Contact line deposits in an evaporating drop

Solids dispersed in a drying drop will migrate to the edge of the drop and form a solid ring. This phenomenon produces ringlike stains and occurs for a wide range of surfaces, solvents, and solutes. Here we show that the migration is caused by an outward flow within the drop that is driven by the loss of solvent by evaporation and geometrical constraint that the drop maintain an equilibrium droplet shape with a fixed boundary. We describe a theory that predicts the flow velocity, the rate of growth of the ring, and the distribution of solute within the drop. These predictions are compared with our experimental results.

Increased monoamine oxidase B activity in plaque-associated astrocytes of Alzheimer brains revealed by quantitative enzyme radioautography

The aetiology and pathogenesis of Alzheimer's disease are currently poorly understood, but symptomatic disease is associated with amyloid plaques, neurofibrillary tangles, neuronal loss and numerous alterations of neurotransmitter systems in the CNS. Monoamine oxidase type B is known to be increased in Alzheimer diseased brains. The distribution and abundance of catalytic sites for monoamine oxidases A and B in post mortem human brains of 11 Alzheimer disease cases and five age-matched controls were investigated by quantitative enzyme radioautography. Using tritiated monoamine oxidase inhibitors (Ro41-1049 and lazabemide)--as high affinity substrates selective for monoamine oxidases A and B, respectively--it was found that monoamine oxidase B activity increased up to three-fold exclusively in temporal, parietal and frontal cortices of Alzheimer disease cases compared with controls. This increase was restricted to discrete patches (approximately 185 microns in diameter) which occupied approximately 12% of the cortical areas examined. In other brain regions (hippocampal formation >> caudate-putamen > cerebellum), patches of [3H]lazabemide-enriched binding were less abundant. [3H]Ro41-1049 binding (i.e. monoamine oxidase A) was unchanged in all tissues of diseased versus control brains. The monoamine oxidase B-enriched patches in all cortical regions correlated, in their distribution and frequency, with glial fibrillary acidic protein-immunoreactive clusters of astrocytes. Diffuse and mature beta-amyloid-immunoreactive senile plaques as well as patches of high density binding of [3H]PK-11195--a high-affinity ligand for peripheral-type (mitochondrial) benzodiazepine binding sites in microglia/macrophages--were found throughout Alzheimer diseased cortices. The up-regulation of monoamine oxidase B in plaque-associated astrocytes in Alzheimer's disease--in analogy to its proposed role in neurodegenerative disorders such as Parkinson's disease--might, indirectly, be a potential source of cytotoxic free radicals. Lazabemide, a selective reversible monoamine oxidase B inhibitor, is currently under clinical evaluation for the treatment of Parkinson's and Alzheimer's diseases. We conclude that enzyme radioautography with [3H]lazabemide is a reliable high resolution assay for plaque-associated astroglioses in Alzheimer's disease. Its clinical diagnostic utility for positron emission tomography or single photon emission computer tomography studies is being investigated.

Longitudinal studies of schizophrenic patients

A sample of 502 schizophrenic patients, who had been admitted to the University Psychiatric Clinic between 1945 and 1959, was systematically followed up between 1967 and 1973. The same well-defined diagnostic criteria were used throughout the study. At the time of the last followup, the average duration of illness was 22.4 years. Twenty-two percent of the patients showed complete psychopathological remissions, 43% had noncharacteristic types of remission, and 35 percent suffered from characteristic schizophrenic deficiency syndromes. Psychopathological outcome in the patients studied was assessed in relationship to such factors as duration of illness, social remission, family history of schizophrenia, primary personality, educational level, social class, age at onset, and presence of precipitating factors. It is concluded that prognostic predictions are possible only when several factors with a similar influence on long-term outcome occur in combination and when factors with a contrary prognostic influence are absent. Even under these circumstances, the individual course is by no means certain. The hypothesis that presenting symptomatology can be used to differentiate between true schizophrenias and schizophreniform psychoses is not supported.

Apoptotic cell death induced by beta-amyloid 1-42 peptide is cell type dependent

beta-Amyloid peptide (A beta), a proteolytic fragment of the beta-amyloid precursor protein, is a major component of senile plaques in the brain of Alzheimer's disease patients. This neuropathological feature is accompanied by increased neuronal cell loss in the brain and there is evidence that A beta is directly neurotoxic. In the present study reduced cell viability in four different neuroblastoma cell types was observed after treatment with human A beta 1-42 for 1 day. Of the cell types tested rat PC12 and human IMR32 cells were most susceptible to A beta toxicity. Chromosomal condensation and fragmentation of nuclei were seen in PC12, NB2a, and B104 cells but not in IMR32 cells irrespective of their high sensitivity to A beta. Electrophoretic analysis of cellular DNA confirmed internucleosomal DNA fragmentation typical for apoptosis in all cell types except IMR32. These findings suggest that the form of A beta-induced cell death (necrosis or apoptosis) may depend on the cell type.

Inflammatory processes induce beta-amyloid precursor protein changes in mouse brain

In Alzheimer disease, a combination of genetic predisposition and environmental factors may contribute to changes in beta-amyloid precursor protein (APP) expression, beta-amyloid peptide deposition, and neuronal loss. Factors such as head injury or acute infection that trigger inflammatory processes may play a crucial role in development of the disease. In the present in vivo study, we showed that, in mouse brain, peripheral stimulation with lipopolysaccharide (LPS) induced a transient increase in the inflammatory cytokine mRNAs (interleukin 1 beta and interleukin 6), followed by changes in expression of APP isoforms in the cerebellum but not in the cerebral cortex. These changes consisted of a decrease in the APP-695 and an increase in the Kunitz protease inhibitor-bearing isoforms (KPI-APP). In the cerebellum of the staggerer mouse mutant, where a severe loss of Purkinje and granule cells occurs, basal mRNA levels of these interleukins were elevated and an increase in the KPI-APP/APP-695 ratio compared to wild-type mice was observed. These abnormalities were further accentuated by LPS stimulation. This study shows that acute and chronic inflammatory processes play an important role in changes in APP expression possibly associated with neurodegeneration.

Blood volume and hemoglobin mass in elite athletes of different disciplines

Although it is well known that athletes have considerably larger blood volumes than untrained individuals, there is no data available describing the blood volume variability among differently trained athletes. The first aim of the study was to determine whether athletes from different disciplines are characterized by different blood volumes and secondly to what extent the blood volume can possibly limit endurance performance within a particular discipline. We investigated 94 male elite athletes subdivided into the following 6 groups: downhill skiing (DHS), swimming (S), running (R), triathlon (TA), cycling junior (CJ) and cycling professional (CP). Two groups of untrained subjects (UT) and leisure sportsmen (LS) served as controls. Total hemoglobin (tHb) and blood volume (BV) were measured by the CO-rebreathing method. In comparison to UT (mean +/- SD: tHb 11.0 +/- 1.1 g/kg, BV 78.3 +/- 7.9 ml/kg) tHb and BV were about 35 - 40 % higher in the endurance groups R, TA, CJ, and CP (e. g. in CP: tHb 15.3 +/- 1.3 g/kg, BV 107.1 +/- 7.0 ml/kg). Within the endurance groups we found no significant differences. The anaerobic discipline DHS was characterized by very low BV (87.6 +/- 3.1 ml/kg). S had an intermediate position (BV 97.4 +/- 6.1 ml/kg), probably because of the immersion effects during training in the water. VO(2)max was significantly related to tHb and BV not only in the whole group but also in all endurance disciplines. The reasons for the different BVs are an increased adaptation to training stimuli and probably also individual predisposing genetic factors.

Molecular cloning of microtubule-associated protein 1 (MAP1A) and microtubule-associated protein 5 (MAP1B): identification of distinct genes and their differential expression in developing brain

cDNA clones encoding microtubule-associated proteins 1 (MAP1/MAP1A) and 5 (MAP5/MAP1B) were isolated and have been used to study their structural relationship as well as their regulated expression in developing rat brain. cDNA clones specific for MAP1 hybridized to a single 10-kb rat brain mRNA, and analysis of genomic DNA by Southern blotting indicated the existence of a single MAP1 gene. A second set of cDNAs specific for MAP5 hybridized to a single 11-kb mRNA in rat brain and also detected a single gene. By analysis of hybrid mouse-hamster cell lines, the MAP1 gene was located to mouse chromosome 2, designated Mtap-1, and the MAP5 gene to chromosome 13, designated Mtap-5. MAP1 and MAP5 mRNAs were expressed with different temporal patterns during rat brain development that mirrored the appearance of their protein products, suggesting that expression of these proteins is under transcriptional control. These results taken together demonstrate that although MAP1 and MAP5 have some properties that are similar, they are structurally distinct proteins whose transcription is differently regulated from separate genes.

Circadian rhythm of tryptophan, serotonin, melatonin, and pituitary hormones in schizophrenia

Circadian rhythm abnormalities have been described mostly with respect to manic-depressive illness; little information is available concerning circadian rhythms and schizophrenia or their influence on neuroleptic drugs. We showed previously that the MESOR of dopamine is higher in schizophrenic patients than in healthy subjects and that women who are drug-free schizophrenic have lower prolactin MESORs and lower amplitudes than healthy women. We now report the data of a cosinor analysis of tryptophan, serotonin, melatonin, and pituitary hormones in the blood of 34 healthy subjects, 90 drug-free schizophrenics, and 25 neuroleptic-treated schizophrenic patients. This data indicated a significant phase advance of serum tryptophan, prolactin, and melatonin concentrations, a trend toward a phase advance in serotonin. Thyroid stimulating hormone (TSH), and growth hormone concentrations, and decreases in the TSH MESORs among patients compared to healthy subjects. These results suggest that circadian changes, such as phase advances and alterations in MESOR, are not only present in depression but also in schizophrenia. Although neuroleptic treatment raised the prolactin MESOR and amplitude, it did not elicit any change in circadian rhythmicity among the other parameters.

Beta-amyloid precursor protein isoforms in various rat brain regions and during brain development

To address the question of the possible functions of different Alzheimer's disease beta-amyloid precursor protein (beta-APP) isoforms in the brain, we studied their expression at different times during postnatal rat brain development and in various regions of the adult rat brain. Polyclonal antibodies directed to two peptide antigens were used. The majority of all beta-APP forms was found to be soluble as revealed by western blot analysis. The highest level of most beta-APP forms was reached in the second postnatal week, which is the time of brain maturation and completion of synaptic connections. Strikingly high concentrations of the Kunitz protease inhibitor-containing beta-APP were present in the adult olfactory bulb, where continuous synaptogenesis occurs in the adult animal. These findings support the idea of an involvement of beta-APPs in the processes of cell differentiation and, probably, in the establishment of synaptic contacts.

Central adenosine A(2A) receptors: an overview

Recent advances in molecular biology, biochemistry, cell biology and behavioral pharmacology together with the development of more selective ligands to the various adenosine receptors have increased our understanding of the functioning of central adenosine A(2A) receptors. The A(2A) receptor is one of four adenosine receptors found in the brain. Its expression is highest in striatum, nucleus accumbens and olfactory tubercles, although it also occurs in neurons and microglia in most other brain regions. The receptor has seven transmembrane domains and couples via Gs to adenyl cyclase stimulation. Antagonistic interactions between A(2A) receptors and dopamine D(2) receptors have been described, as stimulation of the A(2A) receptor leads to a reduction in the affinity of D(2) receptors for D(2) receptor agonists. The A(2A) receptor is thought to play a role in a number of physiological responses and pathological conditions. Indeed, A(2A) receptor antagonists may be useful for the treatment of acute and chronic neurodegenerative disorders such as cerebral ischemia or Parkinson's disease. A(2A) receptor agonists may treat certain types of seizures or sleep disorders. This review discusses the characteristics, distribution, pharmacochemical properties and regulation of central A(2A) receptors, as well as A(2A) receptor-mediated behavioural responses and their potential role in various neuropsychiatric disorders.

cDNA cloning of a novel secreted isoform of the human receptor for advanced glycation end products and characterization of cells co-expressing cell-surface scavenger receptors and Swedish mutant amyloid precursor protein

The receptor for advanced glycation end products (RAGE) has been proposed as a cell surface receptor that binds amyloid-beta protein (Abeta), thereby triggering its cytotoxic effects [S.D. Yan, X. Chen, J. Fu, M. Chen, H. Zhu, A. Roher, T. Slattery, L. Zhao, M. Nagashima, J. Morser, A. Migheli, P. Nawroth, D. Stern, A.M. Schmidt, RAGE and amyloid-beta peptide neurotoxicity in Alzheimer's disease, Nature 382 (1996) 685-691.]. A cDNA library of human lung was screened for RAGE with an appropriate hybridization probe. In addition to cell surface RAGE, one clone was found which encodes a new version of RAGE, termed hRAGEsec, which lacks the 19 amino acids of the membrane-spanning region and is therefore secreted. Comparison with the genomic sequence revealed that the synthesis of the secreted isoform requires alternative splicing. The deduced protein sequence of the mature hRAGEsec consists of 321 amino acids with a predicted molecular mass of 35.66 kDa. The pattern of expression of hRAGEsec in human brain was analyzed by in situ hybridization histochemistry. The most intense expression of the gene in contrast to cell surface RAGE was detected in hippocampal CA3 pyramidal cells, dentate gyrus granule cells, cortical neurons as well as glial cells in white matter. To investigate the interaction between Abeta and RAGE and another scavenger receptor, SRA, under physiological conditions, they were co-expressed with human betaAPP(695)-SFAD in a human cell and the level of Abeta in the condition medium was assessed by immunoprecipitation and enzyme-linked immunosorbent assay (ELISA) analysis. A nearly 100% reduction of Abeta from the conditioned medium of hRAGE cells and approximately 40% reduction from the SRA-cells implied that hRAGE could be a prominent cell surface receptor interacting with Abeta.

Generation of mice with a 200-kb amyloid precursor protein gene deletion by Cre recombinase-mediated site-specific recombination in embryonic stem cells

Gene disruptions and deletions of up to 20kb have been generated by homologous recombination with appropriate targeting vectors in murine embryonic stem (ES) cells. Because we could not obtain a deletion of about 200 kb in the mouse amyloid precursor protein gene by the classical technique, we employed strategies involving the insertion of loxP sites upstream and downstream of the region to be deleted by homologous recombination and elicited excision of the loxP-flanked region by introduction of a Cre expression vector into the ES cells. In the first approach, the loxP sequences were inserted in two successive steps and after each step, ES cell clones were isolated and characterized. Deletion of the loxP-flanked sequence was accomplished by introducing the cre gene in a third step. In the second approach, ES cells containing the upstream loxP cassette were electroporated simultaneously with the downstream loxP targeting vector and the Cre expression plasmid. ES cells were obtained that gave rise to chimeric mice capable of germ-line transmission of the deleted amyloid precursor protein allele.

Early self-experienced neuropsychological deficits and subsequent schizophrenic diseases: an 8-year average follow-up prospective study

The aim of the present study was to investigate the potential predictive value of early self-experienced neuropsychological deficits for the subsequent development of schizophrenia. A total of 96 patients with DSM-III-R diagnoses of personality disorders (formerly called 'neurotic disorders') who had been examined for the presence of such subjective experiences of deficits with standardized instruments were re-examined for the possible development of schizophrenic symptoms. After an average follow-up period of about 8 years, more than 50% of the patients had developed schizophrenia according to DSM-III-R criteria. In 77% of cases the outcome 'schizophrenia vs. no schizophrenia' was correctly predicted by the earlier presence or absence of self-experienced disturbances of thought, speech, memory, perception and action. These findings suggest that certain self-experienced neuropsychological deficits are able to indicate susceptibility to psychosis.

Rat brain glyceraldehyde-3-phosphate dehydrogenase interacts with the recombinant cytoplasmic domain of Alzheimer's beta-amyloid precursor protein

Abundant senile plaques are a histological hallmark in the brain of Alzheimer's disease patients. Such plaques consist of, among many other constituents, aggregated beta A4 amyloid peptide. This peptide is derived from an amyloid precursor protein (APP) by irregular proteolytic processing and is considered to be involved in the development of Alzheimer's disease. To study possible interactions of brain proteins with beta A4 amyloid or other fragments of APP, beta A4 amyloid and beta A4 amyloid extended to the C-terminus of APP were recombinantly produced as fusion proteins termed "Amy" and "AmyC," respectively. Using Amy and AmyC affinity chromatography, a 35-kDa protein from rat brain was isolated that bound tightly to AmyC but not to Amy, thus indicating an interaction of the protein with the C-terminus of APP. This 35-kDa protein was identified as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Binding of GAPDH to AmyC but not to Amy was confirmed by gel filtration. Although AmyC slightly reduced the Vmax of GAPDH, the same reduction was observed in the presence of Amy. These findings suggest that the interaction of the cytoplasmic domain of APP with GAPDH is unlikely to influence directly the rate of glycolysis but may serve another function.

Channeling by Proximity: The Catalytic Advantages of Active Site Colocalization Using Brownian Dynamics

Nature often colocalizes successive steps in a metabolic pathway. Such organization is predicted to increase the effective concentration of pathway intermediates near their recipient active sites and to enhance catalytic efficiency. Here, the pathway of a two-step reaction is modeled using a simple spherical approximation for the enzymes and substrate particles. Brownian dynamics are used to simulate the trajectory of a substrate particle as it diffuses between the active site zones of two different enzyme spheres. The results approximate distances for the most effective reaction pathways, indicating that the most effective reaction pathway is one in which the active sites are closely aligned. However, when the active sites are too close, the ability of the substrate to react with the first enzyme was hindered, suggesting that even the most efficient orientations can be improved for a system that is allowed to rotate or change orientation to optimize the likelihood of reaction at both sites.

A long-term follow-up study of schizophrenia: psychiatric course of illness and prognosis

A systematic psychiatric follow-up study of 502 schizophrenics was carried out using the same well-defined criteria to evaluate the patients throughout the investigation. After an average course of disease of 22.4 years, 22.1% of the patients showed complete psychopathological remission, 43.2% had non-characteristic types of remission and 34.7% suffered from characteristic schizophrenic deficiency syndromes. At the time of the last follow-up investigation, 86.7% of the patients were living at home, while 13.3% were permanently hospitalized. Of the entire sample, 55.9% were found to be "socially recovered". Higher education, psychoreactive provocation, depressive traits, perception of delusions, catatonic agitation, non-characteristic thought disorders and symptoms of depersonalization at the onset of the illness tended to carry with them a favorable prognosis. On the other hand, low intelligence, abnormal primary personality, premorbid disturbances in social behavior, broken homes, prolonged prodromal stages, pneumoence-phalographically measurable atrophic or dysplastic changes in the brain ventricles as well as somatic and auditory hallucinations and predominance of hebephrenic symptoms at the onset of the illness tended to lead to an unfavorable prognosis. The principle of the basic reversibility of typical schizophrenic symptoms and the extensive irreversibility of the non-characteristic defect is important for the psychopathological and social long-term prognosis.

Plasma catecholamines in trained and untrained volunteers during graduated exercise

Ten untrained subjects and nine trained cyclists were examined during graduated ergometric exercise in the supine position. The levels of epinephrine and norepinephrine in the blood as well as the heart rate and oxygen intake were determined. At submaximum levels, epinephrine, norepinephrine, lactate, and the heart rate are lower in tthe trained than in the untrained subjects; the relative oxygen intake shows no significant difference. The ergometric work capacity is approximately 30% higher in the trained cyclists. During maximum ergometric exercise, the plasma catecholamines, lactate, and the heart rate show no differences between the two groups; the oxygen intake is approximately 30% higher in the trained than in the untrained subjects. A direct relationship exists between catecholamine levels and lactate; however, this relationship becomes less exact during higher exercise intensities: In reference to the same catecholamine concentration, the lactate levels as well as the submaximum heart rates are higher in the trained than in the untrained subjects, the cause of which could be an increased beta-adrenoceptor sensitivity in the trained subjects.

alpha-Tocopherol supplementation in racing cyclists during extreme endurance training

This study was undertaken to evaluate the effects of 5 months of alpha-tocopherol supplementation on physical performance during aerobic exercise training in 30 top-class cyclists. Antioxidative effects of supplementation were also studied. Plasma alpha-tocopherol concentration increased significantly in the vitamin E-supplemented group, whereas the placebo group showed a trend toward decrease. Physical performance did not improve in the alpha-tocopherol-supplemented group compared to the placebo group. Heart rates were also not significantly different. Lactate concentrations at the aerobic threshold and the anaerobic threshold were identical. Thus, there was no performance improvement in the alpha-tocopherol-supplemented group. However there was a significant reduction in CK in serum of the E-supplemented group. A trend toward decrease in GOT, GPT, and LDH was observed with alpha-tocopherol supplementation. Moreover, significantly reduced malondialdehyde serum levels were measured in the E-supplemented group. The findings indicate a protective effect of alpha-tocopherol supplementation against oxidative stress induced by strenuous exercise.

Amyloid precursor protein is synthesized by retinal ganglion cells, rapidly transported to the optic nerve plasma membrane and nerve terminals, and metabolized

We have investigated the synthesis, axonal transport, and processing of the beta-amyloid precursor protein (APP) in in vivo rabbit retinal ganglion cells. These CNS neurons connect the retina to the brain via axons that comprise the optic nerve. APP is synthesized in retinal ganglion cells and is rapidly transported into the optic nerve in small transport vesicles. It is then transferred to the axonal plasma membrane, as well as to the nerve terminals and metabolized with a t1/2 of less than 5 h. A significant accumulation of C-terminal amyloidogenic or nonamyloidogenic fragments is seen in the optic nerve 5 h after [35S]-methionine, [35S]cysteine injection, which disappears by 24 h. The major molecular mass species of APP in the optic nerve is approximately 110 kDa, and is an APP isoform that does not contain a Kunitz protease inhibitor domain. Higher molecular mass species containing this sequence are seen mostly in the retina. A protease(s) that can potentially cleave APP to generate an amyloidogenic fragment is present in the same optic nerve membrane compartment as APP.

Influence of material coupling and assembly condition on the magnitude of micromotion at the stem-neck interface of a modular hip endoprosthesis

Hip prostheses with a modular neck exhibit, compared to monobloc prostheses, an additional interface which bears the risk of fretting as well as corrosion. Failures at the neck adapter of modular prostheses have been observed for a number of different designs. It has been speculated that micromotions at the stem-neck interface were responsible for these implant failures. The purpose of this study was to investigate the influence of material combinations and assembly conditions on the magnitude of micromotions at the stem-neck interface during cyclic loading. Modular (n = 24) and monobloc (n = 3) hip prostheses of a similar design (Metha, Aesculap AG, Tuttlingen, Germany) were subjected to mechanical testing according to ISO 7206-4 (F(min) = 230N, F(max) = 2300N, f = 1Hz, n = 10,000 cycles). The neck adapters (Ti-6Al-4V or Co-Cr29-Mo alloy) were assembled with a clean or contaminated interface. The micromotion between stem and neck adapter was calculated at five reference points based on the measurements of the three eddy current sensors. The largest micromotions were observed at the lateral edge of the stem-neck taper connection, which is in accordance with the crack location of clinically failed prostheses. Titanium neck adapters showed significantly larger micromotions than cobalt-chromium neck adapters (p = 0.005). Contaminated interfaces also exhibited significantly larger micromotions (p < 0.001). Since excessive micromotions at the stem-neck interface might be involved in the process of implant failure, special care should be taken to clean the interface prior to assembly and titanium neck adapters with titanium stems should generally be used with caution.