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Biomedical subjects

B Gerson

Publications and source records attributed to B Gerson.

At least 55 records · Page 3Linked to original sources
PubMed1985

Toward a biochemical classification of depressive disorders IX. DST results and platelet MAO activity.

Post-dexamethasone cortisol and platelet monoamine oxidase (MAO) activity levels were examined in 50 depressed patients. The incidence of non-suppression was significantly greater in patients with high platelet MAO activity than in those with low activity. Similar results were obtained when males and females were analysed separately. The mean 4 p.m. post-dexamethasone cortisol level was significantly higher in those patients who had high MAO activity than in their low MAO counterparts. Moreover, a statistically significant positive correlation was observed between platelet MAO activity and 4 p.m. post-dexamethasone cortisol levels.

Adult↗
PubMed1985

Clinical comparison of glucose quantitation methods.

Quantitation of glucose in human serum, plasma, or whole blood by several commercially available methods and a manual hexokinase method were compared in various combinations. The techniques were selected as being representative of those available in large and small laboratory settings. Each differs as to reagent configuration and/or nature of sample required, such that a particular technique is more or less desirable depending on the unique situation of the user. Differences in relative performances in respect to accuracy and precision were revealed. Some are statistically significant and medically important. These differences must be appreciated by professionals of both large and small clinical laboratories, the managing physicians, and the patients.

Blood Glucose↗
PubMed1985

Macro creatine kinase type 1 with electrophoretic mobility identical to that of the MB isoenzyme.

We describe the case of an elderly woman whose symptoms and electrocardiographic pattern initially suggested acute myocardial infarction. The value for total serum creatine kinase (EC 2.7.3.2; CK) was 737 U/L (reference interval: 22-269 U/L), and electrophoresis for CK isoenzymes demonstrated two bands, the more anodal migrating to the CK-MB region and the second migrating between the CK-MB and CK-MM regions. The above-normal total CK and electrophoretic pattern persisted during her 11-day hospital course. The QuiCK-MB (International Immunoassay Labs.) and Tandem-E CK-MB (Hybritech) immunoassays, however, showed CK-MB mass measurements within the normal range. In further investigation with a mixture of patient's serum and human-serum-based control containing all CK isoenzymes, the electrophoretic mobility of only CK-BB was altered, proving that the patient had antibody to the B unit of CK in her serum. Immunofixation revealed the more anodal band to be a CK-IgA lambda complex, and the more cathodal band, a CK-IgG kappa complex. Mixing the patient's serum with polyclonal antibody specific for CK-B slowed the electrophoretic mobility of only the more anodal band. Polyclonal antibody specific for CK-M had no effect on either band. Evidently, this patient had two different types of macro CK type 1, both containing CK-BB. We conclude that macro CK type 1 can mimic CK-MB and be a source of confusion.

Aged↗
PubMed1984

Criteria for monitoring carcinoembryonic antigen: variability of sequential assays at elevated levels.

Fifty-five patients with advanced cancer and elevated plasma carcinoembryonic antigen (CEA) levels greater than 20 ng/mL (Roche assay) were monitored by clinical parameters for disease activity and a daily plasma specimen was obtained and stored frozen. In 45 patients with evaluable metastatic lesions, 35 were stable; five had progressive disease; and five had regressive disease. Plasma CEA in patients with stable disease showed an overall coefficient of variation of 13%. The CV did not differ according to various quantitative CEA levels from less than 100 ng/mL to greater than 1,000 ng/mL. The coefficient of variation in responding and progressive disease patients ranged from 13% to 63%. An analysis of CEA variability relative to the baseline CEA level was possible using the formula square root 2 times the variability about the mean; this yields a value of +/- 36% representing the range within which approximately 95% of sequential CEA levels would lie in the absence of a clinical change in disease. In 225 CEA determinations in stable disease patients, 6% demonstrated an increase beyond this level (36%) and none demonstrated a decrease of 36% or more from the baseline level. This study establishes guidelines for the boundaries of change in plasma CEA that may be applied as a criterion (in conjunction with standard objective disease parameters) for determination of tumor response to therapy.

Analysis of Variance↗
PubMed1984

Plasma clearance of carcinoembryonic antigen following hepatic metastatectomy.

Four patients with isolated hepatic metastases from primary colonic cancer presented with elevated plasma carcinoembryonic antigen (CEA) levels and underwent surgical metastatectomy . Plasma levels were monitored at two to six hour intervals in the immediate postoperative period and daily measurements were obtained for an extended period thereafter, up to 34 days. CEA clearance demonstrated a two-phase decrement with an initial rapid decay followed by a logarithmic decline with plasma half-lives of 66, 75, 150, and 208 hours. The first phase decline of 63% to 89% in circulating CEA levels immediately following tumor removal may reflect the fact that the plasma CEA is in dynamic equilibrium with the tumor CEA. The kinetics of the second-phase decline of CEA is variable and may be related to the quantitative circulating pool or to pathophysiologic processes influencing CEA metabolism or secretion in the liver. Quantitative assessment of tumor CEA content by immunoperoxidase techniques suggests a direct relationship between tissue levels and circulating plasma levels. The study of CEA kinetics may help in understanding the biology of tumor marker production and improve the capacity for clinical monitoring of plasma levels in conjunction with tumor therapy.

Carcinoembryonic Antigen↗
PubMed1983

Lactate dehydrogenase isoenzymes in hamster lung lavage fluid after lung injury.

Lactate Dehydrogenase Isoenzymes in Hamster Lung Lavage Fluid after Lung Injury. Beck, B. D., Gerson, B., Feldman, H. A., and Brain, J. D. (1983). Toxicol. Appl. Pharmacol. 71, 59-71. Lactate dehydrogenase (LD) levels and isoenzyme patterns were determined in the cell-free supernatant fractions of lung lavage fluid from hamsters exposed to alpha-quartz, iron oxide, Triton X-100, 100% O2, or 200 ppm SO2. The isoenzyme patterns were compared to those derived from hamster lung homogenates, serum, polymorphonuclear neutrophils (PMNs), pulmonary macrophages, and red blood cells. The isoenzyme patterns from alpha-quartz- and iron oxide-exposed animals resembled each other and were similar to that of PMNs. In contrast, the pattern seen after Triton X-100 exposure was similar to those of whole lung homogenates and of red blood cells. A 96-hr exposure to 100% O2 yielded an LD isoenzyme pattern in lung lavage fluid similar to that of serum. Exposure to SO2 did not alter LD levels, showing that upper airways damage is not reflected by changes in LD in lung lavage fluid. We conclude that LD isoenzyme patterns of lung lavage fluid can be used to differentiate among types of pulmonary injury and may help identify the sites of injury.

Animals↗
PubMed1981

Insulin resistance and monoclonal gammopathy.

Two maturity-onset diabetic patients developed severe insulin resistance during the course of monoclonal gammopathies. One patient had Waldenström macroglobulinemia and the other had multiple myeloma with IgA gammopathy. The maximum insulin binding capacity (MIBC) was 121 U/liter and 54.7 U/liter, respectively, during insulin resistance. The clinical courses of insulin resistance paralleled the activity of the monoclonal gammopathies (MG) with the insulin resistance disappearing after the monoclonal gammopathies were controlled. Six other diabetic patients with concurrent insulin resistance and monoclonal gammopathies are reviewed.

Aged↗
PubMed1981

Quantitation of tobramycin by solid-phase immunofluorescence.

Tobramycin usage, as for most aminoglycoside antibiotic usage, may require careful monitoring to avoid irreversible toxicity. Several methods for tobramycin quantitation are available. The purpose of this study was to evaluate the performance of solid-phase immunofluorescence as an alternative. Tobramycin was quantitated in the sera of 81 patients by radioimmunoassay and solid-phase immunofluorescence. No statistically significant or medically important difference was demonstrated (bias, 0.006 micrograms/ml, t = 0.09, s = 1.02, r = 0.97). Within-run and run-to-run precision for the two methods were comparable. Interference by gentamicin could not be demonstrated. Solid-phase immunofluorescence may be an acceptable alternative method for tobramycin quantitation in some laboratories.

Anti-Bacterial Agents↗
PubMed1981

Myelin basic protein, oligoclonal bands, and IgG in cerebrospinal fluid as indicators of multiple sclerosis.

There currently are three clinical laboratory procedures for use with cerebrospinal fluid that assist in the diagnosis of multiple sclerosis: measurement of myelin basic protein and IgG, and demonstration of an oligoclonal band. We compared characteristics of these procedures, using CSF samples from 166 patients identified as having (54 patients) or not having (112 patients) multiple sclerosis. We find that oligoclonal band demonstration is the most useful single test in helping to establish the presence of multiple sclerosis; IgG quantitation is the least helpful. Myelin basic protein should be quantitated for following the activity of multiple sclerosis; it may be applied only selectively in the context of screening. The incidence of false-positive results reinforces the view that the diagnosis of multiple sclerosis must be made in clinical context. These laboratory procedures are not suitable for use as screening tests.

Electrophoresis, Agar Gel↗
PubMed1980

Oligoclonal bands and quantitation of IgG in cerebrospinal fluid as indicators of multiple sclerosis.

The authors evaluated two laboratory procedures in respect to usefulness in evaluating patients suspected of having multiple sclerosis (MS). They classified 185 patients as having MS (MS-positive) or as not having MS (MS-negative). Agarose electrophoretic patterns of cerebrospinal fluid (CSF) samples were inspected for the presence of oligoclonal bands. CSF immunoglobulin G (IgG) was quantitated and compared with total CSF protein for 175 patients. Oligoclonal bands were present in specimens from 77% of the MS-positive group; elevated percentages of IgG (18% or more of total CSF protein) were present in specimens from 20%. Oligoclonal bands were present in specimens from 0.6% of the MS-negative group; elevated percentages of IgG were found for 1.4% of the MS-negative group. The presence or absence of oligoclonal bands in agarose electrophoretic patterns is sensitive (77%) and very specific (99%) in respect to MS. CSF IgG quantitation using the authors' criteria does not add useful information.

Demyelinating Diseases↗
PubMed1980

Quality control in therapeutic drug monitoring: intralaboratory precision and medical requirements.

Formal quality control procedures have become a part of the clinical laboratory. Application of these procedures to therapeutic drug monitoring, which has been introduced into the clinical laboratory relatively recently, is incomplete. Most attention has been directed toward questions of accuracy and laboratory-to-laboratory precision, particularly with respect to antiepileptic agents. Intralaboratory precision must be addressed first, since it is fundamental to accuracy and laboratory-to-laboratory variability and most patients are treated based on results generated by a single laboratory. Intralaboratory precision data were gathered from laboratories already offering therapeutic drug monitoring services. In addition, the intralaboratory precision demands of good medical management was gathered from physicians who use therapeutic drug monitoring services. For 20 specified drugs, most laboratories reported intralaboratory precision (relative standard deviations) of 10% or less. Managing physician responses demonstrated that most require precision of 10 to 15% or 20 to 25%. Individual laboratories should use these data as an indication of the level of intralaboratory precision that may be achieved and that is required. The state of the art of intralaboratory precision is acceptable relative to medical management, but may need improvement as it contributes to laboratory-to-laboratory variability.

Drug Therapy↗
PubMed1980

Therapeutic monitoring of tricyclic antidepressants: quality-control considerations.

While the correlation between plasma levels of some tricyclic antidepressants and therapeutic efficacy is well documented and the value of tricyclic antidepressant plasma level measurements is reasonably well established, the sources of error in the collection and analysis of specimens are not generally known and understood. An outline of the factors affecting the interpretation and utilization of plasma level measurements and the procedures needed to insure the accuracy and precision of tricyclic antidepressant plasma level determinations is presented. Problems facing the clinical laboratory attempting to set up a quality-control program for its tricyclic antidepressant analyses are also discussed.

Analysis of Variance↗
PubMed1980

Two agarose electrophoretic systems for demonstration of oligoclonal bands in cerebrospinal fluid compared.

Demonstration of oligoclonal bands by electrophoresis of cerebrospinal fluid is an important aid in establishing the diagnosis of multiple sclerosis. Electrophoretic systems vary in their effectiveness in doing so. We compared two systems in this respect. For a thin-layer agarose system, sensitivity was less (47%) than for a high-resolution agarose system (87%). Each system had good specificity (92 and 85%, respectively). Interpretation of electrophoretic patterns for cerebrospinal fluid should be available in clinical laboratories. Further, the best available system should be used for demonstration of oligoclonal bands.

Electrophoresis↗
PubMed1979

High-density lipoprotein cholesterol. Significant bias between methods.

Cholesterol content of the high-density lipoproteins has become of interest in evaluating the risk of development of coronary heart disease. There is an inverse relationship between high-density lipoprotein cholesterol and risk. The authors found a significant bias (11.1 mg/dl; 0.289 mmol/l) in a comparison of a rapid cholesterol oxidase method and the Abell--Kendall method for quantitating high-density lipoprotein cholesterol. The two methods did not differ in the usual range of total serum cholesterol. Since methodology may vary, each laboratory's performance should be assessed prior to use of published risk factor data. The authors then studied normal male and female volunteers aged 20 to 35 years. They conclude that high-density lipoprotein cholesterol is of value as a risk factor indicator in this age group. The relationship of total serum cholesterol to high-density lipoprotein cholesterol was studied. The authors conclude that they are independent indicators. Further, there is a range of efficiency of the high-density lipoprotein lipid-clearing function. Finally, the authors attempted unsuccessfully to predict high-density lipoprotein cholesterol from lipoprotein electrophoresis patterns.

Adult↗
PubMed1979

Lipoprotein X and alkaline phosphatase as indicators of cholestasis.

Lipoprotein X is considered to be an indicator of cholestasis, but its clinical usefulness is unclear owing to different methods of measurement in use and varying definitions of cholestasis. We investigated the reliability of the qualitative determination of lipoprotein X in predicting cholestasis, defined here as the presence of stainable bile in tissue sections. Liver tissue and serum were collected from 42 patients. Patients were divided into those who did and those who did not have stainable bile in tissue sections. Lipoprotein X was demonstrated by electrophoresis and polyanion precipitation. Lipoprotein X in serum correlated with the presence of stainable bile (p = 0.0006). A normal range of alkaline phosphatase values correlated with the absence (p = 0.04), but elevated values did not correlate with the presence of stainable bile. In patients known to have elevated alkaline phosphatase, the presence of lipoprotein X still correlated with the presence of bile (p = 0.008). We conclude that lipoprotein X is a reliable indicator of cholestasis and that it is more useful than alkaline phosphatase in this application.

Alkaline Phosphatase↗