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A Karmen

Publications and source records attributed to A Karmen.

At least 19 recordsLinked to original sources
PubMed1998

Beta-human chorionic gonadotropin in cervicovaginal secretions as a predictor of preterm delivery.

OBJECTIVE: This study's objective was to determine whether the concentrations of beta-human chorionic gonadotropin in the secretions of the cervix and vagina could be used to predict preterm delivery in a group of women at high risk for this complication. STUDY DESIGN: Women attending a prematurity prevention clinic at an inner-city hospital July 1, 1996-October 1, 1997, were invited to participate. From those who consented, secretions from the cervix and posterior vaginal fornix were sampled every 2 weeks until delivery, beginning at 24 weeks' gestation. Concentrations of beta-human chorionic gonadotropin were measured with a commercially available enzyme-linked immunosorbent assay. Providers of obstetric care were blinded to the results. Levels of beta-human chorionic gonadotropin in those who were delivered before 34 weeks' gestation and those who were delivered at term were compared. A value >50 mIU/mL was considered elevated. This cutoff value was determined according to beta-human chorionic gonadotropin values obtained during pregnancies that were delivered at term. RESULTS: Of the 146 women asked to participate, 77 consented. There was no difference between participants and nonparticipants with respect to age, race, indication for enrollment in the clinic, gestational age at delivery, or parity. Of the 77 participants, 24 (31%) were delivered before 37 weeks' gestation and 12 (16%) were delivered before 34 weeks' gestation. A single beta-human chorionic gonadotropin value >50 mIU/mL obtained between 24 and 28 weeks' gestation was associated with a significant increase in the incidence of delivery before 34 weeks' gestation (P = .03). This cutoff value had sensitivity, specificity, and positive and negative predictive values for predicting delivery before 34 weeks' gestation of 50%, 87%, 33%, and 93%, respectively. CONCLUSION: These data suggest that the concentration of beta-human chorionic gonadotropin in cervicovaginal secretions may be a useful predictor of preterm delivery.

Adult↗
PubMed1997

Troponin-T as a serum marker for myocardial infarction.

We report here our experience with serum troponin T (TnT), measured with the sandwich immunoassay introduced by Boehringer Mannheim as a marker for myocardial infarction. We assayed TnT in serial serum samples from 30 patients with time courses of serum CK, CK-MB, AST, and LD that we consider typical of acute myocardial infarction (MI). In every patient but one, TnT rose in parallel with both CK-MB and AST, but remained elevated significantly longer. The ratios of the elevations of the different markers varied from patient to patient with marked variation in the ratio of TnT to CK-MB. There appeared to be a significant association between the magnitude of that ratio with the level of ALT.

Aspartate Aminotransferases↗
PubMed1994

Measurement of free and total hydroxyproline by automated flow injection of serum or urine samples from maintenance hemodialysis patients with renal osteodystrophy.

An automated measurement of total and free hydroxyproline in serum or urine is presented that uses flow injection analysis. After exclusion of nonspecific substances, hydroxyproline was oxidized by chloramine-T and L-cysteine with Ehrlich's reagent. The linearity obtained was from 3.8 mumole/L to 1.22 mmole/L with good precision (CV < 3%). Comparison of the proposed method with HPLC yielded r = 0.939 as the correlation coefficient. Reference intervals of free and total hydroxyproline are 1.4-9.7 mumole/L, 3.8-27.2 mumole/L for serum, and 10.0-72.5 mumole/L, 25.2-303.6 mumole/L for urine, respectively. Serum free and total hydroxyproline levels in renal osteodystrophy patients on maintenance hemodialysis (N = 71) were significantly higher than in controls (P < 0.0001). This method is superior to the use of HPLC with regard to stability of the color reaction. The measurement of serum free and total hydroxyproline is a useful marker for therapeutic observation of renal osteodystrophy patients.

Chronic Kidney Disease-Mineral and Bone Disorder↗
PubMed1994

Simultaneous automated measurement of serum total CK and CK-MM isoform ratio in serum.

We automated a two-step kinetic procedure for determining serum CK-MM isoform ratio using an immunoinhibition method. By measuring the total CK activity and the residual CK activity (serum CK-MM isoform) remaining after the inhibition by tissue CK-MM isoform specific monoclonal antibody reagent (CK-M01) the CKMM isoform ratio is calculated using the difference between total CK and residual CK activities divided by the residual CK activity. Linearities of total CK and residual CK assays were < or = 7750 U/L and 2,500 U/L, respectively; within-run CVs of isoform ratio (N = 10) were 2.8 and 7.0% (mean 0.14 and 0.60), respectively. The MM3/MM1 isoform ratio obtained with the proposed method (X) correlated well with the results of electrophoretic method (Y) according to the equation: Y = 0.98X-0.3, r = 0.988. The normal reference range of isoform ratios obtained by assaying 1,222 serum samples from healthy subjects was 0.09-0.75. The isoform ratio increased after onset of chest pain, peaking at 2-6 hr thereafter. A mean isoform ratio of 1.86 was obtained with serum sample from 86 patients diagnosed as having an acute myocardial infarction (AMI). This method is accurate and highly sensitive, as the detection and early diagnosis of AMI can be completed in 10 min.

Adolescent↗
PubMed1994

Alkaline phosphatase band-10 fraction as a possible surrogate marker for human immunodeficiency virus type 1 infection in children.

We report the utility of a possible lymphocyte fraction of alkaline phosphatase (ALP band-10) activity in serum to predict human immunodeficiency virus type 1 (HIV-1) infection in children born to HIV-1-seropositive mothers. The presence of ALP band 10 in serum consistently correlated with HIV-1 infection status as judged by positive HIV-1 culture, two consecutive HIV-1 p24 antigen results greater than 30 pg/mL in serum, and the subsequent confirmation of seroconversion to HIV-1 antibody after clearance of maternal IgG anti-HIV-1 antibody ascertained between 15 to 24 months post partum. Infection with HIV-1 was correctly identified in 31 samples from 18 patients ranging in age between 0.1 to 10 years; the absence of similar infection was noted in 14 samples from nine patients who served as controls and whose serum samples did not exhibit ALP band-10 activity. This ability of serum ALP band-10 activity to predict HIV-1 infection status in children as young as 2 months may be useful as a surrogate marker for early identification of HIV-1 infection in infants born to HIV-1-seropositive women long before the clearance of maternal anti-HIV-1 antibodies can be ascertained.

Alkaline Phosphatase↗
PubMed1993

Proteinase K inactivation of cytosolic aspartate aminotransferase isoenzyme for measurement of human serum mitochondrial aspartate aminotransferase.

We studied a new proteinase K assay method for human serum mitochondrial aspartate aminotransferase. We found that proteinase K showed no inactivation of human mitochondrial aspartate aminotransferase isoenzyme and complete inactivation of cytosolic aspartate aminotransferase. Previous studies have shown that selective proteolytic measurement for mitochondrial aspartate aminotransferase in serum using the protease 401 cleaved peptide bond at Leu 20 from the amino-terminal bond shows complete inactivation of cytosolic aspartate aminotransferase and slight inactivation of mitochondrial aspartate aminotransferase isoenzyme, depending on protease concentration. In this investigation, we found that the proteinase K method does not depend on protease concentration. The proteinase K enzyme inactivation of cytosolic aspartate aminotransferase is caused by the cleavage of the peptide bond at Ileu 21 from the aminoterminal bond. In studies with various animal cytosolic aspartate aminotransferase isoenzymes, proteinase K almost completely inactivated cytosolic aspartate aminotransferase. Precision and correlation using proteinase K for measurement of serum mitochondrial aspartate aminotransferase in human showed a good coefficient of variation (within-run < 4.45%) and a coefficient of correlation of r = 0.985 (N = 125).

Adult↗
PubMed1993

Perinatal screening for drugs of abuse: reassessment of current practice in a high-risk area.

Anonymous urine toxicology screening among parturient women during 1 month in 1990 and selective newborn testing during this and the subsequent 4-month period was done to assess prevalence of drug use among parturients in a municipal hospital in the Bronx and to assess impact of infant urine toxicology screening on discharge placement. Infant testing was performed for maternal history of drug use, poor prenatal care (5 or fewer visits), or infant symptoms. Urine was screened for cocaine, opiates, methadone, barbiturates, amphetamines, and benzodiazepines. Of 204 women screened, 9.3% were positive. Of these, 74% were positive for cocaine and 21% revealed polysubstance use. Only 28.6% of cocaine-positive mothers gave a history of use. Selective testing of 1196 newborns during this 5-month period revealed an apparent prevalence of cocaine exposure of 4.9%. Selective infant testing failed to identify 42.1% of newborns of cocaine-positive women. Social work evaluation was performed on all families and was the basis for reporting to state agencies for protective services. Only 6 of 83 drug-positive infants entered foster care, none because of positive toxicology per se. Selective infant toxicology studies miss many cocaine-exposed infants and has little impact on placement. Universal social work evaluation of families may be as effective and freer of bias than selective urine screening.

Female↗
PubMed1993

Leukocyte esterase activity in effusion fluid of patients with otitis media.

Fluid obtained during myringotomy and tube placement in 20 patients with middle ear effusions was assayed for leukocyte esterase activity using a quantitative spectrophotometric assay. This quantitative assay used the synthetic substrate, N-tosyl indoxyl alaninate. Seven of the 20 samples showed no measurable enzyme activity (8 U/ml or less). The remaining samples demonstrated activity ranging from 20 to 1600 units. Although enzyme activity did not correlate well with the physical appearance of the fluid, it did correlate with clinical history, suggesting the presence of a purulent exudate rather than serous effusion. Leukocyte esterase activity in the fluid appears to hold promise as an indicator for the presence of chronic middle ear infection. The enzyme can be assayed by a simple and fast diagnostic strip test, with results available almost immediately.

Adolescent↗
PubMed1992

Specific assay of serum lactate dehydrogenase isoenzyme 1 by proteolysis with alpha-chymotrypsin and protein denaturation.

We devised a method for assaying serum lactate dehydrogenase isoenzyme 1 (LD-1) activity specifically by preincubation with alpha-chymotrypsin and guanidine. Cleavage of phenylalanine bonds in the loop of A and B subunits of LD-3, LD-4, and LD-5 isoenzymes (residues 117-119) by incubation with alpha-chymotrypsin for a short time completely inactivated these isoenzymes and partially inactivated LD-2. Addition of guanidine (0.50 mol/L, pH 7.8) to the incubation mixture containing the chymotrypsin completed the inactivation of LD-2. As much as 4000 U/L of LD-2, LD-3, LD-4, and LD-5 were inactivated, whereas LD-1 was affected only slightly. Results by this method (y) correlated well with those by the Roche Isomune immunochemical LD-1 method (x): y = 0.98 x -0.11, r = 0.99 (n = 60). Within-run CVs were 0.5-2.5%. Several common interferents had no effect. In 500 healthy people, serum LD-1 ranged between 66 and 130 U/L, with a mean +/- SD of 88 +/- 15 U/L.

Chymotrypsin↗
PubMed1990

A study of the CEDIA digoxin immunoassay.

We evaluated the CEDIA digoxin immunoassay (Microgenics, Inc., Concord, CA), as performed with the Cobas-Bio centrifugal analyzer. In assays of sera with known concentrations of digoxin, the enzyme activity, measured when two beta-galactosidase (EC 3.2.1.23) fragments were combined according to the assay format, was proportional to the digoxin concentration. Results of assays of sera containing 0 to 3 micrograms of digoxin per liter correlated well when compared with an RIA method: CEDIA, microgram/L = 1.00 x RIA - 0.06 microgram/L (n = 90, r = 0.95, Sxy = 0.05). Duplicate assays of three control sera containing 0.8, 2.2, or 3.3 micrograms/L, each analyzed 20 times a day with each group of patients' samples, gave within-run CVs of 1-3% and day-to-day CVs of 3-12%. The reconstituted CEDIA reagents were stable for at least a month at 5 degrees C. As many as 25 samples and controls can be assayed in half the time needed to complete a similar number of RIA measurements with comparable results.

Digoxin↗
PubMed1988

High-performance liquid chromatography of hydroxysteroids detected with post-column immobilized enzyme reactors.

Assaying the low concentrations of steroid hormones in extracts of body fluids requires detectors that are both highly sensitive to the steroid and relatively insensitive to interfering compounds usually present in much higher concentrations. To explore the use of moderately specific enzymes in post-column reactors, we immobilized 3 alpha- and beta-hydroxysteroid dehydrogenase on controlled pore glass beads, 37 microns in diameter, and constructed 4.6-mm diameter reactor columns, 3-cm long, packed with one of the two kinds of these beads. Hydroxysteroids eluted from the analytical column were mixed with the coenzyme, nicotinamide adenine dinucleotide (NAD), before passing through the reactor. The effluent from the reactor was passed through the 70-microliters flow cell of a fluorometer in which the fluorescence of the NADH produced in the enzyme-catalyzed oxidation of the hydroxysteroid was monitored. At the conventional high-performance liquid chromatography flow-rates used, oxidation of the steroids was almost complete. The yield depended on both the residence time of steroids in the reactor column and the concentration of organic modifier in the reaction mixture. Maximal yield was obtained with buffer having a low organic solvent concentration and passing through the reactor slowly. In assays of mixtures of epimeric hydroxysteroids, the 3 alpha-hydroxysteroids were detected with the 3 alpha-hydroxysteroid dehydrogenase reactor; the beta-hydroxysteroids were not, confirming the specificity of the enzymatic detection. With the fluorometer used, picomole quantities of steroids could easily be distinguished from noise.

3-Hydroxysteroid Dehydrogenases↗
PubMed1988

A simple spectrophotometric assay for urinary leukocyte esterase activity.

We have developed a sensitive spectrophotometric method for assaying urinary leukocyte esterase activity by employing a synthetic substrate, N-toluene sulfonyl indoxyl alanine ester. This kinetic assay can be performed with a small aliquot of urine, by following the change in absorbance of the chromophore at 385 nm. It is rapid and specific for leukocyte esterase and therefore can be used in the early diagnosis of urinary tract infection.

Carboxylic Ester Hydrolases↗
PubMed1986

Effects of anti-convulsants on fatty acid metabolism in human serum.

The effects of diphenylhydantoin and phenobarbital on lipids metabolism were studied by quantification of lipids in human serum with GC-MS. The ratios of palmitic acid to stearic, oleic and linoleic acids decreased in patients on diphenylhydantoin therapy. Increases of free palmitic, stearic and oleic acids concentrations as well as higher cholesterol ester levels were observed in patients receiving either diphenylhydantoin or phenobarbital. With respect to fatty acids composition of cholesterol esters and phosphatidyl-choline, higher concentrations of palmitic, oleic and linoleic acids were observed in patients on diphenylhydantoin and phenobarbital therapy. Although the concentration of palmitic acid in serum phosphatidylcholine remained the same for all groups, a marked decrease in stearic, oleic and linoleic acids concentrations in serum phosphatidylcholine was observed in diphenylhydantoin treated group, and oleic acid in phenobarbital treated group. These results suggested the relationship to lecithin-cholesterol acyltransferase activity by these drugs.

Anticonvulsants↗
PubMed1986

Activity concentration and mass concentration (monoclonal antibody immunoenzymometric method) compared for creatine kinase MB isoenzyme in serum.

Results of the "Tandem-E CKMB" immunoenzymometric procedure (y) for creatine kinase (CK; EC 2.9.3.2) were compared with electrophoresis (x) for 160 serum samples from patients suspected of having sustained myocardial infarctions. The results correlated well: y, microgram/L (Tandem assay) = 1.3x-6.3 U/L(electrophoresis) (r = 0.95). CK-MB mass measurement was more stable than enzyme activity after storage and appeared to be more sensitive. Sera from 86 other people, which had no detectable CK-MB upon electrophoresis, gave a mean CK-MB value of 1.1 microgram/L (SD 1.3, range 0-8) with the Tandem assay. To determine whether these low values represented actual isoenzyme, we tested for possible interference by heterophile antibodies in the patients' sera by preincubating the samples with mouse serum before the Tandem assay. The mouse serum did not interfere with the assay of sera that had substantial quantities of CK-MB by electrophoresis. However, in five of six samples that were negative by electrophoresis, the CK-MB values were substantially smaller, indicating that the values measured were false-positives caused by the presence of heterophile antibodies directed against mouse proteins, an interference that could be eliminated by pretreatment with mouse serum.

Antibodies, Monoclonal↗