Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Collateral sensitivity”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 631 records · Page 35Linked to original sources
PubMed1986

Calcium and long-term transmission damage following anoxia in dentate gyrus and CA1 regions of the rat hippocampal slice.

The mechanism of long-term anoxic damage in brain tissue is investigated using the rat hippocampal slice as a model system. The effects of short durations of anoxia on subsequent transmission through two neural pathways are studied. 10 min of anoxia irreversibly abolishes transmission between the perforant path and the dentate granule cells while only 7 min of anoxia irreversibly abolishes transmission between the Schaeffer collaterals and the CA1 pyramidal cells. We examine the involvement of Ca2+ in this irreversible transmission damage and, also, the differential sensitivities of the dentate gyrus and CA1 regions. Substitution of a buffer containing 0 Ca2+ and 10 mM-Mg2+ during the anoxic period substantially improves the recovery of synaptic transmission in both regions of the slice. Dentate gyrus transmission recovers completely after 20 min of anoxia and CA1 transmission survives 10 min of anoxia. These results suggest that Ca2+ influx during anoxia may be an important cause of the long-term damage. The uptake of 45Ca2+ into the intracellular space of the slice is increased during anoxia. This effect is approximately twice as large in CA1 as in the dentate gyrus. Thus, in the dentate gyrus the calculated exchangeable pool of Ca2+ is increased 30% by anoxia and in the CA1 it is increased by 70%. Two incubating conditions which decrease the amount of 45Ca2+ uptake during anoxia protect transmission against long-term damage. (a) Pre-incubation of the slices with 25 mM-creatine elevates tissue phosphocreatine and attenuates the fall in adenosine 5'-triphosphate (ATP) during anoxia. This is associated with partial protection against transmission damage and an approximate 50% attenuation of the anoxic uptake of 45Ca2+. (b) Inclusion of 2 mM-cobalt in the buffer reduces the normoxic uptake of 45Ca2+ so that the uptake during anoxia is no greater than normoxic uptake in the absence of cobalt. This is associated with a complete protection against long-term transmission damage following 10 min of anoxia in the dentate gyrus. A kinetic analysis of the 45Ca2+ uptake shows that the anoxic uptake results primarily from inhibition of the unidirectional efflux of Ca2+ from the cells; there is no calculable increase in the undirectional influx. This suggests that anoxia increases Ca2+ uptake by inhibiting one or more Ca2+-extrusion processes and not by opening depolarization-sensitive Ca2+ channels.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Triphosphate↗
PubMed1990

Increased sensitivity to Vinca alkaloids in cells overexpressing calmodulin by gene transfection.

Mouse C127 cells, transfected with the chicken calmodulin (CaM) gene and overexpressing CaM protein, were used to evaluate the effect of elevated levels of CaM on the sensitivity of these cells to various anticancer drugs. Clones C2 and C3 overexpress CaM mRNA by 40- and 80-fold, respectively, and CaM protein 3- and 8-fold, respectively. These cell lines were tested for their sensitivity to vincristine, vinblastine, bleomycin, and Adriamycin by comparing the 50% inhibitory concentration in a 72-h growth inhibition assay. The 50% inhibitory concentration values for vincristine with C2 and C3 cells were 6.27 +/- 0.56 nM and 6.60 +/- 0.96 nM, respectively. These values were significantly lower than 13.9 +/- 0.79 nM for the parental C127 cells and 14.0 +/- 1.55 nM for clone 6.8 (the control cell line for transfection without the chicken CaM gene) at P less than or equal to 0.005. The proliferation of C2 and C3 cells was inhibited at lower concentrations of vinblastine as well. The 50% inhibitory concentration values for the C2 and C3 cell lines were approximately one-half those required for C127 or clone 6.8 cells. However, no significant difference in the sensitivity to the DNA-binding drugs, bleomycin and Adriamycin, was observed between the different cell lines. The uptake of [3H]vinblastine was evaluated and found to be increased 1.6- and 2.8-fold in C2 and C3 cells, respectively, as compared with that value obtained for C127 cells. Moreover, the efflux of [3H]vinblastine from vinblastine-loaded cells was also observed to be decreased in the C2 and C3 cell lines. These data suggest that the increase in CaM expression in the C2 and C3 cell lines might be related to the higher sensitivity of these cells to Vinca alkaloids. This increased sensitivity appears to be due to the increase in intracellular concentration of the Vinca alkaloids as a result of an increase in drug uptake and a decrease in efflux. Moreover, the increased sensitivity of clones C2 and C3 to Vinca alkaloids appears to be specific to this class of drugs in that no collateral effects were observed for the DNA-damaging drugs, Adriamycin and bleomycin.

Animals↗
PubMed1994

Pharmacological identification of two types of presynaptic voltage-dependent calcium channels at CA3-CA1 synapses of the hippocampus.

The effects of voltage-dependent Ca channel (VDCC) antagonists on synaptic transmission were investigated at CA3-CA1 synapses of guinea pig hippocampal slices. After selectively loading presynaptic structures in area CA1 with the calcium indicator fura-2, we simultaneously recorded a presynaptic calcium transient ([Ca]t) and the corresponding field excitatory postsynaptic potential (fEPSP) evoked by a single stimulus given to the Schaffer collateral-commissural (SCC) pathway. Application of nifedipine did not reduce either the [Ca]t of the fEPSP, suggesting that nifedipine-sensitive Ca channels do not significantly contribute to evoked synaptic transmission at low stimulation frequency. Application of omega-conotoxin GVIA (omega-CgTX) or omega-agatoxin-IVA (omega-Aga-IVA) dose-dependently blocked both the [Ca]t and the fEPSP. The time course of the block of the [Ca]t was similar to that of the fEPSP. About 40% of the total [Ca]t was omega-CgTX sensitive, and more than 20% was omega-Aga-IVA sensitive. Combined application of these two blockers showed no overlap of the omega-CgTX-sensitive with the omega-Aga-IVA-sensitive [Ca]t. These results suggest that there are at least two types of presynaptic VDCCs at CA3-CA1 synapses of the hippocampus: omega-CgTX-sensitive and omega-Aga-IVA-sensitive Ca channels. Our results also suggest that these two types of Ca channels are colocalized at a single presynaptic terminal. During application of omega-CgTX or omega-Aga-IVA, the initial slope of the fEPSP varied approximately as the fourth power of the amplitude of the [Ca]t, suggesting that omega-CgTX-sensitive and omega-Aga-IVA-sensitive Ca channels have about equal efficacy in triggering transmitter release. These results in combination with similar findings at the squid giant synapse suggest that the nonlinear relationship between transmitter release and the Ca influx is well conserved from the molluscan to the mammalian nervous system.

Animals↗
PubMed1983

Biochemical pharmacology of paradoxical sleep.

The role of noradrenergic cells in the regulation of paradoxical sleep is still controversial, and experimental data have given rise to contradictory interpretations. Early investigations focused primarily on chemical neurotransmissions. However, the process of information transmission between cells involves many other factors, and the cell surface is an important site for transduction of messages into modifications of the activity of postsynaptic cells. alpha-adrenoceptors are believed to play an important role in the control of wakefulness and paradoxical sleep. Experimental evidence suggests that physiological modulation of receptor sensitivity, possibly by specific neuro-modulators, may be a key mechanism in synaptic transmission. In the investigation of the mechanisms involved in paradoxical sleep regulation, lesions of the locus coeruleus have given equivocal results. Collateral inhibition, probably mediated by alpha 2-adrenoceptors, appears to be a powerful mechanism. The exact temporal relationship between noradrenergic cell activation and paradoxical sleep production is not established, but 5-HT appears to be involved. Differences between paradoxical sleep and waking may be related to a physiological modulation of alpha 2-adrenoceptor sensitivity.

Animals↗
PubMed1995

Medial collateral ligament injuries: evaluation of multiple signs, prevalence and location of associated bone bruises, and assessment with MR imaging.

PURPOSE: To investigate the multiple signs of medial collateral ligament (MCL) sprains, including the location and prevalence of associated bone bruises, and evaluate the accuracy of the criteria proposed for magnetic resonance (MR) imaging in grading these sprains. MATERIALS AND METHODS: MR images were evaluated for signs of MCL injury in 76 patients with MCL sprains and 25 asymptomatic volunteers. These signs were then correlated with standards used to determine MCL injury at clinical evaluation. The grade of MCL injury as determined with MR imaging criteria was compared with clinical findings. RESULTS: All signs demonstrated little interobserver variability and were specific. The most sensitive signs were fascial edema and loss of demarcation from adjacent fat. This MR imaging grading system was inaccurate for classification of grade 3 MCL tears and was only questionably accurate for grades 1 and 2. CONCLUSION: Multiple signs of MCL sprains on MR images have varying sensitivities. MR grading systems may not be accurate for classification of MCL injuries.

Adult↗
PubMed1992

Fatty acid-sensitive acid phosphatase activity of tubercle bacilli.

In a whole cell assay system with p-nitrophenyl phosphate as substrate, strains of Mycobacterium tuberculosis and M. bovis were identical in the pH-activity pattern of acid phosphatase. It was a one-peak curve with a pH optimum at 6.2 and sharp symmetrical slopes. The enzymatic activity did not reflect the virulence. When the cells were subjected to mechanical fractionation, the major part of the enzymatic activity was found in a particulate fraction and a minor portion in supernatant and cell walls, suggesting the location of the enzyme in the membrane. Exposure of the cells to free long-chain fatty acids, especially unsaturated ones, reduced the enzymatic activity in a dose-response manner with concomitant decrease in the viability. However, no causal relationship between these two effects was suggested from the collateral experiments.

Acid Phosphatase↗
PubMed1995

Utility of carbohydrate-deficient transferrin as a marker of relapse in alcoholic patients.

Carbohydrate-deficient transferrin (CDT) has been proposed as a marker of alcoholism. However, its role in monitoring alcoholic patients for relapse has not been extensively studied. We therefore performed sequential serum CDT measurements using a microcolumn/radioimmunoassay method (Kabi Pharmacia, Piscataway, NJ) in 86 male alcoholics participating in a hepatitis vaccination program who were monitored for relapse using self-report and collateral history (when available). The maximum serum CDT was significantly higher in patients who relapsed (n = 38) (33.1 +/- 3.1 mg/liter), as compared with abstinent subjects with collateral verification (n = 39) (18.8 +/- 1.3, p < 0.001) and abstinent patients without collateral verification (n = 9) (17.4 +/- 1.3, p < 0.01). Using the manufacturer's currently recommended threshold of 20 mg/liter for males, serum CDT was elevated in 29 of 38 patients who relapsed (sensitivity 76.3%). In 16 (42.1%) of the relapsed patients, a serum CDT above this threshold preceded the patient's self-report by at least 28 days. However, serum CDT exceeded 20 mg/liter in 10 of 48 patients who remained sober (specificity 79.2%); three of these patients had clinical and/or pathological evidence of cirrhosis. Using a threshold of 25 mg/liter, 21 of 38 patients who relapsed had an elevated serum CDT (sensitivity 55.3%); 12 (31.6%) of these patients had elevated serum CDT before self-report. Only 4 of 48 subjects who remained sober had serum CDT levels that exceeded 25 mg/liter (specificity 91.7%); three of these patients had clinical and/or pathological evidence of cirrhosis. In conclusion, serial serum CDT testing detects relapses before self-report in male subjects. Values between 20-25 mg/liter suggest relapse, but call for collateral verification, whereas CDT values above 25 mg/liter are usually diagnostic of relapse in the absence of cirrhosis.

Alcoholism↗
PubMed1996

Hepatic artery thrombosis after liver transplantation: temporal accuracy of diagnosis with duplex US and the syndrome of impending thrombosis.

PURPOSE: To determine how the interval between ultrasonography (US) and a definitive diagnosis affects the accuracy of duplex US for the diagnosis of hepatic artery thrombosis after transplantation. MATERIALS AND METHODS: Retrospective chart review was performed in 202 patients with liver transplants. Results of duplex US were compared with those of angiography, surgery, or autopsy. RESULTS: Sensitivity for US was 54% up to 1 month before and 82% on the day of the definitive diagnostic study. Specificity remained relatively constant over time (86%-87%). Accuracy reached 85%, and negative predictive value reached 93%. Qualitative changes on the sonogram enabled prediction of subsequent thrombosis. Rejection, recurrent hepatitis, aberrant anatomy, hypotension, arterial collaterals, and operator error caused false-positive or false-negative results. CONCLUSION: Although duplex US remains a good screen for hepatic artery thrombosis, angiography is strongly recommended. Serial US studies are necessary for diagnosis. Sensitivity improves over time as the clinical picture clarifies. Qualitative changes on the sonogram (the syndrome of impending thrombosis) enable prediction of subsequent hepatic artery thrombosis.

Adult↗
PubMed1993

Assessment of portal contribution to liver perfusion by quantitative sequential scintigraphy and Doppler ultrasound in alcoholic cirrhosis. Diagnostic value in the detection of portal hypertension.

To assess the portal contribution to liver perfusion, we carried out quantitative sequential scintigraphy in 110 patients with alcoholic cirrhosis (22 Child-Pugh class A, 39 class B, 49 class C) and 15 normal subjects. Duplex Doppler ultrasound found a type of intrahepatic circulation that made the standard scintigraphic procedure inaccurate in four cases of cirrhosis, which were reevaluated. Portal contribution to liver perfusion was lower in cirrhotics than in normal subjects (48.7 +/- 29% versus 78.4 +/- 6%; p < 0.001). The sensitivity of scintigraphy in detecting portal hypertension, based on portal contribution < or = 66%, was 61.8% (with a 100% specificity) compared with 66.7% for endoscopy (diagnosis based on existence of varices). The overall sensitivity of the two tests together was 86.1%. Portal contribution to liver perfusion was inversely correlated to Child-Pugh score (r = 0.53; p < 0.001), to prothrombin time (r = 0.52; p < 0.001), and to hepatic venous pressure gradient (r = 0.43; p < 0.001) and positively correlated to albuminemia (r = 0.42; p < 0.001). Concurrent alcoholic hepatitis and the existence of large portosystemic collaterals were related to a decrease in portal contribution to liver perfusion. We conclude that quantitative sequential scintigraphy, which shows a direct relationship between portal contribution to liver perfusion, on the one hand, and the amount of portosystemic shunting, the progression of liver disease, and/or acute liver injury, on the other, could serve as a diagnostic test for portal hypertension. The addition of scintigraphy improves the overall sensitivity of endoscopy.

Collateral Circulation↗
PubMed1996

Interactions of sympathetic and primary afferent neurons following nerve injury and tissue trauma.

Sympathetic post-ganglionic neurons may be involved in the generation of pain, hyperalgesia and inflammation under pathophysiological conditions. Two categories of influence of the sympathetic neuron on afferent neurons can be distinguished and this distinction seems to be related to whether the coupling between afferent and sympathetic neuron develops after nerve lesion or after tissue trauma with inflammation (Fig. 15): A. Peripheral nerve lesion generates plastic changes of the afferent and sympathetic postganglionic neurons, depending on the type of nerve lesion (e.g. complete, partial). Both afferent and post-ganglionic neurons exhibit degenerative and regenerative changes and unlesioned neurons may show collateral sprouting in the periphery as well as in the dorsal root ganglion. This reorganization of the peripheral neurons may lead to chemical coupling between sympathetic and afferent neurons. The coupling is responsible for sensitization and/or activation of primary afferent neurons by the sympathetic neurons. The mediator probably is norepinephrine, but other substances cannot be excluded. The afferent neuron expresses or upregulates functional adrenoceptors. The type of adrenoceptor involved is probably alpha 2. The coupling may occur at different sites of the primary afferent neuron, e.g. at the lesion site, remote from the lesion site in the dorsal root ganglion or between nonlesioned sympathetic and afferent neurons which show collateral sprouting. The biochemical signals which trigger these changes probably are neurotrophic substances, their receptors which are synthesized by the peripheral neurons, Schwann cells and other cells in response to the peripheral lesions. B. Sympathetic nerve terminals in peripheral tissues may serve as mediator elements in hyperalgesia and inflammation following tissue trauma without nerve lesion. Experiments show that these functions are largely independent of activity in the sympathetic neurons and independent of vesicular release of transmitter substances (such as norepinephrine). Sensitization of nociceptive afferents for mechanical stimuli and venular plasma extravasation in the synovium which are induced by the inflammatory mediator bradykinin are, at least in part, dependent on the sympathetic terminal. The signal to venules and afferent receptors is synthesized and released from the sympathetic terminal or in association with it. It is a prostaglandin (probably PGE2). Sympathetically mediated (neurogenic) inflammation and neurogenic inflammation mediated by afferents may interact reciprocally and enhance the inflammatory process as well as the sensitization of nociceptive afferents. Norepinephrine may also lead to sensitization of nociceptive afferents under inflammatory conditions. This sensitization is presumably mediated by alpha 2-adrenoceptors in the sympathetic varicosities and by a prostaglandin (probably PGI2) which is synthesized and released by or in association with the sympathetic varicosities.

Extremities↗
PubMedDate not supplied

Hepatofugal flow on computed tomography of arterial portography: its correlation with esophageal varices bleeding.

BACKGROUND/AIMS: To study the portal flow patterns from CTAP (computed tomography of arterial portography), then to predict the existence of esophageal varices bleeding clinically. METHODOLOGY: 192 patients who underwent CTAP from superior mesenteric artery infusion were recruited in this study. The obtained images were classified according to our proposed criteria. Stage 0: hepatopetal flow, when all the contrast medium from the superior mesenteric vein entered the portal vein. Stage 1: when the contrast medium opacified the splenic vein or the other collateral vessels. Stage II: when the contrast medium opacified the paraesophageal vessels without entering the inner wall of the esophagus. Stage III: when the contrast medium opacified the collaterals up to the inner wall of the esophagus. RESULTS: The incidence of bleeding esophageal varices was correlated to the different stages of collateral flows pattern obtained. The esophageal varices bleeding rates were 0/137, 1/16, 1/14, 16/25 for stage 0, I, II and III, respectively. The incidence of bleeding esophageal varices was significantly higher in stage III group than in the other groups (P < 0.001). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of stage III patients in regard to the occurrence of bleeding esophageal varices were estimated as 80.0%, 98.8%, 88.9%, 94.8%, and 94.3%, respectively. CONCLUSIONS: Our results show that CTAP demonstrates the portal flow patterns and collateral veins clearly, which can serve as an excellent imaging modality to predict the risk of esophageal varices bleeding.

Adolescent↗
PubMed2004

Comparative effects of monopolar radiofrequency energy and conservative management of mechanical properties of elongated lateral collateral ligament in rabbits: an experimental study.

OBJECTIVE: We examined the biomechanical effects of shrinkage in elongated rabbit lateral collateral ligament. DESIGN: This study was designed in an attempt to evaluate the energy effects of monopolar radiofrequency on strained but not ruptured ligaments. BACKGROUND: In treatment of ligament injuries difficulty in reducing increased laxity after trauma and recurrence of instability are important factors for failure. METHODS: Ligament elongation and laxity were achieved in operating room by applying varus stress for multiple times. In Group C ( n = 8 ), elongated lateral collateral ligaments were treated only with above-knee cast, while in Group S ( n = 8 ), they were treated with shrinkage and above-knee casts. The un-operated sides were labeled as control groups. At the 12th week after surgery the animals were sacrificed and hind limbs were disarticulated. Removing the other soft tissues around knee, only lateral collateral ligaments were left intact. Biomechanical analyses of the effects of two different treatment methods were compared by performing a pulling-out test. RESULTS: Considering maximum load and stiffness, conservatively treated ligaments were stronger and stiffer than shrunken ligaments ( P < 0.05 ). CONCLUSION: Biomechanical values were altered by both treatment methods. Reflecting an alteration in intra-molecular structure, the main alteration was the decrease of strength in shrunken ligaments. In ligament injuries, we concluded shrinkage not to be superior to conservative treatment.

Animals↗
PubMed1995

Cross-filling of circle of Willis and carotid stenosis by angiography, duplex ultrasound, and oculopneumoplethysmography.

PURPOSE: To evaluate the filling of the Circle of Willis on preoperative arteriograms and to correlate this observation with the results of oculopneumoplethysmography (OPG) and severity of carotid stenosis as determined by duplex ultrasonography and angiography. PATIENTS AND METHODS: Ninety-five patients underwent OPG, duplex ultrasonography, and selective carotid and vertebral arteriography. RESULTS: In all, 45 (88%) patients with a positive OPG had interhemispheric cross-filling of the middle cerebral artery and anterior cerebral artery from a contralateral carotid injection in contrast with 10 (23%) patients with a negative OPG (P < 0.001). Of patients with carotid stenosis > or = 80% on duplex ultrasound, 39 (91%) had cross-filling from a contralateral carotid injection in contrast with 16 (31%) patients with < 80% stenosis (P < 0.001). Of patients with carotid stenosis > or = 80% on arteriogram, 37 (90%) had cross-filling from a contralateral carotid injection in contrast with 18 (33%) patients with < 80% stenosis (P < 0.001). CONCLUSION: These data suggest that the Circle of Willis is frequently incompetent as a collateral pathway and that arteriographic cross-filling is not a reliable index of this pathway. Patients with a positive OPG and corresponding carotid stenosis are likely to have a physiologically incompetent collateral pathway. Perhaps these patients should undergo surgery, even if the stenosis is less than 80%.

Adult↗
PubMedDate not supplied

Transorbital Doppler diagnosis of intracranial arterial stenosis.

Forty-two intracranial internal carotid arteries were visualized by both arteriography and 2 MHz pulse ultrasonic Doppler examinations. The intracranial internal carotid artery Doppler signals were studied at 5-7 cm depth behind the eyelid using frequency spectral analysis. Stenosis criteria were developed and methods of avoiding confusion with collateral effects devised. Among 33 intracranial ICAs visualized on the arteriograms, 22 were normal without stenosis and 11 displayed some degree of stenosis ranging from 20 to 75 percent. An additional 7 were totally occluded. Doppler criteria of stenosis representing elevated frequencies and symmetrical prominent low frequencies (SPLF) were utilized and separated from collateral effects to provide an overall accuracy of the technique of 88 percent with a 95 percent specificity and a 73 percent sensitivity. The technique appears sufficiently promising to justify further development and utilization.

Cerebral Angiography↗
PubMed1994

Axon reflex vasodilatation in cat dental pulp elicited by noxious stimulation of the gingiva.

Antidromic stimulation of sensory nerves has been shown to increase blood flow in the tissue they innervate. This study was designed to determine if antidromic vasomotor responses occur in feline dental pulp and if they are mediated by branched axons supplying both tooth pulp and gingiva. Dynamic changes in pulpal blood flow (PBF) elicited by electrical stimulation, pinching, heating, and capsaicin application to the gingivae were investigated in cat mandibular canine teeth by means of Laser Doppler Velocimetry. All inferior alveolar nerve bundles and the cervical sympathetic trunk had been previously sectioned to avoid the occurrence of brainstem reflexes, e.g., somato-autonomic vasomotor reflexes. Increases in PBF were observed in seven out of 12 cats when a restricted gingival area adjacent to the canine teeth was stimulated as described, but the increases were abolished after the sensitive gingival area was painted with lidocaine jelly, a surface anesthetic. These vasodilator responses, remarkably reduced following repeated application of 30 mM of capsaicin, are considered to be induced via antidromic activation of capsaicin-sensitive nociceptive nerve fibers, presumably by axon reflex mechanisms, suggesting that nerve terminals supplying the gingiva originate from parent axons which have collaterals that innervate the canine tooth pulp.

Animals↗
PubMed2001

Stress thallium-201 myocardial scintigraphy in patients with complete occlusion of the left main coronary artery.

Complete occlusion (CO) of the left main coronary artery (LMCA) is a rare but often fatal condition. The diagnosis is frequently missed because the signs and symptoms are often obscure and diverse. We describe three patients with CO-LMCA who showed unusual myocardial scintigraphic findings. The patients had extensive right-to-left collateral channels and decreased uptake and washout rates at the basal anterior and anterolateral portions of the heart wall during stress thallium-201 scintigraphy. The basal anterior to anterolateral portion of the heart wall is the most distant from the collateral artery and should be the most ischemic area shown during exercise, resulting in this scintigraphic pattern. This scintigraphic finding may be useful for the noninvasive diagnosis of CO-LMCA.

Aged↗
PubMedDate not supplied

Transcranial Doppler findings in middle cerebral arterial occlusive disease in relation to degree of stenosis and presence of concomitant stenoses.

PURPOSE: We evaluated the accuracy of transcranial Doppler (TCD) criteria in detecting middle cerebral artery (MCA) stenoses other than solitary severe stenoses. METHODS: Three TCD criteria were evaluated in patients with acute MCA territory infarction who also underwent angiography: abnormalities in mean velocity (MV), focal areas of spectral waveform abnormalities, and compensatory increase in MV in collateral vessels. RESULTS: Among 102 patients studied, angiography revealed MCA lesions in 48: 16 had uncomplicated lesions (single stenosis of moderate to severe degree), 19 had mildly complicated lesions (single MCA stenosis of other than moderate to severe degree, or moderate to severe MCA stenosis with a concomitant lesion outside the MCA), and 13 had severely complicated lesions (MCA stenosis of other than moderate to severe degree with a concomitant lesion outside the MCA). The sensitivity of abnormalities in MV in uncomplicated MCA lesions was 81%, whereas it was 53% in mildly complicated MCA lesions and 38% in severely complicated MCA lesions. However, a compensatory increase in MV in collaterals was more frequently found in complicated MCA lesions, and focal areas of spectral waveform abnormalities were observed fairly consistently in all groups. CONCLUSIONS: TCD findings of focal areas of spectral waveform abnormalities and compensatory collateral flow were common in complicated MCA lesions and may improve the specificity of TCD in the diagnosis of MCA stenosis.

Adult↗
PubMed1994

[The usefulness of abdominal echography in the diagnosis of portal hypertension in cirrhotic patients].

The differences in sonographic measurements of the splanchnic vessels, their modifications during respiration, the spleen size and the presence of collaterals of the portal system among 110 cirrhotic patients with portal hypertension and 30 control subjects are analyzed to verify the usefulness of conventional sonography in the diagnosis of portal hypertension. We achieved a sensitivity above 70% and a specificity of at least 90% with the following signs: 1) dilation of portal, splenic and superior mesenteric veins, 2) limited variations of the latter two during respiration, and 3) splenomegaly. A higher sensitivity was achieved considering variations in splenic caliber during respiration under 33% (91%) or superior mesenteric vein during forced expiration above or equal than 7 mm (88%). These measurements could be found in 71.8% and 57.2% respectively. On the other hand, values of portal vein and spleen size were easily obtained. The usefulness of all measurements persists if we take into account only patients with Child-Pugh score < 7. Collateral circulation was demonstrated in 18%. Portal vein above 14 mm, variations in splenic caliber under 13% or superior mesenteric vein during forced expiration above or equal than 9 mm were obtained in any of control subjects but respectively in 33%, 46% and 69% of patients in portal hypertension group. We conclude that ultrasonography is a reliable and noninvasive tool in the diagnosis of portal hypertension in cirrhotic patients.

Abdomen↗