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Despite the emergence of a number of new classification systems, the diagnosis of cerebrovascular dementia remains controversial. Also controversial is the significance of periventricular and deep white matter alterations (WMA) as seen on magnetic resonance imaging (MRI). To further clarify this issue, MRI scans were used to regroup patients clinically diagnosed with Alzheimer's disease (AD) or subcortical ischemic vascular dementia (IVD) into cohorts presenting with either little versus significant WMA on MRI. These two groups were then compared to demented patients diagnosed with idiopathic Parkinson's disease (PD) using a comprehensive neuropsychological protocol. Neuropsychological assessment failed to distinguish between patients with PD and significant WMA. By contrast, both of these patient groups exhibited disproportionate impairment on tests of executive systems functioning, whereas patients with little WMA showed greater impairment on tests of declarative memory and semantic knowledge. These findings constitute further evidence that the pattern of cognitive impairment associated with significant WMA is distinctly different when compared to AD. These results are discussed within the context of a growing body of literature suggesting that elements of the underlying neuropathologies in AD and IVD are linked. Implications for the diagnosis of dementia are also discussed.

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This research investigated whether subjects with Alzheimer's disease (AD) and ischaemic vascular dementia (IVD) associated with periventricular and deep white matter alterations can be dissociated on tests of declarative and procedural memory, as well as on MRI indices of white matter alterations and the size of the hippocampal formation. The California Verbal Learning Test (CVLT) and the Pursuit Rotor Learning Tests (PRLT) were used to measure declarative and procedural memory, respectively. Subjects with IVD obtained a higher score on the CVLT recognition discriminability index; however, on the PRLT total time on target, carry-over between trial blocks, and slope calculated for all test trials was low. Subjects with AD exhibited the opposite profile. MRI studies indicated that subjects with IVD had considerably greater white matter alterations, but larger hippocampal formations than subjects with AD. Higher scores on the CVLT recognition discriminability index were correlated with increased size of the body of the hippocampus and parahippocampal gyrus. By contrast, as the severity of white matter alterations increased the slope on the PRLT declined. In sum, subjects with AD and IVD can be dissociated on the basis of differing patterns of impairment on tests of declarative and procedural memory, and MRI indices of white matter alteration and the integrity of the hippocampal formation.

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This research examined the neuropsychological functioning of demented patients with periventricular and deep white matter alterations. Thirty-three outpatients with NINCDS-ADRDA probable Alzheimer's disease (AD) and 27 outpatients with probable/ possible ischaemic vascular dementia (IVD, Chui et al., 1992) associated with periventricular and deep white matter alterations matched for age, education, level of dementia, and functional disability were studied. White matter alterations were measured using a 40-point scale previously described by Junque et al. (1990). Subjects with cortical CVAs were excluded. On executive control tests, IVD subjects made more preservations on tests of mental control and response set, and produced fewer responses on phonemic controlled oral word association tests (letters: F,A,S). IVD subjects also made more preservations and graphomotor errors on clock drawings. On the California Verbal Learning Test the IVD group performed better than AD subjects on the short delay free recall test condition, the recognition discriminability index, and made fewer intrusion errors on both free and cued recall conditions. We conclude that neuropsychological assessment can differentiate AD from IVD associated with white matter alterations, and that the neuropsychological profile of demented subjects with significant periventricular and deep white matter alterations is similar to other subcortical dementing illnesses.

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Human sebocytes obtained as explants after in vitro culture of isolated sebaceous glands were recently shown to maintain in part a sebocytic differentiation. The aim of this study was to further identify markers of sebocytic differentiation in vitro. Therefore, the morphology of cultured human sebocytes, and their differentiation with lipid storing and expression of cellular proteins were investigated by microscopy, electron microscopy, study of cell kinetics, cytochemistry and immunocytochemistry, and were compared to cultured human keratinocytes obtained from the same skin specimens. At first, sebocytes in all stages of sebocytic differentiation were detected in vitro. Abundant cytoplasmic lipids and the absence of desmosomes were identified as their ultrastructural characteristics. Secondly, an increasing number of sebocytes storing lipids was detected during cell proliferation. Sebocytes contained up to 4 times more lipids than keratinocytes in vitro. Squalene and increased quantities of wax/sterol esters could be extracted from secondary sebocyte cultures. Thirdly, the monoclonal antibodies 6B10 (keratin 4), RPN1162 (keratin 7), and OM-1 labeled only sebocytes in vitro. Furthermore, sebocytes presented a marked expression of keratin 19 in comparison to keratinocytes, as detected with CK 4.62, and a lack of RPN1161 (keratins 1 and 2) expression, which was typically found to be expressed in cultured keratinocytes. The culture of human sebocytes possessing several characteristics of sebocytic differentiation in vivo offers unique possibilities in investigating direct effects on sebaceous cell growth, differentiation and their regulation.

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We studied the relative frequency of cavum septum pellucidum (CSP) by CT. Six of 9 men with CSP were boxers or had head trauma. We conclude that some cases of CSP are not congenital variants, but rather may serve as an indicator of prior head trauma, especially in boxers. In such instances, CSP may be a CT sign of traumatic encephalopathy.

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Intracerebral hematomas producing chronic neurological disability are reported rarely. Two cases of chronic intracerebral hematoma are described. Each case was associated with a thick, fibrous capsule found histologically to arise from an occult vascular malformation. When such encapsulation is discovered surgically, a vascular anomaly must be suspected.

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Computerized transaxial tomography was carried out on 50 consecutive unselected patients referred to a neurologic practice for evaluation of focal epilepsy. Structural abnormalities were defined in 35.3 percent of these studies: porencephalic cysts in six patients, diffuse cerebral atrophy in five, cerebral hemiatrophy in three, focal cortical atrophy in two, neoplasms in two, hydrocephalus in one patient, and cerebeller hypoplasia in one. Computerized transaxial tomography is a useful outpatient procedure for evaluation and follow-up of patients with focal seizure disorders.

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A patient who abused multiple drugs developed a rapidly progressive mononeuropathy multiplex, which appeared to respond to corticosteroid therapy with partial resolution. Intravenous methamphetamine had been used almost exclusively from the fourth month prior to the onset of symptoms. Biopsy material revealed a necrotizing angiitis involving medium and small sized arteries, capillaries, and venules, typical of a hypersensitivity-type angiopathy, rather than the previously reported polyarteritis nodosa-type lesions secondary to illicit drugs. The apparent response to corticosteroids suggests that these agents might be useful in the treatment of some complications of drug abuse.

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