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J Eisele

Publications and source records attributed to J Eisele.

18 recordsLinked to original sources
PubMed2005

Lead isotopes reveal bilateral asymmetry and vertical continuity in the Hawaiian mantle plume.

The two parallel chains of Hawaiian volcanoes ('Loa' and 'Kea') are known to have statistically different but overlapping radiogenic isotope characteristics. This has been explained by a model of a concentrically zoned mantle plume, where the Kea chain preferentially samples a more peripheral portion of the plume. Using high-precision lead isotope data for both centrally and peripherally located volcanoes, we show here that the two trends have very little compositional overlap and instead reveal bilateral, non-concentric plume zones, probably derived from the plume source in the mantle. On a smaller scale, along the Kea chain, there are isotopic differences between the youngest lavas from the Mauna Kea and Kilauea volcanoes, but the 550-thousand-year-old Mauna Kea lavas are isotopically identical to Kilauea lavas, consistent with Mauna Kea's position relative to the plume, which was then similar to that of present-day Kilauea. We therefore conclude that narrow (less than 50 kilometres wide) compositional streaks, as well as the larger-scale bilateral zonation, are vertically continuous over tens to hundreds of kilometres within the plume.

Journal Article↗
PubMed2000

A curve-free method for phase I clinical trials.

Consider the problem of finding the dose that is as high as possible subject to having a controlled rate of toxicity. The problem is commonplace in oncology Phase I clinical trials. Such a dose is often called the maximum tolerated dose (MTD) since it represents a necessary trade-off between efficacy and toxicity. The continual reassessment method (CRM) is an improvement over traditional up-and-down schemes for estimating the MTD. It is based on a Bayesian approach and on the assumption that the dose-toxicity relationship follows a specific response curve, e.g., the logistic or power curve. The purpose of this paper is to illustrate how the assumption of a specific curve used in the CRM is not necessary and can actually hinder the efficient use of prior inputs. An alternative curve-free method in which the probabilities of toxicity are modeled directly as an unknown multidimensional parameter is presented. To that purpose, a product-of-beta prior (PBP) is introduced and shown to bring about logical improvements. Practical improvements are illustrated by simulation results.

Bayes Theorem↗
PubMed1998

Modelling of residual variability in toxicokinetic studies with sparse sampling: the case of tetrahydronaphthalene.

The present study describes the kinetics of tetrahydronaphthalene in male and female rats (five animals per dose per sex) at three dose levels (15, 50, and 150 mg/kg daily). Plasma concentration measurements were performed in the course of a subacute toxicity study of 28 days duration in an enriched study design. Two blood samples per animal were taken at different time points after application at day 1 and 16 (150 mg/kg daily) and at day 3 and 18 (15 and 50 mg/kg daily), respectively. Tetrahydronaphthalene was assayed by gas chromatography-mass spectrometry (GC-MS) after extraction. The data of plasma concentration time were analysed using non-linear mixed effects modelling as implemented in NONMEM. The structural model with the best fit employed one compartment kinetics with instantaneous drug input. Interindividual variability in both k and V was found to be very small [k, 0.201 h(-1), 0.013; V, 16.19 (kg), 1.77; population mean and SE]. No unequivocal evidence of dose dependence could be found. The kinetic parameter with the highest extent of variability was the extent of bioavailability which showed an coefficient of variation (CV) of 96%. Both gender and dose had no influence on the variability. The present approach is concluded to offer more insight into the relationship between dose, concentration and effect and into factors which explain variability in kinetics without additional testing or additional animals. Proposals for a refined sampling schedule are made.

Animals↗
PubMed1991

On the acquisition of syntax in Tamil: a comment on Garman (1974).

Garman (1974), reporting on twenty Tamil children aged three to five, postulated a linguistic strategy and two prelinguistic strategies to explain the results of a question-picture choice task involving sentences with embedded and subordinate clauses. In a reanalysis of his data, we identify four processing strategies and show that some of Garman's findings are better explained not as the outcome of prelinguistic strategies but as an artefact of the experimental design. In fact the data provide evidence of a grammatical sensitivity which is consonant with a sensitivity--demonstrated in recent language--acquisition studies-to the branching direction of the language being acquired.

Child Language↗
PubMed1988

Patients with prolonged bleeding time of undefined etiology, and their response to desmopressin.

Between 1981 and 1986, we evaluated 59 patients who presented with isolated prolongation of bleeding time with normal platelet counts, platelet aggregation and coagulation parameters (including von Willebrand's factor), and without evidence of liver or kidney disease, or exposure to anti-platelet agents. These patients, termed as vascular fragility syndrome (VFS), were analyzed to further characterize their bleeding patterns. The pattern of bleeding manifestations was similar to that of patients with platelet dysfunction, such as mucocutaneous bleeding or excessive post-operative bleeding. In 16 patients, desmopressin (1-desamino-8-d-arginine vasopressin, DDAVP) was infused to control active bleeding or as a part of pre-surgical evaluation. Bleeding time improved (pre-DDAVP bleeding time 15.3 +/- 3.4 min, mean +/- S.D.; post-DDAVP bleeding time 10.7 +/- 3.9 min; p less than 0.01) within 30 minutes following the DDAVP infusion with either satisfactory arrest of acute bleeding or good control of subsequent hemostasis with surgery. Side effects with DDAVP were transient and minor, i.e. facial flushing, or conjunctival erythema. These findings indicate that VFS with isolated prolongation of bleeding time is a frequently encountered bleeding disorder and that DDAVP is effective in achieving hemostasis for the management of acute bleeding and may be useful prior to surgical procedures.

Bleeding Time↗
PubMed1988

Human immunodeficiency virus infection in sexually active wives of infected hemophilic men.

PURPOSE: Because of past multiple exposures to contaminated coagulation factor concentrates, the prevalence of human immunodeficiency virus (HIV) infection among adult hemophilic men in the United States is reported to range from 75 to 90 percent. The risk of HIV transmission through a long-term monogamous heterosexual contact can be estimated by studying the spouses of hemophilic subjects since these couples generally do not abuse intravenous drugs, usually maintain stable monogamous relationships, and are usually free of other risk factors. Our purpose was to gather data on the risk of heterosexual transmission of HIV infection in the context of long-term monogamous relations according to the duration of HIV antibody seropositivity and of HIV antigenemia in HIV-infected hemophilic men, and their sexual habits. SUBJECTS AND METHODS: Infection with HIV was studied in 14 sexually active spouses of infected hemophilic men who had been HIV antibody reactive for a mean of 46 +/- 23 (SD) months. One half of the hemophilic men studied had overt HIV antigenemia for a mean duration of 27 +/- 23 (SD) months; six of the men studied fulfilled clinical criteria for the diagnosis of acquired immunodeficiency syndrome (AIDS). All 14 couples were sexually active in a strictly monogamous fashion, in marriages of 13.5 +/- 10.5 (SD) years with an average reported frequency of four sexual encounters per month (range: one to 12). Plasma samples of the hemophilic husbands were retrospectively analyzed for HIV and hepatitis B virus markers. Blood samples were obtained from female spouses on at least two occasions, six months apart. Comprehensive questionnaires regarding sexual habits and other risk factors were filled out by each couple; during this interview, the couple was counseled about safe sexual practices. None of the couples studied used condoms prior to January 1986. RESULTS: Antibodies to HIV developed in only one of the 14 wives. At the time when this seroconversion was detected, her husband, in whom AIDS developed, had been reactive for HIV antibody for 49 months, and showed positive findings for HIV antigen for 26 months. No additional risk factors were identified for this couple. The infected female spouse, however, has a 14-year history of multiple sclerosis, and had been treated with immunosuppressant intermittently. Despite a significantly reduced number of CD4 lymphocytes, she has remained clinically asymptomatic for 17 months since seroconversion. HIV antibodies did not develop in any of the 13 remaining wives, despite the frequent practice of oral sex by six couples and reports of occasional anal intercourse by another couple.(ABSTRACT TRUNCATED AT 400 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1987

Long term follow-up of arthroscopic synovectomy for chronic hemophilic synovitis.

Recurrent hemarthrosis of the knee in hemophiliac patients leads to chronic synovitis, predisposing the joint to further hemarthroses and degeneration. Open synovectomy controls bleeding, however, significant loss of motion frequently results. We are reporting on seven patients who underwent arthroscopic synovectomy and had decreased bleeding episodes while maintaining range of motion. The seven patients had frequent recurrent hemarthroses despite medical management. All had had signs of degenerative arthritis preoperatively. Five of the seven had loss of motion. Length of follow-up averaged 4 years. Six of the seven had reduced bleeding episodes with an average of 0.22 hemarthroses per week. The seventh patient required significantly less Factor to control bleeding. No patient lost more than 10 degrees of motion. Three patients had increases in motion; two were unchanged. Radiographic progression of degenerative changes was noted in five patients, the other two were unchanged. We recommend early arthroscopic synovectomy in the treatment of recurrent hemarthrosis in hemophiliac patients.

Adolescent↗
PubMed1986

Factors related to eating disorders in young adolescent girls.

The objective of this study was to identify factors related to eating disorders in young adolescent girls. Three hundred eighty-five girls who were attending a career conference at a midwestern university completed the Eating Disorder Instrument (EDI) along with a biographical data sheet. The EDI is designed for the assessment of psychological and behavior traits common in eating disorders. While 81% of the young subjects were assessed to be within the range for ideal weight or were underweight, 78% preferred to weigh less. Only 14% were satisfied with their current weight. Findings for each of the subscales used revealed significant differences among the girls based on intact versus broken family; subjects' actual and preferred weight; whether the family ate meals together; average grades; age and grade in school; fathers' occupation; future career plans; place of residence; and feelings toward their mothers.

Adolescent↗
PubMed1978

Pharmacokinetics of fentanyl as determined by radioimmunoassay.

The pharmacokinetics of fentanyl were determined in human surgical patients using radioimmunoassay. Fentanyl was measured in the serum, cerebrospinal fluid (CSF), and urine of patients receiving 0.1, 0.5, or 1.0 mg/m2 of fentanyl intravenously. The kinetics of the disappearance of fentanyl from the serum were very similar at the three administered doses. At all doses, levels fell rapidly in the first five minutes to approximately 20% of the peak value. Thereafter, serum levels fell more slowly with an observed half-life (t 1/2) of approximately 10 to 20 min. depending on dose. By 2 hr serum levels had stabilized at low values (1, 5, and 8 ng/ml) and continued to decrease very slowly thereafter, with an observed t 1/2 of 1 to 2 hr at the low dose (0.1 mg/m2) and greater than 4 hr at 0.5 and 1.0 mg/m2. The serum elimination curves were dissected and described mathematically in terms of a three-compartment model. Urinary excretion of fentanyl accounted for 15% to 20% of the administered dose. Urinary excretion was very low during the first 2 hr, suggesting that this route of elimination is not important in terminating the actions of fentanyl in man. Fentanyl levels in the CSF of patients given terminating the actions of fentanyl in man. Fentanyl levels in the CSF of patients given the high dose (1 mg/m2) were low, and never exceeded 4 ng/ml. Peak levels of fentanyl in the CSF were not seen until at least 15 min after administration.

Adult↗
PubMedDate not supplied

Nephrotic syndrome associated with hypocomplementemia in a 4-year-old boy with hemophilia B.

PURPOSE: The case of a 4-year-old boy with hemophilia B with inhibitor who developed nephrotic syndrome is described. The possible association between factor IX therapy and nephrotic syndrome in patients with hemophilia B is discussed. PATIENT AND METHODS: A chart review of a 4-year-old boy with hemophilia B and an inhibitor who developed nephrotic syndrome with transient hypocomplementemia was performed. In addition, a literature search was undertaken to determine the prevalence of this association and possible etiologic factors. RESULTS: Although the nephrotic syndrome was resistant to steroid therapy and Bebulin (Osterreichisches Institut für Haemoderivate Ges.M.B.H., Subsidiary of Immuno AG, Vienna, Austria) infusions were continued, the edema resolved and proteinuria decreased. Seven month later, proteinuria, accompanied by transient hypocomplementemia, increased again. A rise in factor IX inhibitor level was observed. The patient received no immunosuppressive therapy, and exhibited a continuous decrease in urinary protein excretion over the following months. DISCUSSION: A discussion about possible differential diagnoses and a review of the literature are presented.

Child, Preschool↗