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At least 199 records · Page 11Linked to original sources
PubMed1992

Pulmonary metastases: MR imaging with surgical correlation--a prospective study.

The sensitivity of magnetic resonance (MR) imaging for detection of pulmonary metastases in 11 patients scheduled for thoracotomy and curative resection of metastases was evaluated with a prospective, controlled study. MR imaging performed at 0.5 T was compared with chest radiography, computed tomography (CT), and thoracotomy in 12 cases. (One patient had two separate occurrences of pulmonary metastases.) All images were interpreted in blinded fashion. When all MR sequences were interpreted together, MR imaging enabled correct identification of all patients with pulmonary nodules (100%). CT enabled detection of at least one nodule in all 12 cases (100%) by design; the sensitivity of chest radiography was only 64%. For individual nodules, MR imaging was at least as sensitive as CT (P2 less than .25 [two-sided value]) and significantly more sensitive than chest radiography (P2 less than .01). Among all MR sequences, short inversion time inversion-recovery sequences had the highest sensitivity for detection of individual nodules (82%).

Adult↗
PubMed2002

Sex differences in repolarization homogeneity and its circadian pattern.

The reason for sex differences in arrhythmic risk remains unclear. Heterogeneity of ventricular repolarization is directly linked to arrhythmogenesis; thus we investigated repolarization homogeneity and its circadian pattern in men and women. During 24-h Holter recordings in 60 healthy subjects (27 males), a 12-lead electrocardiogram (ECG) was obtained every 30 s. RR and QT intervals, and, after singular-value decomposition, two characteristics of repolarization homogeneity were calculated in each ECG. Corrected QT (QTc) values were obtained using an individually optimized heart rate (HR) correction formula. All values were averaged over 10-min time bands from 0000 to 2400. There were substantial sex differences in both global repolarization homogeneity (measured by the total cosine of the angle between QRS and T wave vectors) and regional homogeneity of repolarization (quantified independently by the relative T wave residuum). Whereas women throughout the 24 h followed more closely the pattern of inverse sequence between depolarization and repolarization, they also showed much higher localized repolarization heterogeneity than men. In both women and men, repolarization irregularity was greatest during morning hours. A sex difference was also observed for HR and QTc interval; however, the circadian patterns of the repolarization homogeneity descriptors were different from those of HR and QTc intervals.

Adolescent↗
PubMed2003

Subthalamic nucleus deep brain stimulation for Parkinson's disease: magnetic resonance imaging targeting using visible anatomical landmarks.

BACKGROUND: The aim of the present study was to validate a magnetic resonance imaging (MRI) visual procedure to target the subthalamic nucleus (STN) based on surrounding anatomical landmarks. METHODS: 31 consecutive bilaterally implanted parkinsonian patients were included in this study. After identification of the anterior commissure (AC), posterior commissure (PC) and midcommissural point on a three-dimensional T1-weighted sequence, inversion recovery (IR) T2-weighted coronal slices were performed orthogonal to the AC-PC line. On the slice showing the anterior pole of the red nucleus (RN), the target was placed in the inferolateral portion of the subthalamic zone, limited superiorly by the thalamus, laterally by the internal capsule, inferiorly by the substantia nigra and medially by the midline. The distribution of the targets was analyzed in the AC-PC referential. RESULTS: The mean target coordinates were as follows: anteroposterior (AP) = -2.54 mm (+/-1.37 mm), lateral (LAT) = 12.03 mm (+/-0.91 mm) and vertical (VERT) = -6.10 mm (+/-1.52 mm) for the right side, and AP = -2.65 mm (+/-1.36 mm), LAT = -11.97 mm (+/-1.30 mm) and VERT = -5.89 mm (+/-1.52 mm) for the left side. They projected in the inferior portion of the STN on the Schaltenbrand and Wahren atlas [Stuttgart, Thieme, 1977]. CONCLUSION: Identification of the anterior pole of the RN and the subthalamic zone on coronal IR T2-weighted MRI performed orthogonal to the AC-PC line provides a precise visual procedure to target the STN.

Electric Stimulation Therapy↗
PubMedDate not supplied

Amitriptyline in neuropathic cancer pain in patients on morphine therapy: a randomized placebo-controlled, double-blind crossover study.

AIMS AND BACKGROUND: Amitriptyline is the most common analgesic adjuvant used in cancer patients with neuropathic pain, even though no specific studies have demonstrated a benefit. A randomized placebo-controlled, double-blind crossover study was designed to evidence the effects of amitriptyline in patients with neuropathic cancer pain. METHODS: Sixteen advanced cancer patients with neuropathic pain on systemic morphine therapy, no longer receiving oncologic treatment, presenting moderate pain (about 4 or more, but less than 7, on a numerical scale of 0-10) in the last week, and given a stable morphine dose in the last 2 days were admitted to the study. During the first week of study, patients were administered 25 mg of amitriptyline or equivalent drops of placebo at night for 3 days and 50 mg for the following 4 days. Doses for patients aged more than 65 years were 15 mg (first 3 days) and 30 mg (3 days after). After a week, a crossover took place for the second week, with the other treatment at an inverse sequence. Opioid consumption, pain intensity, symptoms and adverse effects, mood, sleep, patient's preference, quality of life before starting the study, the first week after and the second week after were recorded. RESULTS: No significant benefits in analgesia were found in the global pain intensity of the previous week of treatment, the least pain intensity or the pain evaluated just after a week of treatment, at the moment of the visit, when amitriptyline was compared with placebo. A significant difference was evidenced for the worst pain (P < 0.035). No differences in opioid doses during the period of study were found. Drowsiness, confusion and dry mouth were significantly more intense with amitriptyline than with placebo (P < 0.036, 0.003, and 0.034, respectively). There were no substantial differences between the two treatments in Spitzer's quality of life score and for each item. No differences in patients' preference for the two treatment periods were found. The analgesic effects of amitriptyline were slight and associated with adverse effects. CONCLUSIONS: In light of the results obtained in the study, the extensive use of the drug for cancer pain should be questioned.

Aged↗
PubMed2000

[The correlation between the type of positivity of the tilt test and a simultaneous electroencephalogram: the preliminary results].

BACKGROUND: Today the first-choice examination to study neurally-mediated syncope is the tilt test. There are still many aspects to be clarified on the pathophysiology of neurally-mediated syncope, and much uncertainty remains on the therapeutic procedure to adopt. Recent research has investigated the role of neurohumoral agents, thus shifting interest to the pathogenetic role of the central nervous system, over and above that of the already widely studied vegetative nervous system. This is why we decided to carry out the tilt test with simultaneous electroencephalogram (EEG) recordings, with the aim of documenting any possible correlation between test positivity, according to Sutton's classification, and the EEG results. METHODS: We studied 15 patients (8 males, 7 females, age range 18-74 years) with a history of repeated syncopal and presyncopal episodes who had formerly undergone numerous clinical and instrumental examinations, including EEG, with negative results. The tilt test was carried out with continuous measurement of blood pressure (Ohmeda Finapres System) and simultaneous EEG recording. RESULTS: Ten patients (66%) were positive, 6 had experienced syncope episodes (4 type 2A and 2 type 1) and 4 presyncope (1 type 2A and 3 type 1). In all the syncope positive patients the EEG showed modifications in comparison with basal EEG, whereas only 50% of the presyncope positive patients showed slight alterations. There was no EEG alteration for tilt negative patients. The EEG result was markedly different in patients with tilt-induced type 2A syncope in comparison with those with type 1. Type 2A showed the following: 1) slowdown and reduced amplitude of electrical activity during the prodromes; 2) during the syncope, first pseudorhythmic then polymorphic delta activity were followed by total disappearance of activity ("flat" EEG); 3) then, in inverse sequence, reappearance of polymorphic then pseudorhythmic delta activity (average duration of syncope 37 s); 4) lastly, slowdown and reduced amplitude of electrical activity similar to that preceding the syncope. Whereas type 1 revealed: 1) no alteration of electrical activity during the prodromes; 2) during the syncope, first theta then polymorphic delta activity (average duration of syncope 16 s); 3) subsequent normal EEG. CONCLUSIONS: These observations indicate a correlation between the type of tilt test positivity and the EEG results, the latter being markedly more serious in type 2A than in type 1. EEG behavior, different in the two types also during the prodromes and the post-syncopal phase, would suggest a cerebral circle vasoconstriction mechanism in type 2A but not in type 1 mixed with a prevalent vasodepressive component. Should these preliminary results be confirmed by further data there will be evident clinical, prognostic and therapeutic implications. In the light of the considerably different involvement of the central nervous system, we believe it will be necessary to redefine the various types of neurally-mediated syncope in terms of seriousness. Simultaneous EEG could be proposed routinely in tilt test execution and become a determining factor in the choice of a therapeutic option.

Adolescent↗
PubMed2003

MR in the study of knee cartilage pathologies: influence of location and grade on the effectiveness of the method.

PURPOSE: To evaluate the diagnostic effectiveness of magnetic resonance (MR) in knee cartilage pathologies of different regions and grades with the aim of establishing the role of MR in treatment choice. MATERIALS AND METHODS: We enrolled 90 patients who underwent MR and arthroscopy of the knee. To classify cartilage lesions we used a simplified grading system that correlates MR to arthroscopic reports and divides lesions into low and high grades. The MR examinations were performed with a 1.5 T superconducting magnet with a standard protocol to obtain quality images in a short time, using T1-weighted spin-echo sequences, T2* weighted gradient-echo sequences and inversion recovery sequences. The MR diagnostic specificity, sensitivity and accuracy and MR positive predictive value and negative predictive value in identifying and grading the chondral lesions of the femorotibial and patellofemoral compartments were calculated and compared to arthroscopy parameters. RESULTS: The analysis of each grade of chondral lesions reveals an MR accuracy of 94% in high-grade lesions of the femorotibial and patellofemoral compartments and an MR accuracy of 78% in low-grade lesions of patellofemoral compartment and of 70% in low-grade lesions of femorotibial compartment. This result suggests MR is useful for the grading of chondral lesions in clinical practice. CONCLUSIONS: MR diagnostic effectiveness substantially changes according to the different location and grade of chondral lesions. While MR seems to be nearly equivalent to arthroscopy for high-grade lesions subject to surgery, it appears to be less accurate in diagnosing low-grade lesions, in particular femorotibial lesions.

Adult↗
PubMed2004

[Motifs in the primary structure of MHC Class I molecules and their use for the design of synthetic T-cell receptor ligands].

This paper attempts to describe a great variety of allelic forms of mammalian major histocompatibility gene complex (MHC) Class I molecules as a single "formula" that contains information on motifs in their primary structure. The positions of amino acid residues that are invariant even in highly evolutionarily different species have been found in the structure of MHC Class I molecular domains that are recognizable by T-cell receptors (TCR). The spatial arrangement of invariant residues in the tertiary structure of MHC molecules is indicative of their structure-forming function: they are generally located at the sites of contact of alpha-helices and beta-sheets. A study of homology between the structures of MHC Classes I and II molecules has identified a fragment located in the "kink"-region of both MHC Class I and beta-chains of MHC class II molecules, at which the spectra of possible amino acid substitutions significantly coincide. Since this region can act as an "anchor" for interaction with TCR, the authors have synthesized dendrimers with the direct and inverse sequences of AA158-175 of an H-2Ld molecule, whose biological activity has been investigated in the fetal thymic organ cultures isolated from 14-day embryos of B10.D2 (KdIdDdLd) mice. The findings suggest that synthesized peptides can affect the development and shaping of T-cell repertoire.

Adjuvants, Immunologic↗
PubMedDate not supplied

Clinical evaluation of four study protocols with 99mTc-methoxyisobutylisonitrile and SPECT for detecting diseased coronary vessels.

Different techniques have been suggested for coronary artery disease (CAD) detection with single-photon emission computed tomography (SPECT) and 99mTc-methoxyisobutylisonitrile (99mTc-MIBI). We evaluated four protocols employing myocardial SPECT with 99mTc-MIBI in separate groups of patients. The first involved stress and rest studies performed on separate days, whereas the other three involved "same day" studies. Group 1 (n = 23) was examined in separate sessions, after ergometric exercise and at rest. Group 2 (n = 24) was first injected after dipyridamole infusion, then injected again at rest after completion of the stress study. Group 3 (n = 24) was first injected at rest and imaged one hour later. Afterwards an ergometric stress was performed, with injection at peak exercise. The inverse sequence was adopted for group 4 (n = 24). All patients underwent coronary angiography. For all groups and vessels, the sensitivity and specificity for diseased coronary artery identification were not statistically different. Studies using the new myocardial perfusion tracer 99mTc-MIBI may therefore be completed on the same day or on separate days according to laboratory and patient needs. Dipyridamole iv infusion proved to be as effective as ergometric exercise for diseased coronary artery identification.

Clinical Protocols↗
PubMed1985

[Mode of action of purinergic derivatives of adenine on auriculo-ventricular conduction. Experimental study in dogs].

The effects of three purine derivatives of adenine, adenosine triphosphate (Striadyne), purified adenosine triphosphate and adenosine, on conduction tissue, were studied in closed chest dogs with endocavitary recording catheters. The dogs were anaesthetised with pentobarbital and ventilated, then three bipolar catheters were positioned to allow atrial pacing and recordings of atrial and His bundle potentials. The purines studied were administered by rapid bolus intravenous injection. The dosage was identical based on a predetermined dose-response curve (dose of 2 mg/kg). The study of the effects on atrioventricular conduction was carried out before and after administration of antagonists: atropine, 0.08 mg/kg and aminophylline, 10 mg/kg. Twelve dogs were studied for each purine: 6 with initial premedication with atropine and then aminophylline, and 6 with the inverse sequence. Lengthening of AV conduction was due exclusively to nodal depression. No variation in the HV interval was observed (HV = 35 +/- 4 ms). Lengthening of AH interval was observed very soon after injection of the drugs (5 to 10 seconds) with a peak effect between 20 and 40 seconds. Reversion to the initial value always occurred in under 2 minutes. In the model studied, Striadyne and purified adenosine triphosphate were much more powerful than adenosine, both in intensity and duration; high degree AV block was obtained in 10 out of 12 cases with Striadyne and in 8 out of 12 cases with purified adenosine triphosphate, but in only 2 out of 12 cases with adenosine. The use of specific antagonists demonstrated the different modes of action of the three purines.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1996

Effects of captopril and ticlopidine, alone or in combination, in hypertensive patients with intermittent claudication.

Twenty four male hypertensive patients suffering also from peripheral obstructive arterial disease were randomly subdivided in two groups and after a period of farmacological wash-out of one month Group I was treated with Captopril (C 50 mg bid) or Ticlopidine (T 250 mg bid) for three months and then with the association C plus T for three months again. After placebo administration for one month, patients were further treated with C plus T at low doses (25 mg bid and respectively 250 mg daily). In the first part of the study, patients of Group II received an inverse sequence of the drugs (before Ticlopidine 250 mg bid and then Captopril 50 bid). In both groups of patients C induced a significant decrease of blood pressure and an increase of PFWD, TWD, and WI. T did not modify blood pressure but slightly increased PFWD, TWD, and WI. The improvement was more evident during administration of C plus T, whereas placebo administration induced a trend toward baseline values. Finally, the chronic administration of C plus T for twelve months induced a further improvement of all considered parameters. In conclusion, chronic administration of C plus T may be useful in the treatment of hypertensive patients suffering from intermittent claudication, improving significantly PFWD and TWD.

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

[Quantitative patterns in the yield of chromosome aberrations in a human lymphocyte culture with fractionated gamma-neutron irradiation at different stages of the mitotic cycle. The cytogenetic effects at stage G1].

Quantitative regularities of the chromosome aberrations yield in the human lymphocyte culture affected by fractionated gamma/neutron irradiation (in the direct and inverse sequences) at a stage of the presynthesis (G1), with the 1 to 5 h intervals between the dose fractions, were studied. The obtained results were compared with those for the stage G0 described in the previous paper. The cytogenetic effect, with doses and intervals between the dose fractions being equal, depended significantly on a stage of the mitotic cycle of the cells. The effect was opposite for the stages G0 and G1: super- and subadditive, respectively.

Cells, Cultured↗
PubMedDate not supplied

[Quantitative patterns in the yield of chromosome aberrations in a human lymphocyte culture with fractionated gamma-neutron irradiation at different stages of the mitotic cycle. The cytogenetic effects at stage S].

Quantitative regularities of the chromosome aberrations yield in the human lymphocyte culture affected by fractionated gamma/neutron irradiation (in the direct and inverse sequences) at a stage of the replicative DNA synthesis (S), with the 1 to 5 h intervals between the dose fractions, were studied. The obtained results on the cytogenetic effect of interaction of damages were compared with those for the stages G0 and G1. In contrast to the latter cases, where occurrence of superadditive effects was high, only subadditive effects were observed for the stage S.

Cells, Cultured↗
PubMedDate not supplied

Application of Fluid-Attenuated Inversion Recovery pulse sequence in children with tuberous sclerosis.

To evaluate the application of Fluid-Attenuated Inversion Recovery (FLAIR) pulse sequence to increase the sensitivity of detecting tubers in tuberous sclerosis patients compared with fast spin-echo T2-weighted (FSET2W) image, we obtained 12 magnetic resonance (MR) images in 10 patients (mean age = 57.7 months old). Among the 12 examinations, 114 cortical and 128 subcortical tubers were revealed on the FLAIR images, whereas 54 and 72 tubers were found respectively on the FSET2W images. This may be due to the FLAIR pulse sequences remarkably attenuated CSF signals in comparison with the FSET2W images. However, FSET2W image delineated more subependymal nodules than FLAIR imaging did. Gd-DTPA enhanced T1W image is the most suitable pulse sequence to detect giant cell astrocytoma near the foramen of Monro. The results in cases of infants and little children were similar.

Child↗
PubMed1995

MRI in neurofibromatosis type I: using fluid-attenuated inversion recovery pulse sequences.

Cranial magnetic resonance imaging results of 14 patients with neurofibromatosis type I were examined with T2-weighted fluid-attenuated inversion recovery pulse sequences, as well as conventional T2-weighted spin-echo sequences. Definition was better in 62 of 79 lesions or groups of lesions on fluid-attenuated inversion recovery images than on T2-weighted spin-echo images. The lesions were demonstrated not only in the brainstem, cerebellum, globus pallidus, and cerebral white matter, but also in the hippocampus, pulvinar thalami, and splenium of the corpus callosum. The latter 3 lesions have not been demonstrated or emphasized in previous studies. It is concluded that fluid-attenuated inversion recovery imaging is more effective in detecting multiple lesions in patients with neurofibromatosis type I than conventional T2-weighted spin-echo imaging.

Adolescent↗
PubMed1998

Defective forms of cotton leaf curl virus DNA-A that have different combinations of sequence deletion, duplication, inversion and rearrangement.

Tobacco and tomato plants inoculated at least 9 months previously with a Pakistani isolate of cotton leaf curl virus (CLCuV-PK), a whitefly-transmitted geminivirus, contained substantial amounts of circular dsDNA molecules that were mostly about half the size of CLCuV-PK dsDNA-A. They appeared to be derived from CLCuV-PK DNA-A by various combinations of sequence deletion, duplication, inversion and rearrangement and, in a few instances, insertion of sequences of unknown origin. Each of ten tobacco plants contained a different predominant form of such a defective molecule; however, all the forms contained the intergenic region and part of the AC1 (Rep) gene. Some of the forms contained novel open reading frames and might have a role in the evolution of variant geminiviruses. The defective components were not detected at 3 months after the original culture of CLCuV-PK was transmitted by whiteflies (Bemisia tabaci) from cotton to tomato but were present after a further 6 months. They were transmitted, along with full-length DNA-A, between tobacco and tomato plants by grafting and by B. tabaci.

Animals↗
PubMed1991

Ability of a bacterial chromosome segment to invert is dictated by included material rather than flanking sequence.

Homologous recombination between sequences present in inverse order within the same chromosome can result in inversion formation. We have previously shown that inverse order sequences at some sites (permissive) recombine to generate the expected inversion; no inversions are found when the same inverse order sequences flank other (nonpermissive) regions of the chromosome. In hopes of defining how permissive and nonpermissive intervals are determined, we have constructed a strain that carries a large chromosomal inversion. Using this inversion mutant as the parent strain, we have determined the "permissivity" of a series of chromosomal sites for secondary inversions. For the set of intervals tested, permissivity seems to be dictated by the nature of the genetic material present within the chromosomal interval being tested rather than the flanking sequences or orientation of this material in the chromosome. Almost all permissive intervals include the origin or terminus of replication. We suggest that the rules for recovery of inversions reflect mechanistic restrictions on the occurrence of inversions rather than lethal consequences of the completed rearrangement.

Chromosome Inversion↗
PubMed1985

Calculated T1 images derived from a partial saturation-inversion recovery pulse sequence with adiabatic fast passage.

Calculated T1 images of the head and abdomen have been obtained using an alternating partial saturation-inversion recovery pulse sequence. Timing parameters were adjusted to yield optimum T1 contrast-to-noise ratio for this sequence for the range of T1 studied. Adiabatic fast passage (AFP) was implemented for the nonselective inverting pulse, to reduce the sensitivity of the measurement to RF and static field inhomogeneity. A nonlinear frequency sweep was used to improve the efficiency of the AFP pulse. The effect on the T1 calculation of slice selection during the pi/2 pulses was also determined and corrected for in the image reconstruction algorithm. The T1's determined by this method show a standard deviation of less than 10%, and good agreement with the literature.

Abdomen↗