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Dynamic sonography in the diagnosis of ligament and meniscal injuries of the knee.

A total of 84 patients with ligament or meniscal injuries of the knee was prospectively examined clinically and under anaesthesia, by arthroscopy and sonography. The sensitivity, specificity, positive and negative predictive values were compared. For sonography a high resolution scanner (Picker LSC 7000 with a 5-MHz transducer) was used. The sonographical examination was dynamic under normal and stress conditions. The sensitivity of sonography for diagnosis of rupture of the medial collateral ligament (LCM) was 87%, of the anterior cruciate ligament (LCA), 70% and of menisci, 89% and was thereby similar to that for examination under anaesthesia and arthroscopy and significantly superior to clinical examination alone. The specificity of sonography was very high: for rupture of the LCM 96%, the LCA 98% and the menisci 78%. Only for diagnosis of partial ligament rupture, especially partial LCA rupture, was the sensitivity of sonography low. In diagnosing ligament and meniscal injuries of the knee, sonography should be used routinely as a primary diagnostic tool after clinical examination because: 1. It is inexpensive 2. It has no side effects 3. It helps to cut down X-ray exposure 4. Anaesthesia is not required 5. It allows the recognition and avoidance of muscle tightness 6. Repetitions are possible at will 7. Documentation is included 8. Sensitivity and specificity are very good.

Adult↗

Auditory brainstem response findings in brainstem ischemia following selective occlusion of the anterior inferior cerebellar artery in the rat.

Auditory brainstem responses (ABRs) were measured ipsilaterally (n = 13) or contralaterally (n = 5) after inducing permanent right and left anterior inferior cerebellar artery (AICA) occlusion. Three types of wave patterns were classified when ABRs were recorded ipsilaterally. In type 1 (n = 4) all components disappeared; in type 2 (n = 2) all components disappeared transiently and then reappeared; and in type 3 (n = 7) only the latency difference between components I and IV increased. These findings indicate that all components reappeared in type 2 responses because cochlear blood flow was re-established quickly by collateral circulation, while type 3 changes reflected the relative sensitivity of the cochlea to ischemic damage when compared with the rest of the auditory pathways. When the ABRs were recorded contralaterally, characteristic findings included a delay in latency of component IV and a significant increase in inter-peak latency in components I-IV and IIb-IV.

Animals↗

Vulnerability of CA1 neurons in SHRSP hippocampal slices to ischemia, and its protection by Ca2+ channel blockers.

Vulnerability of CA1 pyramidal neurons to hypoxic and hypoglycemic insult was compared in hippocampal slices between the stroke-prone spontaneously hypertensive rat (SHRSP) and its mother strain, Wistar Kyoto rat (WKY). Stimulation of Schaffer collateral-commissural fibers induced D-2-amino-5-phosphonovalerate sensitive multi-component population spikes in slices from both strains when the external K+ concentration was elevated. The K+ concentration required for this phenomenon was significantly lower in SHRSP slice preparations than in those from WKY. The hypoxic and hypoglycemic insult in slice preparations is assumed to be equivalent to ischemic conditions in vivo. Although the short-term 'ischemic' insult caused a complete loss of population spikes in slices from both strains, a transient hyperexcitability, spreading depression-like depolarization, accumulation of extracellular K+ and reduction of extracellular Ca2+ occurred in SHRSP slices, but not in WKY. Time required for partial recovery of the population spike following the 'ischemic' insult was markedly increased in SHRSP slices compared with WKY. Thus, CA1 pyramidal neurons of SHRSP were more vulnerable to 'ischemic' insult than those of WKY. This vulnerability of pyramidal neurons in the SHRSP strain was independent of its hypertensive phenotype. A novel L-type Ca2+ channel blocker, S-312-d, its stereoisomer, S-312-1, and nimodipine protected the 'ischemic' insult-induced neuronal dysfunction at submicromolar concentrations. It is concluded that hippocampal neurons in SHRSP are innately vulnerable. This vulnerability is suggested to be due, at least in part, to some abnormality in K+ channel channels of hippocampal neurons.

Animals↗

Editing status at the Q/R site of glutamate receptor-A, -B, -5 and -6 subunit mRNA in the hippocampal kindling model of epilepsy.

The editing status of mRNA at the Q/R site of the glutamate receptor subtypes -A, -B, -5 and -6 modulates channel conductivity and ion selectivity of glutamate operated ion channels [4,15,26,30]. In order to investigate whether a modification of this editing process may be involved in kindling epileptogenesis, the percentage of edited variant was determined in the hippocampus of kindled rats and compared to the percentage in control animals. In the latter, GluR-A mRNA was detected only in the unedited form (with detection threshold for edited form < 0.7%), whereas GluR-B was completely edited (> 99%). For percentages were not significantly changed in Schaffer collateral/commissural pathway kindled animals that were sacrificed 24 h after the last generalized seizure. It is concluded that the increased sensitivity for the induction of seizures characteristic for Schaffer collateral kindled animals is not related to a less selective or less efficient mRNA editing process of the different glutamate receptor subunits in the hippocampus.

Animals↗

Evaluation of the ulnopalmar arterial arches with pulse oximetry and plethysmography: comparison with the Allen's test in 1010 patients.

BACKGROUND: To avoid ischemic hand complications, the percutaneous transradial approach is only performed in patients with patent hand collateral arteries, which is usually evaluated with the modified Allen's test (MAT). This qualitative test measures the time needed for maximal palmar blush after release of the ulnar artery compression with occlusive pressure of the radial artery. The objectives were to evaluate the patency of the hand collateral arteries and to compare MAT with combined plethysmography (PL) and pulse oximetry (OX) tests before the percutaneous transradial approach. METHODS: Patients referred to the catheterization laboratory were prospectively examined with MAT, PL, and OX tests. PL readings during radial artery compression were divided into 4 types: A, no damping; B, slight damping of pulse tracing; C, loss followed by recovery; or D, no recovery of pulse tracing within 2 minutes. OX results were either positive or negative. Results of both tests were compared in 1010 consecutive patients. RESULTS: MAT results < or =9 seconds on either hand were seen in 93.7% of patients. PL and OX types A, B, or C on either hand were seen in 98.5% of patients. On the basis of the MAT < or =9 seconds criteria, 6.3% of patients were excluded from the transradial approach, whereas with PL and OX types A, B, and C, only 1.5% of patients were excluded. There was more exclusion in men and with increasing age by using both methods. CONCLUSIONS: In the evaluation of hand collaterals, PL and OX were found to be more sensitive than MAT. When applied to transradial approach screening, only 1.5% of patients were not suitable candidates for the transradial approach.

Adult↗

ARF tumor suppressor induces mitochondria-dependent apoptosis by modulation of mitochondrial Bcl-2 family proteins.

A tumor suppressor gene product, ARF, sensitizes cells to apoptosis in the presence of appropriate collateral signals. In this study, we analyzed the mechanism of ARF-dependent apoptosis and demonstrated that ARF induces mitochondria-dependent apoptosis in p53 wild-type, ARF/p16-null cells. We also found that ARF evokes cytochrome c release from mitochondria, decreases mitochondrial membrane potential, and activates pro-caspase-9 to induce apoptosis. Our findings suggest that this apoptotic cellular modulation is brought about by up-regulation of the proapoptotic Bcl-2 family proteins Bax and Bim and down-regulation of antiapoptotic Bcl-2 in mitochondrial fractions. Additionally, ARF seems to down-regulate Bcl-2 in a p53-dependent manner while up-regulating Bax/Bim via a p53-independent pathway.

3T3 Cells↗

Use of collateral airways to assess airway reactivity.

We investigated the correlation between collateral airway reactivity and other indexes of lung reactivity in response to aerosol and intravenous (iv) challenges. In four anesthetized mongrel dogs, we measured the peripheral airway resistance (Rp) to gas flow out of a wedged lung segment in different lobes on multiple occasions. We obtained dose-response curves of peripheral airways challenged with iv histamine or aerosols through the bronchoscope. During the same iv bolus challenge, whole lung airway pressure (Paw) responses to histamine were also measured. On separate occasions, changes in lung resistance (RL) were measured after the whole lung was challenged with a histamine aerosol. Reactivity was assessed from the dose-response curves for Rp and RL as the PD50 (dose required to produce a 50% increase); for changes in Paw we calculated the PD15 (dose required to produce a 15% increase over baseline). Results for Rp showed considerably more variability among different lobes in a given animal with the aerosol challenge through the bronchoscope than with the iv challenge. With aerosol challenge there were no significant differences in the mean PD50 for Rp among any of the animals. However, with the iv challenge two of the dogs showed significant differences from the others in reactivity assessed with Rp (P less than 0.01). Moreover, the differences found in the peripheral airways with iv challenge reflected differences found in whole lung reactivity assessed with either iv challenge (Paw vs. Rp, r2 = 0.96) or whole lung aerosol challenge (RL vs. Rp, r2 = 0.84). We conclude that the measurement of the collateral resistance response to iv challenge may provide a sensitive method for assessing airway reactivity.

Aerosols↗

Presence of the metabolic syndrome does not impair coronary collateral vessel formation in patients with documented coronary artery disease.

OBJECTIVE: The metabolic syndrome confers an increased risk for cardiovascular morbidity and mortality. The presence of coronary collaterals may have beneficial effects during myocardial ischemia and may improve cardiovascular outcome in patients with coronary artery disease. Impaired collateral formation could be one of the reasons for the increased cardiovascular risk in patients with the metabolic syndrome. The aim of the present study was to determine the influence of the metabolic syndrome and insulin resistance on the presence of coronary collaterals. RESEARCH DESIGNS AND METHODS: We conducted a cross-sectional study in 227 patients referred for elective percutaneous transluminal coronary angioplasty to the University Medical Centre Utrecht. The metabolic syndrome was diagnosed according to Adult Treatment Panel III, and homeostasis model assessment of insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) were used to quantify insulin resistance. Coronary collaterals were graded with Rentrop's classification. Rentrop grade >/=1 indicated the presence of collaterals. Results were adjusted for age, sex, and severity of coronary artery disease. RESULTS: A total of 103 patients (45%) were diagnosed with the metabolic syndrome. There was no association between the metabolic syndrome and the presence of coronary collateral formation (odds ratio [OR] 1.2 [95% CI 0.7-2.0]). Also, the degree of insulin resistance was not related to the presence of coronary collaterals. The OR for HOMA-IR (highest versus lowest tertile) was 0.7 (0.3-1.5) and for QUICKI (lowest versus highest tertile) 0.8 (0.4-1.6). CONCLUSIONS: The metabolic syndrome and insulin resistance are not related to the presence of coronary collaterals in patients with documented coronary artery disease.

Adiponectin↗

[Usefulness of carotid artery compression test in the diagnosis of cerebral circulation disorders in patients with cerebral aneurysm. Evaluation by the rheoencephalographic method].

Rheoencephalographic investigations (REG) was carried out in patients with intracranial aneurysms and in healthy subjects. The purpose of the study was to obtain approximate data on the efficiency of collateral circulation of the brain before ligation of the internal carotid artery. For this purpose REG was associated with common artery compression test. It was found that this combined examination gives good prediction of the efficiency of collateral circulation after ligation of one carotid artery. This method is more sensitive than the Matas test combined with EEG used previously.

Adult↗

Proprioception in the ACL-ruptured knee: the contribution of the medial collateral ligament and patellar ligament. An in vivo experimental study in the cat.

In the absence of anterior cruciate ligament (ACL), secondary restraints such as menisci, ligaments, and tendons restrict anterior knee laxity. Strain detection at these sites could define the contribution of this alternative signalling system to knee proprioception after ACL injury. The hypothesis in this study questions if measurements of anterior tibial translation (ATT) from surface strain gauges on the insertions of the medial collateral ligament (MCL) and the patellar tendon (PT) are sufficiently sensitive and specific to differentiate normal, stable knees from acutely unstable knees due to ACL section. Twelve cats received miniaturized strain gauges on the surface of MCL and PT distal insertions. A purpose-made receiver transformed into measurements any voltage variation obtained during passive knee flexion-extension and anterior tibial translation manoeuvres. Variables under evaluation included first peak latency, normalized amplitude, and slope of voltage along time. Femorotibial displacements were video recorded, digitized, and used as the ATT reference. The proposed system detected significant changes in the slope of the voltage/time signal, with higher specificity and sensitivity during ATT after experimental ACL section. Changes were not significant during flexion or extension. It was found that a pattern of earlier and more intense strain in MCL and PT distal insertions was found during ATT in the ACL deficient knee. Enhanced pattern recognition learning from these structures could be a future target for proprioceptive training after ACL injury.

Animals↗

Non-contrast enhanced MR venography using 3D fresh blood imaging (FBI): initial experience.

OBJECTIVE: This study examined the efficacy of 3D-fresh blood imaging (FBI) in patients with venous disease in the iliac region to lower extremity. MATERIALS AND METHODS: Fourteen patients with venous disease were examined [8 deep venous thrombosis (DVT) and 6 varix] by 3D-FBI and 2D-TOF MRA. All FBI images and 2D-TOF images were evaluated in terms of visualization of the disease and compared with conventional X-ray venography (CV). RESULTS: The total scan time of 3D-FBI ranged from 3 min 24 sec to 4 min 52 sec. 3D-FBI was positive in all 23 anatomical levels in which DVT was diagnosed by CV (100% sensitivity) as well as 2D-TOF. The delineation of collateral veins was superior or equal to that of 2D-TOF. 3D-FBI allowed depiction of varices in five of six cases; however, in one case, the evaluation was limited because the separation of arteries from veins was difficult. CONCLUSION: The 3D-FBI technique, which allows iliac to peripheral MR venography without contrast medium within a short acquisition time, is considered clinically useful.

Adult↗

The diagnostic value of colour Doppler ultrasound in central venous catheter related thrombosis.

AIM: This prospective study was performed to establish the correlation between colour Doppler ultrasound (US) observations and venography in detecting catheter-related thrombosis. METHOD: Forty-four patients with subclavian venous catheters were studied. The sensitivity and specificity of colour Doppler US was determined for the diagnosis of central venous thrombosis and compared with contrast venography. Criteria considered to show the presence of catheter-related thrombosis included visualization of thrombus (T), absence of spontaneous flow (S), absence of phasicity of flow with respiration (P), incompressibility of the vein with probe pressure (C) and visualization of increased venous collaterals (V). RESULTS: Analysing each variable separately, P had the highest sensitivity (94%) and S had the highest specificity (100%). The best combinations for diagnosis were T+P, P+S, and T+P+S with a sensitivity of 94% and specificity of 88%. Overall diagnostic value of colour Doppler US had a sensitivity of 94% and specificity of 96%. CONCLUSION: Colour Doppler US is a reliable method for detecting central venous catheter-related thrombosis, especially if several parameters are evaluated in combination.

Adolescent↗

Detection of human collateral circulation by vasodilation-thallium-201 tomography.

Coronary arteriolar vasodilation may provoke redistribution of flow to collateral-dependent jeopardized myocardium. To assess the physiologic significance of collaterals, 80 consecutive post-infarction patients (age 58 +/- 8 years) underwent vasodilation-redistribution thallium-201 tomographic imaging after administration of 0.56 mg of intravenous dipyridamole/kg body weight. Circumferential profile analysis of thallium-201 uptake and redistribution in representative left ventricular tomograms provided quantitative assessment of transient and fixed defects and separation between periinfarctional and distant inducible hypoperfusion. Tomographic perfusion data were correlated to wall motion and collateral circulation between distinct anatomic perfusion territories. Patients were grouped according to presence (59%) or absence (41%) of angiographically visible collateral channels to jeopardized myocardium. In the presence of collaterals, distant reversible defects were larger than in absence of collaterals (p less than 0.05); the extent of combined periinfarctional and distant redistribution was also larger in collateralized patients (p less than 0.025), whereas the size of the persistent perfusion defect was similar in both groups. By prospective analysis the tomographic perfusion pattern of combined periinfarctional and distant redistribution revealed a sensitivity of 85% and a specificity of 78% for the detection of significant collateral circulation in this group of patients. Thus, using the exhausted flow reserve as a diagnostic tool, vasodilation-thallium-201 tomography has the potential to identify and quantitate collateralized myocardium in post-infarction patients and may guide diagnostic and therapeutic decision-making.

Cardiac Catheterization↗

[Noninvasive identification of collateralized myocardium by 201 thallium tomography in vasodilation and redistribution].

Coronary arteriolar vasodilatation may provoke the redistribution of flow to collateral-dependent jeopardized myocardium. To assess the physiologic significance of collateral channels, 80 consecutive postinfarction patients (aged: 58 +/- 8 years) underwent vasodilatation/redistribution thallium-201 tomographic (SPECT) imaging using 0.56 mg dipyridamole/kg body weight. Circumferential profile analysis of redistribution and slow washout in representative left ventricular tomograms provided quantitative evaluation of transient and persistent defects and a separation between a periinfarctional and distant inducible hypoperfusion. Tomographic perfusion data were correlated to subsequent cineangiographic analysis of wall motion and to the extent of collateral circulation between two distinct anatomic perfusion areas, one of which involved the infarct zone. Patients were grouped according to the presence (59%) or absence (41%) of angiographically visible collateral channels to the jeopardized myocardium. In the presence of collaterals, distant reversible defects were larger than in the absence of collaterals (p less than 0.05); the extent of combined periinfarctional and distant redistribution was also larger in collateralized patients (p less than 0.025), whereas the size of the persistent perfusion defect was similar in both groups. In a prospective analysis, the tomographic perfusion pattern of combined periinfarctional and distant ischemia revealed a sensitivity of 85% and a specificity of 78% for the detection of significant collateral circulation in this group of patients. Thus, using the limited collateral flow reserve as a diagnostic tool, vasodilatation/redistribution thallium-201 tomography has some potential for identifying and quantifying collateral-dependent myocardium and may guide diagnostic and therapeutic decision-making.

Aged↗

Relationships between coronary artery obstruction, asynergy, presence of collaterals and the ejection fraction of the left ventricle in patients with coronary heart disease.

Cardioangiographic scores of coronary artery obstructions and corresponding myocardial involvement (MCOS), presence of collaterals (CollS), and asynergy of the left ventricular wall (LVMS) as well as the left ventricular ejection fraction (EF) were examined in 67 patients with coronary heart disease. A covariation was found between LVMS, EF, ECG changes, and a history indicating a previous myocardial infarction (MI). In a multiple regression analysis the EF covariated with LVMS but not with MCOS and CollS. LVMS indicated a previous MI with at least the same sensitivity and specificity as EF. MCOS and CollS give additional information. Collaterals as well as a high MCOS in relation to the LVMS indicate obstruction of coronary arteries which subserve 'non-fibrotic' myocardium. A patient with a high MCOS and CollS and a low LVMS should be expected to gain most functional improvement from coronary bypass surgery. The scores MCOS, CollS and LVMS are comparatively easy to determine and give a more diversified picture of the state of the myocardium than the EF alone.

Angiocardiography↗

Cholinergic modulation of the spatiotemporal pattern of hippocampal activity in vitro.

The aim of this study was to use optical imaging with voltage-sensitive dyes (Di-4-ANEPPS), to examine the cholinergic modulation of CA1 network responses to Schaffer collateral input. By comparing responses recorded with optical imaging and field recordings across the proximodistal axis of CA1, it was initially demonstrated that voltage-sensitive dyes could report reliably both the pattern of activation and cholinergic modulation. The higher spatial resolution of optical imaging was used to explore the somatodendritic profile of cholinergic modulation. It was found that activation of muscarinic acetylcholine receptors (mAChR) (1-10 microM carbachol), inhibited evoked responses across all layers of CA1. This was accompanied by an increase in paired-pulse facilitation in the apical and distal dendritic layers (40 ms inter-stimulus interval), but not in perisomatic regions. The mAChR antagonist, 20 microM atropine, alone increased facilitation at perisomatic sites, suggesting that muscarinic signalling pathways actively suppress perisomatic responses to repetitive stimulation. In contrast, the activation of nicotinic acetylcholine receptors (10 microM nicotine) had no significant effect on single evoked responses, but selectively increased facilitation at perisomatic sites. These results suggest that cholinergic modulation of the hippocampal CA1 network has multiple differential effects on the somatodendritic processing of the Schaffer collateral input.

Acetylcholine↗

The efficacy of magnetic resonance imaging in acute knee injuries.

OBJECTIVE: To evaluate the clinical efficacy of magnetic resonance imaging (MRI) of the knee in acute injuries with indeterminate clinical findings, using arthroscopy as a gold standard. DESIGN: A prospective double-blind study was performed. All patients underwent MRI on a 1.5 T magnet using dual spin echo pulse sequences. This was followed by arthroscopy. SETTING: Tertiary care referral center. PATIENTS: Twenty-three patients with an average age of 26 years satisfied the study criteria. Patients had to have been seen by one of two orthopaedic surgeons within 6 weeks of sudden trauma to the knee complicated by a hemarthrosis, clinical assessment of which was equivocal. RESULTS: The respective sensitivity and specificity for MRI of the knee were 90% (18/20) and 67% (2/3) for detecting any anterior cruciate ligament injury, 50% (1/2) and 86% (18/21) for detecting medial meniscal tears, and 88% (7/8) and 73% (11/15) for detecting lateral meniscal tears. MRI also identified injuries that could not be assessed on arthroscopy, including 14 bone bruises, five posterior cruciate ligament tears, nine medial collateral ligament tears, and one lateral collateral ligament tear. The detection of composite injury requiring surgical intervention yielded a sensitivity of 100% (16/16) and a specificity of 71% (5/7). Prospective use of MRI evaluation of the knee could have prevented 22% (5/23) of diagnostic arthroscopic procedures. CONCLUSION: Equivocal clinical findings in patients with acute knee injury should lead to use of MRI in an appropriate clinical setting. To our knowledge a prospective study of the efficacy of MRI of the knee in this patient population has not been reported. In the presence of such inclusion criteria, the results of our study support the use of early MRI to guide further surgical management.

Acute Disease↗

Endoscopic ultrasound criteria for vascular invasion in the staging of cancer of the head of the pancreas: a blind reevaluation of videotapes.

BACKGROUND: It has been claimed in several prospective studies that endoscopic ultrasonography (EUS) is highly accurate in the locoregional staging of pancreatic cancer. However, the value of the EUS criteria for the diagnosis of vascular involvement is less well established. To totally exclude potential bias introduced by the availability of prior information, a completely blinded analysis of videotapes of patients with cancer of the pancreatic head was therefore conducted. METHODS: Videotape sequences of 75 patients with cancer of the head of the pancreas with surgical confirmation or unequivocally positive angiography demonstrating vascular invasion were reevaluated without any clinical data or information from other imaging studies. Involvement of the vascular system (portal vein with confluence, superior mesenteric vein, celiac axis) was assessed on EUS with special emphasis on EUS parameters of the tumor-vessel relationship. RESULTS: The overall sensitivity and specificity of EUS in the diagnosis of venous invasion were 43% and 91%, respectively, when using predetermined parameters (visualization of tumor in the lumen, complete obstruction, or collateral vessels). If the parameter "irregular tumor-vessel relationship" had been added to these criteria, the sensitivity would have risen to 62%, but the specificity would have fallen to 79%. The only vascular system that could be properly visualized by EUS was the portal vein/confluence area. The positive and negative predictive values for the single parameters chosen to diagnose portal venous involvement were as follows: 42% and 33% for irregular tumor-vessel relationship, 36% and 34% for visualization of tumor in the vascular lumen, 80% and 28% for complete vascular obstruction, and 88% and 18% for collateral vessels. CONCLUSIONS: In a completely blinded evaluation of the EUS diagnosis of vascular invasion by cancer of the head of the pancreas it was not possible to find suitable morphologic parameters with clinically useful sensitivity and specificity values (over 80%).

Adult↗