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At least 1,783 records · Page 99Linked to original sources
PubMed1995

Transtelephonic monitoring and transmission of stored arrhythmia detection and therapy data from an implantable cardioverter defibrillator.

A new transtelephonic monitoring device designed for use with implantable cardioverter defibrillators (ICDs) was evaluated. It is capable of interrogating ICDs and transmitting the following data via telephone: programmed parameters (e.g., ventricular tachycardia [VT] and ventricular fibrillation [VF] detection, therapies), number of VT and VF episodes, identification of successful therapies, the 20 cycle lengths preceding the last episode detected, the 10 cycle lengths after the last delivered therapy, battery voltage, and real-time transmission of the patient's rhythm. Eighteen patients (mean age 64 +/- 17 years; 15 males) were implanted with an ICD and epicardial lead system. The patients who did not live near the primary hospital were provided with this transmitter and instructed to transmit monthly and whenever presyncope, syncope, or a shock were experienced. Five hundred ten episodes of spontaneous arrhythmia (495 VT, 15 VF) were detected in 14 of 18 patients in a 24-month period and the success of each therapy (antitachycardia pacing, cardioversion 0.4-34 J, defibrillation 34 J) was analyzed. The number of therapies delivered and their success (%) in terminating the arrhythmia were: 380 ramp/86%, 116 burst/84%, 119 cardioversion/57%, and 15 defibrillations/100%. Sixty-three (42%) of the 152 transmissions indicated an arrhythmia. Twenty-five (16%) of the 152 were transmitted because of symptoms. Sixteen (9.7%) of 165 VT episodes could not be terminated by the full set of programmed VT therapies. Analysis of the pre- and post-episode intervals along with the patient's transmitted rhythm indicated that sinus tachycardia or atrial fibrillation were likely responsible for these episodes.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation↗
PubMed1985

Acoustic and perceptual correlates of the non-nasal--nasal distinction for vowels.

For each of five vowels [i e a o u] following [t], a continuum from non-nasal to nasal was synthesized. Nasalization was introduced by inserting a pole-zero pair in the vicinity of the first formant in an all-pole transfer function. The frequencies and spacing of the pole and zero were systematically varied to change the degree of nasalization. The selection of stimulus parameters was determined from acoustic theory and the results of pilot experiments. The stimuli were presented for identification and discrimination to listeners whose language included a non-nasal--nasal vowel opposition (Gujarati, Hindi, and Bengali) and to American listeners. There were no significant differences between language groups in the 50% crossover points of the identification functions. Some vowels were more influenced by range and context effects than were others. The language groups showed some differences in the shape of the discrimination functions for some vowels. On the basis of the results, it is postulated that (1) there is a basic acoustic property of nasality, independent of the vowel, to which the auditory system responds in a distinctive way regardless of language background; and (2) there are one or more additional acoustic properties that may be used to various degrees in different languages to enhance the contrast between a nasal vowel and its non-nasal congener. A proposed candidate for the basic acoustic property is a measure of the degree of prominence of the spectral peak in the vicinity of the first formant. Additional secondary properties include shifts in the center of gravity of the low-frequency spectral prominence, leading to a change in perceived vowel height, and changes in overall spectral balance.

Humans↗
PubMed1999

The contribution of nephrology to the development of current concepts of disease.

Historians and philosophers of science rarely comment upon nephrological contributions to the development of general concepts of disease. In the present study, I examine this topic by starting from the premises that an idea of disease pervades most human societies, that received explanations of disease vary between people, societies and eras, and that an understanding of renal disease has often reflected general explanatory trends. Traditionally, most students of disease have belonged to one of four schools: descriptive, causal, mechanistic, or statistical. Descriptivists have tended to focus on manifestations, be these of a symptomatic, a structural, or a functional type. Causationists have focussed upon identification of the origins of diseases. Mechanists have emphasised pathogenetic processes. Statisticians have calculated mathematical differences of parameters from the mean ('the normal'), without explaining the reasons for these. Mechanists currently appear to hold the ascendancy in nephrology through their focus upon the links that connect causes with manifestations. As, however, all schools of thought have historically waxed and waned, I question the wisdom of granting any of them hegemony. Rather, I promote an event idea of disease that encompasses the causal, mechanistic and descriptive schools. Such considerations should assist nephrologists both to treat disease and to identify those of their predecessors who most advanced knowledge.

History, 20th Century↗
PubMed2003

Putative involvement of crustacean hyperglycemic hormone isoforms in the neuroendocrine mediation of osmoregulation in the crayfish Astacus leptodactylus.

This study investigates the involvement of eyestalk neuroendocrine factors on osmoregulation in the crayfish Astacus leptodactylus maintained in freshwater. Eyestalk removal was followed by a significant decrease in hemolymph osmolality and Na(+) concentration and by a 50% increase in mass after one molting cycle. Several neurohormones have been isolated from the sinus gland through high-performance liquid chromatography (HPLC), and different crustacean hyperglycemic hormone (CHH)-related peptides, including stereoisomers (L-CHH and D-Phe(3) CHH), have been identified by direct enzyme-linked immunosorbent assay (ELISA). A glucose quantification bioassay demonstrated a strong hyperglycemic activity following injection of the immunoreactive chromatographic fractions and showed that the D-Phe(3) CHH was the most efficient. Destalked crayfish were then injected with purified CHH HPLC fractions. The D-Phe(3) CHH fraction significantly increased the hemolymph osmolality and Na(+) content 24 h after injection. Two other CHH-related peptides caused a smaller increase in Na(+) concentration. No significant variation was observed in hemolymph Cl(-) concentration following injection of any of the CHH isoforms. These results constitute the first observation of the effects of a CHH isoform, specifically the D-Phe(3) CHH, on osmoregulatory parameters in a freshwater crustacean. The effects of eyestalk ablation and CHH injection on osmoregulation and the identification of different CHH-related peptides and isoforms in crustaceans are discussed.

Analysis of Variance↗
PubMed2002

An incremental test to identify the pain threshold speed in patients with intermittent claudication.

The purpose of this study was to develop a test for identifying the speed of onset of claudication, or pain threshold speed (PTS), in 16 patients affected by intermittent claudication. An echo-Doppler examination and the ankle-brachial index (ABI) determination were also performed. Test repeatability was evaluated in 10 patients retested within a few days. All 16 patients underwent the incremental walking test 3 times during a 6-month rehabilitation training program to verify the test's sensitivity in detecting the expected functional modifications. PTS was identified in all patients examined and the test-retest correlation coefficient (R) for PTS was 0.98. During the 6-month rehabilitation period, the ABI rose from 0.43 +/-0.16 to 0.72+/-0.15 for the worst limb and PTS also rose significantly from 3.9+/-1.4 km/h to 6.1+/-1.1 km/h. The average increments of ABI and PTS were significantly correlated. An incremental walking test for the identification of the walking speed at which claudication occurs has been developed. The PTS is a reproducible parameter that can be combined with other test results to establish the severity of the disease and to check any modifications that occur during rehabilitation.

Adult↗
PubMed2006

Prediction of amyloidogenic and disordered regions in protein chains.

The determination of factors that influence protein conformational changes is very important for the identification of potentially amyloidogenic and disordered regions in polypeptide chains. In our work we introduce a new parameter, mean packing density, to detect both amyloidogenic and disordered regions in a protein sequence. It has been shown that regions with strong expected packing density are responsible for amyloid formation. Our predictions are consistent with known disease-related amyloidogenic regions for eight of 12 amyloid-forming proteins and peptides in which the positions of amyloidogenic regions have been revealed experimentally. Our findings support the concept that the mechanism of amyloid fibril formation is similar for different peptides and proteins. Moreover, we have demonstrated that regions with weak expected packing density are responsible for the appearance of disordered regions. Our method has been tested on datasets of globular proteins and long disordered protein segments, and it shows improved performance over other widely used methods. Thus, we demonstrate that the expected packing density is a useful value with which one can predict both intrinsically disordered and amyloidogenic regions of a protein based on sequence alone. Our results are important for understanding the structural characteristics of protein folding and misfolding.

Amino Acids↗
PubMed1983

Current high performance liquid chromatographic methodology in analysis of nucleotides, nucleosides, and their bases. II.

This review of HPLC technology is presented in two parts, the first of which appeared in Volume 1, Number 5 of this journal. Part I presented an introduction to chromatography, sample preparation, and basic information on chromatographic theory and terminology, modes, and instrumentation. Also covered in Part I was a discussion of stationary and mobile phase parameters which can be varied to optimize separations. Part II of the review which follows covers peak identification, quantification, and selected applications of HPLC for metabolic profiling, for assays of adenosine and cyclic nucleotides in studies of disease processes and for enzyme assays. The paper concludes with a short discussion of future trends for HPLC in biomedical research and clinical chemistry.

Adenosine Deaminase↗
PubMed2004

Intraoperative monitoring for tethered cord surgery: an update.

OBJECT: Intraoperative neurophysiological recording techniques have found increasing use in neurosurgical practice. The development of new recording techniques feasible while the patient receives a general anesthetic have improved their practical use in a similar way to the use of digital recording, documentation, and video technology. This review intends to provide an update on the techniques used and their validity. METHODS: Two principal methods are used for intraoperative neurophysiological testing during tethered cord release. Mapping identifies functional neural structures, namely nerve roots, and monitoring provides continuous information on the functional integrity of motor and sensory pathways as well as reflex circuitry. Mapping is performed mostly by using direct electrical stimulation of a structure within the surgical field and recording at a distant site, usually a muscle. Sensory mapping can also be performed with peripheral stimulation and recording within the surgical site. Monitoring of the motor system is achieved with motor evoked potentials. These are evoked by transcranial electrical stimulation and recorded from limb muscles and the external anal sphincter. The presence or absence of muscle responses are the parameters monitored. Sensory potentials evoked by tibial or pudendal nerve stimulation and recorded from the dorsal columns via an epidurally inserted electrode and/or from the scalp as cortical responses are used to access the integrity of sensory pathways. Amplitudes and latencies of these responses are then interpreted. The bulbocavernosus reflex, with stimulation of the pudendal nerve and recording of muscle responses in the external anal sphincter, is used for continuous monitoring of the reflex circuitry. Presence or absence of this response is the pertinent parameter that is monitored. CONCLUSIONS: Intraoperative neurophysiology provides a wide and reliable set of techniques for intraoperative identification of neural structures and continuous monitoring of their functional integrity.

Anal Canal↗
PubMed2003

Medical nutrition therapy of overweight adolescents.

The long-term goal of medical nutrition therapy for adolescents who are overweight or at risk for becoming overweight is to promote healthy lifestyle behaviors. These behaviors will, in turn, improve metabolic parameters and self-esteem while helping the adolescent achieve and maintain a desirable body weight. The identification of anthropometric, metabolic, nutritional, and environmental risk factors present in the child and family will help formulate the medical nutrition intervention. A well-balanced diet that supports growth and development, aerobic exercise, and cognitive behavioral strategies are essential components of an intervention program. Frequent and long-term monitoring by a registered dietitian and pediatrician will reinforce lifestyle changes and support the adolescent and family in achieving realistic goals of weight loss or weight maintenance. This article covers the assessment and interventions necessary for successful nutrition therapy for obese and superobese adolescents.

Adolescent↗
PubMed1992

Development of a rapid method for detecting bacterial cells in situ using 16S rRNA-targeted probes.

A rapid method for the identification of bacterial cells using 16S rRNA-directed, fluorescently tagged oligonucleotide probes has been developed. The parameters evaluated for their effect on labeling intensity included storage time, type of fixative, time of fixation, treatment time with methanol:formaldehyde and treatment time with borohydride. The results of tests using a variety of microorganisms, both Gram-positive and Gram-negative, are presented. Using this method, cells are spotted onto slides and stored desiccated until hybridized. This method may be especially applicable to environmental samples, which comprise diverse cell types and frequently require storage prior to examination.

Bacteria↗
PubMedDate not supplied

[Selective dorsal rhizotomy as a therapeutic option in spasticity. Indications and results].

AIMS: Spasticity, which is a very frequent sequela of neurological diseases, is useful for compensating for loss of strength and enabling the patient to stand, if it is not excessive. Otherwise, it is contraindicative and requires specific treatment. DEVELOPMENT: Spasticity is a spinal cord dysfunction triggered by the lack of upper motoneuron inhibiting afferents and, hence, its treatment can be centred either on a level above that of the lesion itself, if the descending pathways remain functional, or on the lesion, that is, on the spinal cord, by means of neurostimulation, intrathecal drugs or ablative procedures. Ablative procedures, which are essentially oriented towards reducing the afferents in order to diminish medullar reflex hyperexcitability, are indicated in children with spastic cerebral palsy. Thanks to a rigorous detailed study that is conducted beforehand, selective dorsal rhizotomy (SDR) allows us to determine which groups of muscles must be treated. Based on intraoperative neurophysiological studies and monitoring and the use of microsurgical techniques, the dorsal rhizome turns out to be very selective after the perfect identification of the rootlets that are to be preserved. Following the qualitative and quantitative valuation of diverse parameters, post operative results show significant improvements in the functional performance of the child at one year after the intervention, and these are maintained and increase in the next few years. A strict programme of physiotherapy and rehabilitation is very effective and enables patients to enjoy greater autonomy. CONCLUSIONS: The use of SDR enables us to remove excessive spasticity, correct anomalous postures and reduce collateral pain. Its successful performance is depends on the work of a multidisciplinary team and on the overall approach to the disease in each case.

Humans↗
PubMedDate not supplied

[Genetic aspects of man's adaptation to long-term space flight].

Human genetics may play an important role in medical support of prolonged space flights, which raise serious life sciences questions: what is a normal response or, more specifically, what is norm or pathology. This is a problem of general biology and is related to genetic specificity of every organism. The theoretical basis of pertinent researches is general genetics and cytogenetics with their concepts about the structure and function of the eukaryotic genome. The concept of an individual norm of man's responses is to a certain extent associated with the doctrine of constitutions. From the practical point of view it is suggested to use in space genetics an individual-constitutional approach and the term adaptophenotype (adaptive phenotype) which means a stable complex of genetic and phenotypical characteristics. It can be determined using clinical, genealogical, cytological, and molecular methods, methods of genetic markers, phenotypical analysis, etc. Genetic approaches help reveal not only individual hereditary parameters which manifest as signs but also latent pathological characteristics that may be used for cosmonaut selection. Identification of certain phenotypes of man, i. e. adaptophenotypes, that are suitable for life in space, also means identification of specific genotypes with their response norm at the level of the somatic cell genotype and at the level of a gamete. The role of space genetics is associated with the study of gene, chromosome and population levels of adaptation to long-term space missions. Until recently these levels of adaptation have been neglected. The program of studying human genetics in space proposed here covers both medical aspects and evolutionary approaches.

Adaptation, Physiological↗
PubMed2003

Screening for controlled substance abuse in interventional pain management settings: evaluation of an assessment tool.

There is a need for an assessment tool to identify drug abuse behaviors in patients in pain treatment practices. Many assessment tools are complex, lengthy, lack external validation, and/or are difficult to administer. This prospective evaluation was undertaken to provide external validation for an assessment tool with 12 sections and 27 items. The test was applied in a prospective fashion to 500 consecutive patients: 100 patients in a drug abuse group and 400 patients in a non-abuse group. Drug abuse was defined as the misuse of controlled substances in a clinical setting, including obtaining controlled substances from other physicians or other identifiable sources, dose escalation with inappropriate use, and/or violation of controlled substance agreements. This study was performed in an interventional pain management setting with patients who were in stable therapy and were followed for at least one year. Results identified 8 of 12 parameters to be useful in identifying patients with drug abuse. Three factors were particularly useful, allowing correct identification of patients with abuse behavior in 90% of cases (odds ratios greater than 100 and P values of 0.001 or less). Important factors identified included excessive opiate needs, deception or lying to obtain controlled substances, and current or prior intentional doctor shopping. Together, these factors appear to identify 90% of patients with drug abuse. This tool provides a simple, reliable, and cost effective means of screening for drug abuse during the clinical evaluation of patients in interventional pain management settings.

Journal Article↗
PubMed1991

[Docimological analysis of the anatomy test for the PCEMII final exam in Dakar].

This docimological analysis is based on computer treatment of the results of the anatomy exam for the two sessions of July (159 candidates) and October (56 candidates) of the identification questions, discrimination questions, coupling (paining), grouping, association and diagram labelling. The results were appraised following certain parameters: the gross score revealed a rather low average score for the whole class (14.57 and 9.57 over 30): the low success rate in July and the average figure of October indicate, in general, either the difficulty of the questions for the students or a bad reception of the message; the bad discrimination index, since only 21% of the questions are of the discriminatory type. This finding pointed to a revision of 50 of the 68 questions of July and 53 of the 68 questions of October. On the whole, only 15 questions, over the two sessions, could have been kept unchanged for an eventual bank (stock of data): The correlation coefficient has showed a significant relation between success in the anatomy subject and success in the PCEM2 exam. This work has showed the possibilities that computers may offer in the teaching of anatomy and the evaluation of students. Besides, it emphasizes the importance of the anatomy grade in the PCEM2 exam. Finally, the mode evaluation used help exploring the various levels of the cognitive areas (memorization, interpretation of data, problem-solving) and to build up a bank of anatomy questions.

Anatomy↗
PubMed1989

[Difficulties in the use of the Ridley and Jopling classification--a morphological analysis].

There are many difficulties in the use of the Ridley & Jopling classification in daily practice. The author identified the morphologic parameters whose variations permit to distinguish the polar types and borderline groups according to Ridley. If we avoid the inconstant histologic alterations we believe that this distinction depends basically on the following parameters: epithelioid cell, granuloma of epithelioid cells, numbers of lymphocytes and number of bacilli. A critical analysis is performed of each of these parameters and the author concludes that they are scarce, and that there are great difficulties for the identification and interpretation of their variations for classification purposes. These difficulties are even more important during the reactional episodes.

Diagnosis, Differential↗
PubMed1986

[Cardiac imaging by nuclear magnetic resonance. II. Spectroscopy].

Nuclear magnetic resonance (NMR) spectroscopy is a new technique to study myocardial metabolism in living tissues by noninvasive means. The biochemical studies on intact hearts are performed in multinuclear NMR spectrometers using Fourier transform techniques for data acquisition. The biological NMR experiments preserve the tissues and can be repeated with a temporal resolution of seconds to several minutes in a reproducible fashion. As a marker of the intermediary metabolism P-31, C-13, H-1, F-19, N-14, Na-23, and K-39 isotopes are commonly used. NMR spectrum analysis permits the identification of several important substrates of the myocardial metabolism and their concentrational changes. In addition, the biophysical parameters of magnetic relaxation properties are measured. In some instances enzyme kinetics can be assessed. The disadvantage of NMR spectroscopy is the low sensitivity: only substrates with a intracellular concentration of greater than or equal to 0.5 mM can be detected. Improvements in sensitivity can be achieved, if the number of scans per spectrum and magnetic field strength are increased. The application of NMR spectroscopy in cardiovascular medicine is new and systematic studies on myocardial metabolism in vivo are not yet available. However, using P-31 MR spectroscopy several important results concerning the changes of the high energy phosphates and the intracellular pH changes during myocardial ischemia, as well as interesting insights into the regulatory principles of the cellular respiration were obtained. Similarly, C-13 NMR spectroscopy successfully described some aspects of glycogen metabolism and the kinetics of citric acid cycle in the myocardium. The clinical application of NMR spectroscopy appears feasible in a near future. The practical importance of this promising technique in clinical cardiology will depend on availability of the whole-body MR spectrometers, on the development of pertinent techniques for spatial MR signal resolution, and on our ability to uncover and to understand the biochemical principles of cardiac diseases. However, it is already today evident that MR spectroscopy successfully shifted the research interests towards biochemical processes at the cellular level as important causes and markers of cardiac diseases and extended our knowledge of the pathophysiology of the myocardium.

Animals↗
PubMed1981

[Prognostic validity of biochemical data and immunofluorescence microscopy in acute hepatitis B (author's transl)].

For an early identification of chronic courses of hepatitis virus B infections a statistical prediction model based on simple biochemical parameters and immunofluorescence microscopy for the investigation of virus HBs and HBc antigen expression in liver tissue is established. As early as 3 weeks after maximum liver cell damage it is possible to identify chronic virus B infections and to predict the further course of hepatitis (CPH, CAH).

Alanine Transaminase↗
PubMed1994

Intraoperative facial nerve monitoring in chronic ear surgery: a resident training experience.

Intraoperative facial nerve monitoring has been accepted as a valuable adjunctive modality to be employed in a variety of neurotologic and skull base surgical procedures. However, the role that electrical or mechanical stimulation assessment plays in chronic ear surgery is less well defined, especially in a residency training program. In this study, 250 consecutive operative cases of chronic otitis media, with and without cholesteatoma were monitored with the Xomed-Treace Nerve Integrity Monitor, NIM-2 system. Data regarding electrophysiologic monitoring parameters; electromechanical artifact, including system failure; and surgical outcome were analyzed. Although not a substitute for anatomic identification of the facial nerve, intraoperative monitoring provides an additional technique to optimize resident surgical education.

Adolescent↗