[The development of a sensitive radioimmunoassay for H-TSH and its clinical application (author's transl)]

Using a commercially available h-TSH RIA kit (Daiichi), a sensitive RIA method was developed. When pooled serum from patients with active Graves' disease was used as a carrier, combined applications of a delayed addition of 125-I TSH and utilization of X2 diluted anti-TSH antibody resulted in the consistent detection of 0.156 microunits/ml level of serum TSH. Further, 0.078 microunits/ml level could also be detected when 200 microliter of serum samples were applied. However, usage of 200 microliter sample volume should be determined after further studies concerning possible non specific effects of human serum. Assay results of 29 patient sera by the sensitive assay correlated quite well (r = 0.953, Y = 0.97X-0.06) with those by the regular assay. Serum TSH in all of the 20 normal subjects were detectable and ranged from 0.31 to 3.2 microunits/ml giving mean values of 1.48 +/- 0.65 (s.d.) microunits/ml. Values less than 0.156 microunits/ml were observed in patients with untreated Graves' disease, acute stage of subacute thyroiditis, and panhypopituitarism, and in postoperative cancer patients under suppressive doses of T-4. In conclusion, this sensitive TSH RIA made clear discrimination of low and normal serum TSH possible, and the clinical application of this method was considered quite useful.

Biomedical applications of magnetic fluids. i. Magnetic guidance of ferro-colloid-entrapped albumin microsphere for site specific drug delivery in vivo

Magnetic guidance of magnetic albumin microsphere for site specific drug delivery was investigated in vivo. After intravenous injection in mice, magnetic microspheres localized in the site (lung) at which two permanent magnets were placed. Injection into the renal artery in rats also indicated that the microspheres were concentrated at the kidney by a magnetic field. When magnet was not applied, however, the microspheres were concentrated mainly in the liver. Such preferential localization by magnetic means suggested that magnetic albumin microspheres could become effective drug carriers with site specificity for the delivery of chemotherapeutic agents in cancer therapy.

Increased serum oestrone and oestradiol following spironolactone administration in hypertensive men

The present study was undertaken to evaluate long-term effects of spironolactone on basal serum oestrone, oestradiol, testosterone, LH and prolactin concentrations in hypertensive male patients. Serum prolactin response to TRH was also evaluated. Patients were divided into two groups: a conventional-dosage group, consisting of six males with essential hypertension who took 75 to 150 mg of spironolactone daily for 12 weeks, and a high-dosage group, consisting of two males with idiopathic hyperaldosteronism who took 300 mg of spironolactone daily for more than 40 weeks. In the conventional-dosage group, serum oestrone concentrations significantly increased (P less than 0.01) at 12 weeks, serum oestradiol concentrations gradually increased throughout the study period, however, the increments were not statistically significant (P less than 0.2). Basal serum testosterone, LH and prolactin concentrations were not significantly changed throughout the study period. Enhancement of serum prolactin response to TRH was not found in any of the patients in the conventional-dosage group. In the high-dosage group, serum oestrone maintained high levels from the beginning of this study, and serum oestradiol concentrations increased with the development of gynaecomastia. Serum testosterone, LH and prolactin concentrations did not show any definite change throughout the study period. Thus, long-term spironolactone treatment increased the serum levels of oestrone and oestradiol in hypertensive men followed by the development of gynaecomastia. The elevation in circulating oestrogens could well explain the oestrogenic side-effects of spironolactone treatment.

Circadian rhythm of plasma corticosteroid in adult female rats: chronological shifts in abnormal lighting regimens and connection with oestrous cycle

The circadian rhythm of plasma corticosteroid (CS) levels in adult female rats was studied chronologically under the following conditions: normal light-dark (LD), inverted light-dark (DL), constant dark (DD) and constant light (LL). Animals were accustomed to LD condition for 7 days before exposure to each abnormal lighting regimen. Normal circadian rhythm established under LD condition was clearly inverted on the third day of DL regimen, and the inverted rhythm persisted thereafter under DL condition. The circadian CS rhythm persisted essentially unchanged throughout DD condition, but lost its regular periodicity showing "free running" and changed day by day under LL condition. The average CS levels over a 24 h period were higher under LL than under DD condition. Plasma CS levels in each lighting regimen exhibited diurnal variations regardless of the vaginal smear patterns of autopsied animals. Exposure of rats to LL for 21 days made the circadian CS rhythm flat, but induced persistent oestrus in only a few animals. The data suggest that (1) an unexpectedly rapid inversion of the circadian CS rhythm occurs if animals are exposed to inverted light-dark environment; (2) constant darkness seems to be a near-natural environment for rats, and changes little of the pre-established circadian CS rhythm; (3) constant light, on the contrary, is assumed to be a stress for rats, and disrupts the circadian CS rhythm and elevates CS levels; (4) the change in circadian CS rhythm in adult female rats is not mediated by a change in gonadal function and the two conditions may not be connected directly with each other.

[Effects of various psychotropic drugs on self-stimulation behavior in the rat]

Effects of various psychotropic drugs on tegmental and hypothalamic self-stimulation behavior in rats with chronically implanted electrodes in the brain were studied. Effects of elecrtical stimulation in several brain structures on self-stimulation behavior and influences of drugs on the stimulation effect were also investigated. The hypothalamic self-stimulation behavior was more markedly inhibited by chlorpromazine than the tegmental self-stimulation, whereas the latter was more strongly inhibited by diazepam. The effects of pentobarbital on the self-stimulation behavior were similar to those of diazepam. Methamphetamine facilitated both the tegmental and hypothalamic self-stimulation behavior. Suppressive effect of hypothalamic stimulation on the tegmental self-stimulation behavior was inhibed by chlorpromazine, while those of amygdaloid and septal stimulation were augmented. All the effects of hypothalamic, amygdaloid and septal stimulating on the tegmental self-stimulation behavior were inhibed by diazepam and pentobarbital, while these were facilitated by methamphetamine. Suppressive effects of tegmental, amygdaloid and septal stimulation on the hypothalamic self-stimulation behavior were all facilitated by both chlorpromazine and methamphetamine. The effects of amygdaloid and septal stimulation on this behavior were inhibed by diazepam and pentobarbital, while those of tegmental stimulation were enhanced. The effects of imipramine, in all experiments, were variable in each rat and not significant.