used to suppress the vestibulo-ocular reflex. Our results were from one patient only and any generalizations must be made cautiously. Nevertheless, our findings are comparable with previous "open loop" studies in normal human beings and patients.

Electrooculography↗
PubMed1982

Orbital computed tomography: technical aspects.

Computed tomographic scanning has revolutionized the diagnosis and management of orbital disease. The best use of this methodology requires knowledge of the principles and appropriate attention to scanning protocols. Computed tomographic scanning of the orbit is a demanding technique requiring thin sections through planes precisely positioned from the topographical anatomy. Ideally, orbital CT should include both transverse axial and coronal sections: The pathological condition and its plane of growth will influence the selection of the optimal plane or section. Coronal sections may be obtained either directly or indirectly by computer reconstruction from contiguous transverse images. Sagittal or oblique sections or both also are useful and may be obtained directly or indirectly. Difficulty in patient positioning may preclude direct sagittal imaging, however. The use of intravenous contrast enhancement is not necessary as a routine technique unless a mass is identified or suspected. Where surgical resection or biopsy of a space-occupying lesion is contemplated, contrast enhancement can be valuable in assessing relative vascularity and aiding diagnostic specificity. It should be continually emphasized that CT is a powerful technology which, in orbital diagnosis, produces the highest yield when clinician and radiologist collaborate in the radiodiagnostic workup. The clinical information supplied by the referring ophthalmologist is used by the radiologist both in the selection of the appropriate techniques for investigation and in striving to achieve the most specific conclusion.

Contrast Media↗
PubMed1982

Intoxication with beta, beta' -iminodipropionitrile: a model of optic disc swelling.

Human and experimental pathologic studies have suggested that optic disc swelling is due to enlargement of axons in the optic nerve head. Beta, beta' -Iminodipropionitrile (IDPN), a toxin known to produce neurofibrillary swellings in proximal portions of motor and sensory axons, was used to induce axonal lesions in the visual system of guinea pigs and dogs. Funduscopic examination showed progressive optic disc swelling. The axonal swellings, containing maloriented skeins of neurofilaments, appeared initially in the lateral portions of the optic disc; eventually, the majority of axons in the optic disc and in the retinal nerve fiber layer were enlarged. The swellings developed proximal to the level of Bruch's membrane. In addition, myelinated axons in the optic disc and retinal nerve fiber layer developed swellings proximal to the first heminode, demarcating the junction between the unmyelinated/myelinated segments. The retinal ganglion cells remained normal, and there was little axonal degeneration in the distal optic nerve. When beta, beta' -iminodipropionitrile was discontinued, the axonal swellings gradually disappeared.

Animals↗
PubMed1981

Clinical-angiographic correlation of ophthalmodynamometry in suspected carotid artery disease. Prospective study.

A prospective, clinical study of patients with suspected carotid artery disease compared the accuracy of compression and suction ophthalmodynamometry (ODM) with carotid artery stenosis determined by arteriography. Results were analyzed with respect to current criteria for classification and determination of "substantial" carotid artery disease. The best correlation for both procedures with arteriography was a ratio of the corrected intraocular pressure to the systolic brachial pressure. Both suction and compression ODM findings are equally accurate, with levels approaching 80%; however, neither test is sensitive enough to be used alone as a screening technique. Arteriography remains the best procedure for the determination of carotid artery disease.

Angiography↗
PubMed1981

Atrophy of myelinated retinal nerve fibers after acute optic neuropathy.

A 45-year-old man with extensive myelinated retinal nerve fibers had an attack of anterior ischemic optic neuropathy. Serial fundus photographs documented the loss of myelin. Visual acuity in the affected eye decreased to 6/90 (20/300) and color perception was markedly reduced. The visual fields in the affected eye showed dense superior and inferior arcuate scotomas and central depression. These findings were unchanged nine months later, but the areas of myelinated nerve fibers had become smaller.

Humans↗
PubMed1981

Ischaemic optic neuropathy with painful ophthalmoplegia in diabetes mellitus.

Two patients with mild, adult-onset diabetes mellitus developed a painful ophthalmoplegia and ipsilateral optic neuropathy that was relatively unresponsive to steroids. Histopathological study of the optic nerve of one patient revealed an extensive ischaemic infarct. There was ultimate recovery from the cranial nerve palsies in both patients and the optic neuropathy in one patient. Ischaemic polyneuropathy involving the cranial nerves may cause an orbital apex/cavernous sinus syndrome in patients with diabetes mellitus.

Diabetic Neuropathies↗
PubMed1981

Restricted expression of retrovirus nucleic acids and proteins in primate type C virus (gibbon ape leukemia virus-simian sarcoma virus)-initiated human B-lymphoblast cultures.

Fresh human B-lymphoblasts established in culture following exposure of adult peripheral blood leukocytes to type C retroviruses of the simian sarcoma virus/simian sarcoma-associated virus-gibbon ape leukemia virus group were analyzed in detail for the presence of the infecting virus. Viral expression ranged from production of low levels of intact virus in a few cultures to the presence of viral RNA and protein in the absence of detectable of levels of complete virus in the majority of the cultures. In situ molecular hybridization assays using 3H-labeled complementary DNA and indirect immunofluorescence assays using antibody to purified viral protein indicated that the expression of viral RNA and proteins are preferentially expressed in only a fraction of the cells in some cultures. If expression of the infecting viral sequences is necessary for the sustained growth of these cells, then those cells detectably synthesizing viral RNA and proteins may be influencing the growth of the remaining virus-negative cells. The lack of virus production in cultures synthesizing viral RNA and protein indicate that these human B-lymphocytes restrict the life cycle of these viruses at some step(s) after transcription of viral RNA or translation of viral protein.

B-Lymphocytes↗