Lawrence A. Kaplan’s research while affiliated with Gracie Square Hospital, New York, NY and other places

What is this page?


This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.

Publications (28)


Chylomicron-retinyl palmitate clearance in type I hyperlipidemic families
  • Article
  • Full-text available

October 1991

·

51 Reads

·

52 Citations

The Journal of clinical investigation

·

S L Knauer

·

D M Black

·

[...]

·

Our primary aim was to determine the extent to which intraplasmic retinyl palmitate (RP) transfers to other lipoprotein particles when chylomicron remnants are not produced and/or the plasma RP residence time is increased. The study was conducted on three familial type I hyperlipoproteinemic patients, four lipoprotein lipase (LpL)-deficient heterozygotes, and three controls on a metabolic research unit. To each subject, a fat load was administered containing 16% of total daily calories in type I patients, 40% in heterozygotes and controls, plus 60,000 U/m2 vitamin A. Triglyceride (TG) and RP levels were evaluated in chylomicron and nonchylomicron fractions. Delay in the clearance of chylomicron fraction RP and the marked deficiency in nonchylomicron-RP (presumed lack of remnant production) in all three type I patients suggests that RP does not demonstrate significant intraplasmic transfer from chylomicrons to existent apolipoprotein B100 particles. In contrast to noncoincident TG and RP peaking in the normal subject, heterozygotes were found to demonstrate coincident plasma TG and RP curves, which is consistent with a common catabolic pathway for both TG and RP and inconsistent with intraplasmic RP transfer. This corroborates reports on compromised chylomicron clearance in heterozygotes. We conclude that RP is an appropriate representative marker for intestinally derived particles in LpL-deficient or partially deficient individuals.

Download

Plasma Catecholamine Levels In Cyclic Antidepressant Overdose

February 1991

·

15 Reads

·

25 Citations

Journal of Toxicology Clinical Toxicology

Cyclic antidepressant overdose is a major cause of morbidity and mortality in self-poisoned patients. The major cause of mortality with cyclic antidepressant overdose is cardiotoxicity. We determined plasma catecholamine levels in 41 symptomatic acute overdose patients to identify interactions between QRS duration (a marker for cardiotoxicity) and a presumed hyper-adrenergic state. Using a linear multivariable regression analysis, QRS duration correlated with the presence of cyclic antidepressant, plasma norepinephrine levels, the ratio of norepinephrine to epinephrine level, and pulse rate (p less than 0.001, r2 = 0.42). Commensurate physiologic changes were not found in the presence of elevated catecholamine levels in the cyclic antidepressant overdose group. One possible explanation for the blunted systemic response to the elevated catecholamine levels is adrenergic desensitization. Investigation of serial catecholamine levels during cyclic antidepressant overdose may lead to modification of our current theories of cardiotoxicity and therapy.


Biochemical Markers of Compliance in the Physicians’ Health Study

September 1990

·

25 Reads

·

42 Citations

American Journal of Preventive Medicine

The Physicians' Health Study is a randomized, double-blind, placebo-controlled trial using a 2 x 2 factorial design to test the effects of low-dose aspirin on risk of cardiovascular disease and beta-carotene supplementation on the incidence of cancer. To evaluate self-reported compliance with assigned treatment, we measured serum thromboxane B2, which is decreased after aspirin use, and plasma beta-carotene in samples of study participants drawn from three geographic locations in three different time periods. Thromboxane B2 levels were markedly lower in those assigned to aspirin (median = 63.5 pg/mL) than in those given aspirin placebo (median = 3,600 pg/mL, P less than .0001). Similarly, those assigned to beta-carotene had significantly higher levels (median = 1,176 ng/mL) than those given placebo (median = 306 ng/mL, P less than .0001). In addition, there was a highly significant positive correlation between levels of these biochemical markers and the self-reports of compliance (r = 0.65 for thromboxane B2 and r = 0.69 for beta-carotene, P less than .0001). These findings support the validity of the self-reported compliance in the Physicians' Health Study.


Food predictors of plasma beta-carotene and alpha-tocopherol: Validation of a food frequency questionnaire

June 1990

·

16 Reads

·

82 Citations

American Journal of Epidemiology

Nutrient intakes from a food frequency questionnaire are usually calculated as the product of frequency of intake and nutrient composition of the food, summed over the food items. This involves assumptions about the accuracy of recording, food composition data, stability during storage and preparation, and bioavailability. This usual method of calculation was compared with one using empirical weights derived by multivariate linear regression. Food intakes reported on a food frequency questionnaire by Boston, Massachusetts, area subjects in 1982-1985 were used to predict plasma levels of beta-carotene among 370 male and female nonsmokers and plasma levels of alpha-tocopherol among 339 male and female nonusers of vitamin supplements. Nutrient intake computed using empirical weights yielded a significant correlation with plasma beta-carotene (r = 0.43, p = 0.0001), similar to the correlation using nutrient intake calculated from food composition tables (r = 0.38, p = 0.0001). However, the use of empirical weights significantly improved the correlation of vitamin E intake with plasma alpha-tocopherol levels (r = 0.32, p = 0.0001), compared with the weak correlation obtained using the food composition table method to calculate intake (r = 0.16). The results support the validity of published food composition data used to compute carotenoid intake and illustrate the potential utility of empirically derived weights for foods to predict plasma levels of some nutrients.


Diet, plasma levels of beta-carotene and alpha-tocopherol, and risk of malignant melanoma

May 1990

·

24 Reads

·

135 Citations

American Journal of Epidemiology

Dietary intake and the plasma levels of retinol, alpha-tocopherol, lycopene, alpha-carotene, and beta-carotene for 204 cases with malignant melanoma were compared with those of 248 controls. Cases and controls were patients 18 years of age or older making their first visit to a dermatology subspecialty clinic for pigmented lesions from July 1, 1982 to September 1, 1985. Intakes of nutrients were estimated using a semiquantitative food frequency questionnaire. No significant associations with malignant melanoma were observed for higher plasma levels of lycopene, retinol, or alpha-carotene in logistic regression analyses after controlling for age, sex, plasma lipids, and known constitutional risk factors (hair color and ability to tan). In similar models, the odds ratio comparing the highest with the lowest quintile was 0.9 (95% confidence interval (CI) 0.5-1.5) for plasma beta-carotene, 0.7 (95% CI 0.5-1.3) for plasma alpha-tocopherol, 0.7 (95% CI 0.4-1.2) for carotene intake, and 0.7 (95% CI 0.4-1.3) for total vitamin E intake. A trend toward reduced risk of melanoma was observed for increasing intake of iron (not including supplements); this was related to the more frequent consumption of baked goods, such as cake, among controls. Alcohol consumption was positively associated with risk of melanoma (chi for trend = 2.1, p = 0.03); the odds ratio for consumption of over 10 g/day compared with persons with no alcohol intake was 1.8 (95% CI 1.0-3.3).


Simultaneous, high-performance liquid chromatographic analysis of retinol, tocopherols lycopene, and α- and β-carotene in serum and plasma

February 1990

·

16 Reads

·

45 Citations

Methods in Enzymology

The analysis of plasma (or serum) for retinol, tocopherols, lycopene, and α- and β-carotene is a complex analytical problem. This chapter discusses the simultaneous high-performance liquid chromatographic (HPLC) analysis of retinol, tocopherols, lycopene, and α- and β-carotene in serum and plasma. The single most critical element in this analysis is proper standardization that begins with an accurate assignment of the concentration of each stock standard to be used. As the tocopherols, lycopene, and carotene are transported in plasma in lipoprotein particles, one major concern of the assay is to be able to extract these compounds from the plasma matrix. As the lipoprotein content of samples will differ, it is possible that the efficiency of extraction of these compounds may also vary. To correct for this, the standard curve is based on internal standards that have extraction and chromatographic properties similar to those of the analyte and on standards that are added to a matrix of pooled serum or plasma. The chromatographic analysis is performed on a 5-μm particle C18 Biophase ODS column.


Carotenoid compositions and relationship in various human organs

February 1990

·

103 Reads

·

271 Citations

Clinical Physiology and Biochemistry

The carotenoid content of 10 different organs obtained at autopsy from 16 humans was determined using a high-performance liquid chromatography assay. The same qualitative pattern of carotenoids found in serum was found for all the tissues, although there were important quantitative differences in the different carotenoids between organs. The median levels of zeaxanthins, lycopene and beta-carotene varied disproportionately between organs; similar levels of one carotenoid for two organs would not predict similar levels of another carotenoid for the same organs. Similarly, there was not a consistent relationship between all the carotenoids for a given organ. The uneven but wide tissue distribution of most dietary carotenoids may indicate an active biological role for these compounds.


Hyperthermia, hypertension, hypertonia, and coma in a massive thioridazine overdose

August 1988

·

20 Reads

·

12 Citations

The American Journal of Emergency Medicine

This report characterizes an atypical presentation of a thioridazine overdose. Clinical manifestations included wide Q.R.S. complex, hyperthermia, hypertension, hypertonia, and coma. Plasma catecholamine levels were markedly elevated. The patient was treated with dantrolene sodium and supportive care. The patient's condition improved over time, with questionable response to dantrolene sodium. Supportive care was the mainstay of treatment.


The relation of diet, cigarette smoking, and alcohol consumption to plasma beta-Carotene and alpha-Tocopherol levels

March 1988

·

45 Reads

·

510 Citations

American Journal of Epidemiology

The relation of diet and nutritional supplements, cigarette use, alcohol consumption, and blood lipids to plasma levels of beta-carotene and alpha-tocopherol was studied among 330 men and women aged 18-79 years. Dietary carotene, preformed vitamin A, and vitamin E intake were estimated by a self-administered semiquantitative food frequency questionnaire. The correlation of dietary carotene with plasma beta-carotene was reduced in smokers compared with nonsmokers (r = 0.02 vs. 0.44 among men; r = 0.19 vs. 0.45 among women). Smokers had much lower plasma levels of beta-carotene than did nonsmokers (geometric mean 8.5 vs. 15.3 micrograms/dl for men; 17.3 vs. 26.3 micrograms/dl for women) despite only slightly lower intakes of carotenoids. In multiple regression analyses, men who smoked one pack per day had 72% (95% confidence interval (CI) 58-89) of the plasma beta-carotene levels of nonsmokers after accounting for dietary carotene and other variables; for women, the corresponding percentage was 79% (CI 64-99). In similar models, men drinking 20 g of alcohol per day had 76% (CI 65-88) of the beta-carotene levels of nondrinkers; women had 89% (CI 73-108) of the levels of nondrinkers. An interaction term for carotene intake and smoking was statistically significant in a model combining both sexes. These results suggest that plasma levels of beta-carotene among smokers and, perhaps, heavy consumers of alcohol may be reduced substantially below levels due to differences in diet. The correlation of calorie-adjusted intake of vitamin E with lipid-adjusted plasma levels of vitamin alpha-tocopherol was 0.53 for men (n = 137) and 0.51 for women (n = 193) and did not differ by alcohol consumption and cigarette use; these correlations were largely accounted for by use of vitamin supplements. In linear regression models, vitamin E intake and plasma lipids were significant predictors of plasma alpha-tocopherol levels.



Citations (21)


... Vitamin C level in the serum was measured using the colorimetric method introduced by McMurray and Gowenlock (43). Total lycopene and beta-carotene concentration were measured by high-performance liquid chromatography (HPLC) with ultraviolet detection (44). ...

Reference:

Dietary and Serum Level of Antioxidants in the Elderly with Mild Impaired and Normal Cognitive Function: A Case-Control Study
Simultaneous measurement of serum retinol, tocopherols, carotenes, and carotenoids by high performance liquid chromatography
  • Citing Article
  • January 1987

... In addition, it has structural role as a component of phospholipids, nucleoproteins and nucleic acids. Approximately, 80% of phosphate is bound in the bony skeleton, while the other 20% is distributed in the soft tissues and muscles (Kaplan & Pesce, 2010). The alkaline phosphatases are a group of enzymes that hydrolyze organic phosphates at high pH. ...

Clinical chemistry : theory analysis and correlation / Lawrence A. Kaplan, Amadeo J. Pesce
  • Citing Article

... In addition, some authors include the correction factor 10 6 to convert mol L -1 into µmol L -1 , as in equation There are few authoritative references describing the application of equation 6, presumably because such a calculation is basic enzymology, not research. The most reliable references consist of enzymology manuscripts (Engvall, 1980, Kaplan et al., 1998, Muñoz-Cuevas, 2010, Stewart and Ebel, 2000, although they tend to be confusing, and are void of practical examples. Hence, it would seem that the most popular references are unreferenced documents freely available online. ...

Química clínica : técnicas de laboratorio, fisiopatología, métodos de análisis : teoría, análisis y correlación / Lawrence A. Kaplan, Amadeo J. Pesce
  • Citing Article

... Retinyl palmitate is the ester of retinol (vitamin A) and palmitate which is given in concert with a test meal. In the intestinal mucosa, retinyl palmitate is incorporated into the chylomicron core where it is thought to remain during triglyceride hydrolysis [35,[178][179][180]. This method assumes that the retinyl ester remains associated with apolipoprotein B-48 and does not exchange with other lipoproteins. ...

Chylomicron-retinyl palmitate clearance in type I hyperlipidemic families

The Journal of clinical investigation

... 4-6 Acidosis, hypokalaemia, hypoxaemia, hyperthermia, hypotension and excessive adrenergic stimulation may also predispose to arrhythmias. 7 Blockade of the hERG human potassium channel by amitriptyline may also cause increased automaticity and arrhythmias in this setting of excessive adrenergic activity. 8 In animal models, it appears that the combination of increased sinus node rate and prolonged QRS is key to the occurrence of VT/VF here. ...

Plasma Catecholamine Levels In Cyclic Antidepressant Overdose
  • Citing Article
  • February 1991

Journal of Toxicology Clinical Toxicology

... Enhanced levels of NAD + are known to activate pro-survival pathways (Poljsak and Milisav, 2016). The depletion of NAD + or the NAD+/NADH ratio can influence the formation of ROS by altering the regulation of intracellular ATP production, redox state and metabolic enzymes Kaplan et al., 1990) Vitamin C Blood, Tissues, Urine Dinitrophenylhydrazine method EC-HPLC UV-HPLC Reversed phase HPLC (Zannoni et al., 1974;Masato, 1980) Vitamin Frontiers in Chemistry frontiersin.org 19 (Poljsak and Milisav, 2016). ...

Simultaneous, high-performance liquid chromatographic analysis of retinol, tocopherols lycopene, and α- and β-carotene in serum and plasma
  • Citing Article
  • February 1990

Methods in Enzymology

... Sixteen studies reported data for current smokers, and 12 reported data for former smokers. Most comparisons were relative to never-smokers (25 studies), but 2 studies used not-current-smokers (former plus never-smokers) as their comparator (18,19). Eight studies analyzed data by the quantity of cigarettes smoked, and 12 studies conducted multivariable analyses. ...

Diet, plasma levels of beta-carotene and alpha-tocopherol, and risk of malignant melanoma
  • Citing Article
  • May 1990

American Journal of Epidemiology

... We therefore considered that another statistical method involving multivariable linear regression (empirical weights approach) that extracts relatively more influential determinants of interindividual variation in multiple 24-h urinary sodium excretion may provide better estimation accuracy than the food composition approach 9 , particularly for assessment of total salt equivalent. The adoption of more accurate exposure assessment methods will allow epidemiological studies to detect associations between intake exposure and disease outcomes in a more robust manner 12,13 . Furthermore, it is suggested that the sodium-to-potassium ratio is more positively associated with CVD risk in a dose-response manner than sodium intake 14 , and is also important to ensuring the accuracy of epidemiological assessment. ...

Food predictors of plasma beta-carotene and alpha-tocopherol: Validation of a food frequency questionnaire
  • Citing Article
  • June 1990

American Journal of Epidemiology