Framing K-12 partnerships in order to make a difference.

The Health Professions Partnership Initiative (HPPI) furthered the establishment of partnerships between academic health centers and K-12 school systems. The present article contends that partnerships in efforts such as the HPPI exist in varying degrees of depth with deeper partnerships being those based in a concept of mutuality even as partners continue to maintain institutional identity. In the context of K-12 schools, the article reinforces the view that K-12 students, teachers, and administrators can benefit through partnership contexts, but also suggests that institutions of higher education-including academic health centers-should enter into partnerships because they benefit when they commit as stakeholders in the outcomes, not principally as altruistic good neighbors to the schools.

Role of the dorsomedial nucleus of the thalamus in Alzheimer's disease.

It is not known whether changes in the thalamus play a role in the memory loss or dementia of Alzheimer's disease (AD), although trauma, infarction, and hemorrhage to the thalamus, particularly the dorsomedial nucleus (DMN), can cause these cognitive changes. To determine the pathologic changes in the DMN in AD, we examined the DMN in 16 cases of AD and 7 age-matched controls, with quantitative assessments of the total neuronal population and synaptic density, Alz-50-positive neurons, neurofibrillary tangles (NFT), and senile plaques (SP). We examined sections after staining with cresyl violet, a silver stain, and immunocytochemical staining for Alz-50 and synapsin I.

Dynamics of synapsin I gene expression during the establishment and restoration of functional synapses in the rat hippocampus.

Synapse development and injury-induced reorganization have been extensively characterized morphologically, yet relatively little is known about the underlying molecular and biochemical events. To examine molecular mechanisms of synaptic development and rearrangement, we looked at the developmental pattern of expression of the neuron-specific gene synapsin I in granule cell neurons of the dentate gyrus and their accompanying mossy fibers during the main period of synaptogenic differentiation in the rat hippocampus. We found a significant difference between the temporal expression of synapsin I messenger RNA in dentate granule somata and the appearance of protein in their mossy fiber terminals during the postnatal development of these neurons.

Vascular amyloid deposition in Alzheimer's disease. Neither necessary nor sufficient for the local formation of plaques or tangles.

Objective: To determine the relationship between vascular beta-amyloid (beta A4) and senile plaques (SPs) and neurofibrillary tangles (NFTs).

Design: We counted vascular amyloid deposition with SP and NFT density in the medial temporal lobe (CA1 plus the subiculum) and the cerebellum.

Patients: The brains of seven patients with Alzheimer's disease and of three age-matched nondemented control subjects were studied.

Widespread activation of calcium-activated neutral proteinase (calpain) in the brain in Alzheimer disease: a potential molecular basis for neuronal degeneration.

Calcium-activated neutral proteinases (CANPs or calpains) are believed to be key enzymes in intracellular signaling cascades and potential mediators of calcium-induced neuronal degeneration. To investigate their involvement in Alzheimer disease, we identified three isoforms of muCANP (calpain I) in human postmortem brain corresponding to an 80-kDa precursor and two autolytically activated isoforms (78 and 76 kDa). As an index of changes in the in vivo activity of muCANP in Alzheimer disease, the ratio of the 76-kDa activated isoform of muCANP to its 80-kDa precursor was measured by immunoassay in selected brain regions from 22 individuals with Alzheimer disease and 18 normal controls.

Synapsin I gene expression in the adult rat brain with comparative analysis of mRNA and protein in the hippocampus.

Synapsin I is the best characterized member of a family of neuron-specific phosphoproteins thought to be involved in the regulation of neurotransmitter release. In this report, we present the first extensive in situ hybridization study detailing the regional and cellular distribution of synapsin I mRNA in the adult rat brain. Both the regional distribution and relative levels of synapsin I mRNA established by in situ hybridization were confirmed by RNA blot analysis.

Alzheimer's disease and aging: effects on perforant pathway perikarya and synapses.

The hippocampal perforant pathway originates in the entorhinal cortex (ERC) and terminates in the outer molecular layer of the dentate gyrus (DG). To compare the effects of normal aging and Alzheimer's disease (AD) on the elements of the perforant pathway, we compared relative perikaryal numbers (determined by counting cell bodies and estimating volumes) in layer II of the ERC with synaptic quantities (estimated from immunoreactivity for the synaptic terminal protein synapsin I and DG volume) in the molecular layer of the DG. The brains of 5 young and 9 elderly cognitively normal individuals, and of 9 AD patients were studied.

Expression of heat shock proteins in Alzheimer's disease.

In an investigation of heat shock proteins (HSPs) in the brains of Alzheimer's disease (AD) patients and cognitively intact control subjects, we found that 2 HSPs, termed "HSP72" and "GRP78," underwent major changes in expression in AD. HSP72, which was present at very low levels in control brains, increased dramatically in AD patients, and was localized exclusively in neuritic plaques and neurofibrillary tangles. We hypothesize that HSP72 is induced as an early response to the formation of abnormal proteins, perhaps targeting them for proteolysis.

Synaptic circuitry identified by intracellular labeling with horseradish peroxidase.

During the past two decades new techniques have been developed to directly test the dogma that neuronal structure is correlated with neuronal function. In the earliest experiments, Procion yellow was injected into neurons after they had been characterized physiologically; these neurons were then viewed through the light microscope. Recent advances in the method generally employ horseradish peroxidase as the dye which is injected since it diffuses quite readily throughout the injected neuron and produces a stable reaction product for both light and electron microscopic studies.

Synaptic loss in Alzheimer's disease and other dementias.

The extent and location of neuronal losses necessary or sufficient to produce dementia in patients with Alzheimer's Disease (AD) is unknown. To approach this question, we studied synaptic terminals in postmortem brain tissue utilizing immunohistochemical techniques. We used antibodies against two proteins found in synaptic terminals--synapsin I and synaptophysin--as synaptic markers in the hippocampal complexes of eight patients with autopsy-proven AD and eight nondemented control subjects.

Synaptic circuitry of physiologically identified W-cells in the cat's dorsal lateral geniculate nucleus.

The cat's retinogeniculocortical system is comprised of at least 3 parallel pathways, the W-, X-, and Y-cell pathways. Prior studies, particularly at the level of the lateral geniculate nucleus, have focused on X- and Y-cells. In the present study, we describe the synaptic inputs for 2 geniculate W-cells from the parvocellular C-laminae after these neurons were physiologically identified and intracellularly labeled with HRP.

Characterization and kinetic studies of deglycosylated dopamine beta-hydroxylase.

Dopamine beta-hydroxylase (D beta H) (EC 1.14.17.

Synaptic circuits involving an individual retinogeniculate axon in the cat.

In order to describe the circuitry of a single retinal X-cell axon in the lateral geniculate nucleus, we physiologically characterized such an axon in the optic tract and injected it intra-axonally with horseradish peroxidase. Subsequently, we recovered the axon and employed electron microscopic techniques to examine the distribution of synapses from 18% of its labeled terminals by reconstructing the unlabeled postsynaptic neurons through a series of 1,200 consecutive thin sections. We found remarkable selectivity for the axon's output, since only four of the 43 available neurons in a limited portion of the terminal arbor receive synapses from labeled terminals.

Passive cable properties and morphological correlates of neurones in the lateral geniculate nucleus of the cat.

1. We used an in vivo preparation of the cat to study the passive cable properties of sixteen X and twelve Y cells in the lateral geniculate nucleus. Cells were modelled as equivalent cylinders according to Rall's formulations (Rall, 1959a, 1969, 1977).

Synaptic connectivity of a local circuit neurone in lateral geniculate nucleus of the cat.

Although receptive fields of relay cells in the lateral geniculate nucleus of the cat nearly match those of their retinal afferents, only 10-20% of the synapses on these cells derive from the retina and are excitatory. Many more (30-40%) are inhibitory and largely control the gating of retinogeniculate transmission. These inhibitory synapses derive chiefly from two cell types: intrinsic local circuit neurones and cells in the adjacent perigeniculate nucleus.

Four types of neuron in layer IVab of cat cortical area 17 accumulate 3H-GABA.

Roughly 10% of the neurons in layer IVab of cat area 17 accumulate exogenous 3H-gamma-aminobutyric acid (GABA) but how many types of neuron comprise this population was unknown. We characterized these neurons by partial reconstruction of their somas from serial electron microscope autoradiograms and distinguished four types. GABA 1 was large (greater than 16.

The synaptic organization of the motor nucleus of the trigeminal nerve in the opossum.

The motor nucleus of the opossum trigeminal nerve consists of a main body and a small dorsomedial cell cluster. The cell bodies form a unimodal population with areas that range from 150-2700 mum2. Golgi impregnations reveal that each neuron has three to six primary dendrites which radiate in all planes from the cell body.

The synaptic terminations of certain midbrain-olivary fibers in the opossum.

The nuclear origin and distribution of midbrain-olivary fibers has been described in a previous study utilizing axonal transport techniques (Linauts and Martin, '78a). The present report extends their results to the electron microscopic level and details the postsynaptic distribution of such fibers. Lesions within the ventral periaqueductal grey and adjacent tegmentum, the red nucleus or the nucleus subparafascicularis result in electron dense axon terminals within the olive at survival times of 48, 72 and 96 hours.

Influence of external potassium on the synthesis and deposition of matrix components by chondrocytes in vitro.

The effect of a high external potassium concentration on the synthesis and deposition of matrix components by chondrocytes in cell culture was determined. There is a twofold increase in the amount of chondroitin 4- and 6-sulfate accumulated by chondrocytes grown in medium containing a high potassium concentration. There is also a comparable increase in the production of other sulfated glycosaminoglycans (GAG) including heparan sulfate and uncharacterized glycoprotein components.