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Biomedical subjects

G H Wilson

Publications and source records attributed to G H Wilson.

At least 19 recordsLinked to original sources
PubMed2001

Validation of a novel high-sensitivity radioimmunoassay procedure for measurement of total thyroxine concentration in psittacine birds and snakes.

OBJECTIVE: To validate a novel high-sensitivity radioimmunoassay (RIA) procedure developed to accurately measure the relatively low serum total thyroxine (T4) concentrations of birds and reptiles and to establish initial reference ranges forT4 concentration in selected species of psittacine birds and snakes. ANIMALS: 56 healthy nonmolting adult psittacine birds representing 6 species and 42 captive snakes representing 4 species. PROCEDURE: A solid-phase RIA designed to measure free T4 concentrations in dialysates of human serum samples was used without dialysis to evaluate total T4 concentration in treated samples obtained from birds and reptiles. Serum T4 binding components were removed to allow assay of undialyzed samples. Assay validation was assessed by determining recovery of expected amounts of T4 in treated samples that were serially diluted or to which T4 was added. Intra- and interassay coefficient of variation (CV) was determined. RESULTS: Mean recovery of T4 added at 4 concentrations ranged from 84.9 to 115.0% and 95.8 to 119.4% in snakes and birds, respectively. Intra- and interassay CV was 3.8 and 11.3%, respectively. Serum total T4 concentrations for 5 species of birds ranged from 2.02 to 768 nmol/L but ranged from 3.17 to 142 nmol/L for blue-fronted Amazon parrots; concentrations ranged from 0.21 to 6.06 nmol/L for the 4 species of snakes. CONCLUSIONS AND CLINICAL RELEVANCE: This new RIA method provides a commercially available, accurate, and sensitive method for measurement of the relatively low serum T4 concentrations of birds and snakes. Initial ranges for the species evaluated were established.

Animals↗
PubMed1988

MR evaluation of early myelination patterns in normal and developmentally delayed infants.

This study demonstrates the ability of MR imaging to show progression of myelination in 64 infants and young children (ages 4 days to 36 months). T2-weighted spin-echo pulse sequences, frequently used for routine screening of intracranial disease, were used. Gray-white matter differentiation was seen in all patients, and changes occurring with age were documented. Three distinct patterns were seen, and age ranges were established for each pattern in developmentally normal children: (1) infantile (birth-6 months); (2) isointense (8-12 months); and (3) early adult (10 months onward). There was a statistically significant difference between the age ranges of the normal and developmentally delayed children showing all three patterns. These data should be helpful for identifying and following sequentially both infants with clinically suspected developmental delay and those with dysmyelinating or demyelinating disease.

Brain↗
PubMed1987

MR imaging of the nasopharynx and floor of the middle cranial fossa. Part I. Normal anatomy.

The normal anatomy of the nasopharynx and floor of the middle cranial fossa was analyzed with magnetic resonance (MR) imaging. MR images from five healthy volunteers were correlated with whole-organ cryomicrotome sections from three cadavers. Anatomic connections exist between the paranasopharyngeal spaces and the surface structures of the skull base. These anatomic connections include the intimate relationship between the eustachian tube and the pharyngobasilar fascia, the attachment of the muscles of mastication and deglutition to the skull base, and vascular and nervous structures in the foramina. The inherent contrast between the soft tissues of the nasopharynx and related structures and the bone of the floor of the middle cranial fossa allowed excellent visualization of these anatomic connections.

Cadaver↗
PubMed1987

MR imaging of the nasopharynx and floor of the middle cranial fossa. Part II. Malignant tumors.

The intracranial extension of tumors of the nasopharynx and related spaces presents a difficult imaging problem. Unlike computed tomography (CT) scans, magnetic resonance (MR) images are not limited by beam-hardening artifacts from bone or dental amalgam. Forty-six patients with malignant tumors of the nasopharynx and related spaces affecting the skull base underwent MR imaging. MR images were obtained with a 0.3-T permanent-magnet imaging system in axial, sagittal, and coronal planes. MR findings were compared with clinical records, plain radiographs, CT scans, and pathologic correlates when available. MR imaging could demonstrate neoplastic invasion of the bone of the floor of the middle cranial fossa and the vital soft-tissue structures related to it as well as or better than CT. Tumor extension was viewed directly as a continuous mass or indirectly by marrow replacement or displacement of normal structures. Specific anatomic routes through which tumors extend from the nasopharynx to the middle cranial fossa were inferred from MR findings.

Eustachian Tube↗
PubMed1986

Magnetic resonance imaging of the brainstem and cranial nerves.

Ten normal human volunteers and 44 patients with pathology of the brainstem or cranial nerves were scanned using a. 3 Tesla permanent MR imaging system. MR images were obtained of the cranial nerves and brainstem using various spin-echo pulse sequences and scanning planes. 4 mm thick sections with .75 mm pixels on a 256 display matrix were used whenever possible. The normal MR images were correlated with thin section cryodissection specimens of fresh human cadavers. Brainstem structures including major nuclei and tracts were then identified. The cranial nerves were followed through the subarachnoid cisterns and the base of the skull. Pathological involvement of the brainstem by tumors, infarcts, and demyelinating disease was well shown and correlated with clinical findings. Examples of optic glioma, fifth, eighth, and twelfth nerve schwannomas as well as other cranial nerve pathology were also demonstrated. Magnetic resonance produces excellent images of cranial nerves and brainstem with high contrast resolution. Unlike CT, there is no beam hardening artifact from bone. T1 weighted images maximize brainstem-CSF contrast and are useful for demonstrating the external anatomy of the brainstem and cranial nerves. The T2 weighted images show internal brainstem anatomy, CSF within neural foramina, and highlight many pathological conditions.

Adult↗
PubMed1986

Head and neck MR imaging in the pediatric patient.

Magnetic resonance (MR) imaging studies of the head and neck (excluding the brain) were obtained in 49 children believed to have lesions of the head and neck. Seven children had normal images; in the remaining 42, lesions were divided into four categories: midline lesions, lesions of symmetric paired structures, facial lesions, and nasopharyngeal and oropharyngeal lesions. All entities were well delineated by MR imaging. The imaging planes and sequences chosen depended on the suspected abnormality. Midline lesions were best imaged in the sagittal plane, lesions of paired structures and the face in the axial or coronal planes, and nasopharyngeal and oropharyngeal lesions in the axial or sagittal planes. Intracranial extension of head and neck neoplasms was best evaluated in the coronal plane. Surface coils provided better resolution and were thus more useful in evaluating small superficial lesions; head or body coils were more useful in defining the extent of large lesions. T2-weighted images provided better differentiation between normal and tumor tissue in patients with head and neck neoplasms.

Adolescent↗
PubMed1986

MR imaging of the lumbar spine: anatomic correlations and the effects of technical variations.

A correlative anatomic study, a retrospective review of MR images performed in 35 patients, and a series of tests of the effectiveness of various MR scanning techniques were performed in order to improve comprehension of lumbar spine anatomy depicted on MR images, and thereby facilitate development of an optimal scanning protocol. Correlation of MR images with cryomicrotomed cadaver specimens enhanced understanding of the MR depiction of the intervertebral disks, ligamentum flavum, nerve roots, epidural fat, and epidural veins. Experiments were performed to assess the efficacy of a surface coil applied to the back, a solenoidal surface coil, a standard body coil, and an abdominal compression device in optimizing image quality. Experiments were also performed to determine the effect of alterations in the pulse sequence and variations of the phase-encoding axis. Based on these results, a protocol is proposed for routine imaging of the lumbar spine that yields high-resolution sagittal and oblique images and that does not require a surface coil. The recommended protocol employs heavily T1-weighted images with phase encoding along the z axis for sagittal images and along the x axis for axial images. This protocol yields multiple sagittal and oblique axial images through each of the lumbar disks, a larger field of view than obtained with surface coils, and a reduction of total imaging time to as little as 10 min.

Cadaver↗
PubMed1980

Cerebral CT findings in drug abuse: clinical and experimental observations.

Computed tomographic changes compatible with cerebral atrophy have been observed clinically and in experimental drug abuse animals. Most of the patients were thought to be polydrug users, but amphetamines and alcohol were two of the more commonly misused drugs. In the experimental animals, the effects of amphetamine, secobarbital, and marijuana were studied. Brain damage was present in the animals that received intravenous amphetamine.

Administration, Oral↗
PubMed1978

Giant intracranial aneurysms simulating brain neoplasms on computed tomography.

Giant intracranial aneurysms (GIA) may simulate brain neoplasms on computed tomography (CT) scans. We present three cases in which a GIA was mistakenly diagnosed as a brain neoplasm on the basis of CT findings. The correct diagnosis was made in each case by cerebral angiography. The possibility of GIA must be considered when a nonenhanced CT study shows a well circumscribed mass without edema at the base of the brain and contrast infusion reveals homogeneous or inhomogeneous enhancement.

Adult↗
PubMed1977

Computed tomography in intracranial cysticercosis.

The computed tomography (CT) scans and other radiographic studies of 23 patients with cerebral cysticercosis were reviewed. Parenchymal calcifications, the most common finding, are somewhat better seen on CT scans than on skull films. Ventricular cysts may be suspected by disproportionate enlargement of the involved ventricle. Cysts in subarachnoid cisterns are best detected by performing both CT and pneumoencephalography. Contrast enhancement was not seen with cisternal or ventricular cysts but may be with parenchymal cysticercus lesions.

Adult↗
PubMed1976

Contrast enhancement by arterial perfusion during computerized tomography.

Contrast enhancement of computerized tomography is usually performed by means of intravenous injection of iodinated contrast materials. The authors have utilized a technique of direct arterial infusion of iodinated contrast material supplying intracranial arteries during computerized axial tomography. A representative case is presented with comparison scans which were obtained without contrast enhancement and with conventional intravenous infusion of contrast. Marked improvement of the enhancement was clearly demonstrated in this case, with abnormalities readily defined that were not seen with the conventional intravenous enhancement procedure.

Cerebellopontine Angle↗
PubMed1976

Catheter technique for encephalography.

A catheter technique for encephalography utilizing a polyethylene catheter is described. The advantages are principally that it reduces the possibility of needle displacement during examination and thus the danger of extra-arachnoid injection of air.

Catheterization↗
PubMed1976

Accuracy of scanning, angiography and encephalography in posterior fossa tumors.

A material of 120 cases with posterior fossa tumors examined with scanning, vertebral angiography and encephalography was reviewed to determine the value of the information and accuracy these methods provide. Encephalography was the most accurate procedure (98% positive) compared to angiography (81%) and scanning (44%).

Brain Neoplasms↗
PubMed1975

Neuroradiology of the sphenoidal region.

The neuroradiological techniques employed in diagnosing a series of 54 lesions involving the superior orbital fissure and cavernous sinus (sphenoidal region) were reviewed in order to compare the value of sphenoidal tomography, pneumoencephalography, cerebral arteriography and sphenoidal venography. The patients included in the series exhibited clinical syndromes of sphenoidal region cranial nerve deficits. Confirmation of the sphenoidal region disorder was obtained in all cases. Of the four procedures, sphenoidal venography and basal tomography yielded the highest rate of positive studies.

Aged↗
PubMed1974

Partial pneumoencephalography in following-up pituitary tumours.

The `limited' pneumoencephalogram has been used with excellent success at UCLA for the continuing follow-up of pituitary tumours. It is most useful in following nonsecretory adenomas since tumour regrowth can occur in the absence of clinical signs and symptoms. Total serial pneumoencephalography has not been accepted previously for follow-up of pituitary tumours since there is a significant morbidity. The `limited' pneumoencephalogram of the diseased area drastically reduces the morbidity of the procedure so that the patients are willing to undergo serial studies on an outpatient basis.

Adenoma, Chromophobe↗