The etiology for the progressive organ injury in hypertension is largely speculative. Recent studies have shown that leukocytes play a key role in several cardiovascular diseases. As an initial step toward investigating the role of leukocytes in hypertension, we measured leukocyte counts and spontaneous activation of granulocytes of freshly drawn unseparated blood samples in spontaneously hypertensive rats and in their normotensive counterpart, Wistar-Kyoto rats. The animals were derived from one breeder in the United States and from two breeders in Europe. Total leukocyte counts in young, mature, and old hypertensive rats were 50-100% above the controls. The number of granulocytes in mature and old spontaneously hypertensive rats is more than 100% elevated compared with control rats. In young hypertensive rats the mean granulocyte count was only slightly elevated. The number of spontaneously activated granulocytes, as detected by the nitroblue tetrazolium reduction, increases with age in both species; in mature spontaneously hypertensive rats, it is more than 300% above the values in the controls. Furthermore, in mature hypertensive rats the number of monocytes, activated monocytes, and the lymphocyte count are also significantly elevated over the values in the normotensive controls. It is proposed that these elevated leukocyte counts may constitute an enhanced risk for organ injury in the spontaneously hypertensive rat (Hypertension 1991;17:323-330)

BackgroundRetinal imaging may serve as an alternative approach to monitor brain pathology in Alzheimer’s disease (AD). In this study, we investigated the association between retinal vascular and structural changes and cerebral amyloid-β (Aβ) plaque load in an elderly cohort.MethodsWe studied a total of 101 participants, including 73 elderly subjects (79 ± 5 years, 22 male) with no clinical diagnosis of AD but reporting some subjective memory change and an additional 28 subjects (70 ± 9 years, 16 male) with clinically established AD. Following a complete dilated ocular examination, the amplitude of retinal vascular pulsations and dynamic response, retinal nerve fibre layer thickness and retinal ganglion cell layer (RGCL) thickness were determined in all patients. Systemic blood pressure and carotid-to-femoral pulse wave velocity were measured. The elderly cohort also underwent magnetic resonance imaging and 18F-florbetaben (FBB)-positron emission tomographic amyloid imaging to measure neocortical Aβ standardised uptake value ratio (SUVR), and this was used to characterise a ‘preclinical’ group (SUVR >1.4).ResultsThe mean FBB neocortical SUVR was 1.35 ± 0.3. The amplitude of retinal venous pulsations correlated negatively with the neocortical Aβ scores (p < 0.001), whereas the amplitude of retinal arterial pulsations correlated positively with neocortical Aβ scores (p < 0.01). RGCL thickness was significantly lower in the clinical AD group (p < 0.05).ConclusionsThe correlation between retinal vascular changes and Aβ plaque load supports the possibility of a vascular component to AD. Dynamic retinal vascular parameters may provide an additional inexpensive tool to aid in the preclinical assessment of AD.

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Accurate localization of the prostate and its surrounding tissue is essential in the treatment of prostate cancer. This paper presents a novel approach to fully automatically segment the prostate, including its seminal vesicles, within a few minutes of a magnetic resonance (MR) scan acquired without an endorectal coil. Such MR images are important in external beam radiation therapy, where using an endorectal coil is highly undesirable. The segmentation is obtained using a deformable model that is trained on-the-fly so that it is specific to the patient's scan. This case specific deformable model consists of a patient specific initialized triangulated surface and image feature model that are trained during its initialization. The image feature model is used to deform the initialized surface by template matching image features (via normalized cross-correlation) to the features of the scan. The resulting deformations are regularized over the surface via well established simple surface smoothing algorithms, which is then made anatomically valid via an optimized shape model. Mean and median Dice's similarity coefficients (DSCs) of 0.85 and 0.87 were achieved when segmenting 3T MR clinical scans of 50 patients. The median DSC result was equal to the inter-rater DSC and had a mean absolute surface error of 1.85 mm. The approach is showed to perform well near the apex and seminal vesicles of the prostate.