Cerebral autoregulation is preserved in multiple system atrophy: A transcranial Doppler study.

Patients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 +/- 12 yr of age) and 12 healthy volunteers (61 +/- 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross-spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross-spectral analysis showed a phase for the mid-frequency band (0.07-0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA.     

Measurement of alveolar derecruitment in patients with acute lung injury: computerized tomography versus pressure–volume curve

Introduction  

Positive end-expiratory pressure (PEEP)-induced lung derecruitment can be assessed by a pressure–volume (P–V) curve method or by lung computed tomography (CT). However, only the first method can be used at the bedside. The aim of the study was to compare both methods for assessing alveolar derecruitment after the removal of PEEP in patients with acute lung injury or acute respiratory distress syndrome.     

Malignant peripheral nerve sheath tumour of the cervical vagus nerve in a neurofibromatosis type 1 patient.

One serious complication of neurofibromatosis type 1 (NF1) is the development of malignant peripheral nerve sheath tumours (MPNSTs). These malignancies often develop within pre-existing plexiform neurofibromas and their development is now thought to be associated with both tumour suppressor gene mutations and dysregulated growth factor signalling. Recent work demonstrates that the lifetime risk of malignant transformation is significantly greater than previously thought. Ionising radiation, a long-standing disease, particularly the presence of a large number of plexiform neurofibromas from an early age, are suggested risk factors. We present an NF1 patient who developed an MPNST of the cervical vagus nerve which was successfully treated with surgery. Close monitoring of patients with NF and a high level of suspicion towards rapidly enlarging and painful swellings is merited as these features may signify malignant transformation. Whether a positive history of MPNST in other affected family members predisposes the individual to a higher risk of malignant transformation is unclear.     

Blood velocity assessment using 3D bright-blood time-resolved magnetic resonance angiography.

Blood velocity is a functional parameter that is not easily assessed noninvasively, especially in small animals. A new noninvasive method that uses magnetic resonance angiography (MRA) to measure blood flows is proposed. This method is based on the time-of-flight (TOF) phenomenon. By initially suppressing the signal from the stationary spins in the area of interest, it is possible to sequentially visualize only the signal from the moving spins entering a given volume. With this method, 3D cine images of the blood flow can be generated by positive contrast, with unparalleled spatial (<200 microm) and temporal resolutions (<10 ms/image). As a result, it is possible to measure flow in sinuous paths. The present method was applied in vivo to measure the blood velocity in mouse carotid arteries. Because of its robustness and simplicity of implementation, this method has numerous potential applications for fundamental studies in small animal models.     

Early Low-Grade Proteinuria: Causes, Short-Term Evolution and Long-Term Consequences in Renal Transplantation

Proteinuria 1 year after transplantation is associated with poor renal outcome. It is unclear whether low-grade (<1 g/24 h) proteinuria earlier after transplantation and its short-term change affect long-term graft survival. The effects of proteinuria and its change on long-term graft survival were retrospectively assessed in 484 renal transplant recipients. One- and 3-month proteinuria correlated with donor age, donor cardiovascular death, prolonged cold and warm ischemia times and acute rejection. One- and 3-month proteinuria (per 0.1 g/24 h, hazard ratio (HR): 1.07 and 1.15, p<0.0001)-especially low-grade proteinuria (HR: 1.20 and 1.26, p<0.0001)-were powerful, independent predictors of graft loss. Its short-term reduction correlated with arterial pressure (AP) (the lower the 3-month diastolic and 12-month systolic AP, the lower the risk of increasing proteinuria during 1-3 months and 3-12 months periods, respectively: Odds ratio (OR) per 10 MmHg: 0.78, p=0.01 and 0.85, respectively, p=0.02), and was associated with decreased long-term graft loss (per 0.1 g/24 h: HR: 0.88 and 0.98, respectively, p<0.0001), independently of initial proteinuria. Early low-grade proteinuria due to pre-transplant renal lesions, ischemia-reperfusion and immunologic injuries is a potent predictor of graft loss. Short-term reduction in proteinuria is associated with improved long-term graft survival.     

Panhypopituitarism as first manifestation of a lung cancer

Pituitary metastases of solid tumours are infrequent, specially as a first manifestation. When they happen, they are usually due to breast or lung cancer and are asymptomatic or produce diabetes insipidus. It is very strange that they produce hormonal deficiency. We present a case report of a bronchogenic adenocarcinoma in a 65-year-old man which began with panhypopituitarism, diabetes insipidus and visual alterations. Magnetic resonance imaging revealed a large sellar mass, with clivus infiltration and invading the right cavernous sinus. The biopsy result was adenocarcinoma metastases from lung cancer.