Transcranial color Doppler in stroke-free adult patients with sickle cell disease.

The threshold velocity ≥200 cm/s at transcranial Doppler (TCD) evaluation is a useful cut-off for preventing the stroke (STOP trial) in pediatric patients with sickle cell disease (SCD), term including different types of sickle genotypes. Scanty data are available for adult SCD patients. We compared intracranial blood flow velocities between adult SCD patients and controls using transcranial color Doppler (TCCD), measuring the peak of systolic velocity (PSV) with the insonation angle correction and the pulsatility index (PI), an indicator of endothelial elasticity. Fifty-three adult SCD patients (aged >18 years) were enrolled (15 sickle cell anemia, 26 sickle cell thalassemia, and 12 HbS/HbC). None of the patients presented neurological signs. PSVs in middle cerebral artery (MCA) were higher in SCD patients than in controls (p = 0.001). In sickle cell anemia patients, PSVs were higher when compared to HbS/ßThal (p < 0.0060) and HbS/HbC patients (p < 0.0139). PI was within the lower range of normality in SCD patients compared to controls. Moreover, MCA-PSV was higher with lower Hb levels and higher HbS%; PI did not change with variation of Hb levels and HbS%.PSV and PI in SCD adult patients could be a relevant index to indicate the abnormal cerebral blood flow and to detect the sickle endothelial damage, in order to prevent cerebrovascular accidents.

[X-ray bone densitometry. Study of in vitro and in vivo reproducibility]. / Densitometria ossea a raggi X. Studi di riproducibilità in vitro ed in vivo.

We studied the reproducibility in vitro and in vivo of a new bone densitometer (HOLOGIC QDR-1000, software version 4.03) which uses an x-ray source at two different levels of energy. Short and long term coefficient of variation (c.v.) in vitro is less than 0.5%. In vivo c.v. is less than 1% in normal body weight subjects and less than 3% in obese subjects. The ingestion of 500 mg of calcium element did not modify bone mineral density (BMD), while 1000 mg determined an increase of BMD equal to 2.6% and 1.5% in the two subjects examined. The increase of water thickness on a three femoral heads phantom caused a progressive reduction of bone mineral content (BMC) and BMD until 12.1% less than basal value and an increase of c.v. from 0.1% to 1%. The addition of oil to water at different percentages determined a slight increase of both BMC and BMD, till 3.5% with 66% of oil in water, if compared with the values obtained with water alone. The reduction of soft tissue around the bone determined a progressive decrease of BMD reaching 3.4% less than basal value when the reduction was 30%.

Usefulness of dynamic reno-scintigraphy in the follow-up of patients treated by surgery or percutaneous transluminal angioplasty for renovascular hypertension.

The aim of this study was to assess the role of dynamic reno-scintigraphy (DRS) in follow-up of 21 hypertensive patients who underwent surgery or percutaneous transluminal angioplasty (PTA) for renal artery stenosis. Dynamic reno-scintigraphy was recorded following injection of 0.12 mCi/kg 99Tcm-glucoheptonate i.v. before and after reconstructive vascular surgery or PTA. Serial images and renal time activity were analysed according to established criteria of interpretation. In terms of blood pressure response, 14 patients were cured or improved after surgery or PTA; DRS normalized or markedly improved in all these cases. Dynamic reno-scintigraphy did not change in seven patients who did not benefit from surgery or PTA. In three of them, repeated angiography showed, respectively, a by-pass occlusion, a renal artery re-occlusion after PTA, and a renoparenchymal disease. Dynamic reno-scintigraphy appears to reflect well the recovery of renal perfusion in patients treated by surgery or PTA for suspected renovascular hypertension.

Circadian secretion of ACTH, cortisol, and mineralocorticoids in Cushing's syndrome.

The behaviour of plasma levels of ACTH was studied in five untreated patients with pituitary-dependent Cushing's syndrome, with blood samples taken every half an hour for a total period of 24 hours; plasma cortisol, corticosterone, deoxycorticosterone (DOC) and aldosterone were also measured simultaneously. In all cases, above normal secretory impulses of ACTH and cortisol, at approximately the same height, were present throughout the day, while between these peaks the levels were in the normal range. Few peaks of ACTH and cortisol were simultaneous and rare secretory impulses of corticosterone, and deoxycorticosterone were in synchrony with those of ACTH or cortisol. DOC levels were found to have some peaks above normal levels while corticosterone levels presented rare elevated peaks during the day. Plasma aldosterone values on the other hand, were extremely low in all except in one case, where the variations may be interpreted as pure fluctuations. These findings confirm that: 1) In a number of cases, multiple samples of ACTH and cortisol (during the 24 hrs.) appear to be essential in order to distinguish pituitary-dependent Cushing's syndrome from normal; 2) In conditions of ACTH excess, DOC and corticosterone secretion seems to become progressively less ACTH-dependent as we proceed down the biosynthetic chain towards aldosterone, which is suppressed in most cases.