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Biomedical subjects

J Kline

Publications and source records attributed to J Kline.

At least 19 recordsLinked to original sources
PubMed2001

Experimental observation of the trapped particle pinch effect.

The trapped particle pinch effect (Ware's drift) has been observed in a non-neutral plasma of electrons in a modified Malmberg-Penning trap in which electrons are contained in the annular volume between concentric cylinders. A pulsed azimuthal electric field is applied by increasing the flux within a solenoid on the axis. Radial displacements of the electrons are observed which show that they remain on a surface enclosing constant axial flux. These displacements are independent of the azimuthal field and thus are consistent with Ware's drift and inconsistent with the guiding center drift alone.

Journal Article↗
PubMed2001

Role of the peripheral intravenous catheter in false-positive D-dimer testing.

OBJECTIVE: To determine whether inserting a peripheral intravenous catheter (IV) can significantly increase the circulating D-dimer concentration. METHODS: Twenty healthy young adult volunteers underwent cannulation of an antecubital vein with a 20-gauge Teflon IV. Time 0 venous blood was drawn during IV insertion. The IV was salinelocked and left in place for 90 minutes, at which time a second venipuncture was performed in a contralateral antecubital vein (+90 min). A qualitative D-dimer assay [erythrocyte-agglutination assay, SimpliRED (SRDD)] and a quantitative spectrophotometric assay [enzyme-linked immunosorbent assay (EIA), Dimertest Gold] were performed on all samples. Time 0 means (+/-SD) were compared with +90 min means by paired t-test, and SRDD pairs were compared with McNemar's test. RESULTS: Time 0 initial venipuncture blood samples yielded a mean D-dimer concentration of 15 +/- 24 ng/mL, with 2/20 SRDD tests read as positive (95% CI = 1% to 32%). At +90 min, the D-dimer concentration was 33 +/- 21 ng/mL (p = 0.04 vs time 0), with 5/20 SRDD tests read as positive (95% CI = 9% to 49%, p = 0.248). CONCLUSIONS: Insertion of an IV increased the circulating D-dimer concentration (determined by EIA), but did not lead to a significant increase in false-positive conversion of the SRDD. An effort should be made to perform D-dimer testing on "first-stick" blood to optimize specificity. However, a strongly positive D-dimer reaction cannot be ascribed to the presence of an IV.

Adult↗
PubMed2000

Cocaine use during pregnancy and intrauterine growth retardation: new insights based on maternal hair tests.

Prenatal cocaine use is more accurately measured by maternal hair assay than by urine toxicology screening or self-report. To investigate the consequences of improved measurement, the authors ascertained cocaine use during pregnancy by maternal hair test, urine test, and self-report in a sample of 691 patients recruited from one New York City hospital in 1990-1992. Associations with intrauterine growth retardation, head circumference, and length of gestation were investigated. A positive hair test at delivery was not more strongly associated with birth weight (-38.1 g; 95% CI: -164, 88.3) or head circumference (-1.73 mm; 95% CI: -5.91, 2.44) than a positive urine test at delivery (-182 g (95% CI: -295, -69.8) and -6.11 mm (95% CI: -9.99, -2.24), respectively). Cocaine concentration in hair (which was higher if urine tests were positive) had a dose-response relationship with birth weight: a 27-g decrease (95% CI: -51.9, -1.04) with each log-unit increase in concentration. Birth weights were similar among infants of never users and infants of users who stopped using cocaine before delivery. Heavier use of cocaine, but not lighter use, was associated with intrauterine growth retardation, and exposure in late pregnancy was necessary to the association. Although maternal hair tests were instrumental in clarifying these relations, their clinical use is probably not warranted.

Adult↗
PubMed2000

Trisomic pregnancy and earlier age at menopause.

We tested the hypothesis that the connection between advanced maternal age and autosomal trisomy reflects the diminution of the oocyte pool with age. Because menopause occurs when the number of oocytes falls below some threshold, our hypothesis is that menopause occurs at an earlier age among women with trisomic pregnancies than it does among women with chromosomally normal pregnancies. To determine their menstrual status, we interviewed women from our previous study of karyotyped spontaneous abortions who, in 1993, were age >/=44 years. Premenopausal women completed interviews every 4-5 mo, until menopause or until the study ended in 1997. The primary analyses compare 111 women whose index pregnancy was a trisomic spontaneous abortion with two groups: women whose index pregnancy was a chromosomally normal loss (n=157) and women whose index pregnancy was a chromosomally normal birth (n=226). We used a parametric logistic survival analysis to compare median ages at menopause. The estimated median age at menopause was 0.96 years earlier (95% confidence interval -0.18 to 2.10) among women with trisomic losses than it was among women with chromosomally normal losses and chromosomally normal births combined. Results were unaltered by adjustment for education, ethnicity, and cigarette smoking. Our results support the hypothesis that trisomy risk is increased with decreased numbers of oocytes. Decreased numbers may indicate accelerated oocyte atresia or fewer oocytes formed during fetal development.

Abortion, Spontaneous↗
PubMed2000

Alzheimer's disease in the parents of women with trisomic spontaneous abortions.

We tested whether familial aggregation of Down syndrome and Alzheimer's disease (AD) is present for trisomies of other autosomes. We compared rates of Alzheimer-like dementia in the parents of women with trisomic pregnancy losses (n = 109) with those in parents of women with chromosomally normal losses (n = 151) and births (n = 216). Relative risks of Alzheimer-like dementia in parents of women with trisomic losses were 1.2 (95% CI 0.6, 2.2) and 0.9 (95% CI 0.5, 1.5) in comparison to parents of women with chromosomally normal losses and births, respectively. Associations were similar among women whose index pregnancy occurred before age 35 or later. Our data do not support an association between the occurrence of AD and trisomy of all autosomal chromosomes. They raise the possibility that familial aggregation with AD is specific to trisomy 21.

Abortion, Spontaneous↗
PubMed2000

Lead exposure and motor functioning in 4(1/2)-year-old children: the Yugoslavia prospective study.

OBJECTIVE: To investigate associations between lead exposure and early motor development. STUDY DESIGN: We conducted standardized assessments of motor function (Bruininks-Oseretsky Test of Motor Proficiency and Beery Developmental Test of Visual-Motor Integration) at age 54 months in 283 children whose mothers were recruited in pregnancy from a smelter town and a non-lead-exposed town in Yugoslavia and who have been monitored twice yearly since birth. Blood lead concentration (BPb) was summarized in a measure reflecting the average of the child's semiannual serial log BPbs through 54 months. RESULTS: Multiple regression showed that taken together, anthropometric measures (birth weight, body mass index) and markers of a stimulating and organized home life (HOME scale, parental education and intelligence, availability of siblings) explained a significant 10% to 18% of the variance in motor functioning. Beyond these contributions, BPb was significantly associated with poorer fine motor and visual motor function but was unrelated to gross motor coordination. CONCLUSIONS: Modest associations between early lead exposure and fine motor and visual motor functioning appear even after statistical adjustment is done for other contributors to motor development. Associations with BPb are specific to these areas of motor skill; gross motor development was unaffected.

Child Development↗
PubMed2000

Maternal prepregnant body mass and risk of schizophrenia in adult offspring.

This study examined the relation between maternal prepregnant body mass index (BMI) and development of schizophrenia and schizophrenia spectrum disorders in adult offspring from the Prenatal Determinants of Schizophrenia Study. The study drew on a previously studied cohort of births occurring between 1959 and 1967 to women enrolled in a prepaid health plan. Computerized treatment registries were used to identify possible cases of schizophrenia and spectrum disorders in adult offspring belonging to the health plan from 1981 to 1997. Diagnostic interviews and medical record reviews resulted in diagnosis of 63 cases of schizophrenia and spectrum disorders; these cases and 6,570 unrelated and unaffected cohort members whose mothers also had prepregnancy measures of BMI comprised the sample for analyses. High (> or = 30.0), compared with average (20.0-26.9), maternal prepregnant BMI (kg/m2) was significantly associated with schizophrenia and spectrum disorders in the adult offspring (relative risk [RR] = 2.9; 95% confidence interval [CI] 1.3-6.6), independently of maternal age, parity, race, education, or cigarette smoking during pregnancy. Low (< or = 19.9) maternal BMI was not associated with schizophrenia and spectrum disorders (RR = 1.2; 95% CI 0.64-2.2). Future studies of this cohort will examine factors that may help explain the relationship of high maternal prepregnant BMI with schizophrenia, including nutritional and metabolic factors, toxic exposures, and obstetrical complications.

Adolescent↗
PubMed1999

Cocaine and tobacco use and the risk of spontaneous abortion.

BACKGROUND: Cigarette smoking and cocaine use may be risk factors for spontaneous abortion, but data supporting such a link are limited. METHODS: We studied the associations between cocaine and tobacco use and spontaneous abortion among pregnant adolescents and women (age range, 14 to 40 years) who sought care at an inner-city emergency department. A total of 400 adolescents and women had spontaneous abortions either at study entry or during follow-up (which lasted until 22 weeks' gestation), and 570 adolescents and women remained pregnant past 22 weeks' gestation. Cocaine use was measured at base line by self-reports and analysis of urine and hair samples. Cigarette smoking was measured by self-reports and urine analysis. RESULTS: The adolescents and women in both groups were predominantly black and of lower socioeconomic status. Among those who had spontaneous abortions, 28.9 percent used cocaine on the basis of hair analysis and 34.6 percent smoked on the basis of a urine cotinine assay, as compared with 20.5 percent and 21.8 percent, respectively, of the adolescents and women who did not have spontaneous abortions. The presence of cocaine in hair samples was independently associated with an increase in the occurrence of spontaneous abortion (odds ratio, 1.4; 95 percent confidence interval, 1.0 to 2.1) after adjustment for demographic and drug-use variables. However, the use of cocaine as measured by self-reports and by urine analysis was not. The presence of cotinine in urine was also independently associated with an increased risk of spontaneous abortion (odds ratio, 1.8; 95 percent confidence interval, 1.3 to 2.6). Twenty-four percent of the risk of spontaneous abortion could be related to cocaine or tobacco use. CONCLUSIONS: Cocaine and tobacco use were common in our study population and were associated with a significant risk of spontaneous abortion.

Abortion, Spontaneous↗
PubMed1999

Darryl, a cartoon-based measure of cardinal posttraumatic stress symptoms in school-age children.

OBJECTIVES: This report examines the reliability and validity of Darryl, a cartoon-based measure of the cardinal symptoms of posttraumatic stress disorder (PTSD). METHODS: We measured exposure to community violence through the reports of children and their parents and then administered Darryl to a sample of 110 children aged 7 to 9 residing in urban neighborhoods with high crime rates. RESULTS: Darryl's reliability is excellent overall and is acceptable for the reexperiencing, avoidance, and arousal subscales, considered separately. Child reports of exposure to community violence were significantly associated with child reports of PTSD symptoms. CONCLUSIONS: Darryl possesses acceptable psychometric properties in a sample of children with frequent exposure to community violence.

Arousal↗
PubMed1999

Exercise and spontaneous abortion of known karyotype.

We examined whether exercise during pregnancy is associated with chromosomally normal spontaneous abortion. We hypothesized that associations would be confined to chromosomally normal losses since only these can be influenced appreciably by experiences during pregnancy. The study population comprises women with chromosomally normal (N = 173) and aberrant (N = 173) losses. Women who exercised during pregnancy had a lower risk of a chromosomally normal spontaneous abortion (OR 0.6; 95% CI 0.3-0.9). Other types of physical activity had little effect.

Abortion, Spontaneous↗
PubMed1998

Hyperproduction of erythropoietin in nonanemic lead-exposed children.

Lead (Pb) poisoning has numerous effects on the erythropoietic system, but the precise mechanism whereby high dose exposure causes anemia is not entirely clear. We previously reported that Pb exposure is associated with depressed serum erythropoietin (EPO) in pregnant women residing in a Pb mining town and in a nonexposed town in Kosovo, Yugoslavia. In a prospective study, we tested the hypothesis that blood Pb concentration (BPb) may be associated with depressed EPO in children. BPb, hemoglobin (Hgb), and serum EPO were measured at ages 4.5, 6.5, and 9.5 years in 211, 178, and 234 children, respectively. At 4.5 years of age, mean BPbs were 38.9 and 9.0 microg/dl in the exposed and nonexposed towns, respectively; BPbs gradually declined to 28.2 and 6.5 microg/dl, respectively, by age 9.5 years. No differences were found in Hgb at any age. At age 4. 5 years, a positive association between BPb and EPO (beta = 0.21; p = 0.0001), controlled for Hgb, was found. The magnitude of this association declined to 0.11 at age 6.5 years (p = 0.0103) and 0.03 at age 9.5 years (p = 0.39). These results were confirmed using repeated measures analyses. We concluded that in Pb-exposed children, the maintenance of normal Hgb requires hyperproduction of EPO. With advancing age (and continuing exposure), this compensatory mechanism appears to be failing, suggesting a gradual loss of renal endocrine function due to Pb exposure.

Age Factors↗
PubMed1997

Anionic- and lipophilic-mediated surface binding inhibitors of human leukocyte elastase.

We report the synthesis of a series of diphenylmethane-based oligomers containing anionic and lipophilic functionalities that are potent inhibitors of human leukocyte elastase (HLE). The enzyme inhibition is regulated by the size of the oligomer, as well as, the number of charges. Lipophilicity is an important element in determining potency and specificity against other basic enzymes. Compounds whose scaffolds contain three phenoxyacetic acid groups and three alkyl ethers are competitive and specific inhibitors of HLE with Ki = 20 nM. The mechanism of action of this class of compounds is believed to involve multidendate interactions with the surface of HLE near the active site which prevents substrate access to the catalytic site.

Benzhydryl Compounds↗