We held an international consensus conference on frontotemporal dementia, behavioral disturbances, and parkinsonism linked to chromosome 17 to determine whether these are homogeneous or heterogeneous disorders, to agree on terminology, and to develop strategies for further research. The group identified 13 kindreds with sufficient evidence for linkage, finding in common to all a critical 2 cM between markers D17S791 and D17S800. There was agreement that (1) despite previous descriptions that have emphasized one or another clinical or neuropathological feature, the kindreds share clinical and neuropathological features; (2) until more specific information about the genetic defects becomes available, this disorder is best termed frontotemporal dementia and parkinsonism linked to chromosome 17; and (3) further research will be enhanced by identifying the gene or genes responsible for this disorder, detecting additional cases within known families and, in new families, correlating mutations with phenotypes and more fully delineating the clinical, neuropsychological, and neuropathological characteristics of this disorder.

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This paper discusses the impact of tissue dehydration on the dielectric properties of excised tissue samples. The effect of dehydration on the tissue surface has been characterized as a function of time after excision on freshly excised mouse liver. The dielectric properties of liver were measured over the frequency range of 500 MHz-20 GHz using an open-ended coaxial probe. Tissue samples were obtained from 7 athymic BALB/c Nude mice, and measurements were performed over the first 3.5 h post-excision at the tissue surface and in the middle of the sample (accessed via a small incision). The samples were kept in sealed containers between measurements to avoid excessive dehydration. The measured dielectric data show a change of more than 25% in both the real and imaginary parts of complex permittivity over 3.5 h after excision. Results indicate the impact of tissue dehydration on the dielectric properties, and signify the importance of considering controls in the experimental design of ex vivo dielectric measurements.

This is a review of clinical, cardiologic, electrophysiologic, pathologic, and serum creatine kinase changes in eight families with slowly progressive X-linked Becker-type muscular dystrophy. All but one of the patients were able to walk until the age of 16 years, and most lived beyond 20. In every family, electromyography and muscle biopsy showed features which, on the basis of classical criteria, were interpreted as those of both myopathy and denervation, although among patients and among families, one or the other of these processes predominated. The most frequent biopsy picture was of fiber atrophy and hypertrophy, with many split and angulated fibers, and clumps of pyknotic nuclei. Necrosis, phagocytosis, regeneration, endomysial fibrosis, and some fatty infiltration were commonly seen. Review of a family originally described by Becker showed a similar biopsy picture. These pathologic changes are separable from those of Duchenne muscular dystrophy, but they often overlap with those seen in other chronic neuromuscular diseases.

To evaluate whether in vivo accumulations of heparan sulfate caused by inborn errors in the metabolism of glycosaminoglycans lead to the formation of neurofibrillary tangles and/or senile plaques, as seen in Alzheimer disease (AD), we studied postmortem brains from 9 patients, ages 1 to 42 years, with mucopolysaccharidosis (MPS). The brains of patients with Hurler's syndrome (MPS I: n = 5) and Sanfilippo's syndrome (MPS III; n = 4) as well as from caprine MPS IIID and murine MPS VII models were evaluated by thioflavine-S staining and by immunohistochemistry using antibodies directed against heparan sulfate proteoglycans, hyperphosphorylated tau, amyloid-beta peptide precursor proteins (APP), and amyloid-beta peptides (A beta [1-40], and A beta [1-42]). A two-site sandwich enzyme-linked immunosorbent assay (ELISA) was also utilized to compare levels of total soluble and insoluble A beta (1-40) and A beta (1-42) obtained from temporal cortex of MPS patients. Although no neurofibrillary tangles, senile plaques, or tau-positive lesions were detected in any of the MPS brains studied here, antibodies directed against A beta (1-40) intensely and diffusely stained the cytoplasm of cells throughout the brains of the MPS patients and the caprine MPS model. The ELISA assay also demonstrated a significant 3-fold increase in the level of soluble A beta (1-40) in the MPS brains compared with normal control brains. Thus, at least some of the metabolic defects that lead to accumulations of glycosaminoglycans in MPS also are associated with an increase in immunoreactive A beta (1-40) within the cytoplasmic compartment where they could contribute to the dysfunction and death of affected cells in these disorders, but not induce the formation of plaques and tangles. Models of MPS may enable mechanistic studies of the role A beta and glycosaminoglycans play in the amyloidosis that is a neuropathological feature of AD.