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Biomedical subjects

B Kaufman

Publications and source records attributed to B Kaufman.

At least 91 records · Page 5Linked to original sources
PubMed1987

Ligatin: a peripheral membrane protein with covalently bound palmitic acid.

The ligatin monomer is a polypeptide of Mr = 10,000 which is soluble in acidified chloroform:methanol, a characteristic similar to that of Folch-Lee proteolipid. The hydrophobicity of ligatin is also reflected by its ability to interpolate into the phosphatidylcholine bilayer as shown by a concentration-dependent change in membrane conductance. However, unlike other proteolipids the amino acid composition of ligatin is not enriched in hydrophobic amino acids (isoleucine, leucine, valine, methionine, phenylalanine, tryptophan). Instead, the hydrophobic character of ligatin could be explained, at least in part, by the covalent association of fatty acids, 1.4-1.7 mol of palmitate/10,000 g of protein, as revealed by gas chromatography mass spectrographic analyses. The post-translational addition of fatty acid may therefore be the means by which ligatin acquires an affinity for membranes.

Acylation↗
PubMed1987

Adult metachromatic leukodystrophy. Value of computed tomographic scanning and magnetic resonance imaging of the brain.

Patients with adult-onset metachromatic leukodystrophy (MLD) often present with personality changes or deterioration of cognitive functions. Although rare, this form of MLD should be included in the differential diagnosis of psychotic and dementing disorders. The following case report describes a 38-year-old man with adult-onset MLD, who carried the diagnosis of schizophrenia and was treated as a schizophrenic for a number of years. Metachromatic leukodystrophy was initially suspected because of white matter abnormalities detected on computed tomographic scans and magnetic resonance images of the brain. The diagnosis of MLD was confirmed by the discovery of markedly reduced leukocyte arylsulfatase A activity. The computed tomographic and magnetic resonance imaging findings in MLD are reviewed.

Adult↗
PubMed1987

Biochemical properties of tracheobronchial mucins from cystic fibrosis and non-cystic fibrosis individuals.

Tracheobronchial mucins from healthy individuals and from patients with bronchial asthma or cystic fibrosis (CF) were isolated from lung mucus, purified, and their chemical and physical properties compared. Normal and asthmatic mucins required both a dissociating and a reducing agent for solubilization and exhibited identical chromatographic behavior on Sepharose 4B, Sepharose 2B, and hydroxylapatite and similar amino acid and carbohydrate compositions. In contrast, 1) CF lung mucins were solubilized in the absence of dissociating and/or reducing agents and 2) the majority of the CF mucins analyzed was eluted in the included volume of Sepharose 4B with Kd values of 0.3 +/- 0.1 rather than in the void volume and thus appeared smaller than normal and asthmatic mucins. The lower molecular weight mucins in CF sputum apparently are produced by bacterial or inflammatory cell proteinases since radiolabelled asthmatic mucin was digested to smaller fragments when incubated with crude CF lung mucosal samples. Furthermore, mucins secreted by tracheal explants from CF and from non-CF individuals eluted in the void volume on Sepharose 4B, suggesting that CF tracheobronchial mucins were not inherently smaller than non-CF mucins.

Adolescent↗
PubMed1987

Large pituitary gland adenomas evaluated with magnetic resonance imaging.

Magnetic resonance imaging (MRI), computed tomographic (CT) scanning, and angiography or digital subtraction angiography (DSA) were used preoperatively to evaluate 16 surgically proven cases of sellar tumor with extrasellar extension. There were 15 pituitary tumors and 1 schwannoma. The capabilities of MRI in evaluating these tumors were compared with CT scanning and angiography. Bone destruction and tumor calcification were better detected by CT scanning than by MRI. MRI was as effective as CT scanning in detecting a cyst or variation in tumor consistency. Neither MRI nor CT scanning was capable of distinguishing specific tumor types. In every case, MRI was superior to CT scanning for delineating spatial relationships of the tumor to the 3rd ventricle, the optic apparatus, adjacent brain, and parasellar vasculature. Vessel encasement by tumor was clearly seen on MRI when there was no direct indication of this on other studies. Cavernous sinus invasion was not demonstrated by CT scanning, but was indicated by MRI in 5 cases and was surgically confirmed in 3. MRI can provide more precise spatial information on extrasellar tumor extension. Vascular encasement and cavernous sinus invasion may be determined preoperatively. Treatment expectations and operative approaches can be guided by this information. When MRI is available, it is the test of choice for the preoperative evaluation of patients with suspected large pituitary gland (sellar region) tumors. Contrast-enhanced CT scanning and angiography can be used as supplementary studies to add information inherently unique to these techniques.

Adenoma↗
PubMed1987

MR imaging of lumbar arachnoiditis.

To assess the usefulness of MR in defining the changes of lumbar arachnoiditis, we reviewed retrospectively the MR, plain-film myelographic, and CT myelographic findings in 100 patients referred for evaluation of failed-back-surgery syndrome. In 11 of 12 cases of arachnoiditis demonstrated by plain-film and CT myelography, an abnormal configuration of nerve roots was seen by MR. The correlated MR and CT and plain-film myelographic changes were divided into three anatomic groups: group 1 showed conglomerations of adherent roots residing centrally within the thecal sac, group 2 demonstrated roots adherent peripherally to the meninges giving rise to an "empty-sac" appearance, and group 3 demonstrated a soft-tissue mass replacing the subarachnoid space. There was one false-negative MR study. For the diagnosis of moderate to severe arachnoiditis, we found MR to correlate excellently with CT myelographic and plain-film myelographic findings.

Arachnoiditis↗
PubMed1987

Advances in neuroradiologic imaging of the pituitary gland: changing concepts.

A review of pituitary imaging is presented based on the history of neuroradiologic definition of the sellar contents as well as modern diagnostic techniques. The importance of normal pituitary and seller anatomy is stressed in an attempt to determine the limitations of defining abnormal sellar contents with the imaging techniques of computed tomography and magnetic resonance imaging. The sensitivity and specificity of these techniques are illustrated with histopathologic correlation.

Cerebrospinal Fluid↗
PubMed1985

Immunoenzymatic analysis by monoclonal antibodies of bacterial lipopolysaccharides after transfer to nitrocellulose.

A rapid, sensitive immunoenzymatic technique for the analysis of lipopolysaccharide (LPS) from gram-negative bacteria using monoclonal antibodies is described. After separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the LPS was either stained with silver or electrophoretically transferred to nitrocellulose. After reaction with anti-LPS monoclonal antibodies, the transferred antigens were visualized by reaction with alkaline-phosphatase-labelled anti-mouse antibodies and a substrate containing naphthol phosphoric acid and Fast Red.

Antibodies, Bacterial↗
PubMed1985

Motor neuron disease and adult hexosaminidase A deficiency in two families: evidence for multisystem degeneration.

We studied three patients from two unrelated families with adult hexosaminidase A deficiency. A 30-year-old, non-Jewish proband in the first family had juvenile amyotrophic lateral sclerosis that evolved to mild dementia, ataxia, and axonal (neuronal) motor-sensory peripheral neuropathy. A 36-year-old Jewish proband in the second family had "pure" spinal muscular atrophy. One supposedly healthy brother of the first proband was found to have borderline IQ, mild spasticity, and ataxia but no evidence of motor neuron disease. Marked cerebellar atrophy was detected by head scans in all three patients. In both probands electromyograms were characterized by prominent, complex repetitive discharges in many muscles. Hexosaminidase A activities against the artificial substrate were similar to those reported in infantile Tay-Sachs disease; however, the hexosaminidase A level against GM2 substrates was higher than that found in infantile Tay-Sachs disease. The hexosaminidase A levels of the parents were in the heterozygous range. Motor neuron disease in our patients and in those previously described appears to be part of a multisystem degeneration of the nervous system.

Adult↗
PubMed1985

Defective revisualization: dissociation between cognitive and imagistic thought case report and short review of the literature.

A 38-year-old shifted-sinistral patient displayed a definite deficit in visual imagery accompanied by defective dreaming capacity, loss of hypnagogic imagery, some defects in topographical memory, a mild unilateral right spatial neglect and mild difficulties in right-left orientation on the examiner's body. CT-scan and NMR studies showed evidence of an inborn hypoplasia of the right hemisphere and a stretched corpus callosum in its posterior and superior part. The vicarious compensatory action of the cognitive-verbal function of the defect of visual imagery was obvious. It is concluded that: there are various forms of visual imagery deficits: some are "pure" whereas in the great majority of reported cases the loss of visual imagery is associated to different forms of visual agnosia; the brain mechanisms underlying cognitive thought and imagistic thought could be obviously dissociated.

Adult↗
PubMed1985

Cerebral venous angiomas imaged by MR.

The diagnostic efficacy of magnetic resonance (MR) in the evaluation of cerebral venous angioma was studied. The results of MR and computed tomography (CT) were compared in six cerebral venous angiomas in five patients. MR alone was diagnostically successful in only three of six cases. Venous angiomas appeared as tubular structures of extremely low signal intensity on MR images. Although CT was highly sensitive (100%) in detecting lesions, CT was diagnostically specific in only four of the six cases. Angiography was the only modality able to unquestionably detect all six lesions. By varying the MR pulse sequence, we greatly affected the ability of MR to demonstrate lesions. In the cases where MR helped define the abnormality, T2-weighted MR images were able to clearly demonstrate lesions in five of the six cases whereas T1-weighted images helped detect an abnormality in only two cases. Although MR shows great promise in the evaluation of central nervous system abnormalities, CT remains the best imaging modality for detecting venous angiomas. When CT is not conclusive, angiography can be performed for a definitive diagnosis.

Adolescent↗
PubMed1985

MR imaging in patients with metallic implants.

A total of 305 magnetic resonance (MR) examinations were performed in 236 patients with metallic implants. Most examinations were performed at 0.3 T. The metallic implants included central nervous system shunting devices, tantalum mesh, surgical wire, skin staples, surgical clips, metallic orthopedic devices, and a few miscellaneous metallic objects. Patients with cardiac pacemakers, electrical implants, prosthetic cardiac valves, and aneurysm clips were excluded from MR examinations. The images were reviewed for evidence of metallic artifact. The conspicuity of artifact was related to the composition, mass, orientation, and position of the metallic object in the body. In most instances, the metallic artifact did not interfere with the interpretation of the image. The patients' records were also reviewed for adverse effects noted by each patient during the MR examination. Only two patients reported discomfort that could possibly have been related to their metallic implants, but in both cases it seemed unlikely that the symptoms were actually related to the imaging process. There were no apparent short-term adverse effects demonstrated in these patients.

Cerebrospinal Fluid Shunts↗
PubMed1985

Magnetic resonance imaging: comparative study of radiofrequency pulse techniques in the evaluation of focal cerebral ischemia.

The recently developed technique of magnetic resonance (MR) imaging utilizes radiofrequency (RF) radiation in the presence of a strong magnetic field to provide cross sectional displays of body anatomy similar to computed tomography. When utilizing MR, the operator alters tissue contrast electronically by changing RF pulse sequences. The three most frequently used RF pulse sequences are partial-saturation (PS), inversion-recovery (IR), and spin-echo (SE). We evaluated the sensitivity of these RF sequences to detect ischemic changes in our primate model. Serial MR scans were carried out using all three pulse formats 5 to 60 hours after middle cerebral artery occlusion (MCAO) in four animals. SE- and IR-sequenced proton MR images readily identified areas of evolving infarct 5 to 60 hours after MCAO, whereas PS scans that were performed during this acute period appeared normal. From 24 to 60 hours after MCAO, PS-sequenced scans showed focal areas of progressively decreasing signal intensity. However, SE and IR scans performed at the same intervals always demonstrated more extensive tissue changes. The basis of MR imaging, the effects of altering RF pulse sequences, and the resulting interpretation of changes observed in MR sections are presented.

Animals↗
PubMed1985

Clinical role of magnetic resonance imaging in the neurosurgical patient.

The results of magnetic resonance (MR) evaluation in 18 patients with common neurosurgical problems, including cerebrovascular lesions, intracranial tumors, and craniovertebral junction pathological conditions, are presented. The results are compared with those of routine diagnostic studies. Overall, MR imaging was equivalent or superior to computed tomography in 16 of 18 cases. In 2 cases, MR demonstrated pathological changes when standard diagnostic imaging procedures failed to demonstrate the lesion responsible for the patient's deterioration. MR is a versatile, noninvasive imaging technique that is capable of demonstrating a wide range of disease processes, without exposure to ionizing radiation or contrast agents.

Adult↗
PubMed1984

Structural features of human tracheobronchial mucus glycoprotein.

Electron microscopy of platinum-shadowed preparations of human tracheobronchial mucins showed very flexible filamentous structures that frequently occurred in an intricate random-coiled pattern of filament(s) surrounding a dense core-like domain. The filament(s) associated with cores accounted for 70-80% of the mass of the mucin preparation, the remainder being accounted for by free filaments. On aggregation, the molecules formed a large interwoven network quite different from the massive rope-like structures characteristic of sheep submaxillary mucin aggregates [Rose, Voter, Sage, Brown & Kaufman (1984) J. Biol. Chem. 259, 3167-3172]. Mild sonication resulted in extensive fragmentation of the tracheobronchial mucin molecules and yielded short filaments of various lengths, free cores and some cores associated with short filaments. Mucin glycopeptide fragments obtained by proteolytic digestion were flexible, core-free, filaments. The glycopeptides obtained by Pronase digestion were shorter than those obtained by tryptic digestion. The intricate structures of human tracheobronchial mucin differ markedly from the extended filaments reported for sheep submaxillary and human ovarian-cyst mucins but agree with the roughly spherical expanded model proposed for mucins by Creeth & Knight [(1967) Biochem. J. 105, 1135-1145] on the basis of hydrodynamic measurements.

Bronchi↗