Haptic model fabrication for undergraduate and postgraduate teaching.

Three series of cone-beam computed tomography (CBCT) patient data sets were obtained. These data were exported into DICOM and MIMICS (Materialise's Interactive Medical Image Control System; Materialise, Leuven, Belgium) and were imported for differentiation of various tissues (bone, teeth, and nerve). After transferring the data to an additive manufacturing machine, three-dimensional (3D) haptic models were fabricated using clear and opaque materials. These models were integrated into phantom heads normally used for education in undergraduate dental education. 3D prototype CBCT-based haptic patient models can be used in undergraduate and postgraduate education. Students can simulate routine standard oral surgical procedures with supervision under 'dry conditions'. Residents can simulate advanced and complex cases before performing the real operation.

Swimming behavior and prey retention of the polychaete larvae Polydora ciliata (Johnston).

The behavior of the ubiquitous estuarine planktotrophic spionid polychaete larvae Polydora ciliata was studied. We describe ontogenetic changes in morphology, swimming speed and feeding rates and have developed a simple swimming model using low Reynolds number hydrodynamics. In the model we assumed that the ciliary swimming apparatus is primarily composed of the prototroch and secondarily by the telotroch. The model predicted swimming speeds and feeding rates that corresponded well with the measured speeds and rates. Applying empirical data to the model, we were able to explain the profound decrease in specific feeding rates and the observed increase in the difference between upward and downward swimming speeds with larval size. We estimated a critical larval length above which the buoyancy-corrected weight of the larva exceeds the propulsion force generated by the ciliary swimming apparatus and thus forces the larva to the bottom. This modeled critical larval length corresponded to approximately 1 mm, at which, according to the literature, competence for metamorphosis and no more length increase is observed. These findings may have general implications for all planktivorous polychaete larvae that feed without trailing threads. We observed bell shaped particle retention spectra with a minimum prey size of approximately 4 microm equivalent spherical diameter, and we found that an ontogenetic increase in maximum prey size add to a reduction in intra-specific food competition in the various larval stages. In a grazing experiment using natural seawater, ciliates were cleared approximately 50% more efficiently than similar sized dinoflagellates. The prey sizes retainable for P. ciliata larvae covers the microplankton fraction and includes non-motile as well as motile prey items, which is why the larvae are trophically positioned among the copepods and dinoflagellates. Not only do larval morphology and behavior govern larval feeding, prey behavior also influences the feeding efficiency of Polydora ciliata.

Structural brain abnormalities in early onset first-episode psychosis.

BACKGROUND: Brain morphometry in children and adolescents with first-episode psychosis offer a unique opportunity for pathogenetic investigations. METHODS: We compared high-resolution 3D T1-weighted magnetic resonance images of the brain in 29 patients (schizophrenia, schizotypal disorder, delusional disorder or other non-organic psychosis), aged 10-18 to those of 29 matched controls, using optimized voxel-based morphometry. RESULTS: Psychotic patients had frontal white matter abnormalities, but expected (regional) gray matter reductions were not observed. Post hoc analyses revealed that schizophrenia patients (n = 15) had significantly larger lateral ventricles as compared to controls. Duration and dose of antipsychotics correlated negatively with global gray matter volume in minimally medicated patients (n = 18). CONCLUSION: Findings of white matter changes and enlarged lateral ventricles already at illness onset in young schizophrenia spectrum patients, suggests aberrant neurodevelopmental processes in the pathogenesis of these disorders. Gray matter volume changes, however, appear not to be a key feature in early onset first-episode psychosis.

Transfer of hydrophobic contaminants in urban runoff particles to benthic organisms estimated by an in vitro bioaccessibility test.

An in vitro bioaccessibility test was applied for assessing the transfer of polycyclic aromatic hydrocarbons (PAHs) present in road dust, into benthic organisms living in a receiving water body. The road dust is supposed to be urban runoff particles under wet weather conditions. Sodium dodecyl sulfate (SDS) solution was used as a hypothetical gut fluid. Pyrene, fluoranthene and phenanthrene were the main PAH species in the SDS extractable fraction of road dust, as well as the whole extract. Benzo(ghi)perylene showed relatively low concentrations in the SDS extract in spite of a high concentration in the original dust. The PAH composition in benthic organisms (polychaetes) did not correspond with that of the surrounding sediment and the PAHs detected were also detected in high concentrations in the SDS extract of road dust. When testing the toxicity of the extracted contaminants by a standardised algal toxicity test, SDS extracts of a detention pond sediment showed higher toxicity than the pore water of the corresponding sediment. Sediment suspension showed a comparative toxicity with 0.1% SDS extract. From the results, the in vitro bioaccessibility test seems more suitable to evaluate the exposed contaminants than the traditional organic solvent extraction method and the SDS extracted fraction is applicable to toxicity tests reflecting the digestive process.

Response to the prone position in spontaneously breathing patients with hypoxemic respiratory failure.

OBJECTIVES: The prone position is used for intubated patients with adult respiratory distress syndrome (ARDS) and acute lung injury (ALI). The physiological changes associated with the prone position in nonintubated patients may be even more favorable than in intubated patients. We examined the effect of the prone position on arterial blood gases and patient compliance in four awake, nonintubated patients with hypoxemic respiratory failure. DESIGN: We present four consecutive cases of hypoxemic respiratory failure, in which mechanical ventilation was indicated. An attempt was made to avoid assisted ventilation by placing patients in the prone position, while breathing spontaneously. The effect on the clinical condition and the changes in blood gases were registered. RESULTS: We found good patient tolerance. A rapid increase in PaO2 was found, and intubation was avoided in all patients. No significant complications were registered. CONCLUSION: The prone position may prove beneficial in some cases of hypoxemic respiratory failure, even in awake patients, by avoiding mechanical ventilation and ventilator-associated complications.

[Child and adolescents with psychotic disorders. A literature review of psychology and course]. / Børn og unge med psykotiske tilstande. En litteraturgennemgang af psykopatologi og forløb.

The article is a literature review of psychosis in children and adolescents. Earlier studies point to psychosis in children and adolescence being of the same types as the ones seen in adults. Schizophrenia has an early onset in boys, there are more premorbid dysfunctions, a gradual onset of disease, a number of unspecific symptoms and a poorer prognosis than for adults. For the children with bipolar affective disorder the prognosis is similar to that of adults, and it is better than for the schizophrenics. The relationships between developmental disorders and schizophrenia, and between hyperactivity syndromes and manic-depressive disorders need to be further clarified, as does the validity of the follow-up investigations.

[When time stops... Psychiatric reactions to deportation orders of unaccompanied children and teenagers seeking asylum]. / Når tiden holder op ... Psykiatriske reaktioner på afslag om asyl hos uledsagede børn og unge.

Five cases of psychiatric disturbances in unaccompanied children who were refused political asylum are described. The children showed severe reactions with suicidal thoughts or psychosis, with a characteristic loss of perception of time during the long period of waiting for a decision. These children with severe reactions constituted a minority of the total who were refused asylum.

[Multiple organ failure caused by extraadrenal pheochromocytoma]. / Multiorgansvigt på baggrund af ekstraadrenalt faeokromocytom.

Extraadrenal phaeochromocytomas are very rare tumours, commonly associated with hypertensive paroxysms. We report a 20 year-old man with unsuspected extraadrenal phaeochromocytoma, who at admission presented with septicaemia and adult respiratory distress syndrome, suggesting pneumonia.

Postnatal transient renal insufficiency in the feto-fetal transfusion syndrome.

Twinning and higher-order multiple-gestation pregnancies have become relatively frequent in the current era of assisted reproductive techniques. Vascular interconnections are present in nearly all monochorionic twin placentae, yet hemodynamically significant arteriovenous anastomoses resulting in the feto-fetal transfusion syndrome occur in only 5%-18% of these. When arteriovenous connections through a shared placental cotyledon are present, variable amounts of blood may be transfused from one fetus to the other, and feto-fetal transfusion syndrome may result. While reports of renal failure due to a small non-functioning kidney in the donor infant pre- or postnatally have been published, recoverable renal insufficiency has not been previously delineated in feto-fetal transfusion syndrome. This article describes a case of postnatal transient renal insufficiency in a donor infant from a pair of monozygotic twins.

Three-dimensional structure of the HTLV-II matrix protein and comparative analysis of matrix proteins from the different classes of pathogenic human retroviruses.

The matrix protein performs similar roles in all retroviruses, initially directing membrane localization of the assembling viral particle and subsequently forming a stable structural shell associated with the inner surface of the mature viral membrane. Although conserved structural elements are likely to perform these functions in all retroviral matrix proteins, invariant motifs are not evident at the primary sequence level and three-dimensional structures have been available for only the primate lentiviral matrix proteins. We have therefore used NMR spectroscopy to determine the structure of the matrix protein from human T-cell leukemia virus type II (HTLV-II), a member of the human oncovirus subclass of retroviruses. A total of 577 distance restraints were used to build 20 refined models that superimpose with an rmsd of 0.71 A for the backbone atoms of the structured regions. The globular HTLV-II matrix structure is composed of four alpha-helices and a 3(10) helix. Exposed basic residues near the C terminus of helix II form a putative membrane binding surface which could act in concert with the N-terminal myristoyl group to anchor the protein on the viral membrane surface. Clear structural similarities between the HTLV-II and HIV-1 matrix proteins suggest that the topology and exposed cationic membrane binding surface are likely to be conserved features of retroviral matrix proteins.

Comparison of the NMR and X-ray structures of the HIV-1 matrix protein: evidence for conformational changes during viral assembly.

The three-dimensional solution- and solid-state structures of the human immunodeficiency virus type-1 (HIV-1) matrix protein have been determined recently in our laboratories by NMR and X-ray crystallographic methods (Massiah et al. 1994. J Mol Biol 244:198-223; Hill et al. 1996. Proc Natl Acad Sci USA 93:3099-3104). The matrix protein exists as a monomer in solution at low millimolar protein concentrations, but forms trimers in three different crystal lattices. Although the NMR and X-ray structures are similar, detailed comparisons have revealed an approximately 6 A displacement of a short 3(10) helix (Pro 66-Gly 71) located at the trimer interface. High quality electron density and nuclear Overhauser effect (NOE) data support the integrity of the X-ray and NMR models, respectively. Because matrix apparently associates with the viral membrane as a trimer, displacement of the 3(10) helix may reflect a physiologically relevant conformational change that occurs during virion assembly and disassembly. These findings further suggest that Pro 66 and Gly 71, which bracket the 3(10) helix, serve as "hinges" that allow the 3(10) helix to undergo this structural reorientation.

Crystal structures of the trimeric human immunodeficiency virus type 1 matrix protein: implications for membrane association and assembly.

The human immunodeficiency virus type 1 (HIV-1) matrix protein forms a structural shell associated with the inner viral membrane and performs other essential functions throughout the viral life cycle. The crystal structure of the HIV-1 matrix protein, determined at 2.3 angstrom resolution, reveals that individual matrix molecules are composed of five major helices capped by a three-stranded mixed beta-sheet. Unexpectedly, the protein assembles into a trimer in three different crystal lattices, burying 1880 angstrom2 of accessible surface area at the trimer interfaces. Trimerization appears to create a large, bipartite membrane binding surface in which exposed basic residues could cooperate with the N-terminal myristoyl groups to anchor the protein on the acidic inner membrane of the virus.

Moving the retina: choroidal modulation of refractive state.

The chick eye is able to change its refractive state by as much as 7 D by pushing the retina forward or pulling it back; this is effected by changes in the thickness of the choroid, the vascular tissue behind the retina and pigment epithelium. Chick eyes first made myopic by wearing diffusers and then permitted unrestricted vision developed choroids several times thicker than normal within days, thereby speeding recovery from deprivation myopia. Choroidal expansion does not occur when visual cues are reduced by dim illumination during the period of unrestricted vision. Furthermore, in chick eyes presented with myopic or hyperopic defocus by means of spectacle lenses, the choroid expands or thins, respectively, in compensation for the specific defocus imposed. Consequently, when the lenses are removed, the eye finds its refractive error suddenly of opposite sign, and the choroidal thickness again compensates by changing in the opposite direction. If a local region of the eye is made myopic by a partial diffuser and then given unrestricted vision, the choroid expands only in the myopic region. Although the mechanism of choroidal expansion is unknown, it might involve either a increased routing of aqueous humor into the uveoscleral outflow or osmotically generated water movement into the choroid. The latter is compatible with the increased choroidal proteoglycan synthesis either when eyes wear positive lenses or after diffuser removal.

Postoperative throat complaints after tracheal intubation.

We have investigated the incidence of throat complaints 6-24 h after tracheal intubation in 1325 patients. Variables such as anaesthetic drug, intubation time, number of intubation attempts, gastric tube, sex and age were recorded. The incidence of sore throat was considerably lower (14.4%) compared with other reports in the literature and was significantly greater in females (17.0% vs 9.0%) and after thyroid surgery. The incidence of sore throat was not increased after multiple intubation attempts or after administration of suxamethonium or a non-depolarizing neuromuscular blocker.

Three-dimensional structure of the human immunodeficiency virus type 1 matrix protein.

The HIV-1 matrix protein forms an icosahedral shell associated with the inner membrane of the mature virus. Genetic analyses have indicated that the protein performs important functions throughout the viral life-cycle, including anchoring the transmembrane envelope protein on the surface of the virus, assisting in viral penetration, transporting the proviral integration complex across the nuclear envelope, and localizing the assembling virion to the cell membrane. We now report the three-dimensional structure of recombinant HIV-1 matrix protein, determined at high resolution by nuclear magnetic resonance (NMR) methods. The HIV-1 matrix protein is the first retroviral matrix protein to be characterized structurally and only the fourth HIV-1 protein of known structure. NMR signal assignments required recently developed triple-resonance (1H, 13C, 15N) NMR methodologies because signals for 91% of 132 assigned H alpha protons and 74% of the 129 assignable backbone amide protons resonate within chemical shift ranges of 0.8 p.p.m. and 1 p.p.m., respectively. A total of 636 nuclear Overhauser effect-derived distance restraints were employed for distance geometry-based structure calculations, affording an average of 13.0 NMR-derived distance restraints per residue for the experimentally constrained amino acids. An ensemble of 25 refined distance geometry structures with penalties (sum of the squares of the distance violations) of 0.32 A2 or less and individual distance violations under 0.06 A was generated; best-fit superposition of ordered backbone heavy atoms relative to mean atom positions afforded root-mean-square deviations of 0.50 (+/- 0.08) A. The folded HIV-1 matrix protein structure is composed of five alpha-helices, a short 3(10) helical stretch, and a three-strand mixed beta-sheet. Helices I to III and the 3(10) helix pack about a central helix (IV) to form a compact globular domain that is capped by the beta-sheet. The C-terminal helix (helix V) projects away from the beta-sheet to expose carboxyl-terminal residues essential for early steps in the HIV-1 infectious cycle. Basic residues implicated in membrane binding and nuclear localization functions cluster about an extruded cationic loop that connects beta-strands 1 and 2. The structure suggests that both membrane binding and nuclear localization may be mediated by complex tertiary structures rather than simple linear determinants.

[Involuntary admissions and other compulsions in psychiatry. Patients' knowledge of their rights and ability to receive information concerning these matters]. / Frihedsberøvelse og anden tvang i psykiatrien. Om psykiatriske patienters kendskab til deres rettigheder ved tvangsindgreb og deres evne til at modtage information herom.

The Danish Mental Health Act of 1989 improved the legal rights of psychotic patients and secured that involuntary admissions and retentions could be tried before the courts. Fixations and medication given against the patient's will could be tried before a Patient Review Board. Under the law doctors and "patient advisors" are now obliged to inform patients of their rights. Forty-seven patients and 33 of their relatives were interviewed and questioned about their knowledge of patient rights. It was found that the patients understood the criteria for involuntary treatment when these concerned the risk of the patient endangering themselves and others, whereas the findings suggested that more information about involuntary treatment for reasons of health was needed. Few patients were able to remember information given in the acute situation.

[Use of psychiatric emergency departments by patients with chronic psychotic disorders]. / Langtidspsykotiske patienters brug af psykiatrisk skadestue.

Ninety chronic psychotic patients' use of a psychiatric emergency ward in Copenhagen County was examined. Over a one year period most patients came to the emergency ward once or twice when other treatment facilities were not open. They came because of an exacerbation of symptoms rather than because of social needs.

Solid-state NMR determination of intra- and intermolecular 31P-13C distances for shikimate 3-phosphate and [1-13C]glyphosate bound to enolpyruvylshikimate-3-phosphate synthase.

Rotational-echo, double-resonance (REDOR) 31P NMR was used to obtain internuclear distances for shikimate 3-phosphate (S3P) and N-(phosphonomethyl)-[1-13C]glycine (glyphosate) bound to 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase, a 46-kDa enzyme essential for the synthesis of aromatic amino acids in plants and microorganisms. An intermolecular 31P-13C distance of 7.2 A was measured between the phosphate of S3P and the labeled carbon of glyphosate. This means that S3P and glyphosate are in proximity in the binding site of the enzyme. An intramolecular 31P-13C distance of 5.6 A was measured between the phosphonate 31P and the labeled carbon of glyphosate. This distance can be achieved only if glyphosate is completely extended when bound to EPSP synthase.