Time Of First Observation Research Articles

The Lack of Nocturnal Serum Thyrotropin Surge in Patients with Nontoxic Nodular Goiter May Predict the Subsequent Occurrence of Hyperthyroidism*

TSH secretion, with particular regard to the nocturnal TSH surge, was evaluated in 115 subjects with non-toxic nodular goiter. All patients were clinically and biochemically euthyroid. After 18-36 months of follow-up (mean, 24 months), hyperthyroidism occurred in 21 (18%; group 1), while the remaining 94 remained euthyroid (82%; group II). The analysis of hormonal data at the time of first observation showed that the 2 groups had similar total and free T4 and T3 serum concentrations. Morning serum TSH values in group I were lower than those in group II patients (0.6 +/- 0.1 vs. 1.1 +/- 0.1 mU/L; P less than 0.001); this difference was even more striking for the nocturnal values (0.6 +/- 0.1 vs. 2.2 +/- 0.2 mU/L; P less than 0.0001); nocturnal values were significantly lower than morning values in group II, but not in group I. The mean peak TSH value after TRH was also significantly reduced in group I (5.5 +/- 0.4 vs. 9.2 +/- 0.7 mU/L; P less than 0.001). Morning TSH values in group II did not differ from those in controls (1.3 +/- 0.1 mU/L), whereas nocturnal and TRH stimulated peak TSH values were slightly but significantly lower. The nocturnal serum TSH values in control subjects were 62-390% higher than morning values. The nocturnal TSH surge was abolished in 18 of 21 (86%) group I patients and in 7 of 94 (8%) group II patients. TRH testing resulted in an absent or blunted TSH responses in 5 subjects in group I and 6 in group II. Analysis by the Galen and Gambino predictive model; comparing the abolition of the nocturnal TSH surge and the abnormal TRH test as predictors of the subsequent occurrence of hyperthyroidism, showed that the former had higher sensitivity (86% vs. 24%) and predictivity (72% vs. 45%). In conclusion, the results of the present study demonstrate that the evaluation of the nocturnal TSH surge may be useful in identifying patients with nontoxic nodular goiter in whom hyperthyroidism may eventually occur. Patients who lack the nocturnal serum TSH surge are more prone to develop thyroid hyperfunction; their thyroid status should, therefore, be more carefully and frequently monitored.

Effects of an LHRH antagonist on gonadotrophin and oestradiol secretion, follicular development, oestrus and ovulation in Holstein heifers

Mature cyclic Holstein heifers were given a luteolytic dose of cloprostenol followed by two i.v. injections, 12 h apart, of various doses of [Ac-D-Nal1, D-p-Cl-Phe2, D-Trp3, D-Arg6, D-Ala10]-LHRH, beginning either at the time of first observation of behavioural oestrus, or 48 h after the cloprostenol injection. When treatment began at the first observation of oestrus, the time of ovulation, as determined by ultrasonic echography, was significantly delayed by total doses of 0.8 mg or more of the antagonist. When given at 48 and 60 h after cloprostenol injection, a total dose of 1.5 mg of the antagonist significantly delayed the growth of the ovulating follicle, the onset of oestrus, the preovulatory surges of oestradiol, LH and FSH, and ovulation. It is concluded that the LHRH antagonist can effectively suppress endogenous LH secretion and may therefore be useful in the study of follicular development, ovulation, and other events in the oestrous cycle of the cow.

Prediction of surgery for obstruction in Crohn's ileitis. A study of 64 patients.

The charts of 64 patients with Crohn's ileitis were reviewed to determine what characteristics at the time of first observation at a specialized center were predictive of surgery for irreversible obstruction, using Cox's proportional hazard model. Individual variables which proved significant (P less than 0.01) included age at presentation to the clinic, serum albumin, sedimentation rate, and the presence of radiologic strictures. Patients eventually requiring surgery were older than the rest because of a later date of symptom onset; furthermore, patients with strictures on initial x-rays had not been ill for a longer period of time than those who did not have strictures. These data suggest that fibrosis and stenosis are characteristic of a subgroup of Crohn's patients, rather than being inevitable phases of disease evolution. Multivariate analysis revealed that patients with low serum albumin, high sedimentation rate, and roentgenologic stenosis at first observation were ten times as likely to require surgery for obstruction at 10 years than those without any of these three unfavorable parameters.

Influence of Season on Timed Inseminations of Dairy Heifers Synchronized by Postagladin F2α

Sixty-six cycling Holstein heifers were given two injections of prostaglandin F2α (25mg intramuscular) at an 11-day interval. Average time of first observation of estrus differed little between July (55.7±5.3h) and December, 1980 (50.6±5.1h). Heifers were inseminated artifically at either 65 or 80h following the second injection of prostaglandin. Synchronized heifers inseminated at 65h had a higher conception rate in July (9/18; 50%) than in December (3/15; 20%). However, heifers inseminated at 80h had a similar conception rate in July (9/18; 50%) and in December (8/15; 53%).Progesterone in blood serum was measured prior to the second prostaglandin F2α injection before insemination and on day 21 postbreeding. Averages of progesterone for the 65-h group were 3.91±.48, .39±.07, and 3.80±.76ng/ml in July and 4.25±.44, .33±.08, and 3.91±.63ng/ml in December for the three collections. Averages for the 80-h group were 3.62±.28, 1.06±.56, and 3.60±.65ng/ml in July and 2.17±.35, .22±.07, and 2.77±.43ng/ml in December. An influence of season on response to prostaglandin and timed inseminations in dairy heifers may affect estrus behavior and conception rate.