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Biomedical subjects

A Carolei

Publications and source records attributed to A Carolei.

104 records · Page 6Linked to original sources
PubMedDate not supplied

Cerebrovascular reactivity evaluated by transcranial Doppler: reproducibility of different methods.

Transcranial Doppler is routinely used to assess the cerebrovascular reactivity, despite scarce information on its reproducibility. We evaluated the reproducibility of cerebrovascular reactivity measurements by this method utilizing different vasodilatory and vasoconstrictor stimuli. The cerebrovascular reactivity was measured in 45 healthy volunteers during hypercapnia induced by inhalation of a mixture of 5% CO2 and 95% O2, breath holding and rebreathing, and during hypocapnia induced by voluntary hyperventilation. Three sets of measurements were performed at times 0, 1, and 24 h to assess the within-observer short- and long-term reproducibility. The reproducibility was analyzed using the intraclass correlation coefficient. For the CO2 inhalation method, a good short-term (rI = 0.55; 95% CI = 0.39-0.68) and a good long-term (rI = 0.43; 95% CI = 0.25-0.59) reproducibility was found. For the breath-holding method a good short-term agreement was found (rI = 0.41; 95% CI = 0.22-0. 57), while the long-term reproducibility was poor (rI = 0.17; 95% CI = -0.03-0.36). Rebreathing showed a fair (rI = 0.31; 95% CI = 0.11-0. 48) short-term and a poor (rI = 0.17; 95% CI = -0.03-0.36) long-term reproducibility. For voluntary hyperventilation, the short-term reproducibility was good (rI = 0.53; 95% CI = 0.36-0.66), and the long- term reproducibility was fair (rI = 0.31; 95% CI = 0.11-0.48). In our study, CO2 inhalation and voluntary hyperventilation had the highest reproducibility and should be preferred when assessing cerebral vasoreactivity, especially in follow-up studies.

Adult↗
PubMedDate not supplied

Imaging of leukocytic infiltration in human cerebral infarcts.

The circulating white blood cells of patients with brain infarction were labelled in vitro with Indium-111 tropolonate; the cells were reinjected to study the inflammatory process by gamma camera imaging. Eight patients with acute cerebral ischemic infarct were studied during the first two weeks after the onset of neurological symptoms. In seven cases a well defined area of increased radioactivity was revealed in the infarcted hemisphere indicating active migration and tracking of labelled leukocytes in cerebral infarct. This method allows monitoring of the cellular inflammatory response in human cerebral infarcts and adds another imaging technique.

Acute Disease↗
PubMedDate not supplied

Effects of interferon beta, cyclophosphamide and azathioprine on cytokine profile in patients with multiple sclerosis.

We assessed the in vitro effects of interferon beta-1b (IFNbeta-1b), cyclophosphamide (CY), and azathioprine (AZA) alone and of the combination of IFNbeta-1b with CY or AZA on the production of Th1 and Th2 cytokines in 10 patients with multiple sclerosis. Cytokine levels were determined at baseline and after stimulation with IFNbeta-1b, CY, and AZA alone or with the combination of IFNbeta-1b with CY or AZA. The combination of IFNbeta-1b with CY resulted in a statistically significant decrease in the production of interleukin-2 (IL-2) (P=0.003) and tumor necrosis factor alpha (TNF-alpha) (P=0.03). An additive effect on the production of interferon gamma (IFN-gamma) (P=0.2) and interleukin-10 (IL-10) (P=0.6), and a positive interaction on the production of interleukin-4 (IL-4) (P=0.08) were observed although the findings were not statistically significant. The combination of IFNbeta-1b with AZA resulted in a significant negative effect on the production of IL-2 (P=0.006), whereas TNF-alpha (P=0.02), IFN-gamma (P=0.03), IL-4 (P=0.2), and IL-10 (P=0.3) were not statistically impacted. Our data show that CY was able to improve the effects of IFNbeta-1b on the ratio of Th1/Th2 cytokines.

Adult↗
PubMedDate not supplied

Contrast-enhanced transcranial Doppler sonography in patients with acute cerebrovascular diseases.

The aim of the study was to evaluate the diagnostic potential of galactose-based microbubble suspension (Levovist) in patients with acute cerebrovascular disease and inadequate transtemporal acoustic window, when examined by transcranial Doppler (TCD). We studied 10 patients with either transient ischemic attack (no. = 3) or stroke (no. = 7). Inadequate transtemporal acoustic window was unilateral in 3 patients and bilateral in the remaining 7 patients. Signals from middle, anterior, and posterior cerebral arteries (MCA, ACA, PCA) were recorded after injecting Levovist 300 mg/ml. Six patients needed 3 injections of Levovist, 1 patient two, and 3 patients one. Mean +/- SD duration of optimal signal enhancement was 175.2 +/- 53.2 s, range 70-290 s. Doppler waveform analysis was possible in 14 (82.3%) MCA, 11 (65%) ACA, and 9 (53%) PCA. Levovist improved the reliability of TCD in patients with acute cerebrovascular disease and insufficient transtemporal insonation.

Aged↗
PubMedDate not supplied

Endoscopic ultrasound and Computed Tomography in the diagnosis, locoregional staging and assessment of vascular infiltration of pancreatic carcinoma.

PURPOSE: The aim of this study was to evaluate the diagnostic accuracy of colour-Doppler Endoscopic Ultrasonography (EUS), in the detection, loco-regional staging and assessment of vascular infiltration in pancreatic carcinoma, and to compare the results with those obtained by Computed Tomography (CT). MATERIALS AND METHODS: A series of 57 patients with diagnosed or suspected pancreatic carcinoma was retrospectively analysed. All patients underwent EUS and thin-slice (< 5 mm) spiral dynamic CT. The final diagnosis (carcinoma in 37 patients and benign lesion in 20) was obtained by laparotomy in 21 patients, fine-needle aspiration cytology (FNAC) in 17, and follow-up in 19. RESULTS: The specificity and sensitivity for the diagnosis of malignancy were respectively 45% and 92% for EUS and 45% and 89% for CT, with an accuracy of 75% for EUS (p <0.05) and 74% for CT (p = 0.07). The specificity and sensitivity for the diagnosis of loco-regional nodal metastases were both 100% for EUS. The specificity and sensitivity for the diagnosis of vascular infiltration were 100% and 94% for EUS and 100% and 44% for CT, giving a diagnostic accuracy of 97% for EUS vs 74% for CT (p <0.001). CONCLUSIONS: EUS proved to be more sensitive and specific than CT in the loco-regional staging of pancreatic carcinoma. Its diagnostic accuracy is especially high in assessing vascular infiltration and loco-regional nodal metastases. CT still remains the examination of choice for staging pancreatic carcinoma and for assessing its resectability as it affords a panoramic view and ability to rule out distant metastases. Candidates to resection should all be examined by EUS, as, due to its high accuracy in loco-regional staging and assessing vascular infiltration, it might allow a large proportion of patients to be spared the operation.

Journal Article↗
PubMedDate not supplied

[Physiopathology of cerebral circulation].

Autoregulation of the cerebral circulation is the key mechanism that keeps CBF constant within wide limits of arterial pressure. The mechanism for autoregulation and the influence of arterial hypertension and extracranial carotid stenosis are discussed. Brain function and metabolism are critically dependent on sufficient CBF and oxygen supply. Cerebral ischemia occurs when flow drops below about 10-15 ml/100 g/min. Metabolic and therapeutic aspects of acute cerebral ischemia are discussed.

Acute Disease↗
PubMedDate not supplied

A randomized trial comparing ticlopidine hydrochloride with indobufen for the prevention of stroke in high-risk patients (TISS Study). Ticlopidine Indobufen Stroke Study.

Two treatments, based on either ticlopidine or indobufen at their optimal individual daily dose (median dose: 250 and 200 mg/day, respectively), were compared in an open randomized multicenter trial in patients at risk of cerebral ischemia (men and women, aged 39 to 80 years, who had experienced in the month before entry into the study transient ischemic attack or amaurosis fugax or minor stroke). The total number of patients screened was 4033; 1632 were enrolled, 821 randomized to ticlopidine, 811 to indobufen. The overall frequency of the composite primary end-point (stroke, myocardial infarction, and death from any cause) was 4.4%. The ticlopidine-based regimen proved significantly better than the indobufen one in preventing the composite of fatal and non fatal events (49.6% relative risk reduction), or death alone (54.4% relative risk reduction). The two groups had similar percentages of adverse events (5.5% and 6.4% for ticlopidine and indobufen group, respectively) with withdrawals because of adverse events in 3.4% and 2.5%; gastrointestinal disorders and bleeding were more frequent in the indobufen group, whereas rash and abnormal liver function were more frequent in the ticlopidine one.

Adult↗
PubMedDate not supplied

[Transcranial Doppler sonography in the pre- intra- and post-operative evaluation of 85 patients undergoing carotid endarterectomy].

PURPOSE: To evaluate the usefulness of transcranial Doppler sonography during carotid endarterectomy. PATIENTS AND METHODS: Pre-, intra-, and postoperative transcranial Doppler was performed in 85 patients who underwent carotid endarterectomy. Intracranial collateral pathways were evaluated preoperatively and continuous monitoring of middle cerebral artery flow velocity was performed during carotid surgery. Transcranial Doppler was repeated in each patient 1 and 7 days thereafter. RESULTS: Values of residual middle cerebral artery flow velocity during preoperative digital compression of the common carotid artery were significantly correlated (r = 0.56; P < 0.001) with those obtained during cross-clamping. Middle cerebral artery flow velocity was significantly lower during cross-clamping with respect to pre-clamping (P = 0.006), in patients with neurologic symptoms (P = 0.001), EEG alterations (P = 0.001), or defective collateral blood supply through the anterior communicating artery (P = 0.01). Postoperative flow velocity values of the MCA were significantly higher at day-1 examinations (P < 0.0001) with respect to preoperative values, and were no more significantly different at day-7. CONCLUSIONS: Transcranial Doppler is a useful method to evaluate the risk of cerebral ischemia during carotid endarterectomy cross-clamping, to identify those patients in which shunt insertion is mandatory, and to evaluate the postoperative effect of carotid endarterectomy on cerebral hemodynamics.

Blood Flow Velocity↗