Prevalence Of Instability Research Articles

Instability, an unforeseen diagnosis of the Legion™ hinge knee system

BackgroundInstability is an infrequently encountered diagnosis in rotating hinge knee (rHK) implants. With the introduction of a new rHK implant, we encountered multiple patients who complained of instability. This article presents its prevalence while describing our diagnostic and treatment algorithms. MethodsA retrospective analysis of a cohort of all consecutive patients treated with the Legion™ Hinge Knee System (Smith&Nephew, Memphis, Tennessee) as primary or revision procedure between July 2014 and December 2018 was performed. All patients reporting a sense of instability or having recurrent joint effusion after activity were suspected of experiencing instability. Stress X-rays were performed and brace treatment was started. In patients with insufficient effect of brace treatment, a liner exchange to a thicker liner was performed. Prevalence of instability and the effect of treatment was analysed descriptively. ResultsIn total, six patients were categorized as patients having instability problems (prevalence 3.5%; male:female ratio 5:1; median age 69.5 years; all revision procedures). Indication for revision to the Legion rHK implant was infection (three), instability (two) and aseptic loosening (one). In two patients, a prior rHK implant was revised. All patients showed tilting beyond the tolerance on stress X-ray examination. Brace treatment was adequate in three patients; in the other three patients a liner exchange was performed, two of which were satisfied. ConclusionInstability is an infrequently encountered diagnosis in rHK implants. The design of the Legion rHK implant seems prone to this problem with a prevalence of 3.5%. If brace treatment is insufficient a liner exchange might be considered.

Solving Poisson’s equation for birth–death chains: Structure, instability, and accurate approximation

Poisson’s equation plays a fundamental role as a tool for performance evaluation and optimization of Markov chains. For continuous-time birth–death chains with possibly unbounded transition and cost rates as addressed herein, when analytical solutions are unavailable its numerical solution can in theory be obtained by a simple forward recurrence. Yet, this may suffer from numerical instability, which can hide the structure of exact solutions. This paper presents three main contributions: (1) it establishes a structural result (convexity of the relative cost function) under mild conditions on transition and cost rates, which is relevant for proving structural properties of optimal policies in Markov decision models; (2) it elucidates the root cause, extent and prevalence of instability in numerical solutions by standard forward recurrence; and (3) it presents a novel forward–backward recurrence scheme to compute accurate numerical solutions. The results are applied to the accurate evaluation of the bias and the asymptotic variance, and are illustrated in an example.

Modern methods of diagnosing addiction to psychoactive substances: neurophysiological aspects

Objective:The study of the features of the higher mental functions of the brain in patients suffering from addiction to psychoactive substances is very important for narcology. It is necessary not only to uncover the mechanisms of addiction, a complete understanding of the neurophysiological processes that determine the nature of the development and severity of the disease, but also to solve practical problems related to the development of treatment methods and the implementation of preventive measures.Method:In the study of patients, a specially designed map was used containing information on the hereditary and demographic characteristics, on the course of the disease, as well as on the socio-cultural status of patients. To determine the functional state of cortical activity in the process of perception of unconscious signals, a special technique was used. The obtained results were subjected to dispersive analysis and the significance of differences was calculated according to Student’s t-criterion.Results:An analysis of premorbid personality traits made it possible to establish the prevalence of instability, pathological conformity, and hysteroidal features in patients. It should be noted that a large percentage of the surveyed had a hereditary burden of alcoholism, mainly in the line of the father. Curiosity, passive submission, imitation of friends were among the motives of the first drug use. All patients in the process of addiction formed the following features: increased excitability, increasing effective disorders (depression, dysphoria), aggravated by exacerbation of craving for the drug, a decline in morals and ethics (egoism, deceit, indifference to one’s fate, hedonism, loss of sense of duty), disorders of the emotional-volitional sphere (emotional instability, hypersensitivity, vulnerability).Conclusion:The analysis of the duration of latent periods and magnitude of the amplitudes of the late positive R3OO wave in patients with heroin addiction revealed clear differences between the data obtained upon presentation of an unconscious neutral and motivationally significant word. Patients who use psychoactive substances, using the method of recording induced potentials of the brain, which is a sensitive indicator of the activity of brain structures in relation to the substance used, revealed a clear diffuse activation of the cerebral cortex in response to an unconscious verbal stimulus related to the motivation prevailing in patients, in particular to “heroin”. Such activation, as well as the difficult dying out of the developed reactions to an unconscious stimulus, indicate certain neurophysiological foundations of the mechanism underlying the changes in the motivational sphere and the stability of the pathological craving for the psychoactive substance.

Conservative Management of Elbow Dislocations With an Overhead Motion Protocol

To report the results of using an overhead motion protocol in 27 patients and to assess final range of motion and incidence of persistent instability in this cohort. A total of 27 patients were included who sustained a simple elbow dislocation and were treated nonsurgically with an overhead motion protocol designed to convert gravity from a distracting to a stabilizing force. Motion was initiated within 1 week of injury and average follow-up was 29 months. Final arc of motion and prevalence of instability were the primary outcomes measures. Final mean arc of extension to flexion was from 6° to 137°, and of pronation to supination was from 87° to 86°. No recurrent instability was observed in this cohort and all patients were fully functional and without limitations at latest follow-up. The overhead motion protocol was a reliable rehabilitation program after elbow dislocation that allowed for controlled early motion by placing the elbow in an inherently stable position. Prompt initiation of motion in a protected position can optimize final motion and satisfaction outcomes, and when done in a mechanically advantageous position it can potentially limit the risk of recurrent instability. Therapeutic IV.

Prevalence of Instability in Septic Revision Total Hip Arthroplasty

Hip instability is a common postoperative complication that is disturbing to surgeon and patient alike. The prevalence of dislocation in aseptic revision total hip arthroplasty exceeds that of primary surgery. The increased dissection required in revision surgery is a significant contributing factor in this difference. Two-stage reimplantation with its concomitant shortening of the limb requires even more extensive dissection. We have noted an increased prevalence of postoperative instability after 2-stage reimplantation despite appropriately placed components.

Prevalence and prognostic role of microsatellite instability in patients with rectal carcinoma

BackgroundAssociation between microsatellite instability (MSI) and favorable postoperative survival in patients with colorectal cancer receiving adjuvant chemotherapy has been indicated. To evaluate whether an analogous positive prognostic role of MSI could be present in rectal carcinoma (RC; most RC patients receive adjuvant radiotherapy), PCR-based microsatellite analysis of archival RCs and statistical correlation with clinico-pathological parameters were performed. Patients and methodsDNA from paraffin-embedded paired samples of tumors and corresponding normal tissue from 91 RC patients was analyzed for MSI using five microsatellite markers (tumors were classified as MSI+ when two or more markers were unstable). ResultsSeventeen (19%) RC patients exhibited a MSI+ phenotype. Prevalence of instability was found in patients with earlier RC onset (28% in cases with diagnosis age ≤55 years versus 15% in cases >55 years), whereas similar MSI frequencies were observed in patients with different disease stage or receiving different adjuvant therapies. While MSI was detected in seven (64%) of 11 familial patients, a remarkably lower MSI incidence was observed in sporadic cases (10/80; 12.5%). A significant association with better disease-free survival (DFS) and overall survival (OS) was found for MSI+ patients (median DFS/OS, 30/32 months) in comparison to MSI– ones (median DFS/OS, 18/21 months) (P <0.001). ConclusionsMSI was demonstrated to be a strong molecular prognostic marker in rectal carcinoma, independent of the administered treatment (radiotherapy, chemotherapy or both).

Data from frequency-volume charts versus filling cystometric estimated capacities and prevalence of instability in men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.

The aim was to examine associations of filling cystometric estimated compliance, capacities, and prevalence of bladder instability with data from frequency-volume charts in a well-defined group of men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH). Men with LUTS suggestive of BPH were included if they met the criteria of the International Consensus Committee on BPH, i.e., they voided more than 150 mL during uroflowmetry, their residual volume and prostate size were estimated, and they completed frequency-volume charts correctly. From the frequency-volume charts, voiding habits, and fluid intake in the daytime and at night were evaluated. Filling cystometric studies were performed in these men as well. Decreased compliance was an exceptional finding. Cystometric capacity and especially effective capacity (cystometric capacity minus residual volume) corresponded significantly with the maximum voided volume on the frequency-volume charts. Effective capacity was almost twice as high as the average voided volume. Minimum voided volume on frequency-volume charts was not related to filling cystometric data. The presence of instability in the supine or sitting position or in both positions was not significantly associated with smaller voided volumes, higher nocturia, or diuria. Filling cystometric capacities were strongly associated with maximal and mean voided volumes derived from frequency-volume charts. The presence of detrusor instability during filling cystometry did not significantly affect voided volumes, diuria, or nocturia

Interactions between prostate volume, filling cystometric estimated parameters, and data from pressure-flow studies in 565 men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.

The aim of this study was to establish the characteristics and to investigate the interactions between prostate volume, degree of obstruction, bladder contractility, the prevalence of residual volume, bladder compliance, bladder capacities, and the prevalence of instability in a large, well-defined group of men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH). The 565 consecutive men included in this study met the criteria of the International Consensus Committee on BPH and voided more than 150 mL during uroflowmetry. Their residual urine volume and prostate size were estimated, and filling cystometry and pressure-flow studies were performed. Fifty-three percent of the men appeared to have obstruction. We found a positive correlation between prostate volume and Schäfer's obstruction grade, except that mean prostate volume decreased at Schäfer's grades 5 and 6. Significant negative correlations existed between Schäfer's grade and cystometric bladder capacity and effective capacity. Bladder outlet obstruction results in incomplete emptying. Of all men, 26% had a significant residual volume ( > 20% of cystometric capacity). Thirty-nine percent did not have residual volume. Of the 565 men, 46% had an unstable bladder. In particular, patients with an unstable bladder in the sitting and lying positions have a significantly higher Schäfer's grade and contractility grade and a significantly lower cystometric and effective bladder capacity compared with patients without instability. Patients with a residual volume or instability were significantly older. We conclude that in men with LUTS suggestive of BPH, abnormalities of bladder and bladder outlet function vary greatly and have complex mutual interactions.

Microsatellite analysis at 10q25-q26 in Sardinian patients with sporadic endometrial carcinoma: identification of specification patterns of genetic alteration.

Loss of heterozygosity (LOH) at chromosome 10q25-q26 has been reported previously in endometrial carcinoma (EC), suggesting the presence of tumor suppressor gene(s). Nevertheless, frequency of genome-wide microsatellite instability (MSI) has been demonstrated higher in EC than in other common malignancy, mostly due to defective DNA mismatch repair. The authors further evaluated the role of the chromosome 10q25-q26 in endometrial tumorigenesis as well as the clinical significance of any observed genetic alteration in sporadic EC. Paired normal and tumor samples from 94 Sardinian patients with sporadic EC at various stages of disease were screened by polymerase chain reaction (PCR)-based microsatellite analysis. Genomic DNA was isolated from paraffin embedded tissues and amplified by PCR using microsatellite markers spanning approximately 14 cM at 10q25-q26. Microsatellite instability was studied at four loci mapping to different chromosomal locations. Thirty-two (34%) EC patients were found negative for genetic alterations within the 10q25-q26 region. Among the remaining 62 (66%) EC cases, the authors identified 1) a minimum consensus region of LOH of approximately 1 cM, between D10S610 and D10S542 markers; and 2) a subset of tumors with prevalence of instability at 10q25-q26 (10qMI+), as expression of the presence of a MSI+ phenotype. The authors' data establish the existence of significant correlations between disease stages and 10qMI+ (with or without MSI+). However, longer follow-up and additional studies are required to define the clinical significance of these findings as prognostic factors. Moreover, the minimum region of LOH at 10q25-q26 will be further analyzed for identifying the putative tumor suppressor gene involved in EC pathogenesis.

Diuresis cystometry versus filling cystometry: The diagnostic value of diuresis cystometry in patients with frequency, urgency, and/or urge incontinence complaints

AbstractFilling cystometry was performed in 16 asymptomatic patients. Cystometry under high diuretic conditions (diuresis cystometry) was also performed in 37 asymptomatic patients.It appeared that diuresis cystometry is not more complicated than filling cystometry. The prevalence of detrusor instability in the asymptomatic groups is independent of the type of cystometry.Diuresis cystometry was performed in 36 patients with frequency, urgency, and/or urge incontinence, in whom the prevalence of instability during filling cystometry was comparable with that found in the asymptomatic patients. It appeared that the prevalence of instability in the symptomatic group is significantly higher than in the asymptomatic group during diuresis cystometry. This difference is even much higher with respect to the prevalence of detrusor instability with pressure rises of more than 15 cm H2O.

Towards a Theory of Power and Political Instability in Latin America

o N^NE MAY consider James B. Conant has observed, an attempt... lower the degree of empiricism or extend the range of theory.... Almost all significant work of scientists today, I believe, comes under the heading of attempts reduce the degree of empiricism. 1 Despite the conception of science and theory prevalent in the natural sciences and reflected in the formulation of Conant, the discipline of political science has yet reject decisively the notion of theory as an aggregation of metaphysical speculations unrelated experience and practice. Academically, in fact, the field of political theory, within the discipline of political science, traditionally has defined its role as recording, with varied degrees of interpretation, the history of metaphysical speculations in the area of politics and the state.2 But theorizing, even about politics, as Lasswell and Kaplan correctly assert, not be confused with metaphysical speculation in terms of abstractions hopelessly removed from empirical observation and control. 3 Within a scientific framework, consequently, a theory of power and instability in Latin America must attempt discharge at least four functions. (1) An adequate theory must serve to reduce the degree of empiricism; that is, it must place in a broad and meaningful context the apparently disconnected manifestations of instability in Latin America. (2) It must offer generalizations regarding the exercise of power and the prevalence of instability in Latin America which are compatible with the available evidence. (3) It must offer a guide and provide a framework for relevant research. A scientific theory neither anticipates every future event nor solves every practical problem. A theory with scientific pretensions, however, does provide directions for the investigation and solution of subsequent problems. (4) A theory of Latin American instability, if it is