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Showing papers by "University of Hamburg published in 1991"


Journal ArticleDOI
TL;DR: In this article, the authors presented the complete calculation of the order α s 2 correction in the MS scheme to the Drell-Yan K-factor, and showed that the O(α s 2) part of the Kfactor is dominated by the qq, qg, gg and qq subprocesses.

754 citations


Journal ArticleDOI
28 Nov 1991-Nature
TL;DR: expression from cRNA in Xenopus oocytes leads to 9-anthracene-carboxylic acid-sensitive currents with time and voltage dependence typical for macroscopic muscle Cl− conductance, and the functional destruction of this channel in mouse myotonia suggests that the major skeletal muscle chloride channel is cloned.
Abstract: Skeletal muscle is unusual in that 70-85% of resting membrane conductance is carried by chloride ions. This conductance is essential for membrane-potential stability, as its block by 9-anthracene-carboxylic acid and other drugs causes myotonia. Fish electric organs are developmentally derived from skeletal muscle, suggesting that mammalian muscle may express a homologue of the Torpedo mamorata electroplax chloride channel. We have now cloned the complementary DNA encoding a rat skeletal muscle chloride channel by homology screening to the Cl- channel from Torpedo. It encodes a 994-amino-acid protein which is about 54% identical to the Torpedo channel and is predominantly expressed in skeletal muscle. Messenger RNA amounts in that tissue increase steeply in the first 3-4 weeks after birth, in parallel with the increase in muscle Cl- conductance. Expression from cRNA in Xenopus oocytes leads to 9-anthracene-carboxylic acid-sensitive currents with time and voltage dependence typical for macroscopic muscle Cl- conductance. This and the functional destruction of this channel in mouse myotonia suggests that we have cloned the major skeletal muscle chloride channel.

402 citations


Journal ArticleDOI
TL;DR: It is concluded that radiofrequency current catheter ablation is both effective and safe for patients with symptomatic tachyarrhythmias mediated by accessory atrioventricular pathways.

364 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the QCD corrections to the cross section and single-particle inclusive differential distributions for p + p → Q(Q) + X where Q and Q are heavy quarks.

350 citations


Proceedings ArticleDOI
01 Jun 1991
TL;DR: It is shown that even in cases where the solution is not near the geometric unstable region considerable care must be exercised in the calculation, and an analytical method is presented which produces a numerically stable calculation.
Abstract: The major direct solutions to the three-point perspective pose estimation problems are reviewed from a unified perspective. The numerical stability of these three-point perspective solutions are discussed. It is shown that even in cases where the solution is not near the geometric unstable region considerable care must be exercised in the calculation. Depending on the order of the substitutions utilized, the relative error can change over a thousand to one. This difference is due entirely to the way the calculations are performed and not to any geometric structural instability of any problem instance. An analytical method is presented which produces a numerically stable calculation. >

345 citations


Journal ArticleDOI
28 Nov 1991-Nature
TL;DR: In ADR mice a transposon of the ETn family has been inserted into the corresponding gene, destroying its coding potential for several membrane-spanning domains, which strongly suggests a lack of functional chloride channels as the primary cause of mouse myotonia.
Abstract: MYOTONIA (stiffness and impaired relaxation of skeletal muscle) is a symptom of several diseases caused by repetitive firing of action potentials in muscle membranes. Purely myotonic human diseases are dominant myotonia congenita (Thomsen) and recessive generalized myotonia (Becker), whereas myotonic dystrophy is a systemic disease. Muscle hyperexcitability was attributed to defects in sodium channels and/or to a decrease in chloride conductance (in Becker's myotonia and in genetic animal models). Experimental blockage of Cl- conductance (normally 70-85% of resting conductance in muscle) in fact elicits myotonia. ADR mice are a realistic animal model for recessive autosomal myotonia. In addition to Cl- conductance, many other parameters are changed in muscles of homozygous animals. We have now cloned the major mammalian skeletal muscle chloride channel (ClC-1). Here we report that in ADR mice a transposon of the ETn family has inserted into the corresponding gene, destroying its coding potential for several membrane-spanning domains. Together with the lack of recombination between the Clc-1 gene and the adr locus, this strongly suggests a lack of functional chloride channels as the primary cause of mouse myotonia.

338 citations


Journal ArticleDOI
TL;DR: The past development and the present technical parameters of the luminescence experimental stations HIGITI, SUPERLUMI, CLULU and VISUV at HASYLAB are described in this paper.
Abstract: The past development and the present technical parameters of the luminescence experimental stations HIGITI, SUPERLUMI, CLULU and VISUV at HASYLAB are described. The experimental possibilities and limitations are demonstrated with recent results from various fields including rare gas solids, rare gas clusters, matrix-isolated and dense gaseous systems. The future development of luminescence spectroscopy at HASYLAB with undulator—monochromator systems for primary excitation are briefly discussed.

329 citations


Journal ArticleDOI
TL;DR: In this paper, an effective action Γ k for averages of fields taken within a volume of size k −d is formulated, and the average potential becomes convex as k → 0.

320 citations


Journal ArticleDOI
TL;DR: The laterally confining potential of quantum dots on semiconductors is approximated by a two-dimensional harmonic-oscillator well and the discrete level diagram for two interacting electrons in this potential is calculated in the effective-mass approximation.
Abstract: The laterally confining potential of quantum dots on semiconductors is approximated by a two-dimensional harmonic-oscillator well. The discrete level diagram for two interacting electrons in this potential is calculated in the effective-mass approximation as a function of the dot size and the strength of a magnetic field directed perpendicularly to the dot plane.

317 citations


Journal ArticleDOI
TL;DR: A new hypothesis has been formulated for the pathogenesis of vitiligo based on a consistent reduction in levels of catalase compared to normal healthy controls of matched photo-skin types and a increase in the concentration of hydrogen peroxide in the epidermis of these patients.

307 citations


Journal ArticleDOI
TL;DR: Immunohistochemistry shows complementary distributions of tau and MAP2, with tau being concentrated in axons and high molecular mass MAP2 being confined to dendrites in nerve cells.

Journal ArticleDOI
TL;DR: In this article, the π0-form factor of the η-meson was determined from its decay modes π+π−π0, π +π−γ and the neutral decay mode γγ.
Abstract: We present measurement of the π0γ*γ, ηγ*γ and η′γ*γ form factors. The π0-form factor is for the first time observed in the space-like region. The transition form factor of the η-meson is determined from its decay modes π+π−π0, π+π−γ and the neutral decay mode γγ. The decay of the η′ is observed in the decay channels ργ, ηπ+π− with η→γγ and in the four charged prong final state stemming from ηπ+π− with the η decaying into π+π−(π0/γ). All form factors agree well with a simple ρ-pole predicted by the vector meson dominance model and also with the QCD inspired Brodsky-Lepage model.

Journal ArticleDOI
TL;DR: The results suggest that early Myf-6 expression may be restricted to a population of myogenic cells that does not contribute to the embryonic muscle masses in limb buds and visceral arches, and the reappearance of My f-6 mRNA in fetal skeletal muscle coincides approximately with secondary muscle fiber formation and the onset of innervation.
Abstract: The spatial and temporal expression pattern of the muscle regulatory gene Myf-6 (MRF4/herculin) has been investigated by in situ hybridization during embryonic and fetal mouse development. Here, we report that the Myf-6 gene shows a biphasic pattern of expression. Myf-6 transcripts are first detected in the most rostral somites of the mouse embryo at 9 d of gestation and accumulate progressively in myotomal cells along the rostro-caudal axis. This expression is transient and Myf-6 mRNA can no longer be detected in myotomal cells after day 12 post coitum (p.c.). In contrast to other muscle determination genes (MyoD1, myogenin, Myf-5), Myf-6 mRNA is not detected in limb buds or visceral arches and skeletal muscle of the mouse embryo (day 8-15 p.c.). In fetal mice, Myf-6 transcripts appear at day 16 p.c. in all skeletal muscles, and the gene continues to be expressed at a high level after birth. These results suggest that early Myf-6 expression may be restricted to a population of myogenic cells that does not contribute to the embryonic muscle masses in limb buds and visceral arches. The reappearance of Myf-6 mRNA in fetal skeletal muscle coincides approximately with secondary muscle fiber formation and the onset of innervation.

Journal ArticleDOI
TL;DR: Results from a mortality follow-up of 1583 workers employed in a chemical plant in Germany that produced herbicides, including processes contaminated with TCDD support the hypothesis that T CDD is a human carcinogen.

Journal ArticleDOI
01 Feb 1991-Nature
TL;DR: In this article, the discovery of enormous tower-like microbialites from alkaline (pH>9.7) Lake Van, eastern Anatolia, was reported, and they resemble Proterozoic marine stromatolites.
Abstract: MICROBIALITES are organosedimentary deposits produced by benthic microbial communities interacting with detrital or chemical sediments1. Calcareous cyanobacterial microbialites defined as stromatolites and thrombolites were common in ancient shallow marine environments2. Today, they are restricted to a few lacustrine and perimarine settings. This restriction may result from changes in seawater chemistry through time3–6, particularly from alteration in supersaturation with respect to carbonate minerals7. The largest known calcareous microbialites (several metres high) were formed in the late Precambrian8. Here we report the discovery of enormous (∼40 m high) tower-like microbialites from alkaline (pH>9.7) Lake Van, eastern Anatolia. Growth is by mats of coccoid cyanobacteria (Pleurocapsa group) permineralizing in situ with aragonite and by inorganically precipitated calcite. Certain aspects of these microbialites resemble Proterozoic marine stromatolites9.

Journal ArticleDOI
TL;DR: The forward and rear calorimeters of the ZEUS experiment are made of 48 modules with maximum active dimensions of 4.6 m height, 0.2 m width, 7 λ depth and maximum weight of 12 t as mentioned in this paper.
Abstract: The forward and rear calorimeters of the ZEUS experiment are made of 48 modules with maximum active dimensions of 4.6 m height, 0.2 m width, 7 λ depth and maximum weight of 12 t. It consists of 1 X 0 uranium plates interleaved with plastic scintillator tiles read out via wavelength shifters and photomultipliers. The mechanical construction, the achieved tolerances as well as the optical and electronics readout are described. Ten of these modules have been tested with electrons, hadrons and muons in the momentum range 15–100 GeV/ c . Results on resolution, uniformity and calibration are presented. Our main result is the achieved calibration accuracy of about 1% obtained by using the signal from the uranium radioactivity.

Journal ArticleDOI
TL;DR: It is concluded that intraductal mucin-hypersecreting neoplasm is a pancreatic tumor with favorable prognosis and a common pathogenesis of these pancreatic tumors is suggested.

Journal ArticleDOI
TL;DR: B-Scan-guided, pulsed Doppler ultrasonography of central Retinal vessels and ophthalmic arteries of 72 normal subjects gave the following average peak flow velocities: central retinal artery, 9.5 +/- 3.1 cm/s; central retina vein, 5.7 +/- 1.5 cm/S; and ocular artery systolic, middiastolic, and end-diastolic velocITIES significantly declined as a function of
Abstract: • B-Scan-guided, pulsed Doppler ultrasonography of central retinal vessels and ophthalmic arteries of 72 normal subjects gave the following average peak flow velocities: central retinal artery, 9.5±3.1 cm/s; central retinal vein, 5.7±1.5 cm/s; and ophthalmic artery, 31.6±9.0 cm/s. Doppler shifts in the central retinal vessels were absent at intraocular pressures above 80 mm Hg. Ophthalmic artery systolic, middiastolic, and end-diastolic velocities significantly declined as a function of age. The technique is independent of the status of the ocular media, is noninvasive, requires little time, and causes minimal discomfort.

Journal ArticleDOI
01 May 1991-Nature
TL;DR: In this article, the authors investigated how fresh water injection might influence particle fluxes in the ocean, and hence the uptake of atmospheric CO2, and deployed three sediment-trap moorings (two traps in each mooring) in the northern, central and southern parts of the Bay of Bengal, respectively.
Abstract: THE melting of ice sheets during deglaciation results in the injection of large amounts of fresh water into the oceans1. To investigate how such injections might influence particle fluxes in the ocean, and hence the uptake of atmospheric CO2, we deployed three sediment-trap moorings (two traps in each mooring) in the northern, central and southern parts of the Bay of Bengal, respectively. The Bay of Bengal is suitable for such a study, because some of the world's largest rivers2 supply pulses of fresh water and sediment to the bay, resulting in large seasonal changes in surface salinity3. We find that the maximum river discharge, which occurs during the southwest monsoon, coincides with the maximum observed flux of participate matter. From north to south, the carbonate flux increases, whereas fluxes of opal, organic carbon and particulate matter decrease. The overall flux pattern seems to be controlled by the seasonally varying input from the rivers and the accompanying shift in marine biogenic production. We conclude that fresh-water pulses during deglaciation may therefore have caused similar shifts in marine biogenic production, resulting in short-term episodes of increased oceanic uptake of atmospheric CO2.

Journal ArticleDOI
TL;DR: Observations suggest that lymphocyte activation may play an important role in underlying immune processes that lead to chronicity and perpetuation of inflammatory bowel disease and may implicate an additional mechanism for the therapeutic action of 5-aminosalicylic acid.

Journal ArticleDOI
TL;DR: The authors' simulations suggest that the combined effect of disorder and Coulomb interaction provides a new mechanism for under-standing non-Debye relaxation, which is experimentally known for a wide class of materials.
Abstract: We perform Monte Carlo simulations for diffusion of charged particles in structurally disorderd lattices. As a consequence of the Coulomb interaction, pronounced backward correlations occur which lead to power-law behavior of the relevant transport quantities at intermediate time and frequency scales. Both the exponents and the size of the dispersive regime depend on temperature. Our simulations suggest that the combined effect of disorder and Coulomb interaction provides a new mechanism for understanding non-Debye relaxation, which is experimentally known for a wide class of materials.

Journal ArticleDOI
TL;DR: Enzyme activities for the oxidation of chlorobenzenes and halogenated metabolites were induced by both strains during growth on these haloaromatics and, to a considerable extent, during growth of strain PS12 on acetate.
Abstract: Two Pseudomonas sp. strains, capable of growth on chlorinated benzenes as the sole source of carbon and energy, were isolated by selective enrichment from soil samples of an industrial waste deposit. Strain PS12 grew on monochlorobenzene, all three isomeric dichlorobenzenes, and 1,2,4-trichlorobenzene (1,2,4-TCB). Strain PS14 additionally used 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB). During growth on these compounds both strains released stoichiometric amounts of chloride ions. The first steps of the catabolism of 1,2,4-TCB and 1,2,4,5-TeCB proceeded via dioxygenation of the aromatic nuclei and furnished 3,4,6-trichlorocatechol. The intermediary cis-3,4,6-trichloro-1,2-dihydroxycyclohexa-3,5-diene (TCB dihydrodiol) formed from 1,2,4-TCB was rearomatized by an NAD+-dependent dihydrodiol dehydrogenase activity, while in the case of 1,2,4,5-TeCB oxidation the catechol was obviously produced by spontaneous elimination of hydrogen chloride from the initially formed 1,3,4,6-tetrachloro-1,2-dihydroxycyclohexa-3,5-diene. Subsequent ortho cleavage was catalyzed by a type II catechol 1,2-dioxygenase producing the corresponding 2,3,5-trichloromuconate which was channeled into the tricarboxylic acid pathway via an ordinary degradation sequence, which in the present case included 2-chloro-3-oxoadipate. From the structure-related compound 2,4,5-trichloronitrobenzene the nitro group was released as nitrite, leaving the above metabolite as 3,4,6-trichlorocatechol. Enzyme activities for the oxidation of chlorobenzenes and halogenated metabolites were induced by both strains during growth on these haloaromatics and, to a considerable extent, during growth of strain PS12 on acetate.

Journal ArticleDOI
TL;DR: A specific assay is developed for the ‘inner membrane protease I’ which shares several key features with the leader peptidase of Escherichia coli and the signal peptid enzyme of the endoplasmic reticulum and may be a hetero‐oligomer.
Abstract: Several precursors transported from the cytoplasm to the intermembrane space of yeast mitochondria are first cleaved by the MAS-encoded protease in the matrix space and then by additional proteases that have not been characterized. We have now developed a specific assay for one of these other proteases. The enzyme is an integral protein of the inner membrane; it requires divalent cations and acidic phospholipid for activity, and is defective in yeast mutant pet ts2858 which accumulates an incompletely processed cytochrome b2 precursor. The protease contains a 21.4 kd subunit whose C-terminal part is exposed on the outer face of the inner membrane. An antibody against this polypeptide inhibits the activity of the protease. As overproduction of the polypeptide does not increase the activity of the protease in mitochondria, the enzyme may be a hetero-oligomer. This 'inner membrane protease I' shares several key features with the leader peptidase of Escherichia coli and the signal peptidase of the endoplasmic reticulum.

Journal ArticleDOI
TL;DR: The concept of axonal mRNA transport is supported by embryonic developmental studies showing that appearance of vasopressin transcripts in the hypothalamus and the pituitary anlage is correlated and during axonal transport the respective mRNAs are subject to specific modification at the poly(A) tails.
Abstract: Hypothalamic vasopressin and oxytocin transcripts have been detected in the posterior pituitary suggesting either transcription of the respective genes in pituicytes or axonal mRNA transport from the hypothalamus to the nerve terminals of the posterior pituitary. The concept of axonal mRNA transport is supported firstly, by Northern blot and in situ hybridization analysis indicating that vasopressin and oxytocin mRNAs are also present in the neural stalk; secondly, by intron analysis and transcription run on experiments demonstrating the absence of primary vasopressin and oxytocin transcripts in non-neuronal cells of the posterior pituitary; thirdly, by embryonic developmental studies showing that appearance of vasopressin transcripts in the hypothalamus and the pituitary anlage is correlated. Furthermore, during axonal transport the respective mRNAs are subject to specific modification at the poly(A) tails.

Journal ArticleDOI
15 Sep 1991-Cancer
TL;DR: Results suggest that duodenal location and multicentricity of gastrinomas are associated with the MEN‐1 syndrome, and solitary gastrinoma, either in the pancreas or the duodenum, are predominantly seen in sporadic ZES.
Abstract: Specimens from the pancreas and duodenum of 26 patients with sporadic Zollinger-Ellison syndrome (ZES) and 18 patients with multiple endocrine neoplasia type 1 (MEN-1) and hypergastrinemia (17 with ZES) were screened immunocytochemically for gastrinomas. Location, size, multicentricity, and malignancy of the gastrinomas were evaluated. The MEN-1 patients had gastrinomas in the duodenum (nine of 18), pancreas (one of 18), and periduodenal lymph nodes (two of 18). No gastrinoma was identified in six patients. Most duodenal gastrinomas were multiple (five of nine) and smaller than 0.6 cm (six of nine). Lymph node metastases were present in eight of 12 patients. All 26 patients with sporadic ZES had a solitary gastrinoma; 14 were found in the pancreas and had a diameter greater than 2 cm. Ten patients had a duodenal gastrinoma, two with a diameter less than 0.6 cm. In two patients, only periduodenal "lymph node gastrinomas" were detected. Eighteen of the sporadic gastrinomas were malignant. These results suggest that duodenal location and multicentricity of gastrinomas are associated with the MEN-1 syndrome, and solitary gastrinomas, either in the pancreas or the duodenum, are predominantly seen in sporadic ZES.

Journal ArticleDOI
TL;DR: The cultivation of the hyperthermophilic archaeobacterium Pyrococcus woesei on starch under continuous gassing caused the formation of 250 U/l of an extremely thermoactive and thermostable α-amylase, which hydrolyzed exclusively α-1,4-glycosidic linkages present in glucose polymers of various sizes.
Abstract: The cultivation of the hyperthermophilic archaeobacterium Pyrococcus woesei on starch under continuous gassing (80% H2:20% CO2) caused the formation of 250 U/l of an extremely thermoactive and thermostable α-amylase. In a complex medium without elemental sulphur under 80% N2 and 20% CO2 atmosphere enzyme production could be elevated up to 1000 U/l. Pyrococcus woesei grew preferentially on poly-and oligosaccharides. The amylolytic enzyme formation was constitutive. Enzyme production was also observed in continuous culture at dilution rates from 0.1 to 0.4 h-1. A 20-fold enrichment of α-amylase was achieved after adsorption of the enzyme onto starch and its desorption by preparative gel electrophoresis. The α-amylase consisted of a single subunit with a molecular mass of 70 000 and was catalytically active at a temperature range between 40°C and 130°C. Enzymatic activity was detected even after autoclaving at a pressure of 2 bars at 120°C for 5 h. The purified enzyme hydrolyzed exclusively α-1,4-glycosidic linkages present in glucose polymers of various sizes. Unlike many α-amylases from anaerobes the enzyme from P. woesei was unable to attack short chain oligosaccharides with a chain length between 2 and 6 glucose units.

Journal ArticleDOI
15 Mar 1991-Gene
TL;DR: It is found that the gene conferring resistance to puromycin from Streptomyces alboniger does not influence adjacent promoters, and the neo gene is frequently used in eukaryotic vectors as a dominant selectable gene.

Journal ArticleDOI
TL;DR: In this paper, two extended integrations of general circulation models (GCMs) are examined to determine the physical processes operating during an ENSO cycle, and the atmospheric model results show an eastward propagation of information from the western to eastern Pacific along the equator, although this signal is somewhat weaker than observed.
Abstract: Two extended integrations of general circulation models (GCMs) are examined to determine the physical processes operating during an ENSO cycle. The first integration is from the Hamburg version of the ECMWF T21 atmospheric model forced with observed global sea surface temperatures (SST) over the period 1970–85. The second integration is from a Max Planck Institut model of the tropical Pacific forced by observed wind stress for the same period. Both integrations produce key observed features of the tropical ocean-atmosphere system during the 1970–85 period. The atmospheric model results show an eastward propagation of information from the western to eastern Pacific along the equator, although this signal is somewhat weaker than observed. The Laplacian of SST largely drives the surface wind field convergence and hence determines the position of large scale precipitation-condensation heating. This statement is valid only in the near-equatorial zone. Air-sea heat exchange is important in the planetary boundary layer in forcing the wind field convergence but not so important to the main troposphere, which is heated largely by condensation heating. The monopole response seen in the atmosphere above about 500 mb is due to a combination of factors, the most important being adiabatic heating associated with subsidence and tropic-wide variations in precipitation. The models show the role of air-sea heat exchange in the ocean heat balance in the wave guide is one of dissipation/damping. Total air-sea heat exchange is well represented by a simple Newtonian cooling parameterization in the near-equatorial region. In the wave guide, advection dominates the oceanic heat balance with meridional advection being numerically the most important in all regions except right on the equator. The meridional term is largely explained by local Ekman dynamics that generally overwhelm other processes in the regions of significant wind stress. The principal element in this advection term is the anomalous meridional current acting on the climatological mean meridional SST gradient. The eastward motion of the anomalies seen in both models is driven primarily by the ocean. The wind stress associated with the SST anomalies forces an equatorial convergence of heat and mass in the ocean. Outside the region of significant wind forcing, the mass source leads to a convergent geostrophic flow, which drives the meridional heat flux and causes warming to the east of the main wind anomaly. West of the main anomaly the wind and geostrophic divergence cause advective cooling. The result is that the main SST anomaly appears to move eastward. Since the direct SST forcing drives the anomalous wind, surface wind convergence, and associated precipitation, these fields are seen also to move eastward.

Journal ArticleDOI
TL;DR: Pseudomonas sp.
Abstract: Pseudomonas sp. CBS3 converted various nitro-aromatic compounds under aerobic resting-cell conditions to the corresponding amino compounds. Mononitro-compounds were reduced to anilines. 1-Chloro-2,4-dinitrobenzene was reduced via the two possible chloronitroanilines to 4-chloro-1,3-diaminobenzene. In the case of 2,4,6-trinitrotoluene, two monoaminodinitrotoluenes and one diaminomononitrotoluene were obtained. In addition to the reduction, in most cases the amines were partially acetylated. In experiments under an argon atmosphere conversion of the nitro-compounds was as fast as under aerobic conditions. Cells of Pseudomonas sp. CBS3 cultivated on complex medium showed higher nitro-reducing activity than those cultivated on mineral salts medium with 4-chlorobenzoate as substrate, which is normally used as medium for this strain. Several other Pseudomonas species (ATCC 4359, ATCC 23937, ATCC 15005, ATCC 17933) also showed nitro-reducing activities. In crude cell-free extracts of Pseudomonas sp. CBS3 an enzyme catalysing the reduction of nitro-aromatics was detected. The enzyme was inactivated by dialysis and was reactivated by the addition of NADH or NADPH. NADPH was the more efficient co-substrate.

Journal ArticleDOI
TL;DR: A new technique of combinded two- and three-dimensional analysis of bone specimens is presented, which are fundamental for morphological investigation of bone.
Abstract: For reliable quantitative and qualitative analysis of bone specimens undecalcified preparation is essential. The "conventional" technique for this purpose is embedding in methylmethacrylate. Larger bone specimens, highly sclerotic specimens, cortical bone or bone implants consisting of metals or ceramics require modifications of this technique or completely new methods. We report our experience with the undecalcified preparation of 47,700 bone specimens. New techniques such as the cutting of large area sections up to a size of 5 x 6 cm and grinding procedures for completely artefact-free preparation which are applied in special cases are also described. A new technique of combined two- and three-dimensional analysis of bone specimens is presented. In our experience these methods are fundamental for morphological investigation of bone.