Atypical clinical features associated with mixed pathology in a case of non-fluent variant primary progressive aphasia

A 66-year-old woman presented with agrammatism and apraxia of speech, meeting criteria for non-fluent/agrammatic variant primary progressive aphasia (nfvPPA). However, three years later, she developed frontal/executive, short-term phonological memory, visuospatial, and visual memory deficits suggesting involvement of multiple brain networks. Multimodal neuroimaging showed damage of both fronto-striatal and posterior brain regions. She was found to have multiple pathological processes: corticobasal degeneration (CBD), Alzheimer's disease (AD), and TAR DNA-binding protein (TDP)-43 type A. We hypothesize that cognitive and neuroimaging findings consistent with damage to multiple brain networks, each associated with vulnerability to certain molecular disease subtypes, could indicate mixed pathology.

Responses of Cultured Astrocytes, C6 Glioma and 1321NI Astrocytoma Cells to Amyloid beta-Peptide Fragments

The effect of amyloid beta-peptide (betaAP), which can have both neurotrophic or neurotoxic effects on neurons and has been implicated in the pathogenesis of Alzheimer's disease (AD), was studied on astrocytes using primary cultures and astrocyte cell lines (rat C6 glioma, human 1321NI astrocytoma cells). The cultures were exposed to 0.0005-50 mug/ml) betaAP fragments 1-40, 25-35, 31-35, or 40-41 (control) for 24 hr. Some of the fragments were maintained at 37 degrees C for 48 hr to induce aggregation and some of the cell cultures were pretreated with the differentiating agent dBcAMP before the experiments. The astrocyte responses were evaluated for lysosome activity (neutral red assay) and levels of structural proteins, glial fibrillary acidic protein, vimentin, and S-100, which are altered in the dystrophic plaques with associated astrogliosis in AD. The cells frequently responded with biphasic responses, with initial (low-dose) activation-type responses (i.e., increases of indicator compared to controls), before reductions with altered morphology (increased branching of cells) at higher concentrations. However, cell death (with EC(50) values) was not observed, even at the maximum concentrations of betaAP fragments. The findings suggest that the astrocytes have a relatively high resistance against the betaAP toxicity.

The use of inert carriers in regulatory biodegradation tests of low density poorly water-soluble substances

Many poorly water-soluble compounds fail regulatory ready biodegradation tests as the method of test material preparation limits the bioavailability of the chemical. The recognised method for delivery of poorly soluble materials into biodegradability tests consists of coating test material inside the test vessel or onto inert substrates (i.e., glass cover slide, boiling beads, filter paper, or Teflon stir bar) that are placed inside the vessels. Volatile solvents are often used to augment this process. Although these substrates work fairly well for delivering many poorly soluble materials into biodegradability tests, they have not been effective in keeping low density, poorly water-soluble substances in the test medium. Soon after medium is added to the test vessels, these chemicals break loose from the substrates and float on the surface where they have limited contact with micro-organisms in the test medium. Hence, there is a reduced potential for measuring substantial biodegradability in the test. This paper describes the work undertaken to establish a standard method of adding low density, poorly water-soluble substances into test vessels of biodegradability studies to ensure these materials remain in contact with micro-organisms in the test medium. The substances are prepared for testing by adsorption onto silica gel followed by dispersion into the culture medium. This method of delivery may provide greater intra- and inter-laboratory consistency in biodegradability test results for low density, poorly water-soluble substances and it may more closely mimic the probable transport and fate of these substances in the environment.

The nursing terminology summit: collaboration for progress

The Nursing Terminology Summit has used collaborative processes to bring about significant changes in the development of terminology standards for nursing. This paper draws on agendas, reports, notes, and other documents from the Summit, in addition to the authors' own experience as Organizer, Steering Committee, and participants, to provide a brief history of the Summit process. The analysis identifies factors that increased the risk of failure as well as factors that fostered success. The paper concludes with lessons learned that can be applied in other arenas to promote change in medical informatics.

Wavelength-programmed solute release from photosensitive liposomes

Liposomes of dipalmitoylphosphatidylcholine containing a photochromic lipid "Bis-Azo PC" release entrapped solutes on exposure to UV light. We have now demonstrated that on addition of cholesterol (up to 25 mol%) to the liposomal membrane the liposomes also release their contents in response to visible light in the region of 470 nm, to which liposomes lacking steroid are insensitive. In a mixed population of liposomes prepared with and without cholesterol, this enables wavelength-dependent release of entrapped solutes on sequential exposure to visible and UV light. Furthermore, the cholesterol-containing liposomes allow stepped partial release of entrapped solute following multiple periods of short visible illumination. It is suggested that the cholesterol-containing liposomes may be potentially useful for drug delivery and for "caging" of reagents.

Active uptake of drugs into photosensitive liposomes and rapid release on UV photolysis

Liposomes containing high concentrations of the anticancer drug doxorubicin, prepared by active-loading techniques, have been intensively investigated as potential agents for chemotherapy. The present study investigates the possibility of active uptake and photoinduced release of such solutes from liposomes incorporating a photoisomerizable lipid. The active loading of acridine orange and doxorubicin was investigated using liposomes containing entrapped ammonium sulfate. The liposomes were prepared with dipalmitoyl-L-alpha-phosphatidyl choline (DPPC) and a photochromic lipid, (1,2-(4'-n-butylphenyl)azo-4'-(gamma-phenylbutyroyl))-glycero-3- phosphocholine (Bis-Azo PC), which isomerizes on exposure to near-UV light with resulting changes in membrane permeability to solutes. The rate of loading of the vesicles below the phase transition temperature of DPPC was investigated as a function of Bis-Azo PC and cholesterol concentrations in the liposome. The rate of doxorubicin uptake was found to be greatly decreased in the presence of cholesterol, while below 30 degrees C the rate of acridine orange uptake was increased in the presence of cholesterol. On exposure to a single UV laser pulse, actively loaded acridine orange was rapidly released from liposomes containing Bis-Azo PC at a rate similar to that found for the indicator dye calcein. However while cholesterol had previously been shown to greatly enhance the rate of photo-induced calcein leakage, it had no significant effect on the rate of acridine orange release. After active loading into DPPC vesicles containing Bis-Azo PC, doxorubicin was also released after exposure to a single laser pulse, but at a rate slower than for acridine orange and calcein. The difference in behavior between these systems is ascribed to the interactions of acridine orange and doxorubicin with the liposome bilayer. Photoinduced release of pharmacologically active materials from sensitized liposomes might provide a useful adjunct or alternative to conventional photodynamic therapy.

Lymphocyte populations and adhesion molecule expression in bovine tonsils

Bovine tonsils are mucosal-associated lymphoid tissue (MALT) located at the entry of the pharynx where both inhaled and ingested antigens can induce an immune response. This study was conducted to determine the lymphocyte populations and adhesion molecule expression in the palatine tonsil (PT) and pharyngeal tonsil (PhT) of adult cattle and compare them with typical MALT (discrete Peyer's patches, PP) and a peripheral lymph node (parotid lymph node, PLN). The distribution of various lymphocyte subsets was determined in situ by immunofluorescence, and their proportions were determined by multicolor flow cytometry. The tonsils were similar to PP in the proportions of B- and T-cells (25-32% T-cells, 39-45% B-cells), and T cell subpopulations (CD4, CD8, and gammadelta). The PP contained the highest proportion of memory T-helper cells with beta7 integrin (30.3%+/-5.4), the tonsils intermediate (PT: 19.8%+/-4.4 and PhT: 19.7%+/-4.9), and the PLN had the lowest proportion (15.4%+/-3.1). The opposite relationship was observed with CD62L on naïve T- helper cells as PP had the lowest proportion (14.2%+/-6.4), the tonsils intermediate (PT: 17.4%+/-2.5 and PhT: 24.3%+/-7.3), and the PLN the highest proportion (45.3%+/-6.5). MAdCAM-1 was highly expressed in the high endothelial venules (HEV) of PP, with variable and weak expression in the tonsils and PLN. PNAd, on the other hand, was highly expressed in HEV of tonsils and PLN, and weakly expressed in the PP. These results indicate that the bovine tonsils share characteristics with both PP and PLN. The alpha4beta7/MadCAM-land CD62L/PNAd interaction may be involved in lymphocyte migration to the tonsils, but it is likely that other adhesion molecules participate as well. Similarities between the human and bovine tonsils suggest that cattle may provide a good model to study the role of the tonsil in the respiratory immune response.

Photosensitive liposomes as 'cages' for laser-triggered solute delivery: the effect of bilayer cholesterol on kinetics of solute release

Liposomes containing acyl chains incorporating azobenzene chromophores have been investigated as potential 'caging' agents for fast solute release. On photolysis, trapped marker dye can be released from gel-phase liposomes within milliseconds. Solute release is markedly sensitive to the presence of cholesterol in the bilayer. Phospholipids bearing one saturated acyl chain and an azobenzene-substituted chain are ineffective as sensitisers unless cholesterol is present, while doubly substituted phospholipids sensitise release in its absence. Cholesterol markedly affects the temperature profile of solute release depending on the host phospholipid chain length. Solute release is not seen for lipid hosts with unsaturated acyl chains.

Fast laser-induced solute release from liposomes sensitized with photochromic lipid: effects of temperature, lipid host, and sensitizer concentration

Liposomes of gel-phase phospholipid have been prepared containing a photochromic lipid sensitizer. A fast UV laser pulse isomerizes the sensitizer destabilizing the lipid bilayer structure and causing release of trapped solute. The kinetics of solute release have been investigated as a function of host lipid chain length, sensitizer concentration, and temperature, and the limits of liposome stability have been established. At low concentrations of sensitizer, pulsed laser irradiation induces some solute release when continuous UV illumination is ineffective. Although rates of solute release usually increase with temperature, at low sensitizer concentration in a rigid host, leakage at first increases but then decreases rapidly above a threshold temperature. The results presented are relevant to the design of photostimulated drug delivery systems and to potential applications of photosensitive liposomes as caging agents for biological effectors.

Influences of the Unified Service Action Model on the HL7 Reference Information Model

Modeling information for the electronic medical record (EMR) builds on a century of study on information and its relationship to cost and quality improvement. An initiative to examine the focus of cost and quality improvement and its relationship to information modeling resulted in the development of the Unified Service Action Model of healthcare processes, which focuses on the action as the center of cost accounting, quality accounting and privacy management. The application of this model to the HL7 Reference Information Model produced a simplification of the HL7 model at the cost of increased reliance on vocabulary terms for actions.

Evaluation of toxicity indicators in rat primary astrocytes, C6 glioma and human 1321N1 astrocytoma cells: can gliotoxicity be distinguished from cytotoxicity?

A comparison was made of rat primary astrocytes, C6 glioma cells pre-treated with dibutyryl cyclic AMP, and the human astrocyte 132N1 cell line using a range of 40 compounds and the neutral red (NR) assay. The 40 chemicals included substances known to be toxic to astrocytes or neurons, to be generally cytotoxic or not thought to be toxic to nervous tissue. For those compounds which were toxic, changes in glial fibrillary acidic protein (GFAP) levels were measured in the primary and C6 cultures, and changes in vimentin and S-100 measured in the C6 cells. The number of compounds with EC50 values < 2000 microg/ml for the NR assay for the different cell cultures were as follows: primary astrocytes, 19; C6 cells, 15; and 1321N1 cells, 11. The log of the EC50 values for the NR assay for the test compounds between the three cell types was not significantly different at the 5% level by paired Student's t-test. For the toxic substances the correlation coefficients of the EC50 values between primary cells and the C6 or 1321N1 cells were r > 0.5, and between the C6 and 1321N1 cells r > 0.9. For GFAP there was a similar degree of correlation in EC50 values between the different cell types. The GFAP, vimentin and S-100 levels showed similar EC50 values for the toxicants, but were not as sensitive as the NR assay. The toxic substances caused altered morphology in the primary, C6 and 1321N1 cells, with increased branching of cell processes. The combined astrocyte systems identified 8 out of 9 substances reported to be toxic to astrocytes in vivo, together with substances which have general cytotoxic properties. A number of substances (including the 1 out of 9 reported gliotoxic substances), which may primarily affect neurons, which may affect nervous tissue after long-term exposure, or which are not thought to be toxic to nervous tissue, were not detected. The astrocyte systems positively identify gliotoxic and cytotoxic substances and will allow detailed mechanistic studies to be made on the different underlying mechanisms.

n-pentyl N-acetylprolinate. A new skin penetration enhancer

The activity of n-pentyl N-acetylprolinate (PNAP) as a transdermal penetration enhancer was investigated. PNAP was synthesized from L-proline by acetylation with acetic anhydride, followed by acid-catalyzed esterification with 1-pentanol. Structure confirmation was accomplished by IR and NMR spectroscopy and elemental analysis. Benzoic acid (BA) was used as a model drug, and the effect of PNAP on the flux of BA through human cadaver skin was evaluated. The central nervous system (CNS) toxicity of PNAP was evaluated by comparing the effects of intraperitoneal administration of PNAP to mice with those of laurocapram (Azone), a known penetration enhancer. Based on preliminary studies, PNAP appears to be an effective transdermal penetration enhancer, is nontoxic at low doses, and exhibits dose-related CNS toxicity at higher doses.

An outbreak of measles in a highly immunised population: immunisation status and vaccine efficacy

An outbreak of 18 cases of measles in a primary school in the Australian Capital Territory in August and September 1993 provided the opportunity to study measles immunisation status and measles vaccine efficacy. Parents of 384 (78 per cent) of 491 children answered a questionnaire on recent illness consistent with measles and measles immunisation. Parents transcribed details of measles immunisation from the personal health record of the child to the questionnaire. Thirty-three per cent of cases and 3.4 per cent of the other children had not been immunised. Overall, 95 per cent of children had been immunised. The efficacy for all measles vaccines was estimated to be 90 per cent (95 per cent confidence interval (CI) 75 to 96) and for measles-mumps vaccine 87 per cent (CI 70 to 95). All of the immunised cases had received measles-mumps vaccine. There was no increased risk of measles infection in those who had been immunised at under 15 months of age compared with those immunised at 15 months or older, or in those who could not provide a date of immunisation compared with those who could. None of the children who had received two doses of vaccine caught measles. The date of immunisation was provided by 65 per cent of the respondents who said their children had been immunised. Asking parents to provide this date instead of viewing the health record is a less expensive way of assessing immunisation status but this method needs to be evaluated. Measles outbreaks still occur in highly immunised populations when vaccine efficacy appears to be acceptable.

Silicon modeling of pitch perception

We have designed and tested an integrated circuit that models human pitch perception. The chip receives as input a time-varying voltage corresponding to sound pressure at the ear and produces as output a map of perceived pitch. The chip is a physiological model; subcircuits on the chip correspond to known and proposed structures in the auditory system. Chip output approximates human performance in response to a variety of classical pitch-perception stimuli. The 125,000-transistor chip computes all outputs in real time by using analog continuous-time processing.

Cholesterol granuloma of the petrous apex. Case report

✓ The authors report a cholesterol granuloma that originated from the sphenoid sinus, eroded through the petrous apex, and presented as a tumor of the cerebellopontine angle. The differences between these rare tumors and cholesteatomas are discussed.