Functional circulation images by angio-CT in the assessment of small deep cerebral infarctions.

We analyzed circulation time (rABCT) and vascular volume density images obtained by angio-computerized tomography (angio-CT) in 63 patients with small deep cerebral infarctions. Abnormalities in the rABCT image were found in 88% of the patients and in the vascular volume image in 48%. Two groups with different clinical pictures were picked out by rABCT changes: one with major-vessel involvement, the other with small-vessel involvement. The perfusional changes found were mainly due to altered vascular canalization rather than to altered vasomotility. The hemodynamic theory could explain the spatial relations between perfusion changes and CT hypodense areas without needing assumptions linking blood flow and metabolism.

Functional perfusion and blood-brain barrier permeability images in the diagnosis of cerebral tumors by Angio CT.

We performed rapid sequential CT scanning following iv injection of a bolus of contrast medium and generated three functional images relating to intravascular circulation time (rABCT), vascular volume (Vv) density and blood-brain barrier (BBB) unidirectional constant uptake rate (Ki), respectively. This was accomplished by calculating the first mathematical moment of the monitored time-density curves about the injection time and from the multiple time graph analysis described by Patlack and co-workers. A satisfactory resolution was achieved, allowing separate appreciation of changes in rABCT both in large vessels and in tissue small vessels. Combined evaluation of rABCT and Vv images allowed us to differentiate between tumors.

Functional circulation and blood-brain permeability images by Angio CT in the assessment of cerebral ischemia.

We performed rapid sequential computerized tomography (CT) scanning following i.v. injection of a bolus of contrast medium, and generated three functional images related, respectively, to intravascular circulation time (rABCT), vascular volume density (Vv) and blood-brain barrier (BBB) unidirectional constant uptake rate (Ki). This was accomplished by calculating the first mathematical moment of the monitored time-density curves about the injection time, and by the multiple time graph analysis described by Patlack and coworkers. A satisfactory resolution was achieved, allowing separate appreciation of changes in rABCT both at large vessels and at tissue small vessels. Combined evaluation of rABCT and Vv images allowed us to draw qualitative conclusions about blood flow and perfusion reserve.

Prevalence of hepatitides in our hemodialyzed population.

We evaluated the prevalence of hepatitis in our hemodialysed population (65 patients, 37 M and 28 F). Screening for A and B hepatitis was tested with the RIA method and research of the anti-HCV with the immunoenzymatic method (Ortho HCV ELISA test of 2nd generation). 15 patients (23.07%) were anti-HCV positive (anti-HCV+); 23 (35.38%) showed positivity for 1 or more markers of B hepatitis (HBV+). A meaningful greater prevalence of B virus infections in anti-HCV+ patients (86.66%), compared to negatives, (20.00%) resulted. All non-A, non-B hepatitides are anti-HCV+. The dialytic treatment of the anti-HCV+ patients was meaningfully longer than in the negatives (p less than 0.05). The prevalence of the seropositive patients to B and C virus is not correlated to the number of transfusions, while it is to the number of surgical operations carried out in the predialytic period. This information suggests common pathogenetic mechanisms between the 2 forms of hepatitis and increased probability to find anti-HCV+ with a longer dialytic treatment.

Enalapril in the treatment of hypertension associated with renal failure: results from a multicenter study.

Forty-eight hypertensive patients affected by various levels of renal failure entered this open, non controlled study, lasting 12 weeks. Patients were divided into two groups according to baseline creatinine clearance: Group I (29 patients): creatinine clearance greater than or equal to 25 ml/min but less than 45 ml/min; Group II (19 patients): creatinine clearance greater than or equal to 10 ml/min but less than 25 ml/min. Patients in Group I started with enalapril 5 mg q.d. and patients in Group II with enalapril 2.5 mg q.d. Enalapril could be titrated up to 20 mg/day. At the end of the study in both groups of patients blood pressure normalization was reached in a high percentage of patients without any significant change in renal function parameters. Plasma potassium showed a significant increase during the study but no patient discontinued treatment due to hyperkaliemia. In conclusion this study shows antihypertensive therapy with enalapril during chronic renal insufficiency to be effective at low dosage (5-10 mg) in lowering blood pressure and to have a good safety profile.

Selective effects of repetition rate on frontal and parietal somatosensory evoked potentials (SEPs).

The effects of changing the stimulus presentation rate on early parietal (N20-P25) and frontal (P22-N30) somatosensory potentials (SEPs), evoked by median nerve stimulation, were investigated in 15 normal subjects. Stimuli were presented at 0.1, 0.4, 1.0, 4.0 and 10/sec. Only minor latency changes, mainly for the frontal P22 component, were observed when the stimulus rate was increased up to 10/sec: while the frontal P22-N30 complex was more rapidly and severely reduced in amplitude than the parietal N20-P25 complex. The differential effects of stimulus presentation rate on early frontal and parietal SEPs support the hypothesis of separate neural generators and suggest that the choice of the stimulation frequency may be critical for the interpretation of diagnostic SEP studies.