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Biomedical subjects

P Ekman

Publications and source records attributed to P Ekman.

At least 73 records · Page 4Linked to original sources
PubMed1993

Quantification of subnanomolar amounts of phosphate bound to seryl and threonyl residues in phosphoproteins using alkaline hydrolysis and malachite green.

An assay for protein-bound phosphate with a capacity to determine 100 pmol of phosphate is described. It is based on the combination of two well known methods: the alkaline hydrolysis of phosphate from seryl and threonyl residues in phosphoproteins and the quantification of the released phosphate by the use of malachite green and phosphomolybdate.

Adenosine Triphosphate↗
PubMed1993

Facial expression and emotion.

Cross-cultural research on facial expression and the developments of methods to measure facial expression are briefly summarized. What has been learned about emotion from this work on the face is then elucidated. Four questions about facial expression and emotion are discussed: What information does an expression typically convey? Can there be emotion without facial expression? Can there be a facial expression of emotion without emotion? How do individuals differ in their facial expressions of emotion?

Arousal↗
PubMed1993

Behavioral markers and recognizability of the smile of enjoyment.

Ekman and Friesen (1982) predicted that smiles that express enjoyment would be marked by smoother zygomatic major actions of more consistent duration than the zygomatic major actions of nonenjoyment smiles. Study 1 measured the duration and smoothness of smiles shown by female subjects in response to positive emotion films while alone and in a social interaction. Enjoyment smiles in both situations were of more consistent duration and smoother than nonenjoyment smiles. In Study 2 observers who were shown videotapes of enjoyment and nonenjoyment smiles were able to accurately identify enjoyment smiles at rates greater than chance; moreover, accuracy was positively related to increased salience of orbicularis oculi action. In Study 3, another group of observers were asked to record their impressions of the smiling women shown in Study 2. These women were seen as more positive when they showed enjoyment compared with nonenjoyment smiles. These results provide further evidence that enjoyment smiles are entities distinct from smiles in general.

Adult↗
PubMed1993

Substrate specificity of protein kinase C studied with peptides containing D-amino acid residues.

A set of stereoisomeric nonapeptides KRPSQRAKY with one, two, or all L-amino acid residues replaced by the corresponding D-amino acids, and two analogs with L- and D-threonine instead of serine, were synthesized and tested as substrates for protein kinase C. All of the peptides were phosphorylated by the enzyme. The maximal rate of the reaction with the all-D peptide was more than one order of magnitude lower than that for all-L peptide with serine. The same applied to the peptides with D-Ser or with D-Arg in position +2 with respect to Ser. The Km values for the peptides containing one D-amino acid were close to that for the prototype peptide (53 microM). On the other hand, when two or more D-amino acids were present, the Km value increased considerably. Replacement of serine by threonine also reduced the phosphorylation rate and increased the Km values. One can conclude that the stereospecificity of protein kinase C is much less pronounced than that of protein kinase A, which is in agreement with the less clearly pronounced substrate specificity of the former enzyme.

Amino Acid Sequence↗
PubMed1993

Epinephrine reduces the severity of catheter-induced urethral inflammation by action at the alpha 2-adrenoceptors.

We have studied the contribution of epinephrine to experimentally induced urethral inflammation in the rat. Inflammation was induced by inserting latex strips into the urethra. The effects of various experimental procedures were assessed according to a 4-point scale based on histological findings. The results showed that 0.5 mg/kg epinephrine decreased the severity of catheter-induced urethral inflammation. This effect was blocked by the alpha 2-adrenergic agonist, yohimbine, but not by alpha 1 (prazosin), beta 1 (M32 MTC), or beta 2 (butoxamine) antagonists. The results suggest that the suppressive effect of epinephrine is mediated by action at the alpha 2 adrenergic receptor.

Animals↗
PubMed1993

Interstitial cystitis: correlation with nerve fibres, mast cells and histamine.

Interstitial cystitis (IC) is a painful condition in the urinary bladder of unknown aetiology and pathogenesis. To assess the contribution of the nervous system to IC a biopsy was taken from 6 patients with IC and from a control group of 6 patients with non-ulcerative IC. Mast cells were counted and histamine measured in bladder washings from all patients. There were significantly more nerve fibres within the sub-urothelium and detrusor muscle in chronic IC than there were in non-ulcerative IC. The bladder washings from all patients with IC contained mast cells and histamine, while only occasional mast cells and traces of histamine were found in washings from patients with non-ulcerative IC. There was a good correlation between the number of nerve fibres and number of mast cells as well as between the number of nerve fibres and the amount of histamine.

Aged↗
PubMed1993

Dilemma of microscopic lymph node metastases in human prostate cancer.

During radical surgical procedures for prostatic carcinoma, lymph node metastases are not infrequently discovered unexpectedly. Microscopic lymph node metastases, on the other hand, are generally overlooked and identified first by routine histology following surgery. In both these situations there is some controversy about how to proceed therapeutically. When lymph node metastases are discovered during radical prostatectomy, many authors favor discontinuing surgery, which is associated with a high morbidity, and then start the patient on hormonal treatment. This approach, however, is not favored by all investigators. When microscopic lymph node metastases are reported, the complexity of the situation increases. The various dilemmas posed to urologists when confronted with lymph node metastases are discussed.

Humans↗
PubMed1993

Workshop summary: hormonal suppression in the neoadjuvant setting and advanced disease.

For advanced prostate cancer, hormonal suppression has long played an important role in patient management. Furthermore, the concept of combined androgen blockade using a luteinizing hormone-releasing hormone agonist in combination with an antiandrogen such as flutamide is gaining increasing acceptance. The novel regimen of finasteride (a 5-alpha-reductase inhibitor) plus flutamide may also have a role to play in the future. In the neoadjuvant setting, androgen suppression prior to radical prostatectomy is a novel approach. This strategy aims to reduce the size of the tumor as much as possible, hopefully downstaging the disease, and thus increasing the chances of a successful outcome at operation. Data from studies presented at this symposium revealed a clear reduction in tumor size by this method but the effects on both staging of disease and long-term outcome were not so definitive. Questions were put to the audience and the expert panel to assess their opinion of hormonal therapy and staging techniques, both in the neoadjuvant and advanced disease settings.

Androgen Antagonists↗
PubMed1993

[Finasteride in the treatment of benign prostatic hypertrophy].

Finasteride acts by blocking the conversion of testosterone to 5a-dihydrotestosterone, the active androgen metabolite in the human prostate. In large, double-blind, placebo-controlled phase III-studies recruiting over 1,600 patients, it was shown that the administration of Finasteride, either 5 or 1 mg a day, reduced the size of the prostate by a mean of 22%, following 6 months of therapy. Despite this reduction in prostate size, urinary flow rate only improved by a mean of 1.7 ml per second, and symptom score improved only marginally, but statistically significantly different from placebo. The future role for Finasteride therapy is emerging but it appears as if patients with mild to moderate symptoms would be a group who could benefit the most. Whether or not Finasteride can stop the long-term natural course of benign prostatic hyperplasia has still to be demonstrated.

Finasteride↗
PubMed1993

Phospholipid-dependent and EGTA-inhibited protein kinase from maize seedlings.

Chromatography of a maize seedling extract on DEAE-cellulose, followed by Octyl-Sepharose yielded a fraction with protein kinase activity which was stimulated by phosphatidylserine plus diolein. The activity was not enhanced by calcium ions but was inhibited by chelating agents and could then be restored by the addition of calcium ions. All these facts indicated that the maize protein kinase was similar to mammalian protein kinase C. The maize enzyme phosphorylated myelin basic protein (MBP) and histone H1, but the MBP-peptide4-14 and protamine were poor substrates for the enzyme. Further purification of the enzyme fraction followed by phosphorylation and SDS-polyacrylamide gel electrophoresis, revealed two labeled bands of Mw 59 and 83 kDa the former of which probably being the protein kinase C.

Animals↗
PubMed1992

Increased phosphate content of fibrinogen in vivo correlates with alteration in fibrinogen behaviour.

Fibrinogen was purified from five patients admitted for hip-replacement surgery the day before (day 0), the day after (day 2) and and one week after the operation (day 8). The behaviour of each patient's three fibrinogens was compared in thrombin gelation assays and plasmin degradation experiments to investigate whether the reported increase in protein-bound phosphate at day 2 and day 8 had any effect on the functional behaviour of fibrinogen as has been demonstrated in vitro. It was found that the thickness of the fibrin fibres produced by thrombin increased markedly at day 2 and declined thereafter. Susceptibility to plasmin appeared to decrease post-operatively by 50% and remained at that level on day 8 despite the phosphate content returning to normal. This has also been shown for fibrinogen phosphorylated in vitro. We conclude, after testing the fibrinogens with and without alkaline phosphatase pretreatment, that our data most resemble the published findings for in vitro phosphorylation of fibrinogen by casein kinase II.

Acute-Phase Reaction↗
PubMed1992

A potential pitfall in protein kinase assay: phosphocellulose paper as an unreliable adsorbent of produced phosphopeptides.

The ability of phosphocellulose paper to retain phosphorylated peptides containing basic amino acid residues was investigated. Some peptide substrates that are commonly used for three different protein kinases were tested. The adsorption onto phosphocellulose paper was strongly dependent on the amino acid composition of the peptides. None of the phosphopeptides studied was adsorbed completely, the amount bound varied from 7 to 93%. Phosphopeptides containing two basic amino acids each differed remarkably in the degree of binding to the phosphocellulose paper (40% RRASVA, 60% FRRLSI, and 80% HRASV was bound). The results presented here indicate that data from phosphorylation experiments obtained so far for different peptides using the phosphocellulose paper method should be judged with caution.

Adsorption↗
PubMed1992

Model studies on iron(III) ion affinity chromatography. II. Interaction of immobilized iron(III) ions with phosphorylated amino acids, peptides and proteins.

The chromatographic behaviour of phosphoamino acids, phosphopeptides and phosphoproteins and their non-phosphorylated counterparts was studied on Fe(III)-Chelating Sepharose and Fe(III)-Chelating Superose. The phosphorylated compounds, in contrast to their non-phosphorylated or dephosphorylated counterparts, adsorb to immobilized iron(III) ions at pH 5.5 and can be desorbed by an increase in pH. Phosphoamino acids were eluted at pH 6.5-6.7, whereas monophosphopeptides and phosphoprotamine eluted in the pH range 6.9-7.5. Molecules possessing clusters(s) of carboxylic groups are weakly retained (gamma-carboxyglutamic acid, Ala-Ser-Glu5) or bound (polyglutamic acid, beta-casein) to the immobilized iron(III) ions at pH 5.5. Dephosphorylated beta-casein was desorbed at pH 7.0, whereas for elution of native (non-dephosphorylated) beta-casein, phosphate buffer of pH 7.7 was required. The homopolymer of polyglutamic acid was desorbed in the pH range 6.0-6.3, whereas copolymers of glutamic acid and tyrosine require pH 7.0-7.3 or even phosphate buffer at pH 7.7 for elution.

Amino Acid Sequence↗
PubMed1992

The contribution of epinephrine to experimentally induced urethral inflammation in the rat.

We have studied the effect of the adrenal medulla and epinephrine on experimentally induced urethral inflammation in the rat. Urethral inflammation was induced by inserting latex strips into the urethra. The effects of different experimental procedures were assessed by using a 4-graded inflammation scale based on histological findings. Adrenal medullectomy significantly reduced experimentally induced urethral inflammation. This effect was reversed if the rats were treated repeatedly with epinephrine or salbutamol. On the other hand high doses of epinephrine reduced the experimentally induced urethral inflammation.

Adrenal Medulla↗
PubMed1992

Facial expressions of emotion: an old controversy and new findings.

Evidence on universals in facial expression of emotion and renewed controversy about how to interpret that evidence is discussed. New findings on the capability of voluntary facial action to generate changes in both autonomic and central nervous system activity are presented, as well as a discussion of the possible mechanisms relevant to this phenomenon. Finally, new work on the nature of smiling is reviewed which shows that it is possible to distinguish the smile when enjoyment is occurring from other types of smiling. Implications for the differences between voluntary and involuntary expression are considered.

Emotions↗
PubMed1992

Immunohistochemistry and biochemistry in detection of androgen, progesterone, and estrogen receptors in benign and malignant human prostatic tissue.

The relative distribution of androgen (AR), progesterone (PR), and estrogen receptors (ER) was localized and estimated in human prostate tissue by immunohistochemistry in five normal tissue samples, in eight benign hyperplastic (BPH) samples, in nine primary cancers, and in seven prostate cancer metastases. Moreover, three prostatic cancer cell lines (LNCaP, DU 145, and PC 3) were analyzed. A comparison between the results obtained by radioligand binding assays and immunohistochemistry was performed for the AR and PR. Using immunohistochemistry, the AR was exclusively detected in the nuclei of both benign and malignant prostatic epithelial cells. The highest proportion of AR-positive cells was found in BPH and in prostate cancer metastases as compared with normal prostatic tissue. In a majority of the cases, the PR was only present in the nuclei of stromal cells. Benign hyperplastic prostates contained higher proportions of PR-positive cells as compared with primary carcinoma. PR was sparse in epithelial cells. ER-positive stromal cell nuclei were only detected in carcinomatous prostates. A few ER-positive epithelial cell nuclei were found in one sample each of a BPH and normal prostate. All cells from the androgen-dependent, LNCaP, cell line and a majority of the cells from the androgen-independent, DU 145, cell line were AR-positive. In contrast, the cells from the androgen-independent, PC 3, cell line were all AR-negative. All three cell lines were PR- and ER-negative. The radioligand binding technique detected the AR in extracts from both the cytosol and the nucleus. Again BPH contained higher amounts of AR as compared with normal prostatic tissue. The LNCaP cells contained high amounts of cytosolic AR while cells from the DU 145 and PC 3 cell lines lacked detectable AR as estimated by biochemical techniques. There seemed to be a discrepancy between biochemically measured and immunohistochemically estimated receptor content.

Epithelium↗
PubMed1992

Emotion and autonomic nervous system activity in the Minangkabau of west Sumatra.

Physiology and emotional experience were studied in the Minangkabau of West Sumatra, a matrilineal, Moslem, agrarian culture with strong proscriptions against public displays of negative emotion. Forty-six Minangkabau men were instructed to contract facial muscles into prototypical configurations of 5 emotions. In comparison with a group of 62 Ss from the United States, cross-cultural consistencies were found in (a) autonomic nervous system (ANS) differences between emotions and (b) high configuration quality being associated with increased ANS differentiation and increased report of emotional experience. These findings provide the first evidence that these patterns of emotion-specific ANS activity and the capacity of voluntary facial action to generate this activity are not unique to American culture.

Adolescent↗