Computer aided time-lapse video analysis of hepatocyte morphology during adhesion to cellulose membranes.

An investigation was performed to demonstrate that time-lapse cinematography and computer aided video analysis of cell morphology is suitable to study and compare the characteristics of hepatocytes during the adhesion process to membranes. We chose to compare ordinary cellulose Cuprophan membranes and membranes coated with collagen or fibronectin. Striking differences between uncoated cellulose and fibronectin or collagen coating were seen in the cell count per square millimeter and adhesion behaviour.

Remoxipride, a new selective D2 antagonist, and haloperidol in cebus monkeys.

1. Nine Cebus monkeys, 6 with mild spontaneous oral dyskinesia (tongue protrusions), were tested with two dopamine D2 antagonists, remoxipride (a new substituted benzamide) and haloperidol, and with two dopamine agonists, methylphenidate and apomorphine. 2.

Isolation of vascular endothelial cells for investigations on hybrid prostheses.

Hybrid vascular prostheses are coated with vascular endothelial cells (EC) in an attempt to reduce thrombogenicity through the metabolic activities of living cells. The present studies were planned to develop a standardized method of isolating bovine aortic EC with high yield for studies of endothelial coating of vascular prostheses. The best results were achieved using a combination of incubation with collagenase and mechanically scraping the mobilised cells from the donor vessel.

Use of hepatocytes in adhesion and suspension cultures for liver support bioreactors.

Hepatocyte cultivation in bioreactors for hybrid liver support systems is possible under two conditions: attached to a substrate like membranes or microcarriers or in suspension culture. To compare the ammonia metabolism of hepatocytes cultivated under these two conditions, cultures of primary seeded rat hepatocytes were cultivated either attached to collagen coated tissue culture plastic or as a suspension culture. During the time course of culture, the ability of hepatocytes to reduce the ammonia content of the medium decreased in both adhesion and suspension cultures, though to different extents.

Isoelastic polyurethane prosthesis for segmental trachea replacement in beagle dogs.

Porous polyurethane (nonwoven) was used for the development of tracheal prosthesis, which--in a special testing design--was adapted to shape and biomechanic properties of the natural organ. This prosthesis was implanted into 19 beagle dogs using inverted, everted, and end-to-end anastomosis. Insufficiency of the anastomosis or infection was observed in the everted and end-to-end anastomosis, whereas the inverted anastomosis showed complete incorporation into surrounding tissue of the porous prosthesis but was complicated by airway obstruction due to anastomosis granuloma.

Endothelial cell seeding on PTFE vascular prostheses using a standardized seeding technique.

A standardized method was developed for seeding endothelial cells (EC) in tubular vascular grafts. A rotational cell seeding device for tubular prostheses is presented and parameters influencing the kinetics of cell adhesion (rotation speed, graft diameter, cell suspension level, inoculated cell number) are reported. Seeding EC in 14 mm ID PTFE vascular grafts with rotation rate of 10 rph gave an adhesion rate of 80% in a homogeneous monolayer.

Endothelial cell seeding on different polyurethanes.

Six polyurethanes (PUs) were tested with respect to their cytocompatibility. Initial adhesion, initial spreading, and the proliferation of endothelial cells were investigated. All smooth PUs showed similar initial adhesion.

Long-term experience with clozapine in Denmark: research and clinical practice.

In Denmark, the use of clozapine has increased markedly (15-25% per year) since 1983, when the drug was relaunched--after its withdrawal in 1975. Several factors have contributed to this development: 1) the interesting pharmacology of clozapine, especially the atypical influence on dopamine transmission, including a relatively high D-1/D-2 receptor affinity ratio, 2) the potent anti-anxiety and anti-psychotic effect in severe and otherwise therapy-resistant psychotic patients, and 3) the lack of extrapyramidal side effects. A special monitoring form (for registration of total and differential leucocyte counts, ECG, body weight, drugs, doses and reason for possible withdrawal of the clozapine) is used in most Danish psychiatric institutions.

Structure and function of P-glycoprotein.

P-glycoprotein remains the best understood molecule that has been implicated in the multidrug resistance phenomenon. As I have attempted to show, our understanding of this molecule is still in its infancy, with many questions as yet unanswered. It is anticipated that the answers to these questions will contribute to our understanding of drug resistance, as it relates to cancer, and also to our understanding of what appears to be a fundamental transport system.

Arginine is a physiological precursor of endothelium-derived nitric oxide.

ATP dose dependently stimulated the formation and release of nitric oxide (NO) from perfused rabbit aorta. L-Canavanine, an inhibitor of various L-arginine-utilizing enzymes, abolished basal and ATP-induced NO formation and release. ATP increased the accumulation of presumably NO-derived NO2- in the medium of primary cultures of bovine aortic endothelial cells.

Tardive dyskinesia. Pathophysiological mechanisms and clinical trials.

Recent observations from human and animal studies indicate that the traditional dopamine supersensitivity theory in tardive dyskinesia (TD) is insufficient. Instead, a new hypothesis is proposed: TD may be due to an increased D-1 receptor function or an increased ratio between D-1/D-2 receptor functions in the brain, maybe associated with a diminished activity in certain striatofugal GABA neurons. This hypothesis is based on experiments with selective D-1 and D-2 drugs in rodents and monkeys, but has not yet been tested clinically due to lack of D-1 agonists and antagonists for human use.

Behavioural effects of dopamine D-1 and D-2 receptor agonists in monkeys previously treated with haloperidol.

The effects of dopamine D-1 and D-2 receptor agonists were evaluated in five Cebus apella monkeys. During a previous haloperidol treatment (2 years), three of the monkeys had developed oral tardive dyskinesia (tongue protrusion and/or chewing). The partial D-1 agonist, SKF 38393, induced/aggravated oral dyskinesia and slight sedation, but no non-oral repetitive movements.

The ontogeny of sex differences in estrogen-induced progesterone receptors in rat brain.

The sex and age-related changes in the concentration of cytosol progesterone receptors (CPR) induced by estrogen (E) treatment in rat brain and pituitary were investigated by a modification of the Palkovits punch procedure using fresh tissue. Young male and female gonadectomized rats, 15, 21, 30, and 42 days of age, were treated for 44 h by a single sc injection of synthetic E. [Moxestrol (Ru2858)].

Autoradiographic localization of estradiol-binding neurons in the rat hippocampal formation and entorhinal cortex.

This study has examined the distribution of [3H]estradiol and [1 alpha,2 alpha-3H]testosterone uptake in the hippocampal formation and entorhinal cortex of male and female rats. In both males and females, [3H]estradiol-binding neurons in Ammon's horn are located deep in stratum pyramidale and may correspond either to polymorphic interneurons or to early maturing pyramidal cells. Interneurons of strata oriens, lucidum and radiatum of Ammon's horn and of stratum moleculare of the subiculum also bind [3H]estradiol, as do basket cell interneurons in the polymorphic, infragranular layer of the dentate gyrus.

Tardive dyskinesia.

Tardive dyskinesia (TD) is a syndrome of involuntary movements that develops in predisposed individuals during neuroleptic drug treatment, with an average prevalence of 15%. Neuroleptic (antidopaminergic) drugs are the predominant etiological factor. Although no simple correlation can be established, both dosage and treatment duration seem to be of importance for the development of dyskinesia.

Perseverative structuring of responses by schizophrenic and affective disorder patients.

Some theoretical implications from a CNS stimulation model of psychosis were tested by analysing the response patterns of schizophrenic (N = 34), affective disorder patients (N = 18), schizoid personality disorder patients (N = 9), neurotic patients (N = 9) and normal controls (N = 34) on a visual two-choice task with reinforcement. The subjects were required to press a left and right button in order to cause a cross (+) to appear on the monitor screen above one of the buttons. Certain subsequences of right and left presses were required in order for the cross to appear, and a coin-reinforcement was delivered on a variable-ratio schedule with respect to the cross condition.

Future treatment of schizophrenia.

In spite of 35 years of experience with antipsychotic drugs, the psychiatrists are still faced with the limitations of these drugs: no or minimal therapeutic effect in hallucinations and delusions in about 25% of schizophrenic patients; persisting anergia and emotional withdrawal in otherwise successfully treated patients; a great spectrum of side effects, some irreversible. Quo vadis? An incidental discovery of a completely new drug, a new "chlorpromazine" would be the ideal solution, but for the present, one has to continue with the small pragmatic steps, especially within the following areas: (a) the selective antidopaminergic drugs, especially the substituted benzamides, may be further developed in the direction of antipsychotic selectivity with fewer and fewer extrapyramidal side effects; (b) the atypical clozapine ought soon to have successors, hopefully without the risk of bone marrow depression and cardiovascular side effects; (c) the D1 antagonists as well as the D1 agonists may imply therapeutically valuable effects; (d) the dopamine autoreceptor has long been in focus, but until now, no pure agonist has been found, and the drugs available, including (-)3-PPP, appear to have many side effects; (e) serotonin antagonists may be an interesting possibility; and (f) when it may be possible to influence brain peptides more efficiently than up to now, this area will probably provide us with several psychotropic drugs. Furthermore, during the search for new antipsychotic drugs, one must not forget to improve the practical use of available neuroleptics and of nonpharmacological, psychosocial treatment modalities.

Simultaneous expression of two P-glycoprotein genes in drug-sensitive Chinese hamster ovary cells.

Overexpression of P-glycoprotein is characteristic of multidrug-resistant cells. We analyzed four P-glycoprotein transcripts that are simultaneously expressed in a drug-sensitive Chinese hamster ovary cell line. We concluded that these transcripts are encoded by two distinct members of a P-glycoprotein multigene family, each of which has two alternative polyadenylation sites.

Selective D1 and D2 receptor manipulation in Cebus monkeys: relevance for dystonia and dyskinesia in humans.

Selective D1 and D2 dopamine (DA) antagonists and agonists were given to 4 Cebus monkeys who had previously received haloperidol treatment for 4 years. SCH 23390 (a selective D1 antagonist) and raclopride (a selective D2 antagonist) induced identical syndromes consisting of dystonia and oral dyskinesia. Biperiden (an anticholinergic drug) and LY 171555 (a selective D2 agonist) completely antagonized the dystonia and dyskinesia induced by SCH 23390 as well as raclopride.

P-glycoprotein in human sarcoma: evidence for multidrug resistance.

Overexpression of an immunologically conserved, cell-surface glycoprotein (P-glycoprotein) is consistently associated with multidrug resistance in cell lines in vitro. A preliminary survey of specimens from 12 solid tumor types in our laboratories indicates significant overexpression of P-glycoprotein in some sarcomas. When tested by immunoblotting with monoclonal antibodies directed against P-glycoprotein; tumors from six of 25 sarcoma patients displayed elevated levels of P-glycoprotein.