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At least 919 records · Page 51Linked to original sources
PubMed1994

PDGF-like growth factor from SV40-transformed smooth muscle cells promotes growth in an autocrine or paracrine manner.

We investigated the growth characteristics of smooth muscle cells transformed by oridefective simian virus 40 plasmid DNA (TSMCs). TSMCs demonstrated a significantly higher proliferative activity when compared with nontransformed smooth muscle cells (SMCs). The SMCs were not able to proliferate in media with 5% plasma-derived serum (PDS) instead of fetal bovine serum, while TSMCs grew under this condition. When the DNA synthesis of quiescent SMCs was reinitiated by the addition of serum or platelet-derived growth factor (PDGF), the amount of [3H]thymidine incorporation into DNA varied with the concentrations of serum or PDGF and decreased on type V collagen compared with the other collagen substrates. In contrast, the TSMCs showed no differences in the amount of [3H]thymidine incorporation into DNA among the various concentrations of serum or PDGF and different types of collagen. When quiescent SMCs were cocultured with TSMCs, they showed a remarkable increase in the amount of [3H]thymidine incorporation into DNA, which was most intensively inhibited by type V collagen. These results suggest that TSMCs can promote the growth of TSMCs and SMCs in either an autocrine or paracrine manner and that they proliferate independently of the collagen matrices. Trapidil, a pyrimidine derivative that may inhibit the action of PDGF, decreased the number and cAMC levels of TSMCs in the media with 5% PDS in a concentration-dependent manner. The addition of polyclonal anti-PDGF-B antibody induced up to 59.5% inhibition of enhancement of DNA synthesis of SMCs cocultured with TSMCs. The level of cyclic adenosine monophosphate (cAMP) increased in the TSMCs compared with the SMCs. There was, however, no difference in the cAMP levels of either cells between the various types of collagen. Thus, the release of PDGF-like growth factor and an accumulation of cellular cAMP may be related to an increased DNA synthesis of TSMCs.

Animals↗
PubMed1994

Mechanical comparison of 10 suture materials before and after in vivo incubation.

The material properties of ten 2-O suture materials were evaluated tensiometrically at time = 0 and again after 6 weeks incubation in rats. All suture material was incubated and tested without knots. Specialized machinery was used with a custom securing apparatus to pull suture material apart at constant speed. Stress-strain curves were derived, and from these strength, toughness, strain at rupture, and elastic modulus were determined. Sutures tested included Vicryl [poly(glycolide-lactide)], Dexon (polyglycolic acid), Ethibond (polyester), silk, plain gut, chromic gut, Maxon (polyglyconate), PDS (polydioxanone), nylon, and Prolene (polypropylene). Elastic modulus was greatest for braided, least for monofilament, and intermediate for gut sutures, regardless of chemical composition (ANOVA, P = 0.0001). Strength, strain, and toughness decreased in all of the sutures over time in vivo with the exception of braided polyester (Ethibond), which remained stable. Silk demonstrated the least strength and toughness while PDS and Maxon were the strongest and toughest at time = 0. Vicryl, Dexon, and gut sutures were absorbed to the point that they could not be tested after 6 weeks in vivo. Performance tables are provided for all sutures.

Animals↗
PubMed2000

Increasing Cooperation in Prisoner's Dilemmas by Establishing a Precedent of Efficiency in Coordination Games.

Coordination games have multiple Nash equilibria (i.e., sets of strategies which are best responses to one another). In weak-link coordination games players choose a number 1-7. Their payoff is increasing in the minimum number (or weakest link) and decreasing in the difference between their number and the minimum. Choosing 7 is an efficient equilibrium because it gives everybody a higher payoff than any other coordinated choice. Higher-payoff equilibria are riskier, however, so the game expresses the tradeoff between group efficiency and personal risk present in many social and organizational settings. We tested whether choosing efficiently in a weak-link game increases cooperative play in a subsequent prisoner's dilemma (PD) game. This cross-game transfer resembles the transfer of cooperative norms in small firms (which are more like coordination games than PDs) as firms grow larger and become like PDs. In two experiments, if a group of players share a history of playing the weak-link game efficiently, that efficiency precedent can transfer to a subsequent PD game, improving the level of cooperativeness. The effect of transfer is much larger in magnitude (increasing cooperation from 15-30% to 71%) than the effects of most variables in previous PD studies. However, the transfer effect depends on descriptive similarity of strategies in the two games, since it largely disappears when the strategies are numbered differently in the weak-link game and the PD. Copyright 2000 Academic Press.

Journal Article↗
PubMedDate not supplied

The effectiveness of dapiprazole in preventing exercise-induced IOP increase in patients with pigmentary dispersion syndrome.

PURPOSE: The authors investigated the use of dapiprazole, an alpha-adrenergic blocking agent, in preventing pigment release and IOP increase after exercise in patients affected with PDS. METHODS: Three young myopic males (31, 34 and 35 years old) affected with pigmentary dispersion syndrome performed 30 minutes of jogging on a computerized treadmill. Telemetric heartbeat measurement was performed to obtain constant pulse rate training. Computerized tonography and IOP measurement were performed 10 minutes after the exercise. After one month the patients repeated the same exercise after pre-treatment with dapiprazole 0.5% eyedrops (one drop 30, 20 and 10 minutes before the exercise). Ten minutes after the exercise IOP measurements and computerized tonography were repeated. RESULTS: After 30 minutes of exercise IOP measurements showed values ranging from 19 to 45 mmHg (mean 30.33; SD 8.73). Computerized tonography C values after exercise ranged from 0.04 to 0.16 (mean 0.09; SD 0.04). After pre-treatment with dapiprazole 0.5% eyedrops, IOP values ranged from 18 to 28 mmHg (mean 23.33; SD 3.44) and tonography C values ranged from 0.10 to 0.20 (mean 0.14; SD 0.03). CONCLUSIONS: The study supports the concept that exercise-induced pigment release temporarily obstructs the acqueous outflow channels, causing IOP increase in some patients with PDS. Pre-treatment with dapiprazole was useful in reducing IOP spikes and in increasing tonographic total outflow facility after exercise. The absence of induced myopia and the lack of dangerous vitreoretinal tractions on retinal periphery make dapiprazole a safe method to reduce exercise-induced pigment dispersion.

Administration, Topical↗
PubMed1996

[Alloplastic augmented femoral reinserted anterior cruciate liganent. Value of 2 channel augmentation for postoperative rehabilitation].

The rupture of the anterior cruciate ligament (ACL) near its femoral origin is a common injury of the knee and can lead to lesions of the meniscus due to instability and to early gonarthrosis. One procedure applied in current orthopaedic practice to prevent such impairment of knee joint function is ACL repair reinforced with a synthetic intraarticular ligament. In this study we used twelve knees of cadavers and after sectioning the ACL in each repaired it according the Marshall technique with USP 1 PDS II sutures. We augmented the repair in each case with a 3-mm PET (Trevira hochfest) band inserted by the through-the-condyle (TTC) procedure and attached without preload to the femoral and tibial condyle with a 4-mm staple. We then measured the length of the ACL, the length of the Marshall sutures-ACL complex, the partial lengths, and the deviation angles and adherence-friction force of the 3-mm PET augmentation device, and applied the law of Hooke to calculate the load-sharing between the USP 1 PDS II sutures-ACL complex and the 3-mm PET band and between the ACL and the 3-mm PET band, respectively. We also evaluated the load on the femoral and the tibial fixation of the augmentation device. The results showed that the 3-mm PET band took over 60% of an externally applied load on the knee during the hypothetic period of ACL healing and 27% of the force acting on the knee thereafter. It was calculated that a maximum of 75% of the load taken over by the augmentation device was at the tibial staple and only up to 45% of the force at the femoral one. With due consideration for the requirement for absolute protection ("stress shielding") of the healing ACL but also for the aim of early postoperative accelerated functional rehabilitation without casts, splints or other restrictions of joint movement, we believe that a pretensioned 3-mm PET band is the best choice, since augmentation without preload cannot fulfil these requirements.

Anterior Cruciate Ligament↗
PubMed1994

The chemical morphology of extracellular matrix in experimental rat liver fibrosis resembles that of normal developing connective tissue.

The time course of development of extracellular matrix (ECM) in experimentally induced fibrosis (thioacetamide administration followed for 12 weeks or bile duct ligation for 8 weeks) in adult rats was examined by light and electron microscopy, using Alcian blue or Cupromeronic blue staining for sulphated proteoglycans (PGs) in critical electrolyte concentration techniques. Proteodermatan sulphate (PDS) was regularly observed at the gap zone of the collagen fibrils. Morphometry of uranyl acetate-stained collagen fibrils, polarity of their banding patterns (a-e), statistics of d/e band occupancies by PDS, and lengths and thicknesses of PG filaments were quantified. Biochemical analyses showed that the ECM components collagen, hyaluronan, chondroitin and dermatan sulphates increased by 5-10 fold, roughly in parallel, as did heparan sulphate and DNA. Water and lipid contents also increased sharply. Thioacetamide treatment was much slower than bile duct ligation in producing fibrotic changes of equal severity. Sulphation of anionic glycosaminoglycans (AGAGs) decreased with increasing severity of fibrosis. Biochemical and ultrastructural methods correlated well. The large increase in dermatan sulphate was quantitatively as expected, given that it is collagen fibril surface-associated, and there was an increase of collagen content together with a decrease in fibril thicknesses. The increase in DNA reflected the marked increase in cell numbers in fibrotic livers. The chemical morphology of the new connective tissue closely resembled that in e.g. developing young tendon, in that fibrils were thinner, and AGAG levels were higher. The collagen fibrils were often disarranged, rather than ordered and parallel as in normal ECM. No other indication of abnormality in the new ECM was obtained.

Alcian Blue↗
PubMed1989

Calcium-dependent potassium current following penicillin-induced epileptiform discharges in the hippocampal slice.

Penicillin-induced paroxysmal depolarization shifts (PDS) are followed by prolonged afterhyperpolarizations of about 2 seconds duration. Intracellular injection of EGTA blocked a late component of the afterhyperpolarizations; an early one lasting up to one second was only slightly reduced by EGTA. It is concluded that afterhyperpolarizations following penicillin-induced PDS comprise different components: an initial one lasting up to one second which is not Ca2+-dependent and a slow one lasting up to two seconds which is caused by a Ca2+-dependent K+ current.

Action Potentials↗
PubMed1986

Actions of pentylenetetrazol (PTZ) on CA3 neurons in hippocampal slices of guinea pigs.

The actions of the convulsant drug pentylenetetrazol (PTZ) were studied on CA3 neurons of hippocampal slices (300-400 microns thick). In 9 out of 109 neurons, epileptic reactions were elicited during a single application of PTZ. After repeated applications of PTZ, 53 neurons showed periodic paroxysmal activity. They developed according to the following sequence: (i) Paroxysmal hyperpolarizations, (ii) burst activity, and (iii) typical paroxysmal depolarization shifts (PDS). The rate of occurrence was about 8/min. Paroxysmal hyper- and depolarizations appeared synchronously in pairs of neurons. The developmental sequence occurred in reverse during washing. After the onset of paroxysmal activity, bursts and PDS persisted if PTZ concentration in tissue ranged between about 2 and 10 mmol/l. When this range was exceeded in either direction, epileptic activity was abolished at a calcium concentration of 2.75 mmol/l. Decreasing and increasing the calcium concentration shifted the epileptogenic concentration range to lower and higher levels, respectively. It is concluded that repetition of PTZ application alters membrane properties of neurons and thus leads to paroxysmal events triggered by synaptic processes.

Animals↗
PubMed1985

Characterization of growth factor(s) produced by chemically transformed hamster dermal fibroblasts.

Cell lysates from transformed hamster dermal fibroblasts (HDF cells) induced colony formation of normal HDF cells in soft agar medium and also stimulated proliferation of normal HDF cells in medium supplemented with plasma-derived serum (PDS). The colony forming activities of cell lysates correlated well with their growth stimulating activities in PDS-supplemented medium. The growth factor(s) were shown to be sensitive to trypsin and dithiothreitol (DTT), but heat stable. However, these transformed HDF cell lines did not all produce tumor nodules when injected into hamsters. This was not due to immunological rejection because similar results were obtained in hamsters treated with anti-hamster thymocyte serum (ATS). Thus it was concluded that production of these growth factor(s) by transformed HDF cell lines is not itself sufficient for acquisition of complete malignancy in vivo.

Animals↗
PubMed1994

Surgical treatment of acromioclavicular dislocation.

Sixty-five patients were operated on for acromioclavicular dislocation between 1980 and 1991. Seventeen type II and 48 type III dislocations according to the criteria of Tossy et al. were treated. Three different surgical techniques were employed. (1) tension band wiring, (2) a modification of the Bosworth repair, (3) reconstruction of the ligaments with augmentation by a PDS (polydioxanon) cord. Forty-four patients could be investigated retrospectively, and an additional 12 were recorded by questionnaire. The Taft score was used, representing self-assessment, clinical statements and radiological findings. Of all investigated patients 87.5% had a normal range of motion without any loss of strength, and 32% suffered an osteoarthritis of the acromioclavicular joint. The average Taft score was 9.8. With respect to the three surgical techniques, reconstruction of the ligaments augmented by a PDS cord produced the best result, an average Taft score of 10.8.

Acromioclavicular Joint↗
PubMed1995

Anterior cruciate ligament suture in comparison with plasty. A 5-year follow-up study.

In this retrospective study we analyse the results of primary anterior cruciate ligament (ACL) sutures, primary ACL plasties and secondary ACL plasties 5 years after operation. All operations were performed with an additional PDS augmentation. Follow-ups of 100 of 130 patients could be done (80 male and 20 female). The average age at time of operation was 29.2 years. ACL rupture in 81 patients occurred due to a sport accident. In 26 patients a primary ACL suture was performed, in 59 patients a primary ACL plasty and in 15 patients an ACL plasty due to instability. There was no difference between the primary and secondary plasty groups, but there was between the suture and the plasty groups. In all, 92% of the suture group and 69% of the plasty group were satisfied with the surgical results. The pivot shift, Lachman and anterior drawer sign were less frequent in the ACL suture group, and the Lysholm score was higher. Primary suture combined with a PDS augmentation seems to represent an adequate treatment of acute proximal ACL ruptures.

Adult↗
PubMed1975

[PTZ-induced paroxysmal depolarization shift on Helix p. neurons: mechanism of plateau and pacemaker potentials (author's transl)].

The convulsant pentylenetetrazol (PTZ), 1% induces paroxysmal depolarization shifts (PDS) on regularly firing neurones of Helix. Synaptic or antidromic stimulation or transmembrane current produces PDSs followed by a refractory period. For 5% of PTZ-treated neurons the membrane depolarizes up to -15 mV and PDS can be obtained by injected inward current. In voltage clamp experiments the steady i equals f(V) characteristic of PTZ-treated neurons is N-shaped with a current flowing inwardly between -45 and -15 mV. The negative conductance is enhanced by warming and disappears at temperatures lower than 15 degrees C. Besides, a slow triangular function (less than or equal to 10 mV/sec) applied to the voltage clamp system indicates an important hysteresis in the i equals f(V) curves according to the direction of sweeping: depolarization or repolarization. From a hyperpolarized state (-70 mV) the stable point of the N-shaped i equals f(V) characteristic is at -15 mV bringing the membrane potential to this level. From a depolarized state congruent to 10 mV) the i equals f(V) characteristic shows no local negative slope and the stable point is at -45 mV bringing the membrane potential down to this level. PDSs correspond to the voltage transition between these two stable points. The amplitude of PDSs is directly related to the amplitude of hysteresis and their frequency to the kinetics of the i equals f(V) characteristics. The different modes of activity under PTZ are explained by the position of the i equals 0 axis in relation with the region of negative resistance. It is suggested that increase of K+ -inactivation by PTZ is the main phenomenon leading to a N-shaped characteristic.

Animals↗
PubMed1991

Developmental, structural, and clinical approach to narcissistic and antisocial personalities.

The conception of personality disorders (PDs) as distinct units of mental disorders is neither precise nor useful. At least some PDs, classified as separate units, reflect different behavioral expression of the same personality deviation. In this article we describe structural, developmental, and clinical continuum between relatively distinct entities of antisocial PD and narcissistic PD. The two disorders represent different endpoints sharing a borderline level of personality organization and pathological narcissism. We propose a spectrum relation for antisocial and narcissistic PD because the disorders tend to co-occur in the same individual and to run in the same family more often than expected by chance.

Antisocial Personality Disorder↗
PubMed1989

[Experimental studies of stabilization of refixation following median sternotomy].

So far several methods have been established for refixing the sternum halves after longitudinal sternotomy like steel wire or steel strap according to Parham. The use of twisted absorbable PDS-strings is new. During experimental investigations in corpse sterna during tension load the different refixing methods were compared. As a result we found an increased tension stability of the sternum refixation as well as the reversibility of suture dehiscences, if occurred, after employment of the elastic PDS-string. Polydioxanon is a suggestive alternative compared with the usual not absorbable materials for refixation of the sternum.

Biomechanical Phenomena↗
PubMed1989

Prevalence of DSM-III personality disorders in the community.

A community sample of adults with a standardized DSM-III, Axis II self-report instrument yielded an age adjusted community prevalence of 11.1% of DSM-III personality disorders. When those with personality disorders (PDs) (n = 26) were compared to those without personality traits (n = 167) the PD group had less education 14.9 (3.0) years vs 16.5 (3.3) years, p = 0.02) and a greater percentage with difficulty with alcohol (19% vs 0.6%, p = 0.0001). Of those married, more PDs reported marital difficulties (29% vs 3.5%, p = 0.002). There was a trend for the PD group to have longer unemployment (p = 0.07).

Adult↗
PubMed1996

Validation of coronary artery saphenous vein bypass graft diameter measurements using quantitative angiography.

The accepted value for reproducibility (true change) is two standard deviations (SD) of the differences between repeat measurements. It has been well established for coronary artery measurements using several different quantitative coronary angiography (QCA) systems, but it has not been well documented for saphenous vein grafts (SVG). The purpose of this study was to assess, using the Cardiovascular Measurement System (CMS), the measurement reproducibility of 24 vein grafts from 24 patients who had symptom-directed control angiography. Three equal graft segments were studied separately. Focal narrowings expressed in percent stenosis varied from 5 to 80% (mean 20.8 +/- 15.9%). The average minimum lumen diameter (MLD) was 3.07 +/- 0.81 mm and the average interpolated reference diameter (Ref. D) was 3.87 +/- 0.58 mm. We assessed the reproducibility of measurements obtained from two separate imagings of the graft in the same view but at least 20 minutes apart, near the beginning and at the end of the angiographic procedure (simulating baseline and end-trial examinations). The SD for differences in measurements (variability) was 0.183 mm for the MLD, 0.193 mm for the Ref.D, 0.184 mm for the mean diameter (Mean D) and 3.72% for the percent diameter stenosis (PDS). A reasonable true change cut-off for SVG measurements in our laboratory is > or = 0.4 mm for the minimum and mean lumen diameters, and > or = 10% for the PDS, when QCA is obtained with the QCA-CMS analytical software package.

Cineangiography↗
PubMed1975

Noise measurements in squid axon membrane.

A small area (10(-4) to 10(-5) cm2 patch) of the external surface of a squid (Loligo pealei) axon was "isolated" electrically by means of a pair of concentric glass pipettes and sucrose solution to achieve a low extraneous noise measurement of spontaneous fluctuations in membrane potential and current. The measured "small-signal" impedance function of the isolated patch in seawater was constant at low frequencies and declined monotonically at frequencies beyond 100Hz. It is shown that the power-density spectrum (PDS) of voltage noise, which generally reflects the current-noise spectrum filtered by the membrane impedance function, is equivalent to the power spectrum of current-noise up to frequencies where the impedance decline is significant (Fishman, 1973a, Proc. Nat. Acad. Sci. USA 70:876). This result is in contrast to an impedance resonance measured under uniform constant-current (internal axial wire) conditions, for which the voltage-noise PDS reflects the impedance resonance. The overdamped resonance in the patch technique is a consequence of the relatively low resistance (1 Momega) pathways through the sucrose solution in the interstitial Schwann cell space which surround and shunt the high resistance (10-100 Momega) membrane patch. Current-noise measurements during patch voltage clamp extend observation of patch ion-conductance fluctuations to 1 kHz. Various tests are presented to demonstrate the temporal and spatial adequacey of patch potential control during current-noise measurements.

Animals↗
PubMed1994

Paramedian diencephalic syndrome.

The clinical characteristics of paramedian diencephalic syndrome (PDS) are described on the basis of two recently observed cases: one with paramedian thalamic infarct, the other with paramedian thalamopeduncular infarct. Analysis of the clinical symptoms and the results of CBF study show that PDS is a complex neurological syndrome characterized by symptoms due to both anatomical lesions and functional disconnections.

Aged↗