Mitotic inhibition and aneuploidy induction by naturally occurring and synthetic estrogens in Chinese hamster cells in vitro.

We used a predominantly diploid Chinese hamster cell line to test a number of naturally occurring and synthetic estrogens for their ability to arrest cells at metaphase, their potential for allowing anaphase recovery, and their capability of inducing aneuploid progeny. The chemicals employed included diethylstilbestrol, dienestrol, hexestrol, beta-estradiol, ethynylestradiol and estriol. We also tested progesterone, estrone and testosterone in this regard.

Decreased hypothalamic growth hormone-releasing hormone content and pituitary responsiveness in hypothyroidism.

The effects of thyroidectomy (Tx) and thyroxine replacement (T4Rx) on pituitary growth hormone (GH) secretion and hypothalamic GH-releasing hormone (GRH) concentration were compared to define the mechanism of hypothyroid-associated GH deficiency. Thyroidectomized rats exhibited a complete loss of pulsatile GH secretion with extensive reduction in GRH responsiveness and pituitary GH content. Cultured pituitary cells from Tx rats exhibited reduced GRH sensitivity, maximal GH responsiveness, and intracellular cyclic AMP accumulation to GRH, while somatostatin (SRIF) suppressive effects on GH secretion were increased.

Receptor-associated resistance to growth hormone-releasing factor in dwarf "little" mice.

Anterior pituitaries from the dwarf mouse strain "little" did not release growth hormone or accumulate adenosine 3',5'-monophosphate (cyclic AMP) in response to human and rat growth hormone-releasing factor (GRF). Dibutyryl cyclic AMP, as well as the adenylate cyclase stimulators forskolin and cholera toxin, markedly stimulated growth hormone (GH) release. The basis of the GH deficiency in the little mouse may therefore be a defect in an early stage of GRF-stimulated GH release related either to receptor binding or to the function of the hormone-receptor complex.

Identification of a putative GH-releasing factor (GRF) batch as predominantly ovine CRF with a small quantity of human GRF.

The existence of discordant results regarding the effects of intracerebroventricular (icv) administration of GRF on GH secretion prompted a reexamination of the central actions of GRF and a detailed chemical characterization of the peptide designated as hpGRF-44-NH2. The icv injection of 10 micrograms rat (r) GRF to freely-moving rats caused an acute stimulation of GH release, whereas 10 micrograms of the putative hpGRF peptide icv continued to suppress spontaneous GH secretion. Through a series of biochemical and immunologic studies we demonstrate that peptide hpGRF-44-NH2, code number 92-81-5G-41-47, is predominantly ovine (o) CRF and also contains a small amount (3-5%) human (h) GRF-44-NH2.

Effects of intravenous, subcutaneous, and intranasal administration of growth hormone (GH)-releasing hormone-40 on serum GH concentrations in normal men.

In addition to stimulating GH release in normal subjects, GH-releasing hormone-40 (GHRH-40) stimulates GH secretion in some adults and children with GH deficiency. Recognizing that GHRH-40 may have potential as a therapeutic agent for the treatment of GH deficiency, we examined the effects of iv, sc, and intranasal (in) GHRH-40 administration on GH secretion and measured the plasma levels of immunoreactive GHRH achieved after the administration of the peptide via these different routes. Normal men were given vehicle or GHRH-40 iv (0.

Production of monoclonal antibodies against parainfluenza 3 virus and their use in diagnosis by immunofluorescence.

Monoclonal antibodies were produced against parainfluenza virus type 3 (PI-3) and used to identify PI-3 clinical isolates in cell culture and PI-3 antigen in cells obtained from nasopharyngeal (NP) washes of patients. Two (2E9 and 4G5) of the three monoclonal antibodies characterized reacted by immunoblotting with a 67,000-dalton PI-3 protein, and one antibody (4E5) reacted with two viral proteins in the range of 29,000 to 31,000 daltons. The three monoclonal antibodies did not cross-react by indirect immunofluorescence (IFA) with PI-1 or PI-2 and identified by IFA 18 isolates of PI-3 in cell culture.

An in vitro model for studies of intercellular communication in cultured rat anterior pituitary cells.

The formation of intimate associations among different hormone-secreting cells within the rat adenohypophysis may serve as a possible site for physiologic regulation. In this report we describe a high density plating method which enables us to study cell-to-cell interactions within anterior pituitary cell cultures. Trypsin-dispersed pituitary cell suspensions attach rapidly (within 6 hr) and quantitatively (95-97%) to glass or plastic surfaces when plated in medium containing microM calcium concentrations (pH 7.

Fluorometric quantification of DNA in cells and tissue.

The validation of a simple and rapid DNA solubilization procedure is described. Quantitative extraction of intact, polymerized DNA was achieved by cell lysis or tissue homogenization in an ammonium hydroxide-Triton X-100 solution. The solubilization procedure inactivates endogenous DNAase and increases the fluorescence-enhancement activity of the extracted DNA, thereby eliminating the need for enzyme treatment or exposure to high salt solutions.

Mortality and influenza.

Systematic virologic surveillance in Houston over the past seven years has revealed that influenza virus infections have been epidemic during each respiratory disease season. The peak of the occurrence of acute respiratory illnesses that caused patients to seek medical care always coincided with the peak of influenza virus activity. The peak number of deaths attributed to pneumonia or influenza followed the peak of influenza virus activity by about two weeks.

Time as a factor in atmospheric sampling.

Differences in results of simultaneous air monitoring of ozone with three different methods in the field are described. The argument is advanced that the differences are due largely to sampling turbulent atmospheres with instruments utilizing different sampling intervals and time constants. It is concluded that when sampling natural turbulent atmospheres, a stable mean value can only be achieved through integrated sampling periods of greater than ten minutes.

Circadian rhythmicity in heart rate and duration of cardiac cycle (P-P interval) in donor and recipient cardiac tissue of heart homograft patients.

Chronobiologic analyses of data collected during one or more continuous 72-hr spans from 3 heart-transplant patients adhering at diurnal activity (0700-2230) and nocturnal rest (2230-0700) reveal statistically significant circadian rhythmicity in the P-P time interval of recipients (P-P)R and the donor (P-P)D, as well as in the reciprocal measure of the latter, the heart rate. The circadian acrophase for (P-P)D and (P-P)R differ slightly (the 95% confidence arcs overlap). For the group, the acrophases for (P-P)D and heart rate at 0344 (2056 to 0528) and 1656 (0940 to 2100) agree in anti-phase, as expected.