Formation of electrical connections between cultured identified neurons and muscle fibers of the snail Helisoma.

We studied the formation of connections between identified neurons removed from the buccal ganglion of the snail Helisoma and muscle fibers dissociated from the buccal mass. Three types of identified neurons--B19, B5, and B4--were placed into cell culture and muscle fibers from the supralateral tensor muscle (SLT), normally innervated by B19, were subsequently plated adjacent to the neuronal cell bodies. Growth cones from the neurons contacted the muscle fibers within 6-12 h after isolation.

Human thyroid cells transfected with SV40 DNA retain the TSH receptor.

Human thyroid cells were transfected with SV40 DNA using the calcium phosphate co-precipitation technique. The transfected cells grew rapidly and could be passaged readily. TSH and the immunoglobulin fraction from a patient with hyperthyroid Graves' disease stimulated adenylate cyclase activity in the transfected cells.

Pharmacokinetics of nalbuphine during parturition.

Nalbuphine hydrochloride (Nubain) is a relatively new agonist-antagonist analgesic, chemically related to both oxymorphone and naloxone, which can be used as a systemic obstetric analgesic. After intravenous administration to six patients in labor at term, serial maternal serum specimens were obtained and assayed for their nalbuphine concentration. The maternal disposition of nalbuphine followed a two-compartment pharmacokinetic model, with an initial distribution phase of 4 to 20 minutes and a terminal elimination half-life of 2.

Thyrotropin-induced formation of functional follicles in primary cultures of ovine thyroid cells.

In primary cultures of ovine thyroid cells, TSH induced the expression of several differentiated functions including the formation of follicles, and synthesis and storage of iodinated thyroglobulin in the follicular lumen. In the present report, these follicles were shown by transmission (TEM) and scanning electron microscopy (SEM) to be intact, comprised of two or more cells and to possess numerous microvilli on the inner cell membranes facing the follicular lumen. The TSH-induced formation of follicles was reversible and dynamic, with the kinetics of formation preceding that of iodination.

A dosing nomogram for continuous infusion intravenous naloxone.

Naloxone hydrochloride is extremely valuable for diagnosing and managing the opioid overdose. Due to naloxone's short half life and a long duration of action of most opioids, repeated naloxone dosing often is required to prevent the recurrence of respiratory depression. An alternative to repeated bolus administration is a continuous IV infusion.

Growth and differentiation in cultured human thyroid cells: effects of epidermal growth factor and thyrotropin.

Human thyroid cells were grown and subcultured in vitro to examine their responses to known hormones and growth factors, and to serum. The cells were obtained from surgical specimens and were either neoplastic or nonneoplastic. The effects of culture conditions on cell growth were measured by changes in cell numbers and by stimulation of [3H]thymidine incorporation.

Epidermal growth factor inhibits thyrotropin-mediated synthesis of tissue-specific proteins in cultured ovine thyroid cells.

Primary cultures of ovine thyroid cells were induced to differentiate by addition of thyrotropin (TSH). This was demonstrated as an accumulation of 2 thyroid-specific proteins, thyroglobulin and thyroid peroxidase, using immunofluorescent staining methods and immunoprecipitation of biosynthetically labeled cultures. As an additional measure of differentiation, cells exhibited a morphological response to TSH and regained the ability to incorporate radioactive iodide.

The effects of growth factors and serum on DNA synthesis and differentiation in thyroid cells in culture.

The effects of three putative growth factors and serum on [Me-3H]thymidine and Na125I incorporation into thyroid cell cultures have been examined. We found that serum and EGF could stimulate radioactively labelled thymidine incorporation into confluent cultures. However, both factors completely inhibited iodine uptake and organification at low concentrations.

Phosphatidylethanolamine synthesis in ethanolamine-responsive and -nonresponsive cells in culture.

Mammalian cells can be classified into two types based upon whether or not they show growth response to ethanolamine (Etn) in culture. The content of phosphatidylethanolamine (PE) in phospholipid and incorporation of radioactive Etn into the cells were examined in the Etn-responsive and -nonresponsive cells in order to elucidate the mechanisms of growth stimulation by Etn. In all Etn-responsive cells tested, 5 microM Etn significantly altered the composition of cellular phospholipid compared to that grown without Etn, while Etn-nonresponsive cells had a similar phospholipid composition whether the growth medium contained Etn or not.

Growth responsiveness to prolactin and its loss in normal rat mammary cells in culture.

Growth response of mammary epithelial cells to hormones, particularly to prolactin, was studied by using a primary culture of rat mammary gland organoids. After allowing the cells to attach and spread on the surface of plastic culture dishes, the effect of hormones was tested by means of [3H]-thymidine incorporation and autoradiography in a medium containing 1% fetal calf serum. In this system, prolactin showed a modest but significant growth-stimulatory activity (50% over control), and addition of insulin or hydrocortisone or both enhanced the growth stimulation of prolactin to a large extent.

Nalbuphine. A preliminary review of its pharmacological properties and therapeutic efficacy.

Nalbuphine is an agonist/antagonist analgesic. After parenteral administration of 'usual' doses it is approximately equipotent in analgesic activity to morphine on a weight basis. In studies in patients with moderate to severe pain, usually following surgery, the characteristics of analgesia with nalbuphine were comparable to those seen with equianalgesic doses of morphine or pentazocine.

Pharmacokinetic and hemodynamic effects of caffeine in the pregnant sheep.

Caffeine citrate in doses of 6.96 mg/kg (equivalent to 3.50 mg/kg of caffeine) of combined maternal and fetal weight and 69.

Analog-computer method for rapid estimates of theophylline clearance using presteady-state plasma concentrations.

An analog-computer method is described that provides estimates of steady-state plasma theophylline concentration nd total body clearance well before steady-state is achieved. An analog computer was programmed to simulate single compartment disposition of plasma theophylline for a constant rate infusion and an initial bolus. The two simulations were algebraically summed and the curve displayed on an oscilloscope.

Nuclear actin: an apparent association with condensed chromatin.

In Amoeba proteus the concentration of actin is the same in the nucleus and cytoplasm. Certain characteristics, e.g.