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Biomedical subjects

H A Ross

Publications and source records attributed to H A Ross.

At least 55 records · Page 3Linked to original sources
PubMed1989

Thyroid hormone binding in early pregnancy and the risk of spontaneous abortion.

Serum thyroxine (T4), free thyroxine (FT4) and thyroxine binding globulin (TBG) were measured at 6, 8, 10, 12, 14 and 16 weeks menstrual age (MA) in 32 pregnant females, who had been selected for a high risk of spontaneous abortion on account of previous abortion (18 cases) or ovulation induction (14 cases). Eight of these subjects experienced a spontaneous abortion occurring between 8 and 20 weeks. The other women, who carried to term, served as controls. In the abortion group, mean pre-abortion TBG and T4 levels were lower than in the control group from the 6th week on. In spite of this, the way T4 changes with TBG was very similar in both groups. No detectable change or difference with respect to control values were observed for FT4. These observations are taken as evidence against impaired maternal thyroid function playing a role in the unsuccessful outcome of pregnancy. Decreased TBG was detected on the average at 5.2 (range 0-13) weeks before abortion. Diagnostic sensitivity and positive predictive value were estimated as about 70 and 80%, respectively, for the high-risk group, indicating that serum TBG might only play a minor role as a predictor of the outcome of pregnancy.

Abortion, Spontaneous↗
PubMed1988

Salivary and plasma free testosterone and androstenedione levels in women using oral contraceptives containing desogestrel or levonorgestrel.

The effect of oral contraceptives (OC) containing a combination of ethinyloestradiol (EE2) and either desogestrel (Dg/EE2) or levonorgestrel (Lg/EE2) on plasma concentrations of sex hormone binding globulin (SHBG), total testosterone (T), free T, total androstenedione (A), free A and on salivary T and A concentrations have been studied. SHBG concentrations were higher in the Dg/EE2 group than in the Lg/EE2 group. Total T, measured by RIA with prior extraction and chromatography, is also higher in the Dg/EE2 group. Per cent free T was lower in the Dg/EE2 group. Plasma free T and free A concentrations were the same in both groups. However, free T and free A were significantly lower in the OC-groups than in controls. In contrast, by direct assay, no difference in total T was observed between the OC-groups. Since the per cent free T was lower in the Dg/EE2 group, it would be concluded that free T in the Dg/EE2 group is lower than in the Lg/EE2 group. Salivary free T and free A concentrations did not differ between control and OC-groups. There was good correlation between salivary and free hormone concentrations within each group. We conclude that the concentrations of androgens in saliva do not necessarily directly reflect their free concentrations in plasma.

Adolescent↗
PubMed1987

A symmetric dialysis method for the determination of free testosterone in human plasma.

We describe a symmetric dialysis (SYD) method for the determination of the fraction (fT), and the concentration (FT) of non-protein-bound testosterone (T) in human plasma. In SYD fT is estimated from the rate at which radiolabelled testosterone redistributes between two identical (undiluted) plasma aliquots separated by a dialysis membrane. We compared the effect of tracer contamination and sample dilution on FT as measured by SYD and equilibrium dialysis (EQD) in five plasma pools differing in Sex Hormone Binding Globulin (SHBG) and total T concentration. In addition, FT was calculated by computer simulation of the interaction between binding proteins and steroid hormones. With SYD relatively small decreases in FT were observed following two- to tenfold dilution (14.3 +/- 4.4%). A comparable decrease was calculated by computer simulation (13.3 +/- 2.2%). The apparent fall in FT as estimated by EQD was much larger (44.7 +/- 2.2%) and, contrary to assessment by SYD, this fall depended on the radiochemical purity of the 3HT-tracer. Moreover, since SYD allows the assessment of fT in undiluted samples, problems relating to the interference of buffer components with T-binding are circumvented. We conclude that SYD is to be preferred over EQD for the accurate and precise measurement of fT and consequently FT.

Dialysis↗
PubMed1987

The effect of oral contraceptives on plasma-free and salivary cortisol and cortisone.

The effect of a low estrogen oral contraceptive (OC) on glucocorticoid levels in plasma and saliva as well as glucocorticoid binding was studied in 23 healthy women using 30 micrograms ethinyl estradiol (EE2) + 150 micrograms desogestrel (Marvelon) (II). Fifteen healthy females with normal menses served as controls (I). Blood and salivary samples were taken between 9.00 and 9.30 a.m. on the 18th day of menstrual or pill cycle. Assay accuracy had been optimised by applying extraction and chromatographic purification before radioimmunoassay (RIA) of cortisol and cortisone in both plasma and salivary samples. Free steroid assays were performed by applying the same procedure to equilibrium dialysates obtained after dialysing plasma against an equal volume of buffer, instead of measuring tracer distribution. Corticosteroid Binding Globulin (CBG) was measured by a commercial RIA. As expected, CBG as well as plasma total cortisol were elevated in the pill group. Interestingly both plasma free and salivary cortisol were higher than in controls (free cortisol I: 18.0 +/- 7.95 nmol/l; II: 32.3 +/- 9.03 nmol/l; salivary cortisol I: 9.2 +/- 3.88 nmol/l; II: 18.8 +/- 6.92 nmol/l. Salivary cortisol closely parallelled plasma free cortisol both within and between the groups, though at a much lower level (about 50%). Free cortisone was slightly lower in the pill group (I: 10.8 +/- 2.55 nmol/l; II 8.5 +/- 1.86 nmol/l) whereas salivary cortisone was 2.3 (I) and 4.4 (II) times higher than plasma free cortisone and tended to follow the plasma free and salivary cortisol pattern, both within and between the study groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Hypotensive effects of ovine and human corticotrophin-releasing factors in man.

The haemodynamic effects of i.v. bolus injections of 100 and 200 micrograms ovine CRF and human CRF in man have been compared. Neither ovine CRF 100 micrograms nor human CRF 100 micrograms caused a significant change in blood pressure, although the pulse rate was increased in all the subjects tested. The mean maximum increase in pulse rate after human CRF was almost twice that after ovine CRF (21 vs 12 beats X min-1; p less than 0.05). After 200 micrograms ovine CRF in all subjects the diastolic blood pressure declined gradually from 77 mm Hg to a nadir of 67 mm Hg at 22 min (p less than 0.002). After 200 micrograms human CRF diastolic blood pressure fell from 78 mm Hg to a nadir of 61 mm Hg at 6 min (p less than 0.002); the fall after human CRF was significantly greater than after ovine CRF (p less than 0.05). After 200 micrograms ovine CRF there was a slight increase in pulse rate lasting for 6 min, and after 200 micrograms human CRF there was a marked (reflex) tachycardia for 30 min. Only after the highest dose of human CRF did a slight increase in systolic blood pressure occur. The haemodynamic effects of both doses of human CRF were accompanied by significant increases in plasma noradrenaline concentrations, which were significantly greater after the higher dose.

Adolescent↗
PubMed1986

Optochiasmatic arachnoiditis with treatment by surgical lysis of adhesions, corticosteroids, and cyclophosphamide: report of a case.

A 24-year-old woman presented with progressive optochiasmatic arachnoiditis causing progressively worsening visual loss associated with headache and amenorrhea. Treatment with the standard initial therapy of dexamethasone, warfarin, and dipyridamole was unsuccessful at halting her disease process. Surgical lysis of adhesions led to a temporary improvement and then deterioration. A course of therapy with cyclophosphamide was initiated and her response to this therapy resulted in resolution of her headaches, return of her vision to normal, and resumption of her normal menstrual cycles.

Adrenal Cortex Hormones↗
PubMed1985

Disparity of thyrotropin (TSH) and prolactin responses to TSH-releasing hormone in obesity.

The effect of TRH administration on TSH and PRL release was investigated in 11 obese women and 16 normal weight women. There were no differences in basal serum levels of estradiol, T3, T4, TSH, or PRL between the 2 groups. The increment of TSH levels in the obese group [mean maximum change (delta max), 19.3 +/- 3.0 (+/-SEM) mIU/liter] was significantly higher (P less than 0.025) than that in the control group (delta max, 11.3 +/- 1.3 mIU/liter), whereas PRL levels rose significantly less (P less than 0.025) in these obese women than in the control group (delta max, 738 +/- 132 and 1311 +/- 133 mIU/liter, respectively). Since serotonin is known to stimulate PRL and inhibit TSH release, deficiency of serotonin has been hypothesized as the cause of this disparity between TSH and PRL levels in obesity.

Adolescent↗
PubMed1983

A controlled clinical trial of alprazolam for the treatment of anxiety.

The authors report the results of a large-scale double-blind study comparing the anxiolytic effects of alprazolam, a triazolobenzodiazepine; diazepam, a 1,4-benzodiazepine; and placebo in 151 anxious outpatients. Alprazolam and diazepam produced similar clinical improvement, which was significantly larger than improvement produced by placebo and was clearly evident after only 1 week of treatment. The incidence of sedation was lower with alprazolam than with diazepam.

Adult↗
PubMed1982

A comparative study of free thyroxine estimations.

Two commercial methods (Immophase, Corning and FT4, Lepetit) for the measurement of free thyroxine (FT4) in serum have been experimentally evaluated. Ease of handling and rapidity were satisfactory. Precision profiles showed intra-assay coefficients of variation not exceeding 5% over the entire measurement range (0-70 pmol/l) for both methods. Interassay coefficients of variation were below 8%. Assay results of both methods correlated well with those obtained with a symmetric dialysis method, with correlation coefficients of 0.95 for the Immophase and 0.93 for the Lepetit method and slopes not significantly different from unity. Comparison with this reference method did not give any indication of serious methodological error in either of the kits in spite of theoretical doubts with regard to one of them.

Female↗
PubMed1982

Discussion groups.

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Group Processes↗
PubMed1981

Clobazam and diazepam in anxiety.

The anxiolytic effects of clobazam, diazepam, and placebo were compared in a 4-wk double-blind study of 159 anxious outpatients, primarily from family practice. Clobazam (30 to 80 mg/day) and diazepam (15 to 40 mg/day) were found to induce similar side effect, primarily sedation, and although both active drugs induced greater clinical improvement than placebo, clobazam induced the largest degree of improvement in most aspects. It was speculated that the relatively high daily dosage of diazepam may have been contributed to these results.

Adult↗
PubMed1977

Seasonal variation in serum T3 and T4 levels in man.

In a group of 13 healthy male adults in the Netherlands, a seasonal variation in circulating serum thyroxine (T4) and triiodothyronine (T3) levels was found, inversely correlating with the seasonally altering environmental temperature. Lowest serum T4 and T3 levels were found in the summer.

Adult↗