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PubMed2004

M-wave analysis and passive tilt in patients with different degrees of carotid artery disease.

BACKGROUND AND PURPOSE: Carotid artery disease (CAD) is able to critically impair cerebral autoregulation which increases the risk for stroke. As therapeutic strategy largely depends on the degree of CAD, we investigated whether this gradation is also related to significant changes in autoregulatory capacity. We applied cross-spectral analysis (CSA) of spontaneous Mayer-wave (M-wave) oscillations and passive tilting (PT) to test cerebral autoregulation. METHODS: Cerebral autoregulation was tested in 102 patients with carotid stenosis (> or =70%) or occlusion and 14 controls by comparison of continuous transcranial Doppler sonography of the middle cerebral artery and beat-to-beat arterial blood pressure (ABP) during PT to 80 degrees head-up position as well as by CSA of M-waves (3-9 cpm). RESULTS: The orthostatic decrease of cerebral blood flow velocity (CBFV) was not correlated with the degree of CAD and showed a lower sensitivity and specificity than phase angle shifts between M-waves in ABP and CBFV (sensitivity: 75-80%, specificity: 86%). Phase angles were gradually lowered in carotid stenoses > 70%, but apparently, they were only moderately correlated with the degree of CAD (r = -0.35, P < 0.01). An additional influencing factor seemed to be the sufficiency of collateralization. CONCLUSIONS: The results show that CSA of M-waves is more appropriate for testing autoregulation than PT. CSA suggests that the capacity to autoregulate depends to a certain extent on the degree of CAD but is also influenced by the sufficiency of collateral pathways and pre-existing strokes.

Adult↗
PubMed2002

Diagnosis of gastroesophageal varices and portal collateral venous abnormalities by endosonography in cirrhotic patients.

BACKGROUND AND STUDY AIMS: The role of endosonography (EUS) in the management of portal hypertension is not well defined. We aimed to study the use of a new generation video-echo endoscope in the diagnosis of gastroesophageal varices (GEV) and extraluminal venous abnormalities in cirrhotic patients. PATIENTS AND METHODS: Cirrhotic patients were studied by echo endoscopy to assess esophageal varices endoscopically, and gastric varices and extraluminal venous abnormalities sonographically. The results were compared with esophagogastroduodenoscopy (EGD) examination. Dyspeptic patients served as controls. RESULTS: A total of 52 cirrhotic and 166 dyspeptic patients were studied. EUS identified esophageal varices (EV) endoscopically in 28 patients (53.8 %), which showed a good correlation with EGD findings (r = 0.855, P < 0.001). The red color sign and portal hypertensive gastropathy were diagnosed in six and seven patients, respectively, by both methods. EUS detected gastric varices sonographically in 16 patients (30.8 %), compared with detection in nine patients by EGD. Extraluminal venous abnormalities were detected in 48 cirrhotic patients (92 %) and in only nine dyspeptic patients (5.4 %) (P < 0.001). The size of extraluminal adventitial venous dilatation was significantly correlated with the severity of GEV and cirrhosis (P < 0.001). Perforating veins were identified in all patients with GEV. CONCLUSION: The new generation video-echo endoscope could be used as a single investigation in assessing both the intraluminal GEV and extraluminal venous abnormalities in cirrhotic patients. It may improve the management of patients with portal hypertension.

Collateral Circulation↗
PubMed2002

Preliminary results of Tc-99m ECD SPECT to evaluate cerebral collateral circulation during balloon test occlusion.

PURPOSE: The authors obtained noninvasive quantitative measurements of regional cerebral blood flow using Tc-99m L,L-ethyl cysteinate dimer (Tc-99m ECD) SPECT to evaluate cerebral collateral circulation during balloon test occlusion (BTO) of the internal carotid artery and vertebral artery (VA). METHODS: Five cases associated with an aneurysm and a brain tumor were investigated. After 10 minutes of BTO, a bolus of Tc-99m ECD was injected intravenously and radionuclide angiography was performed. The balloon remained inflated for an additional 5 minutes. After radionuclide angiography was completed, brain SPECT imaging was performed. For quantitative analysis, regions of interest were defined on the transverse images on each side of the anterior cerebral artery and middle cerebral artery territories in cases of occlusion of the internal carotid artery. Regions of interest were defined for the posterior cerebral artery territory and cerebellum in cases of occlusion of the VA. The percentage activity change during BTO was calculated. RESULTS: In two of the three patients in whom BTO of the internal carotid artery was performed, the percentage activity reduction of more than 30% was noted in the anterior cerebral and middle cerebral artery territories. These two patients underwent bypass grafting before carotid occlusion. In one of the two patients in whom BTO of the VA was performed, the percentage activity reduction of 16% was noted in the posterior cerebral artery territory. This patient underwent bypass grafting before occlusion of the VA. CONCLUSION: This noninvasive and quantitative method of cerebral blood flow measurement using Tc-99m ECD during BTO appears to have the potential to help select patients who may tolerate temporary or permanent arterial occlusion.

Balloon Occlusion↗
PubMed1989

Exercise treadmill testing is a poor predictor of anatomic restenosis after angioplasty for acute myocardial infarction.

This study evaluated whether an exercise treadmill test could predict restenosis in 289 patients 6 months after a successful emergency angioplasty of the infarct-related artery for acute myocardial infarction. After excluding those with interim interventions (64), medical events (36), or medical contraindications to follow-up testing (25), both a treadmill test and a cardiac catheterization were completed in 144 patients, 88% of those eligible for this assessment. Four patients with left bundle branch block or pacemaker rhythm at the time of treadmill testing were also excluded from analysis. Of six follow-up clinical and treadmill variables examined by multivariable logistic regression analysis, only exercise ST deviation was independently correlated with restenosis at follow-up (chi 2 = 5, p = 0.02). The clinical diagnosis of angina at follow-up, although marginally related to restenosis when considered by itself (p = 0.04), did not add significant information once ST deviation was known. The sensitivity of ST deviation of 0.10 mV or greater for detecting restenosis was only 24% (13 of 55 patients), and the specificity was 88% (75 of 85 patients). The sensitivity of exercise-induced ST deviation for detection of restenosis was not affected by extent or severity of wall motion abnormalities at follow-up, by the timing of thrombolytic therapy or of angioplasty, or by the presence of collateral blood flow at the time of acute angiography. A second multivariable analysis evaluating the association of the same variables with number of vessels with significant coronary disease at the 6-month catheterization found an association with both exercise ST deviation (p = 0.003) and exercise duration (p = 0.04). Angina symptoms and exercise treadmill test results in this population had limited value for predicting anatomic restenosis 6 months after emergency angioplasty for acute myocardial infarction.

Angina Pectoris↗
PubMed1997

Clinicopathological correlations in postasphyxial organ damage: a donor organ perspective.

OBJECTIVES: 1) To assess pathology in the heart, kidneys, lungs, liver, and intestine in babies dying of postasphyxial hypoxic ischemic encephalopathy (HIE), and their suitability for organ transplantation. 2) To analyze the correlation between in vivo clinical markers of collateral organ damage and autopsy findings. STUDY DESIGN: Retrospective cohort study of 58 infants who died of postasphyxial HIE and had autopsies during 1985 to 1994. Collateral organ damage was evaluated clinically and pathologically, and the results compared. RESULTS: Severe pathological changes were observed in 6% to 62% of the five organs studied; 59% of the four major organs had either minor or no pathology. The sensitivity of the clinical predictors ranged from 69% to 100%, and specificity from 50% to 97%. CONCLUSIONS: The organs of newborns dying of severe HIE may be suitable for use as donor organs; predictions of their suitability were most accurate for liver, kidney, and lungs, and least accurate for the heart.

Asphyxia Neonatorum↗
PubMed1995

Gain and loss of hypersensitivity to resistance modifiers in multidrug resistant Chinese hamster ovary cells.

Some, but not all, multidrug resistant cell lines exhibit collateral hypersensitivity to resistance modifiers. We have examined the relationship between levels of P-glycoprotein expression and resistance modifier hypersensitivity in Chinese hamster ovary cell lines. We have defined a model system for the gain and loss of such sensitivity which indicates that its presence is not simply proportional to P-glycoprotein levels, but is acquired only above a certain level of P-glycoprotein expression. We also show that previously reported differences in such sensitivity between lines is not attributable to differences in genetic background of the cell lines used for selection of drug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

[The pathophysiological mechanisms of disorders of cerebral circulation and the new directions in their prevention and treatment].

The contribution of Laboratory of Nervous System's Experimental Pathology (Institute of Neurology of Russian Academy of Medical Sciences) to cerebrovascular circulation investigations is described. The following questions were considered: cerebral circulation in cerebrovascular disturbances, collateral circulation in the "turned off" state of different brain arteries, and immunological brain alterations as the result of brain organic diseases. Results of the investigation of the damaging effect of acute increase in arterial pressure as well as individual sensitivity to brain ischemia and to drug administration were presented. The particular importance of researches of blood circulation biomechanics as well as of factors of its normalization were also emphasized.

Academies and Institutes↗
PubMed1996

Intracranial stenoocclusive disease: MR angiography with magnetization transfer and variable flip angle.

PURPOSE: To assess time-of-flight MR angiography that uses magnetization transfer contrast (MTC) pulses, tilted optimized nonsaturating excitation (TONE), and a 256 x 512 image matrix for the detection of small intracranial arteries and for the detection and quantification of intracranial arterial stenoocclusive disease. METHODS: To assess anatomic sensitivity, six interpreters, in a blinded fashion, reviewed the MTC/TONE MR angiograms and selective intraarterial angiograms obtained in 70 patients within a mean interval of 5.5 days (SD, 1.5). In addition, all intracranial angiograms were evaluated with regard to presence and degree of arterial stenosis and anatomic variants. RESULTS: Interobserver correlations for determining vessel length were comparably high for both methods. A strong correlation was found between measurements obtained on MR angiograms and those obtained on intraarterial angiograms. The mean vascular length averaged across all arteries was 34.8 mm (SD, 28.1) on MR angiograms and 53.2 mm (SD, 36.8) on intraarterial angiograms. Forty-one stenoses and occlusions and 30 anatomic variants were identified with intraarterial angiography. All arterial variants and 100% of occluded vessels were graded correctly. Moreover, 80% of stenoses greater than 70% and 88% of stenoses less than 70% were quantified correctly at MR angiography. Specificity for identifying stenotic disease was 99%. CONCLUSION: Despite inferior display of vessel length, MTC/TONE MR angiography with increased spatial resolution was able to show the vast majority of high grade lesions visible at selective intraarterial angiography and may suffice for clinical decision making in many patients.

Adolescent↗
PubMed1998

A multicenter, prospective, open label, randomized, controlled phase IIIb study of SH U 508 a (Levovist) for Doppler signal enhancement in the portal vascular system.

PURPOSE: Assessment of the accuracy of SH U 508 A (Levovist) enhanced Doppler sonography in the evaluation of blood flow abnormalities in the portal vascular system. METHOD: In an open label, controlled, prospective multicenter study, patients referred for Doppler sonography of the portal vascular system were randomized to receive SH U 508 A if indicated or to an observation group (ratio of 4:1). Patients who had diagnostically insufficient Doppler signals received SH U 508 A (2.5 g [200, 300 or 400 mg/ml]), followed by confirmatory dynamic CT. Corresponding patients in the observation group received alternative imaging procedure(s). RESULTS: Of 588 patients 265 patients received SH U 508 A. In 253 (95.5%) of these patients a diagnosis was possible following administration of SH U 508 A (Levovist). Diagnostic confidence improved from 35.3% to 89.7%. If compared with dynamic CT, SH U 508 A enhanced Doppler had a sensitivity of 80.5% and a specificity of 89.7%. Whereas diagnosis was not possible with SH U 508 A enhanced Doppler in only 12 patients, a diagnosis was not possible in 29 patients with dynamic CT. SH U 508 A enhanced Doppler in particular improved visualization of the portal vein (15.6%), TIPS (15.8%), superior mesenteric vein (16.1%), collateral circulation (20.7%) and inferior mesenteric vein (25%). SH U 508 A was very well tolerated; only eight patients experienced minor adverse events possibly related to SH U 508 A administration. CONCLUSION: SH U 508 A enhanced Doppler improved the diagnostic confidence and visualization of the portal vascular system compared to base line scans with insufficient Doppler signal and proved reliable compared to dynamic CT.

Adult↗
PubMed2001

Computer-automated dementia screening using a touch-tone telephone.

BACKGROUND: This study investigated the sensitivity and specificity of a computer-automated telephone system to evaluate cognitive impairment in elderly callers to identify signs of early dementia. METHODS: The Clinical Dementia Rating Scale was used to assess 155 subjects aged 56 to 93 years (n = 74, 27, 42, and 12, with a Clinical Dementia Rating Scale score of 0, 0.5, 1, and 2, respectively). These subjects performed a battery of tests administered by an interactive voice response system using standard Touch-Tone telephones. Seventy-four collateral informants also completed an interactive voice response version of the Symptoms of Dementia Screener. RESULTS: Sixteen cognitively impaired subjects were unable to complete the telephone call. Performances on 6 of 8 tasks were significantly influenced by Clinical Dementia Rating Scale status. The mean (SD) call length was 12 minutes 27 seconds (2 minutes 32 seconds). A subsample (n = 116) was analyzed using machine-learning methods, producing a scoring algorithm that combined performances across 4 tasks. Results indicated a potential sensitivity of 82.0% and specificity of 85.5%. The scoring model generalized to a validation subsample (n = 39), producing 85.0% sensitivity and 78.9% specificity. The kappa agreement between predicted and actual group membership was 0.64 (P<.001). Of the 16 subjects unable to complete the call, 11 provided sufficient information to permit us to classify them as impaired. Standard scoring of the interactive voice response-administered Symptoms of Dementia Screener (completed by informants) produced a screening sensitivity of 63.5% and 100% specificity. A lower criterion found a 90.4% sensitivity, without lowering specificity. CONCLUSIONS: Computer-automated telephone screening for early dementia using either informant or direct assessment is feasible. Such systems could provide wide-scale, cost-effective screening, education, and referral services to patients and caregivers.

Aged↗
PubMed1991

A long-lasting decrease in the inhibitory effect of GABA on glutamate responses of hippocampal pyramidal neurons induced by kindling epileptogenesis.

Experiments were carried out to test whether changes in the sensitivity of hippocampal pyramidal neurons to the neurotransmitters glutamate, GABA and noradrenaline may be associated with the establishment of an epileptogenic focus induced by kindling. The effects of iontophoretically applied neurotransmitters on the firing rate of single units were quantified in the rat hippocampal CA1 area in kindled and control animals. Kindling was induced by electrical tetanic stimulation of the Schaffer collateral/commissural fibers. Firing was evoked by local glutamate iontophoresis while simultaneous GABA or noradrenaline application suppressed this response. A significant reduction of the GABAergic inhibitory action on the firing rate in kindled animals studied around four or around 42 days after the last convulsion was found. In the same neurons, the suppressive effect of noradrenaline was not different from controls. The neurons of kindled animals, investigated around four days after the last seizure, had a reduced sensitivity for glutamate; more glutamate ejection current was needed to evoke firing or to evoke the maximum firing rate. In contrast, the responsiveness for glutamate was significantly increased long-term after the last convulsion. These findings demonstrate that hippocampal Schaffer collateral kindling is associated with a long-lasting reduced effectiveness of the GABA-mediated response on glutamate-evoked firing in CA1.

Analysis of Variance↗
PubMed2003

Mu-opioid receptors facilitate the propagation of excitatory activity in rat hippocampal area CA1 by disinhibition of all anatomical layers.

Hippocampal mu-opioid receptors (MORs) have been implicated in memory formation associated with opiate drug abuse. MORs modulate hippocampal synaptic plasticity acutely, when chronically activated, and during drug withdrawal. At the network level, MORs increase excitability in area CA1 by disinhibiting pyramidal cells. The precise inhibitory interneuron subtypes affected by MOR activation are unknown; however, not all subtypes are inhibited, and specific interneuron subtypes have been shown to preferentially express MORs. Here we investigate, using voltage-sensitive dye imaging in brain slices, the effect of MOR activation on the patterns of inhibition and on the propagation of excitatory activity in rat hippocampal CA1. MOR activation augments excitatory activity evoked by stimulating inputs in stratum oriens [i.e., Schaffer collateral and commissural pathway (SCC) and antidromic], stratum radiatum (i.e., SCC), and stratum lacunosum-moleculare (SLM; i.e., perforant path and thalamus). The augmented excitatory activity is further facilitated as it propagates through the CA1 network. This was observed as a proportionately larger increase in amplitudes of excitatory activity at sites distal from where the activity was evoked. This facilitation was observed for excitatory activity propagating from all three stimulation sites. The augmentation and facilitation were prevented by GABAA receptor antagonists (bicuculline, 30 microM), but not by GABAB receptor antagonists (CGP 55845, 10 microM). Furthermore, MOR activation inhibited IPSPs in all layers of area CA1. These findings suggest that MOR-induced suppression of GABA release onto GABAA receptors augments all inputs to CA1 pyramidal cells and facilitates the propagation of excitatory activity through the network of area CA1.

Animals↗
PubMed1997

Delayed signal propagation via CA2 in rat hippocampal slices revealed by optical recording.

Signal propagation from mossy fibers to CA1 neurons was investigated in rat hippocampal slices by a combination of electrical and optical recordings. The slices were prepared by oblique sectioning of the middle part of the hippocampus to preserve fiber connections. The mossy fibers were stimulated to induce population spikes (PSs) and excitatory postsynaptic potentials in the middle part of the CA1 region. Latencies of maximal PSs in CA1 varied widely among slices; they ranged from 7 to 13.5 ms, with two maxima at 9 and 11.5 ms. The fastest PSs probably are evoked by the Schaffer collaterals that connect the CA3 and CA1 regions in the well-known trisynaptic circuit. However, the slower PSs suggest the existence of additional delayed inputs. To determine the source of the delayed input, slices were stained with a voltage-sensitive dye, RH482, and the optical signals relevant to membrane potential changes were detected by a high-resolution optical imaging system. Optical recording of responses to mossy fiber stimulation indicated two distinct types of signal propagation from CA3 to CA1. In preparations evincing the fast type of propagation, signals spread to CA1 within 7.2 ms after the mossy fiber stimulation. During such propagation, activity flowed directly from CA3 to the stratum radiatum of CA1. Other preparations illustrated slow signal propagation, in which optical signals were generated in CA2 before spreading to CA1. During such slow signal transmission, activity persisted in CA2 and its surrounding area for 3 ms before propagating to the strata radiatum and oriens in CA1. In such cases, CA1 activity was detected within 10.8 ms of mossy fiber stimulation. In some slices, a mixture of the fast and slow propagation patterns was observed, indicating that these two transmission modes can coexist. Our data reveal that CA2 neurons can transmit delayed excitatory signals to CA1 neurons. We therefore conclude that consideration of electrical signal propagation through the hippocampus should include flow through the CA2 region in addition to the traditional dentate gyrus-CA3-CA1 trisynaptic circuit.

Animals↗
PubMed2002

Beyond alcoholism: identifying older, at-risk drinkers in primary care.

OBJECTIVE: To evaluate the validity and reliability of two self-report instruments: the Alcohol-Related Problems Survey (ARPS) and its shorter version the Short ARPS (shARPS) that identify older persons whose use of alcohol alone or with their comorbidities may be placing them at risk for or causing them harm. METHOD: We compared the two measures against a "LEAD" (longitudinal evaluation done by experts employing all available data) standard among a sample of 166 drinkers aged 60 years and older in 10 internal medicine clinics. The LEAD standard included a medical record review, a clinical interview and a telephone interview with a collateral informant. We tabulated reasons the LEAD identified subjects as harmful or hazardous drinkers. We also compared the Alcohol Use Disorders Identification Test (AUDIT) and the Short Michigan Alcoholism Screening Test-Geriatric Version (SMAST-G) to the LEAD. RESULTS: Sensitivity and specificity of the ARPS and the shARPS as compared to the LEAD were 93% and 63%, and 92% and 51%, respectively. After minor changes were made in the scoring rules, specificity increased to 66% for both the ARPS and shARPS while sensitivity remained stable, 93% and 91%. Harmful and hazardous drinkers were most often identified because of alcohol use with comorbidities, symptoms, and medication use. Sensitivity and specificity of the AUDIT and the SMAST-G as compared to the LEAD were 28% and 100%, and 52% and 96%, respectively. CONCLUSIONS: The ARPS and shARPS are quite sensitive in identifying older drinkers with a spectrum of alcohol use disorders. They are more sensitive than the AUDIT and the SMAST-G in identifying older persons who may be at risk or experiencing harm as a result of their alcohol use and comorbidities. They also provide information on specific risks associated with alcohol use not obtained by other screening measures and may therefore facilitate interventions by busy clinicians to reduce such risks.

Aged↗
PubMed2005

[Echocardiography and the painful aorta].

The acute painful aortic syndrome is a clinical enity observed in four conditions: dissection, intramural haematoma, penetrating atheromatous ulcer and aneurysm. The diagnosis is based on three imaging techniques: echocardiography, CT scan and magnetic resonance imaging. They have displaced angiography which is incomplete and even dangerous in some cases. Their sensitivity and specificity are comparable in terms of diagnosis. However, each has a specificity. Transthoracic and transoesophageal echocardiography are useful in the diagnosis, the quantification and analysis of the mechanism of aortic regurgitation which may complicate dissection. CT scan visualises the collateral arteries, investigates the physiopathological mechanisms of poor perfusion syndromes and detects parietal fissuration. Magnetic resonance imaging is better adapted to the study of stable forms. In conclusion, transoesophageal echocardiography is a rapid and reliable diagnostic method, it can be used as the investigation of first intention and is essential in patient management. The use of other imaging modes is only required in some cases. The choice, guided by the clinical history, depends on its aptitude to complete the missing or partial data of transoesophageal echocardiography.

Aortic Dissection↗
PubMed1993

Is fine needle aspiration biopsy of salivary gland masses really necessary?

The use of fine needle aspirate biopsies (FNAB's) in the outpatient setting has progressively escalated, particularly in the area of head and neck pathology. An increasing percentage of these are for salivary gland masses. We present our experience with salivary gland FNAB's at our institution for four years, from 1988-1992. One thousand and twenty-two (1,022) FNAB's of superficial masses were performed by two pathologists. One hundred sixty-three (15.9%) were salivary gland biopsies. Of these 163 cases, 21 (12.9%) were normal tissue, 77 (47.2%) were inflammatory processes, 50 (30.7%) were benign tumors, and 15 (9.2%) were malignant tumors. None of the aspirates were unsatisfactory. Tissue correlation was possible in 47 (28.8%) cases. Two false negative cases (4.3%) were identified; these were a Warthin's tumor diagnosed as chronic sialoadenitis by FNAB; and a poorly differentiated squamous cell carcinoma diagnosed as adenocarcinoma by FNAB. There were no false positive cases. Overall sensitivity was 95.7% and specificity was 100%. Our experience indicates that FNAB of salivary glands is an effective screening procedure in evaluating salivary gland masses. The cytologic diagnosis may assist the clinician in allaying patients' anxieties, as well as in further collateral workup prior to definitive therapy.

Adolescent↗
PubMedDate not supplied

Magnetic resonance first-pass perfusion imaging: overview and perspectives.

The data from clinical studies with quantitative MR first-pass perfusion imaging suggests that this technique outperforms SPECT--widely available clinical imaging tool--in sensitivity and specificity. Moreover, MRFP imaging may be combined with the assessment of global and segmental function of the heart and regional wall thickening, and in addition, performed with pharmacological stress agents. The inter- and intra-observer reproducibility of quantitative MRFP is comparable with clinically used nuclear medicine techniques. MRFP measurements can discern collateral myocardium and are able to identify small changes in myocardial blood flow and myocardial perfusion reserve (the ratio of stress blood flow over resting). MRFP imaging has been mainly used in context of coronary artery disease but many other exciting areas in clinical cardiology are awaiting of new insights that can be accomplished with this technique. Trials are needed to obtain the approval of the contrast agent (Gd-DTPA) and perfusion sequences by the Food and Drug Administration and to establish reimbursement procedures with the third-party insurance companies and health maintenance organizations.

Coronary Disease↗