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At least 217 records · Page 12Linked to original sources
PubMed2000

Functional evidence of a constitutively active population of alpha(1D)-adrenoceptors in rat aorta.

After depletion of intracellular calcium stores sensitive to noradrenaline, a spontaneous increase in the resting tone (IRT) when incubated in Ca(2+)-containing solution was observed in isolated rat aorta, but not in tail artery. This IRT does not depend on agonist activation of alpha(1)-adrenoceptors but it is inhibited by prazosin. A close relationship was found between the inhibitory potencies of prazosin (pIC(50) = 9.833), BMY 7378 (pIC(50) = 8.924), and 5-methylurapidil (pIC(50) = 7.883) against IRT and their affinities for cloned alpha(1D)-adrenoceptors. Chloroethylclonidine (100 micromol. l(-1)) did not inhibit the IRT. After depletion of internal calcium stores by noradrenaline in absence of the agonist, loading in Ca(2+)-containing solution also brings about an increase in the inositol phosphate (IP) levels in rat aorta (not seen in tail artery) that is inhibited by prazosin (1 micromol. l(-1)), BMY 7378 (10 micromol. l(-1)), and 5-methylurapidil (10 micromol. l(-1)), thus confirming the results obtained in contractile studies. Chloroethylclonidine (100 micromol. l(-1)) did not inhibit this IP accumulation. The fact that the IRT and the IP accumulation related to it can be selectively inhibited by different alpha(1)-adrenoceptor antagonists suggests the existence of a population of alpha(1D)-adrenoceptors that show constitutive activity in rat aorta, not in tail artery.

Adrenergic alpha-Antagonists↗
PubMedDate not supplied

Item response theory in affective instrument development: an illustration.

The benefits of item response theory (IRT) analysis in obtaining empirical support for construct validity make it an essential step in the instrument development process. IRT analysis can result in finer construct interpretations that lead to more thorough descriptions of low- and high-scoring respondents. A critical function of IRT is its ability to determine the adequacy with which the attitude continuum underlying each dimension is assessed by the respective items in an instrument. Many nurse researchers, however, are not reaping the benefits of IRT in the development of affective instruments. The purpose of this article is to familiarize nurse researchers with this valuable approach through a description of the Facets computer program. Facets uses a one parameter (i.e., item difficulty) Rasch measurement model. Data from a survey of 525 new mothers that assessed the psychometric properties of the Postpartum Depression Screening Scale are used to illustrate the Facets program. It is hoped that IRT will gain increased prominence in affective instrument development as more nurse researchers become aware of computer programs such as Facets to assist in analysis.

Affect↗
PubMed1992

[Mucoviscidosis screening with immunoreactive trypsin. Initial experiences in Austria].

Up to now, 16.338 IRT-measurements have been carried out on dried blood spot specimens; 15.505 of them were taken in the first week of life. Related to a provisionally chosen cut-off point of 750 ng/ml, 134 newborns (= 0.86%) showed an elevated IRT-value and subsequently were recalled between the fourth and sixth week of life for a second IRT-determination. Twenty-five out of 116 reinvestigated children again showed an elevated value, as based on likewise provisional, age-dependent reference values. Four of these children subsequently were identified as CF patients by sweat testing. So far, we did not encounter any false-negative IRT values. We also commenced to establish a profile of reference values for the first twelve weeks of life; as yet, there are not enough data for definitely defining these limits of normality. In conclusion, IRT-screening appears to be a reliable method for identifying CF patients in the newborn period. Our preliminary results indicate an incidence of CF of 1 to 3880 in the southeast of Austria.

Austria↗
PubMedDate not supplied

[Epidemiology and causes of autoimmune male infertility].

To study epidemiology and etiopathogenesis of male autoimmune infertility, we examined ejaculate samples from 3660 males of reproductive age, clinico-laboratory data on 560 males from infertile couples with antispermal antibodies (ASAB), 647 males without ASAB and 40 fertile males. Ejaculate was tested according to WHO recommendations, ASAB were identified by mixed agglutination reaction (MAR) and flow cytofluorometry (FCFM), infections of the reproductive tract (IRT)--by polymerase chain reaction (PCR). Experiments were made on 136 white non-inbred mature male rats and 40 mature female rats: 1/3 of the only testis was removed in male rats, then morphology of the operated on testis was studied as well as real fertility. ASAB were detected in 18% males of reproductive age. Factors of risk of antispermal immunity are the following: IRT (52%), varicocele (35%), blunt scrotal injuries without orchitis (21%) and previous epididymoorchitis (6%), obstruction (3%), cryptorchism and anejaculation (1%). Absolute risk of immune infertility makes up 67% after orchitis and epididymoorchitis, 66% after blunt scrotal injuries without clinical orchitis, 39-43% in clinical and previously operated varicocele, 32% after IRT. Combination of the risk factors raises immune infertility probability 1.2-4.1 fold. The efficacy of antibiotic therapy for bacterial IRT in ASAB is described. It is shown than it is possible to preserve spermatogenesis after testicular trauma by stimulation of its regeneration. Immunological mechanisms of male autoimmune infertility are analysed. Thus, main causes of male autoimmune infertility are mechanical, infectious or other affection of the testis leading to impairment of hematotesticular barrier, varicocele increases the risk of autoimmune reactions and orchitis after traumas; cross-over interaction between antigenic determinants of sperm and IRT; obstruction of the ejaculatory tract; specific features of antiinfectious immunity.

Animals↗
PubMed1990

[Early diastolic dysfunction of the left ventricle and its relation to histopathological findings in patients with diabetes mellitus].

The relation of left ventricular diastolic function and the histopathological findings of the myocardium in patients with diabetes mellitus were observed using echocardiography and endomyocardial biopsy. The subjects consisted of six diabetic patients (mean age 49.3 years) and eight normal control subjects (mean age 44.8 years). Coronary angiography had no significant stenotic lesions in their coronary arteries. Their diabetic complications were mild to moderate in severity. Echoes from the left ventricular margin of the septum and from the posterior left ventricular wall were traced on a digitizing board; then the isovolumic relaxation period, rapid filling period, slow filling period and atrial contraction period were determined to calculate fractional shortening (FS), isovolumic relaxation time (IRT), and three filling volumes (RFV, SFV and ACV). The quotients of the left ventricular filling volume and stroke volume were also determined. Right ventricular endomyocardial biopsies were performed to determine the diameters of myocytes, the percentage of fibrosis and the eccentricity e, as a parameter of the degree of myocardial dysarrangement. The results were as follows: IRT was significantly longer and RFV/SV was significantly greater in patients with diabetes mellitus than those among the controls. Also the diameters of myocytes and the percentage of fibrosis were significantly greater, while the eccentricity e was less compared to that of the controls. There were no significant correlations, among IRT, RFV/SV, the diameters of myocytes, and eccentricity e, but the percentage of fibrosis significantly correlated with IRT and RFV/SV (r = 0.62, r = -0.63). IRT and RFV/SV were mainly responsible for the percentage of fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Salivary amylase and pancreatic enzymes in Sjögren's syndrome.

Concentrations of immunoreactive trypsin (IRT) and pancreatic and salivary amylase activities were measured in 22 patients with primary Sjögren's syndrome (SS) and in 13 patients with secondary SS. Nineteen of the 22 patients with primary SS had above-normal IRT, and six had above-normal pancreatic isoamylase activity. Six of the 13 patients with secondary SS had above-normal IRT; none had above-normal isoamylase activities. Serum IRT and pancreatic isoamylase were correlated significantly (r = 0.7; p less than 0.0001). Above-normal values for IRT and pancreatic isoamylase were more frequent in patients who had SS for longer than 10 years, but were not related to the presence of salivary gland autoantibodies or to salivary isoamylase activity. We conclude that the concentration and activity of pancreatic enzymes are frequently abnormal in SS; that the abnormality is greater and more frequent in patients with primary SS; and that it increases with the duration of the disease.

Adolescent↗
PubMed1989

Exocrine pancreatic function in Sjögren's syndrome.

Pancreatic function testing was carried out in 19 patients with Sjögren's syndrome (SS) (nine primary type, ten secondary) by the N-benzoyl-tyrosil-p-aminobenzoic acid (PABA) test, serum immunoreactive trypsin (IRT) levels, and stool fat measurements to evaluate the incidence and type of exocrine pancreatic alterations in this disease. Exocrine pancreatic impairment was found to be present in 63% of the patients. Three types of secretory patterns were observed: (1) normal PABA test results and normal IRT levels (37% [7/19] of the patients); (2) normal PABA test results and elevated IRT levels (42% [8/19]; and (3) low PABA test results and elevated IRT levels (21% [4/19]), including two patients with steatorrhea. Functional pancreatic impairment tended to be more severe in patients with longer disease duration and it was related to the degree of alteration of salivary flow but not to labial salivary gland histologic changes or the type of SS. Inasmuch as hypertrypsinemia was the common marker of pancreatic dysfunction in all patients, we suggest a periodic measurement of serum IRT levels in the follow-up of patients with SS to detect early stages of pancreatic involvement.

4-Aminobenzoic Acid↗
PubMedDate not supplied

Biochemical pathways of acute lung injury.

Complement fragments (C3, C3d, C5a), thromboxane B2 (TxB2), 6-keto-PGF1 alpha and immunoreactive trypsin (IRT) were measured in 98 patients at risk of developing the adult respiratory distress syndrome (ARDS): 53 multiple trauma, 28 abdominal surgery and 17 acute pancreatitis. Sixty-five of these patients developed ARDS: 30 multiple trauma, 19 abdominal surgery and 16 acute pancreatitis patients. Forty of the 65 ARDS patients and 9 out of the 33 non-ARDS patients died. Mean value of the C3d to C3 ratio was abnormal in both ARDS and non-ARDS patients. C5a-like activity was detected in 70 out of the 98 patients (49 ARDS and 22 non-ARDS patients). TxB2 abnormal values (greater than 100 pg . ml-1) were found in 70% of the patients, especially when sepsis occurred. No correlation could be made between abnormal 6-keto PGF1 alpha values and ARDS or sepsis. The mean peak IRT value was 675 micrograms . 1(-1) for ARDS patients and 274 micrograms . 1(-1) for non-ARDS patients (p less than 0.05). A firm correlation was also measured between IRT and sepsis (p less than 0.01). C5a-like activity was regularly detected soon after injury, while TxB2 and IRT tend to appear later in patients developing ARDS. Neither C3d/C3, nor C5a-like activity, nor TxB2, nor IRT are specific markers of ARDS, since they also appeared in severely ill patients who did not develop ARDS.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

Cytopathology of pleural effusions after radiotherapy.

The cytomorphology of pleural effusions following ionizing radiotherapy (IRT) has not been studied systematically. To determine if IRT produces alterations in pleural fluids that affect the cytopathologic interpretation of these specimens, two reviewers, without clinical information, independently assessed 55 specimens obtained following IRT and 39 control specimens obtained from nonirradiated cancer patients. None of the 24 cytologic features studied were identified significantly more frequently by both reviewers in the irradiated specimens. Only one feature (bizarre cells) was found to occur significantly more frequently in the irradiated specimens (36% versus 15%, P = .03) by either reviewer (reviewer B). Four other features showed a tendency to occur more frequently in the irradiated fluids by one or the other reviewer. They included degenerative changes (27% versus 13%, P = .09 [reviewer A]), smudgy chromatin (16% versus 5%, P = .09 [reviewer A]), large cytoplasmic vacuoles deforming the nuclei (44% versus 26%, P = .07 [reviewer B]) and cytomegaly (38% versus 23%, P = .12 [reviewer B]). The utility of these five features in identifying irradiated specimens was rigorously retested in a second masked review conducted jointly by the two pathologists. None of these features was found more frequently in the irradiated specimens in the second analysis. The results suggest that IRT does not consistently produce distinctive cytologic changes in pleural effusions and that a history of IRT should not affect the interpretation of these specimens.

Exudates and Transudates↗
PubMed1996

Atraumatic method of intraoperative retrograde transhepatic biliary stent insertion.

A significant risk of hepatic injury remains using reported methods of intraoperative retrograde transhepatic stenting (IRTS). Our hypothesis was that we could minimize this risk by: (1) using a pliable sheath to create a stent tract that follows the curve of the biliary tree, (2) decreasing the stent diameter, and (3) avoiding the hepatic hilum. We evaluated the safety of a novel technique of intraoperative stenting employing these three concepts. Twenty-four patients underwent IRTS between 1992 and 1995 at our institution after potentially curative resection (one bypass). Malignant disease was present in 22 of 24 patients. Bile ducts were normal caliber in all patients. There was no operative mortality and 38% operative morbidity, all readily treated. All complications were due to stent dislodgment. There were no deaths. This novel atraumatic method of IRTS has acceptable morbidity and mortality. Complications due to stent insertion are minimal. The technique compares favorably with previous methods of IRTS and offers a viable alternative to the surgeon when a transhepatic stent is required. Anchoring the stent securely to the skin is essential to prevent catheter dislodgement.

Bile Duct Neoplasms↗
PubMed2003

Use of restenting should be minimized with intracoronary radiation therapy for in-stent restenosis.

Restenting at the time of intracoronary radiation therapy (IRT) for in-stent restenosis (ISR) potentially increases the risk of late total occlusion (LTO) of the treated vessel. Prolonged antiplatelet therapy with clopidogrel (6 months) has been shown to be effective in reducing LTO risk. The purpose of this study was to assess the impact of restenting on clinical outcomes following IRT for ISR with 6 months of clopidogrel. We retrospectively evaluated 1,275 patients with 6-months clinical follow-up who were enrolled in radiation trials for ISR using gamma- and beta-emitters conducted at Washington Hospital Center. Patients were analyzed according to whether additional stents were deployed at the time of IRT. The predominant indication for restenting was to optimize the final angiographic result in the event of tissue prolapse or to cover edge dissections. All patients received a minimum of 6 months of clopidogrel. Baseline clinical and angiographic characteristics were similar between the restented and nonrestented groups. Radiation was delivered successfully in all cases. At 6 months, patients treated with additional stents and IRT had a significantly higher rate of target vessel revascularization than patients without additional stents (24.6% vs. 18.7%; P = 0.011). Restenting caused more frequent late thrombosis, late total occlusion, and Q-wave myocardial infarction than no restenting (4.0% vs. 2.2%, P = 0.09; 6.1% vs. 4.3%, P = 0.14; and 1.9% vs. 0.4%, P = 0.009, respectively). Restenting for the treatment of ISR is associated with increased adverse events and should be avoided after intracoronary radiation therapy for in-stent restenosis, as restenting results in a higher recurrence rate and the potential for increased late total occlusion.

Brachytherapy↗
PubMed2005

Real-world clinical practice of intracoronary radiation therapy as compared to investigational trials.

Intracoronary radiation therapy (IRT) is well established in clinical practice as an effective treatment for in-stent restenosis. We aimed to determine if the 6-month clinical outcome of patients treated postapproval for marketing [commercial radiation (CR)] is equivalent to those patients enrolled in the Washington Radiation for In-Stent Restenosis Trials [Gamma WRIST and Beta WRIST; investigational radiation (IR)]. The 6-month clinical outcome of 110 consecutive patients with 125 lesions who received IRT (gamma, (192)Ir, 15-18 Gy, n = 6; or beta, (32)P, 20 Gy, n = 20; or (90)Sr/Y, 18.4-23.0 Gy, n = 99) in CR was compared with the 6-month clinical outcome of 117 patients with 117 lesions who received IRT ((192)Ir, 15 Gy, n = 65, in Gamma WRIST; and (90)Y, 20.6 Gy, n = 52, in Beta WRIST) in IR. Patients in CR were treated with wider radiation margins. The CR received antiplatelet therapy for at least 6 months and the IR for 1 month. The baseline characteristics of both groups were similar. Use of atheroablation devices was less in CR than IR (15.2% vs. 32.8%, respectively; P = 0.001). The overall major adverse cardiac events (death, Q-wave myocardial infarction, and target vessel revascularization; 18.2% vs. 29.1% in IR; P = 0.05) were significantly lower in the CR when compared with patients in the IR. The real-world clinical practice of IRT demonstrates lower events and better clinical outcomes. This is most likely a result of implementation of the lessons learned from the clinical trials such as optimizing the dosimetry by using a higher dose, treating wider margins to minimize edge effect, and administering prolonged antiplatelet therapy to abolish late thrombosis.

Aged↗
PubMed2005

Three-year follow-up after intravascular gamma-radiation for in-stent restenosis in saphenous vein grafts.

The Washington Radiation for In-Stent Restenosis Trial in Saphenous Vein Grafts (SVG WRIST) demonstrated safety and efficacy of intravascular radiation therapy (IRT) for the treatment of in-stent restenosis (ISR) in SVG at 12 months. In this study, we aimed to examine whether the safety and efficacy of IRT is durable up to 36 months. One hundred twenty patients with diffuse ISR in SVG underwent balloon angioplasty, laser or atherectomy ablation, and/or additional stenting. After successful intervention, patients were randomly assigned in a double-blind fashion to intravascular treatment with a ribbon containing either iridium (Ir)-192 (n = 60) or nonradioactive seeds (n = 60). The prescribed dose at 2 mm from the source was either 14 or 15 Gy in vessels 2.5-4.0 mm or 18 Gy in vessels > 4.0 mm in diameter. At 36 months, target lesion revascularization (TLR; 43% vs. 66%; P = 0.02) and target lesion revascularization-major adverse cardiac event (TLR-MACE; 49% vs. 71%; P = 0.02) rates continued to be lower in the IRT group, but both target vessel revascularization (TVR; 59% vs. 71%; P = 0.17) and TVR-MACE (63% vs. 77%; P = 0.11) rates were not. In SVG WRIST, patients with ISR treated with IRT had a marked reduction in the need for repeat TLR at 36 months, with sustained clinical benefit at 3 years despite late recurrences, which were more pronounced in the radiation group.

Aged↗
PubMed1985

Serum immunoreactive trypsin and pancreatic lipase in cystic fibrosis.

Serum immunoreactive trypsin (IRT) and pancreatic lipase have been measured in 59 patients with cystic fibrosis (age 1 month-27 years). Follow-up values were obtained from 49 patients. Their serum enzyme levels were compared to those of 120 healthy children of all age groups. Faecal fat excretion was determined in selected patients (n = 23) to elucidate the relationship between serum enzyme levels and pancreatic exocrine function. In cystic fibrosis IRT and lipase showed a very similar age-correlated pattern: in infancy levels were markedly elevated. During the following years the concentrations of both enzymes decreased rapidly and were found to be far below the normal range after the 10th year of life. Elevated enzyme levels in infancy as well as low levels in all age groups coincided with steatorrhea. Older patients (11-27 years) without severe pancreatic insufficiency however, had IRT and lipase levels in or above the normal range. In healthy children there was no age dependency of IRT levels, whereas in the first 12 months of life lipase levels were significantly lower than in later childhood.

Adolescent↗
PubMed1993

Non-specific elevation of immunoreactive trypsinogen in sick infants.

To determine the effect of neonatal illness on immunoreactive trypsinogen (IRT) levels, the IRT values obtained in sick infants transferred to a neonatal intensive care ward were compared with those found in matched controls. IRT levels from dried blood spots collected on day 4-5 of life from 372 sick infants had a mean value of 0.095 log transformed multiples of the median, whilst controls had a mean of -0.013: a highly significant difference. Classification of the sick infants into principal diagnostic categories failed to show any group contributing disproportionately to the observation. In particular, the level of elevation observed in 33 infants with gut abnormalities such as bowel obstruction, duodenal atresia, exomphalos and gastroschisis, in which some degree of pancreatic obstruction might be expected, was not greater than in other hospitalised infants. These data show that sick infants are at increased risk of being identified by an IRT screening programme aimed at detecting infants with cystic fibrosis.

Gastrointestinal Diseases↗
PubMed1997

Molecular diversity and evolution of blaTEM genes encoding beta-lactamases resistant to clavulanic acid in clinical E. coli.

The molecular diversity of inhibitor-resistant TEM (IRT) enzymes was explored using a strategy which involved DNA amplification by polymerase chain reaction (PCR), analysis of restriction fragment length polymorphism (RFLP), and direct nucleotide sequencing. The study of plasmid-borne genes from 27 strains, resistant to amoxicillin and beta-lactamase-inhibitor combinations, identified mutations resulting in amino acid change at positions 69, 244, 275, and 276 known to be associated with the IRT phenotype and a mutation at nucleotide position 162 in the promoter region. These mutations were found to lie on two different gene sequences, described here as "TEM-1B like" and "TEM-2 like" restriction linkage groups. Further analysis, of nucleotide sequences of promoter and coding regions of the beta-lactamases, confirmed that a given mutation causing IRT phenotype could be associated with two different gene sequence frameworks and two different causal mutations could lie on identical gene sequence framework. These data argue in favor of convergent phenotypic evolution of IRT enzymes under the selective pressure imposed by the intensive clinical use of beta-lactam-beta-lactamase inhibitor combinations.

Amoxicillin↗
PubMed1997

BIMT 17: a putative antidepressant with a fast onset of action?

BIMT 17, the only compound reported to be a full 5-HT1A agonist and a 5-HT2A antagonist at the frontal cortex, was assessed in three animal paradigms sensitive to antidepressants in rats: olfactory bulbectomy (OB), differential-reinforcement-of-low rate 72-s (DRL 72-s) and learned helplessness (LH). In the OB rats, BIMT 17, given once daily for 14 consecutive days at an i.p. dose of 10 mg/kg, but not of 20 mg/kg, reduced the increase in ambulation of OB rats, 24 h after the last administration. In the DRL 72-s test, BIMT 17 had a different profile than imipramine. A single i.p. injection of 5, 10, 15 or 20 mg/kg BIMT 17, in contrast to the same doses of imipramine, did not affect response and reinforcement rate in DRL 72-s 1 h after the administration. On the other hand, BIMT 17 slightly shifted the peak of the interresponse time (IRT) distribution towards shorter IRT duration, while imipramine shifted the peak of the IRT distribution towards longer IRT duration. In the LH test, acute oral doses (36, 48 or 60 mg/kg) of BIMT 17, given 30 min before testing, reduced the number of escape failures in LH without altering the intertrial crossings. This effect was also induced by a repeated, but not single, administration with 8 or 16 mg/kg imipramine. The plasma levels following i.p. 10 or oral 48 mg/kg BIMT 17 were in the same range. These results indicate that BIMT 17 does not behave like imipramine in all the tests, and suggest that BIMT 17 acts through different mechanisms of action than imipramine. Only clinical trials will tell whether these mechanisms will be relevant, but if so, BIMT 17 might induce a faster onset of therapeutic activity.

Animals↗
PubMedDate not supplied

Effect of dobutamine on a Doppler echocardiographic index of combined systolic and diastolic performance.

Dobutamine stress echocardiography has become accepted in the evaluation of cardiac functional reserve. Although the Doppler-derived index of combined systolic/diastolic myocardial performance (Tei index) has been reported to be easily obtainable and useful for predicting left ventricular performance, the effect of dobutamine on the Tei index has not been determined in children. To assess the effect of dobutamine on the Tei index, 8 patients who had undergone surgery for ventricular septal defect and 7 patients who had a history of Kawasaki disease were examined. Echocardiographic recordings were obtained before and after dobutamine infusion (5 microg/kg per minute). Variables measured were transmitral flow velocities (E, A, E/A), rate-corrected mean velocity of circumferential fiber shortening (rate-corrected Vcf), and IMP. We measured isovolumic contraction time (ICT), isovolumic relaxation time (IRT), and ejection time (ET) and then calculated the Tei index using the following formula: Tei index = (ICT + IRT)/ET. Dobutamine infusion increased rate-corrected Vcf (29%, p < 0.01), peak E (7%, p < 0.05), and peak A (13%, p < 0.05). E/A ratio did not change during dobutamine infusion. ET, ICT, and IRT were found to decrease during dobutamine infusion. The magnitude of the change in the ICT (-21%, p < 0.01) was greater than those in IRT (-12%, p < 0.01) and ET (-8%, p < 0.05). The decrease in Tei index (-16%, p < 0.01) resulted in a decrease in ICT/ET (-21%, p < 0.01) and a slight decrease in IRT/ET (-12%, p < 0.05). The Tei index has potential as a sensitive indicator of the effects of inotropic stimilation on global left ventricular function.

Adolescent↗