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Biomedical subjects

J Katz

Publications and source records attributed to J Katz.

At least 397 records · Page 22Linked to original sources
PubMed1991

Purification and properties of an esterase from human breast cyst fluid.

Levels of estradiol 17 beta-ester hydrolytic activity in the breast cyst fluid (BCF) from 25 different women with fibrocystic disease of the breast were found to vary over a wide range (0-2.4 nmol/min/mg protein for estradiol acetate). On the basis of electrophoretic mobility on agarose gels, the activity from different individuals appeared to be identical. The esterase activity from a single BCF sample was purified to near homogeneity by differential ammonium sulfate precipitation, ion-exchange, and hydrophobic interaction chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, after the final purification step, showed two bands with molecular weights of approximately 22,000 and 23,000, neither of which was immunoreactive with a rabbit antibody raised to a crude esterase-free BCF preparation. Esterase activity could be demonstrated after extraction and renaturation of the protein eluted from the Mr 22,000 band. Resolution of the gel, however, was not good enough to rule out the presence of esterase activity in the Mr 23,000 protein. High performance liquid chromatography gel exclusion chromatography indicated a molecular weight of 90,000-95,000 for the esterase activity in crude BCF and approximately 225,000 for the purified activity, suggesting the native protein to be a tetramer which aggregated during purification. Although the natural substrate of the BCF esterase is unknown, the enzyme is able to cleave a variety of esters including acetate, valerate, and stearate esters of estradiol and p-nitrophenyl hexanoate. It is completely inhibited by diisopropylflurophosphate and diethylnitrophenyl phosphate and partially inhibited by NaF and ebelactone. The substrate and inhibitor profile of the enzyme indicates that it is a "B"-type carboxylesterase and not a protease. A comparison of the properties of the BCF esterase with those of esterases from the formed elements of the blood or from plasma suggests that the BCF esterase is not of blood origin and is probably derived from the cyst itself. Physiologically inactive lipoidal estrogens have been shown to be present in many human body fluids and tissues and it is possible that these esters serve as storage forms of the active hormone in hormonally sensitive tissues where the free steroid could be regenerated by hydrolysis.

Anti-Bacterial Agents↗
PubMed1991

Clinically detectable nerve fiber atrophy precedes the onset of glaucomatous field loss.

Standardized perimetry and nerve fiber layer and color fundus photography were performed annually on 1344 eyes with elevated intraocular pressures. In 83 eyes, glaucomatous field defects developed that met rigid criteria on manual kinetic and suprathreshold static perimetry. Individual nerve fiber layer photographs were read by two masked observers. The more sensitive of the two identified nerve fiber layer defects in 88% of readable photographs at the time field loss first occurred; 60% (6/10) of eyes already had nerve fiber layer defects 6 years before field loss. In contrast, the nerve fiber layer was considered abnormal in only 11% (3/27) of normal eyes and 26% (84/327) of hypertensive eyes. The location of nerve fiber layer and field defects closely corresponded, but nerve fiber layer loss was generally more widespread. Examiner experience and severity of optic nerve damage influenced results. Mild focal defects were more readily recognized than more severe diffuse atrophy. Nerve fiber layer defects expanded with time, often by the development and coalescence of adjacent areas of damage.

Adult↗
PubMed1991

Socioeconomic status and visual impairment among urban Americans. Baltimore Eye Survey Research Group.

The Baltimore Eye Survey is a population-based study of ocular disorders conducted in East Baltimore, Md, designed to determine the prevalence and severity of vision loss and ocular disease and their relationships to socioeconomic and other risk factors. This survey comprised 5300 subjects (2911 whites and 2389 blacks). Visual impairment was associated with age, race, general health status, educational level, income, and employment status. An identified association of race with blindness and visual impairment was reduced, but not eliminated, after adjustment for these socioeconomic factors, indicating that socioeconomic status itself is an important determinant of visual impairment.

Adult↗
PubMed1991

Relationship between intraocular pressure and primary open angle glaucoma among white and black Americans. The Baltimore Eye Survey.

A detailed ocular examination, including perimetry, was conducted on 5308 black and white subjects aged 40 years and older in a population-based prevalence survey in east Baltimore, Md. Repeated, detailed examinations were carried out on selected subjects. Roughly half of all subjects with optic nerve damage from primary open angle glaucoma, regardless of race, were unaware that they had the condition. The average intraocular pressure (IOP) among black patients with glaucoma who were receiving treatment was virtually identical to that in those black patients who were not receiving treatment (median IOP, 20 mm Hg); treated eyes of white patients had a lower IOP than those eyes of white patients who were not receiving treatment (mean [+/- SD] IOP, 18.69 +/- 3.23 mm Hg vs 24.15 +/- 5.23 mm Hg; P less than .001). The risk of glaucomatous optic nerve damage increased with the height of the screening IOP, particularly at levels of 22 to 29 and 30 mm Hg and above (relative rate compared with IOP of 15 mm Hg or lower, 12.8 and 40.1 mm Hg, respectively). More than half of all glaucomatous eyes had a screening IOP below 21 mm Hg, whether these eyes were receiving treatment or not. The IOP in glaucomatous eyes tended to rise on follow-up, in contrast with nonglaucomatous eyes in which the IOP was as likely to rise as to fall. Results confirmed that IOP is an important factor in glaucoma, but did not support the traditional distinction between "normal" and "elevated" pressure, nor its corollaries, "low-tension" glaucoma and "high-tension" glaucoma.

Black People↗
PubMed1991

Comparison of analytic algorithms for detecting glaucomatous visual field loss.

The sensitivity and specificity of alternate analytic strategies for recognizing glaucomatous visual field loss from automated threshold perimetry (C-30-2 test of the Humphrey Field Analyzer) were compared among one eye each of 106 patients with glaucoma and 249 normal subjects. Algorithms included commercially available global indexes and cross-meridional differences (Statpac 1 and Statpac 2), as well as cross-meridional and cluster analyses that were developed independently for natural history studies and clinical trials. The sensitivity of most algorithms was high, except for those that used only diffuse loss as an indicator of abnormality. Specificity was acceptably high for all algorithms. Subjects who failed to meet the manufacturer's standard for reliability had much reduced specificity, but sensitivity was also affected. Algorithms that were based on any of the alternate definitions of localized reduction in retinal sensitivity performed equally well, which suggests that any of these approaches is useful in searching for glaucomatous visual loss as typified by this database. Availability, familiarity, and convenience may govern the selection of any one analytic approach for use in a particular setting.

Algorithms↗
PubMed1991

A case of Sjögren's syndrome with repeatedly negative findings on lip biopsy.

We report a case of Sjögren's syndrome characterized by keratoconjunctivitis sicca, parotid swelling, reduced salivary flow, and abnormalities on nuclear scanning. Two labial gland biopsies showed complete atrophy. Biopsy of an enlarged submandibular gland revealed lymphoid follicles and glandular replacement consistent with the diagnosis of Sjögren's syndrome. This case supports the concept that a negative finding on labial biopsy does not rule out a diagnosis of Sjögren's syndrome.

Aged↗
PubMed1991

Effect of immune bovine milk on Streptococcus mutans in human dental plaque.

The use of a mouthrinse of bovine milk containing antibodies to Streptococcus mutans resulted in an initial reduction in the numbers of recoverable Strep. mutans in a group of 9 individuals. Ten volunteers who used control bovine milk that contained no antibody activity to Strep. mutans had variable levels of plaque Strep. mutans. In addition, after culture on Mitis Salivarius and Gold's agar, the plaque Strep. mutans from subjects who used the immune bovine milk rinse formed smaller colonies than those from pre-treatment plaque and from all plaque samples of subjects who used the control rinse.

Adult↗
PubMed1991

Compliance in acute and chronic patients receiving a health belief model intervention in the emergency department.

We compared compliance behavior in acute (n = 670) and chronic (n = 172) patients visiting the Emergency Department (E.D.) of an acute care, private hospital; compliance was operationalized as scheduling or keeping a follow-up referral appointment originating in the Emergency Department. The purposes of the study were to assess demographic and illness experience differences among patients and to assess the relative impact of a Health Belief Model Intervention on compliance in acute versus chronic patients. Within the acute and chronic categories patients were randomized into four experimental groups to test the efficacy of the HBM intervention. Although chronic patients were generally more compliant than acute patients, the HBM interventions were equally effective in increasing compliance in both groups. Chronic patients were older, more likely to have had previous treatment for an illness, and more likely to regard the potential consequences of their illness as serious; these factors were associated with greater compliance.

Acute Disease↗
PubMed1991

Auricular transcutaneous electrical nerve stimulation (TENS) reduces phantom limb pain.

The present paper evaluates the efficacy of low frequency, high intensity auricular transcutaneous electrical nerve stimulation (TENS) for the relief of phantom limb pain. Auricular TENS was compared with a no-stimulation placebo condition using a controlled crossover design in a group of amputees with (1) phantom limb pain (Group PLP), (2) nonpainful phantom limb sensations (Group PLS), and (3) no phantom limb at all (Group No PL). Small, but significant, reductions in the intensity of nonpainful phantom limb sensations were found for Group PLS during the TENS but not the placebo condition. In addition, 10 min after receiving auricular TENS, Group PLP demonstrated a modest, yet statistically significant decrease in pain as measured by the McGill Pain Questionnaire. Ratings of mood, sleepiness, and anxiety remained virtually unchanged across test occasions and sessions, indicating that the decrease in pain was not mediated by emotional factors. Further placebo-controlled trials of auricular TENS in patients with phantom limb pain are recommended in order to evaluate the importance of electrical stimulation parameters such as pulse width and rate, and to establish the duration of pain relief.

Adult↗
PubMed1991

Estradiol esters can replace 17 beta-estradiol in the stimulation of DNA and esterase synthesis by MCF-7 cells: a possible role for the estrogen-sensitive MCF-7 cell esterase.

In this communication we extend our earlier observations on estrogen-sensitive carboxyl esterases in MCF-7 human breast cancer cells able to hydrolyze esters of estradiol. Using either estradiol acetate or p-nitrophenyl hexanoate as substrates, esterase activity was found to increase 2-3-fold in MCF-7 cells maintained in the presence of 10(-8) M estradiol. Following sucrose density centrifugation, over 85% of total esterase activity was found in the cytoplasmic fraction. No esterase activity was found in spent media from growing cells. By size exclusion chromatography, estradiol acetate esterase activity exhibited a mol. wt of 45-50 kDa. Attempts to demonstrate incorporation of [3H]estradiol into estradiol fatty acid esters by the above MCF-7 cell line (203P) were unsuccessful, although, such incorporation could be demonstrated in two other MCF-7 cell sublines. Incubation of the 203P cells with 10 nM [3H]estradiol in the presence of 0.5 mM radioinert estradiol acetate resulted in the incorporation of 35 +/- 12% of the label into the estradiol acetate in 10 min. In the absence of radioinert estradiol acetate, no incorporation was observed. When MCF-7 cells were incubated with [3H]estradiol in the presence of a large excess of radioinert estradiol valerate, label was found only in estradiol valerate. Similarly, when the incubation was carried out in the presence of a mixture of radioinert estradiol acetate and valerate, label was incorporated into both esters. We conclude that the apparent formation of radiolabeled estradiol esters by MCF-7 cells incubated under the above conditions, results at least in part, from an esterase-catalyzed exchange reaction. Under conditions where no ester hydrolysis could be detected in the absence of cells, valerate and stearate esters of estradiol were found to be as effective as unesterified estradiol in stimulating esterase synthesis and the incorporation of [3H]thymidine into DNA. These results are consistent with a model in which an intracellular esterase in MCF-7 cells can generate estradiol from an exogenous lipoidal steroid and elicit an estrogen response.

Acetates↗
PubMed1991

The course of peptic ulcer disease.

Peptic ulcer disease usually has periodic exacerbations and remissions. Pain can disappear without total healing of the ulcer crater and can be absent when an ulcer is present. Changes in the incidence of ulcer disease have been noted in recent years. Genetic predisposition, infection with H. pylori, and the use of anti-inflammatory drugs are involved in causation. Stress; the use of alcohol, tobacco and caffeine; and other diseases have been implicated as etiologic factors. Ulcer pain has a recognizable pattern, but the symptoms can be variable, particularly in older people and in patients taking ulcerogenic medications. The familiar complications of hemorrhage, perforation, and obstruction still occur, and nonulcer dyspepsia has not been fully explained. Duodenal ulcers have a disturbing tendency to return; new therapeutic approaches offer hope.

Humans↗
PubMed1991

Acid secretion and suppression.

Hydrochloric acid is involved in the causation of peptic ulcer, but the exact role has not been defined. Suppression of acid secretion is associated with ulcer healing. The acid secreting cell is the parietal cell, which possesses a proton pump in the secretory membrane; morphologic changes accompany and facilitate the active secretion of hydrochloric acid. Stimulation of acid secretion occurs by three major pathways, which utilize acetylcholine, histamine, and gastrin. The predominant effects of histamine are mediated by adenylate cyclase, whereas those of gastrin and acetylcholine involve cytosolic calcium. There is a complicated arrangement of receptors and pathways that culminate in the activation of the proton pump. The parietal cell is influenced by neurocrine, hormonal, and paracrine mechanisms. Peptides join the more familiar neurotransmitters in affecting the parietal cell. Somatostatin is present in the gut and acts to decrease acid secretion. The hormone gastrin is released, in a feedback fashion, when the antrum is alkalinized. Most stimuli of acid secretion are blocked by H2-antagonists. Inhibitory hormones are released when acid arrives in the intestine. Inhibition of acid secretion can be achieved by influencing the parietal cell at the level of histamine, gastrin, and muscarinic receptors. The proton pump itself can be blocked by drugs that inhibit the final phase of acid secretion.

Central Nervous System↗
PubMed1991

Reliability of visual field results over repeated testing.

Fifty-one normal subjects, 337 with ocular hypertension, and 55 patients with glaucoma underwent C-30-2 testing on the Humphrey Field Analyzer on at least three occasions over a 6-year period. The time between tests was approximately 1 year. Using the manufacturer's standard for a reliable field (false-positive and false-negative rates, less than 33%; fixation losses, less than 20%), no trends in the proportion of reliable fields or the component indices were observed over time. Four percent of normal subjects, 9% of those with ocular hypertension, and 8% of patients with glaucoma were unable to meet the reliability standard every time they were tested. This repeated lack of reliability was due almost exclusively to fixation losses. However, patients with glaucoma were more likely to have repeatedly high false-negative responses than those with ocular hypertension or normal subjects, providing further evidence that false-negative responses are more indicative of glaucoma than of patient reliability.

Adult↗
PubMed1991

Injury prior to neurectomy alters the pattern of autotomy in rats. Behavioral evidence of central neural plasticity.

A common property of phantom limb pain is that a preamputation lesion continues to be felt in the same location of the phantom limb after amputation. A model of the phantom limb in the rat is provided by sectioning the sciatic and saphenous nerves. This procedure leads to self-mutilation of the denervated hindpaw, a behavior known as autotomy. There is strong evidence that autotomy is a response to painful or dysesthetic sensations referred to the anesthetic limb. The present study examined the hypothesis that the site of autotomy behavior can be altered by an injury given prior to denervation. Experiment 1 evaluated the effects of a thermal injury applied (under sodium pentobarbital anesthesia) to the medial or lateral hindpaw and digits before or after sciatic and saphenous nerve transections in order to determine whether autotomy is directed specifically to a previously injured site. The results revealed that autotomy onset occurred in the injured region of the paw in a significantly greater proportion of rats, compared to an uninjured control group, if the thermal injury had been induced before denervation: 100% of the rats with medial paw injury induced prior to neurectomy initiated autotomy in the medial digits, and 55.6% of rats with lateral paw injury initiated autotomy in the lateral digits. Rats injured after autotomy showed no such preference (medial, 33.3% and lateral, 37.5%) relative to the uninjured controls (medial, 33.3% and lateral, 17%). These results suggest that central cells, sensitized by the thermal injury, contribute to enhanced autotomy in the absence of further inputs from the injured paw.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Effects of drugs on the radiographic appearance of the heart.

Despite the exposure of the general population to a wide variety of exogenous environmental toxins, a growing armamentarium of potent medications, and an array of licit and illicit drugs, relatively little evidence of related pathophysiologic effects is seen on the radiographic appearance of the heart. When radiographic changes are manifested, however, specific alterations are observed in the contour of the cardiac silhouette. Generalized enlargement of the cardiac silhouette may be secondary to development of dilated cardiomyopathy or the accumulation of pericardial fluid. Localized changes in the contour of specific portions of the cardiac silhouette may be the result of ventricular hypertrophy or valvular stenosis or regurgitation. This article describes the cardiac radiographic findings resulting from the use of specific substances and discusses possible mechanisms that ultimately result in these changes. Identification and characterization of these morphologic changes may be helpful in the clinical management of patients.

Cardiomegaly↗