Laboratory and clinical studies on the mechanism of action of timolol

Timolol is now widely used in the treatment of glaucoma but its mechanism of action is unclear. The drug decreases aqueous humor formation by the ciliary processes and is a potent beta-adrenergic antagonist. However, the physiological basis for such a drug to decrease intraocular pressure has not been clearly demonstrated.

Endogenous opioid regulation of gonadotropin-releasing hormone release from the human fetal hypothalamus in vitro

Endogenous opioid regulation of GnRH release from the human fetal (21-23 weeks gestation) mediobasal hypothalamus was investigated in an in vitro perifusion system. Pulse injection of an opiate receptor antagonist, naloxone, reproducibly elicited an acute increase in GnRH release within 30 min. Constant infusion of naloxone (60 min) induced a sustained increase in GnRH release, which was promptly inhibited by a pulse of beta-endorphin administered halfway during the naloxone infusion. These studies unequivocally demonstrate that endogenous opiates exert an inhibitory effect on GnRH release from the human fetal mediobasal hypothalamus in vitro.

Augmentation of ACTH-releasing activity of synthetic corticotropin releasing factor (CRF) by vasopressin in women

In order to study the interaction between vasopressin (VP) and hypothalamic corticotropin releasing factor (CRF) on the release of ACTH, VP and CRF were administered separately and in combination to normal cycling women. The combined hormones raised plasma ACTH levels higher than the sum of the separate responses and 5 times more than CRF alone. This study reveals for the first time synergism between VP and CRF in their ACTH releasing effects in humans.

Induction of midcycle gonadotropin surge by ovarian steroids in women: a critical evaluation

Despite major efforts, the roles of estradiol (E2) and progesterone (P4) as signals for triggering the midcycle gonadotropin surge in women remain incompletely defined. In the present study, a preovulatory configuration of E2 and P4 levels was achieved during the midfollicular phase of normal women and in hypogondal women (with E2 implants) by stepwise incremental infusions of E2 and P4. During the 96 h of E2 infusion alone, reproducible and concomitant surges of LH and FSH occurred after latency periods of (mean +/- SE) 58 +/- 6.9 and 68.2 +/- 2.6 h in midfollicular and hypogonadal subjects, respectively. The mean duration of the E2-induced surge was shorter for both normal midfollicular (22.7 +/- 3.9 h) and hypogonadal women (21.8 +/- 2.5 h) than is the spontaneous midcycle surge (48 h). When P4 infusion was superimposed 48 h after the initiation of E2 infusion, a LH/FSH surge that approximated the dimension of the spontaneous surge was achieved in both groups of women. For the hypogonadal women, but not midfollicular women, P4 infusion also advanced the surge onset by 14.7 h (P less than 0.001). Our data represent the first unequivocal demonstration that incremental E2 sustained for about 60 h constitutes the ovarian signal for initiating the midcycle gonadotropin surge and that a small increment of P4 secreted by the preovulatory follicle is required to establish the normal dimension of the surge. Thus, P4, although essential for creating a normal gonadotropic surge, operates by synergizing the obligatory action of E2.

Effects of l- and d-timolol on cyclic AMP synthesis and intraocular pressure in water-loaded, albino and pigmented rabbits

Topical 2% l- or d-timolol reduced the elevation of intraocular pressure induced by water-loading in conscious rabbits. This drug effect appeared on the peak elevation (in pigmented eyes) and on the down-phase (in albino and pigmented eyes) of elevated intraocular pressure. The contralateral eye and the treated eye responded similarly. In urethane anesthetized, water-loaded rabbits, a greater inhibitory effect of l-timolol was observed in pigmented eyes than in albino eyes. Two per cent l-timolol caused alterations of heart rate and arterial blood pressure in water-loaded anesthetized rabbits, but time courses of these alterations did not correlate with the inhibitory effect on the elevation of intraocular pressure. The beta-adrenergic antagonistic activity of l-timolol and d-timolol were compared by their ability to inhibit l-isoproterenol-stimulated cyclic AMP synthesis in the rabbit iris-ciliary body preparation in vitro. The I50S for l- and d-timolol differ by about 1.5 log units. In our studies, d-timolol has little of the intraocular pressure lowering and the beta-adrenergic antagonistic activity of l-timolol. Thus, the conscious, water-loaded, pigmented rabbit can be used as a model for studying the effects of beta-adrenergic antagonists on intraocular pressure.

Induction of multiple ovulation by pulsatile administration of gonadotropin-releasing hormone

Pharmacologic doses of gonadotropin-releasing hormone (GnRH) pulses (10 micrograms) were used for the induction of multiple follicular development in six normal cycling women. GnRH administration via an autoinfusion pump (intravenously at 60- to 120-minute intervals) was begun on day 5 after the onset of menses. During these stimulated cycles, two to five follicles of preovulatory size were detected by sonography in all subjects. In two subjects, follicle aspiration was performed with successful oocyte recovery. Assessment of the follicular fluid steroid concentrations from these follicles suggests that two of three (subject 5) and four of five (subject 6) follicles were mature. Gonadotropin levels of treated cycles were significantly higher than in normal cycles. Both follicular and luteal phases were of normal duration but were associated with significantly elevated estradiol and progesterone levels, respectively. Timely midcycle gonadotropin surges occurred by days 12 to 14 in all cases. Thus, ovarian steroid feedback control of gonadotropin secretion can be overridden by larger pulses of GnRH, resulting in the development of multiple follicles. This technique may prove useful for in vitro fertilization.

Fetal pulmonary maturity: relationship between optical density (650 nm) to the lecithin/sphingomyelin ratio and phosphatidylglycerol in amniotic fluid

An optical density value greater than or equal to 0.15 at A650 n m of amniotic fluid obtained through transabdominal amniocentesis from a high risk obstetrical population, which excluded diabetes mellitus, isoimmunization, and amniotic fluid infection, correlated 98.6% with a mature lecithin to sphingomyelin ratio (L/S) greater than or equal to 2.0% and 41.6% with the presence of phosphatidylglycerol (PG). The corresponding false positive rates were 1.4% and 16.8%, respectively. In 30 infants delivered within 48 h of testing, A650 n m greater than or equal to 0.15 correlated 100% with absence of respiratory distress syndrome. A650 n m is not recommended for Rhesus immunized gestations, diabetic pregnancies and amniotic fluid infection due to a high false positive rate with A650 nm compared to L/S and PG.

Effects of synthetic corticotropin-releasing factor and dopamine on the release of immunoreactive beta-endorphin/beta-lipotropin and alpha-melanocyte-stimulating hormone from human fetal pituitaries in vitro

The effects of synthetic corticotropin-releasing factor (CRF) and dopamine on immunoreactive beta-endorphin/beta-lipotropin (i beta-END/LPH) and alpha MSH release were studied in superfused human fetal pituitary glands. CRF (20 ng) stimulated the release of i beta-END/LPH in four anterior hemipituitaries from fetuses older than 20 weeks in gestation. There was no effect on three anterior hemipituitaries from fetuses of 19-20 weeks gestation. CRF had no effect on i beta-END/LPH or alpha MSH secretion from neurointermediate lobes regardless of fetal age. Dopamine (10(-6) M) had no effect on i beta-END/LPH or alpha MSH secretion from either anterior or neurointermediate lobes. The data suggest that anterior pituitary responsiveness to CRF develops at about 20 weeks gestation and that fetal neurointermediate lobe secretion of peptides is not regulated by CRF.

Preliminary observation on Langerhan's cells in leprosy

Langerhans' cells were enumerated in the skin of eight borderline and tuberculoid leprosy patients by the enzymatic histochemical demonstration of ATPase in these cells in epidermal sheets. The number of Langerhans' cells was significantly reduced in the skin lesions of these patients compared with normal appearing skin from the same patients. The morphological details of these cells were not clear under light microscopy; further study with electron microscopy is desirable.

Fingerprint comparison. II: On the development of a single fingerprint filing and searching system

A FORTRAN program has been written to compare the minutiae coded in an"unknown" fingerprint with the minutiae of fingerprints stored in a data base. The criteria for matching are scores based on the type and number of minutiae matched. Minutiae of low relative frequency have higher scoring weights than those that are more common. The matching mechanism is tested by using a fingerprint coded several times, first by a single individual and then by six other individuals who have no previous knowledge about fingerprints. These tests yield satisfactory results.

Fingerprint comparison. I: Similarity of fingerprints

Fingerprints from 61 pairs of male monozygotic twins (MZ), 47 pairs of female MZ, 40 pairs of same-sex male dizygotic twins (DZ), 44 pairs of same-sex female DZ, 4 pairs of opposite-sex DZ, and 28 brothers and 31 sisters of those twins are used for the study of fingerprint similarities. Similarities of fingerprint pattern, ridge count, and minutiae are evaluated for two population groups genetically related to each other in different degrees. It is concluded that fingerprint similarities, including pattern, ridge count, and possibly minutiae, between MZ individuals are significantly higher than those between other population groups, including DZ twins.

Mass spectrometric differentiation of cannabinoid-containing samples

A direct-inlet probe mass spectrometry/multiple regression procedure is described for the confirmation of the presence of cannabinoids and the comparison of various cannabinoid-containing samples. The relative intensities of selected mass units are first established on control cannabinoids. These standards are then regressed on mass spectra of samples of interest. High values of coefficients of determination are used to confirm the presence of cannabinoid mixtures; regression coefficients are used for sample comparisons.

An exploratory study on the characterization of A1 and A2 bloodstains using a fluorescence immunoassay

A fluorescence immunoassay method is used in the differentiation of A1 and A2 bloodstains. Anti-A antiserum is first absorbed onto the stain. The IgM content in the eluate is then quantified by commerical Immuno-Fluor kits. The binding difference of A1 and A2 cells is retained in stains. This difference and the quantitative evaluation method provide a potential basis for blood typing or subtyping application.

Synthesis and biological properties of some novel heterocyclic homoprostanoids

In the search for prostaglandin-like structures capable of exerting specific and desirable biological properties, a variety of simple heterocyclic homoprostanoidal derivatives was synthesized from readily available stearic acid derivatives. Compounds 5b and 5e were found to be more than 100 times as potent as PGE1 and PGE2 in a tracheal chain bioassay and, like 6, 9, and 12, inhibited PGE2-induced diarrhea. Derivatives 6 and 7a showed significant PG-synthetase inhibitor activity.

Muscle postjunctional membrane: changes in chemosensitivity produced by calcium

Increases in the extracellular concentration of calcium ions above 1.8 millimoles per liter caused a reversible decrease in the sensitivity of tmuscle postiunctional membrane to carbamylcholine. A quantitative study of the inhibitory effect of calcium ions on membrane depolarization produced by carbamylcholine indicates that calcium ions compete with carbamylcholine for some common binding sites on the postjunctional membrane. Calcium ions (20 millimoles per liter) caused a neuromuscular block wherein prolonged end plate potentials were produced after nerve stimulation. Calcium ions applied ionophoretically to the postjunctional membrane decreased the amplitude and prolonged the time course of the transient depolarization produced by ionophoretically applied carbamylcholine.