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Biomedical subjects

G Crowley

Publications and source records attributed to G Crowley.

7 recordsLinked to original sources
PubMed1988

Determination of the antidepressant fluoxetine and its metabolite norfluoxetine in serum by reversed-phase HPLC with ultraviolet detection.

A procedure has been developed for measuring fluoxetine and its desmethyl metabolite, norfluoxetine, in serum by reversed-phase high-performance liquid chromatography (HPLC), with ultraviolet detection at 226 nm. Fluoxetine and norfluoxetine are isolated from serum by liquid-liquid extraction. They are then separated by HPLC and quantified, with reduced haloperidol as the internal standard. Fluoxetine, norfluoxetine, and the reduced haloperidol are separated from all interfering peaks in about 15 min. The standard curve is linear (r = 1.000) for both fluoxetine and norfluoxetine concentrations over the range of 25 to 800 micrograms/L. Between-run CVs for 60 and 200 micrograms/L controls (n = 8) were 6.8 and 4.1% for fluoxetine, and 8.8 and 6.2% for norfluoxetine, respectively. In a study of 24 patients with depression who were being treated with 20-60 mg of fluoxetine per day, fluoxetine and norfluoxetine concentrations in serum, measured during the last three weeks of treatment, were 47-469 micrograms/L and 52-446 micrograms/L, respectively.

Antidepressive Agents↗
PubMed1987

Data-reduction methods for immunoradiometric assays of thyrotropin compared.

In an attempt to optimize curve fitting for immunoradiometric assays, we investigated eight data-reduction methods with two commercially available assays of thyrotropin. In four of these methods linear data-reduction models are used: logit-log programs of Iso-Data, Micromedic, and Hewlitt-Packard, and probit-log of Hewlitt-Packard. The other four were nonlinear data-reduction models: Iso-Data's "French curve" (modified spline), four-parameter logistic function, and point-to-point methods, as well as a nonlinear least squares method. In using the eight data-reduction methods on data from analyses of 78 patients' samples, we found clinically relevant differences between models. In fact, differences found by changing data-reduction models were greater than the difference between the two commercial kits.

Humans↗
PubMed1985

Free triiodothyronine (T3) and thyroxine (T4) in a group of unipolar depressed patients and normal subjects.

We examined levels of free triiodothyronine (fT3) and free thyroxine (fT4) in serum from a group of 32 patients with unipolar major depression and 46 normal control subjects using the Amerlex (Amersham, Arlington Heights, IL) RIA procedures for these hormones. Free T3 levels were significantly lower (p less than 0.004) in the depressed patients as a group (5.02 +/- 1.01 pmol/L, mean +/- SD) than in the normal control subjects (5.74 +/- 1.23 pmol/L). Free T3 levels were lower (p less than 0.01) in depressed men (5.25 +/- 1.43 pmol/L) when compared with male control subjects (6.46 +/- 1.01 pmol/L). Depressed women (4.78 +/- 0.60 pmol/L) also had lower T3 levels than did the female control subjects (5.09 +/- 1.06 pmol/L), but the difference was not statistically significant. Lower fT3 levels were also observed in melancholic depressed patients when compared with nonmelancholic depressed patients or when compared with normal control subjects. No differences in fT4 were observed between groups in this study.

Adolescent↗
PubMed1984

TRH-induced prolactin release is blunted in females with endogenous unipolar major depression.

Twenty-five women with unipolar primary major depressive disorder (20 endogenous, 5 nonendogenous) and 20 female control subjects were studied with the thyrotropin-releasing hormone stimulation test (TRH-ST). Prolactin (PRL) levels were measured before and after TRH administration for patients and control subjects. For patients, thyrotropin (thyroid-stimulating hormone; TSH) levels were measured from the same serum specimens as PRL levels, and the 1 mg dexamethasone suppression test (DST) was performed. Patients with endogenous depression (ED) had significantly lower maximal serum PRL levels (max PRL) following TRH, and a significantly reduced increase over basal serum PRL (delta max PRL) compared to normal controls (NC). Nonendogenous depressed (NED) patients did not differ significantly from the ED or NC groups on either of these measures. For the ED group, delta max PRL was inversely correlated with severity of depressive symptomatology. Basal PRL levels did not differentiate the depressed subgroups (ED, NED) from each other or from the NC group. Depressed patients with blunted delta max PRL values tended to have blunted delta max TSH values and vice versa. Almost all patients with blunting of either delta max PRL or delta max TSH were also DST nonsuppressors; conversely, only about half (7 of 12) of patients who were DST nonsuppressors had either blunted delta max PRL or delta max TSH. Patients with clinical diagnoses of melancholia or psychotic features were significantly more likely to have blunted delta max PRL values than patients without these diagnoses. A disturbance of central noradrenergic function could explain these findings.

Adult↗
PubMed1977

Progesterone and 5alpha-pregnane-3,20-dione in peripheral blood of normal young women: Daily measurements throughout the menstrual cycle.

The peripheral plasma concentrations of progesterone and 5alpha-pregnane-3,20-dione were measured daily throughout the ovarian cycle of five presumptively ovulatory women. The concentrations of progesterone and 5alpha-pregnane-3,20-dione during the follicular phase were 0.11 +/- 0.02 ng/ml (mean +/- SE) and 0.16 +/- 0.01 ng/ml, respectively. In four of these women the concentrations of both progesterone and 5alpha-pregnane-3,20-dione began to rise immediately after the luteinizing hormone (LH) peak and reached maximal concentrations five to eight days later (progesterone: 8.6 to 19.9 ng/ml; 5alpha-pregnane-3,20-dione: 1.4 to 2.8 ng/ml). The luteal phases in these women, measured from the day of the LH peak to the onset of the next menses, varied from 13 to 18 days. In the other woman with a late LH surge (day 27 of the cycle) the peak concentrations of progesterone and 5alpha-pregnane-3,20-dione were reached four days after the LH peak (8.9 ng/ml and 0.8 ng/ml, respectively). The luteal phase in this woman was 11 days. From the results of this study, it appears that the concentrations of 5alpha-pregnane-3,20-dione in peripheral blood during the luteal phase are proportional to the availability of progesterone as substrate for the 5alpha-reductase enzyme system.

Female↗