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Biomedical subjects

B Katz

Publications and source records attributed to B Katz.

At least 127 records · Page 7Linked to original sources
PubMed1988

Prostaglandin concentrations in cerebrospinal fluid of rabbits under normal and ischemic conditions.

Clinical studies have demonstrated elevated levels of both arachidonic acid and prostaglandins in the cerebrospinal fluid of humans after ischemic stroke and subarachnoid hemorrhage. Such increases in free fatty acid, arachidonic acid, and prostaglandin concentrations suggest excessive production and accumulation of these substances in the ischemic brain. We used a rabbit model of ischemic infarction to examine the relation between controlled central nervous system ischemia and cerebrospinal fluid prostaglandin levels. We found that following stroke PGF2 alpha and not PGD2 was the predominant prostaglandin present in the cerebrospinal fluid. PGF2 alpha also underwent the largest percent increase over control prostaglandin concentrations. This is similar to human and dog cerebrospinal fluid studies, which demonstrate PGF2 alpha as the predominant prostaglandin following ischemic injury. The lack of PGD2 elevation under ischemic conditions may suggest that the rabbit model is more like stroke in humans than the rat or gerbil models. Our preliminary work demonstrates that it is practical to study postischemic prostaglandin changes in cerebrospinal fluid rather than in brain tissue in a rabbit model of central nervous system ischemia.

Animals↗
PubMed1988

Legal implications and considerations in dental practice management.

This article deals with the legal aspects and ramifications of several common situations that arise in dental practices. The authors deal specifically with the areas of contracts and guarantees; unilateral termination of treatment while avoiding charges of abandonment; treatment of minors and the necessity for informed consent; fraud and misrepresentation; and employer-employee considerations. These areas are briefly analyzed with suggestions for prevention of problems.

Age Factors↗
PubMed1987

Spatial and temporal sequence of corneal crystal deposition in nephropathic cystinosis.

We studied 15 patients with infantile nephropathic cystinosis. We found that anterior corneal cystine crystal deposition began early in life and proceeded posteriorly as the patient aged; deposition advanced more rapidly in the periphery. Ultrastructural analysis of a corneal button obtained from a 20-year-old patient undergoing corneal transplantation confirmed our clinical observations that crystals were deposited throughout the entire central stroma.

Adolescent↗
PubMed1987

Corneal sensitivity in nephropathic cystinosis.

We measured corneal sensitivity in 14 patients with infantile nephropathic cystinosis and in 13 age-matched controls. All patients with cystinosis had the pathognomonic anterior segment findings of crystal deposition within conjunctiva and cornea. Transcutaneous stimulation of the supraorbital nerve and surface electromyographic recording of the orbicularis oculi muscle performed on four patients showed a normal afferent limb to the blink reflex. The corneal sensitivity in patients with cystinosis was 3.18 g/mm2; in the control subjects it was 0.43 g/mm2. This difference was statistically significant (P less than .001).

Adolescent↗
PubMed1987

Contrast sensitivity function in nephropathic cystinosis.

Cystinosis is a rare autosomal recessive metabolic disorder in which nonprotein cystine accumulates within most body organs due to a defect in lysosomal cystine transport. The pathognomonic ocular manifestations of cystinosis are the presence of distinctive iridescent crystals within ocular tissue and a pigmentary retinopathy. We measured spatial contrast sensitivity in seven patients with infantile-onset nephropathic cystinosis and compared their contrast sensitivity function with that measured in ten age-matched controls. Spatial contrast sensitivities in the patient group were significantly lower than those in the normal group. Loss of contrast sensitivity in the patients with nephropathic cystinosis was more pronounced at higher spatial frequencies. We speculate that this loss of contrast function is primarily a manifestation of corneal disease, with secondary contributions from retinal changes and central nervous system dysfunction.

Adolescent↗
PubMed1987

Glare disability in nephropathic cystinosis.

Cystinosis is a rare metabolic disorder in which nonprotein cystine accumulates within lysosomes due to a defect in lysosomal cystine transport. Although cystine accumulates within most ocular tissues, patients with cystinosis generally complain only of photophobia and glare. We measured glare sensitivity in 12 patients with infantile cystinosis and compared their results with an age-matched control population. Ten of the 12 patients with cystinosis had demonstrable glare disability when compared with the control group. Glare disability scores in the patients with cystinosis ranged from 5% to 50%. Dazzle glare resulting from the accumulation of cystine crystals in ocular tissue may account for glare disability seen in these patients and contribute to their complaints of photophobia.

Adolescent↗
PubMed1987

Optic nerve hypoplasia and the syndrome of nevus sebaceous of Jadassohn. A new association.

The nevus sebaceous of Jadassohn (NSJ) syndrome is a not uncommon pediatric dermatosis, with malignant potential. It is the cutaneous manifestation of another phakomatosis, characterized by neurologic, ophthalmic, cardiovascular, skeletal, and urogenital involvement. The features of this syndrome overlap those of the oculo-auriculo-vertebral dysplasia of Goldenhar and tuberous sclerosis. The extent of system involvement suggests a developmental insult during the first few weeks of gestation. A clearly genetic basis has not been established. An infant with NSJ syndrome is described who had associated optic nerve hypoplasia. His clinical, pathologic, and radiologic findings, including computed tomography (CT) and magnetic resonance imaging, are presented.

Humans↗
PubMed1987

Catecholaminergic horizontal and amacrine cells in the ferret retina.

Enzymes involved in the synthesis of catecholamines were detected in amacrine and what appeared to be a specific class of horizontal cells in the ferret retina. Antisera directed against the enzymes tyrosine hydroxylase (TH), which converts tyrosine to DOPA, and phenylethanolamine N-methyl-transferase (PNMT), which converts norepinephrine to epinephrine, were used with conventional immunohistochemical techniques. A population of perikarya located at the outer margin of the inner nuclear layer (INL) exhibited TH-like immunoreactivity. The cell bodies were 9-12 micron in diameter and gave rise to stout dendrites that tapered rapidly after emergence from the somata. The processes formed a planar array in the inner half of the outer plexiform layer (OPL) slightly external to the cells of origin. We could not detect any inwardly directed processes. A population of PNMT-positive cells was also observed in the outer tier of cells in the INL. These cells were very similar to those exhibiting TH immunoreactivity. An apparent difference between the 2 populations was that there were areas of intense, somewhat punctate PNMT immunoreactivity in the outer OPL. These were not observed in the TH-stained sections. Examination of horizontal sections showed that each TH-positive cell body gave rise to 4-5 major dendrites that branched to form a roughly circular dendritic field. In the periphery of the retina, an individual cell's dendrites encompassed an area up to 170 micron in diameter. The dendritic fields of cells near the center of the retina were substantially smaller.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Improvement of photostress recovery testing after extracranial-intracranial bypass surgery.

A patient with carotid occlusive disease experienced episodes of light-induced amaurosis in an eye with changes of venous stasis retinopathy. Though his macula appeared normal on examination, the macular photostress test (MPST) was prolonged. After anastomosis of a superficial temporal artery with the middle cerebral artery his symptoms resolved and his MPST returned to normal. The MPST may serve as a diagnostic stress test for the retinal circulation in cases of carotid disease.

Arterial Occlusive Diseases↗
PubMed1986

Migrainous central retinal artery occlusion.

A 29-year-old man experienced a migrainous central retinal artery occlusion coincident with the initiation of propranolol therapy. The pharmacological effects of beta-blockade are discussed, and the use of beta-blockade in the acute management of anterior visual pathway migraine is examined.

Adult↗
PubMed1986

Exophthalmos induced by exogenous steroids.

Two cases of bilateral exophthalmos secondary to chronic steroid therapy are presented. Exophthalmos has been reported in Cushing's disease, in which endogenous steroid production is elevated. Exophthalmos associated with chronic exogenous steroid administration is an unusual although benign form of ocular proptosis.

Aged↗