Review of the reticulated python (Python reticulatus Schneider, 1801) with the description of new subspecies from Indonesia

The geographically widespread Python reticulatus, the world's longest snake, has been largely neglected by taxonomists. Dwarfed individuals from Tanahjampea Island, Indonesia, differ strikingly in morphology. Phylogenetic relationships were analyzed using a 345-bp fragment of the cytochrome b gene for 12 specimens from different populations. Both genetic differences and morphological characters distinctly revealed two taxonomic subunits. The island populations of Tanahjampea and Selayar form two monophyletic lineages, supported by high bootstrap values, with distinct differences in color pattern and scalation. We consider these forms to represent two new subspecies. The Tanahjampea form is genetically related to populations of the Sunda Islands and mainland Southeast Asia, whereas the Selayar form is related to populations of Southwest Sulawesi. We conclude that, due to strong directional surface currents in this region, gene flow between Tanahjampea and Selayar is prevented. Sea-level changes during the Pleistocene probably contributed to the isolation of the two taxa described. Aspects of ecology and conservation status are briefly discussed. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00114-002-0320-4.

[Calculation of 3-D deformity in scoliosis by MRI of the total spine in two perpendicular reconstructed planes]

AIM

Scoliosis is a spinal deformity that is more complex and does not exist in one plane only. There have been many attempts to analyse three-dimensional spinal deformity, however, these procedures necessitate higher radiation doses.

METHOD

In this study we define angles according to the Cobb Definition. By means of trigonometrical evaluation, 3D calculation of spinal deformity is demonstrated using MRI of the total spine in two reconstructed perpendicular planes. 3D spinal analysis was performed on 41 female and 7 male patients with scoliosis.

RESULTS

79 angles were measured by using the Cobb angle in reconstructed coronal plane of MRI of the total spine and, in addition, by using our method. The scoliosis Cobb angles ranged from 11 - 59 degrees (mean: 23 degrees +/- 9 degrees ), the real angles ranged from 12 - 70 degrees (mean: 32 +/- 14 degrees ). There was a poor correlation between Cobb angles and the 3D calculated angles (r = 0.37; p < 0.0001).

CONCLUSION

Our method enables us to determine the real angle of scoliosis and to avoid techniques with any radiation risk for the patient.

[Ultrasound topometric measurements of thoracic kyphosis and lumbar lordosis in school children with normal and insufficient posture]

AIM

The posture of school children was examined in order to establish whether possible differences in clinically normal and insufficient posture can be detected by means of ultrasound topometry.

METHOD

105 healthy school children (56 female, 49 male) with an average age of 8 years (+/- 0.9) were examined. To classify the children as having sufficient or insufficient posture the Matthiass posture test was used. While the child stood in a relaxed position, the profile of the spine was measured with a topometric digitiser, recording each spinal processus from C7 to L5.

RESULTS

42 children (22 female, 20 male) showed an insufficient posture during the Matthiass test. The topometrically measured angles of kyphosis and lordosis were significantly smaller in these children, corresponding to a clinically greater thoracic kyphosis and lumbar lordosis. No significant differences in the lateral and anterior-posterior trunk deviation, nor in the range of trunk sway in the relaxed standing position could be observed.

CONCLUSION

Using ultrasound topometry, the posture of children with sufficient and insufficient posture can be differentiated by measuring, the angles of kyphosis and lordosis. This quantification could be used for objective monitoring of the posture.

[Butterfly vertebrae and scoliosis: Alagille syndrome]

INTRODUCTION

Alagille syndrome is a dominantly inherited disorder affecting the liver (arteriohepatic dysplasia), the heart, the eyes and the face. Butterfly vertebrae in the thoracic and lumbar spine are detectable in 50 to 80 per cent of the patients; most of them remain asymptomatic. The management of progressive cholestasis in early childhood is the main aspect of therapy.

CASE

A 14-year-old female patient with Alagille syndrome was referred to our hospital for examination of a right thoracic scoliosis. Magnetic resonance imaging verified butterfly deformity in thoracic vertebrae 2, 4, 6, 7, 8, 10, 11, and lumbar vertebra 3. Asymmetries of thoracic vertebrae 6, 8 and especially, 7 were responsible for the scoliosis.

CONCLUSION

The highly variable expression of these typical characteristics in mildly affected patients can cause some difficulties. When diagnosing a scoliosis with asymmetric butterfly vertebrae, an Alagille syndrome should be considered, especially if the patient shows a liver dysfunction.

The biological role of the Alzheimer amyloid precursor protein in epithelial cells

Proteolytic processing of the Alzheimer amyloid precursor protein (APP) results in the generation of at least two distinct classes of biologically relevant peptides: (1) the amyloid beta peptides which are believed to be involved in the pathogenesis of Alzheimer's disease and (2) the soluble N-terminal ectodomain (sAPP) which exhibits a protective but as yet ill-defined effect on neurons and epithelial cells. In this report we present an overview on the functions of sAPP as an epithelial growth factor. This function involves specific binding of sAPP to membrane rafts and results in signal transduction and various physiological effects in epithelial cells as different as keratinocytes and thyrocytes. At nanomolar concentrations sAPP induces a two to fourfold increase in the rate of cell proliferation and cell migration. Specific inhibition of APP expression by antisense techniques results in decreased sAPP release and in reduced proliferative and motogenic activities. Proliferation and migration are known to be part of complex processes such as wound healing which, therefore, might be facilitated by the growth factor function of sAPP.

A new method of MR total spine imaging for showing the brace effect in scoliosis

Bracing is a method of early, nonsurgical treatment for scoliosis, but a hypokyphotic effect on the thoracic spine is reported. We developed a magnetic resonance tomography (MR) procedure presenting an image of the whole spine in the coronal and sagittal planes (MR total spine imaging), and studied the brace effect, using this technique. We examined 26 female patients with idiopathic scoliosis treated with a Cheneau brace (mean age, 13.2 years; mean duration of brace treatment at the time of investigation, 1.5 years). The MR examinations were performed with the patient in the supine position with and without the brace in direct sequence. As measured on the coronal MR images, the thoracic curve was corrected, on average, from 29 degrees to 22 degrees (mean correction, 24%). There was a slight reduction in the sagittal Cobb angle measured between T4 and T12 (mean sagittal Cobb angle without brace, 14 degrees; with brace, 12 degrees ), which was still a significant change. MR total spine imaging could be a useful tool for studying the brace effect in scoliosis in two planes. Using this technique, we found reduced sagittal Cobb angles for the thoracic kyphosis with brace. Because there is no radiation exposure, the MR procedure has a potential use in the monitoring of brace treatment.

Bimodal breathing in jumping spiders: morphometric partitioning of the lungs and tracheae in Salticus scenicus (Arachnida, Araneae, Salticidae)

In jumping spiders, both the book lungs and the tracheal system are well-developed. The tracheal system consists of four thick primary tracheae that branch into small secondary tracheae, some of them ending in the opisthosoma and others entering the prosoma. We used stereological morphometric methods to investigate the morphological diffusing capacity of the lungs and of the walls of the secondary tracheae (‘lateral diffusing capacity’) of two groups of Salticus scenicus with mean body masses of 2.69 mg (group A) and 5.28 mg (group B). The thickness of the gas-exchange epithelium of the lungs was 0.164 μm (group A) and 0.186 μm (group B) for the total diffusion barrier. The secondary tracheae were divided arbitrarily into seven classes according to their inner diameter (1–7 μm). The diffusion barriers of the tracheal walls tend to be thinnest (0.17 and 0.18 μm) for the smallest tracheae, the walls of the other tracheal classes having approximately the same thickness of diffusion barrier (0.24–0.32 μm).

The calculated oxygen-diffusing capacity (DO2) for the lungs was 16.4 μl min–1 g–1 kPa–1 for group A and 12 μl min–1 g–1 kPa–1 for group B; the DO2 of the walls of all secondary tracheae was 5.91 μl min–1 g–1 kPa–1 for group A animals and 6.63 μl min–1 g–1 kPa–1 for group B animals.

Our results are consistent with the hypothesis that the tracheal system plays an important role in gas exchange in jumping spiders. Resting and low-activity oxygen consumption rates can be met by the lungs or the tracheae alone, while high oxygen demands can be met only if both respiratory systems are working together. Tracheae entering the prosoma have only 4–10 % of the total tracheal diffusing capacity, thus providing sufficient oxygen for the nervous system but not being able to prevent muscle fatigue. The similar thickness of the walls of all tracheal classes is consistent with the hypothesis that the secondary tube tracheae function as ‘tracheal lungs’, supplying the haemolymph and organs by lateral diffusion.

Fluorine-18 fluorodeoxyglucose positron emission tomography findings in spondylodiscitis: preliminary results

Nuclear medicine procedures can be helpful in diagnosing spine infections. The purpose of the study was to evaluate the findings of positron emission tomography with fluorine-18 fluorodeoxyglucose (FGD-PET) in the detection of spondylodiscitis. We performed FDG-PET in 16 patients with suspected spondylodiscitis. All the patients were operated and underwent histopathological examination. The FDG-PET findings were graded and evaluated by two independent nuclear medicine physicians. Of the 16 patients, 12 had a histopathologically confirmed spondylodiscitis. In all these 12 patients, FDG-PET was true-positive. In the four patients without spondylodiscitis, FDG-PET showed three true-negative and one false-positive result. In spondylodiscitis, the mean standard uptake value (SUV) of FDG was 7.5 (SD+/-3.8). The PET scans depicted the paravertebral soft tissue involvement in cases of spondylodiscitis. Our first results showed that FDG-PET is a very sensitive imaging procedure in the detection of spondylodiscitis. Compared to other nuclear medicine procedures, PET enables a rapid imaging with acceptable radiation dose and high spatial resolution.

Morphology of a thermosensitive multipolar neuron in the infrared organ of Merimna atrata (Coleoptera, Buprestidae)

Two pairs of infrared (IR) organs are situated ventrolaterally on the second and third abdominal sternites of the Australian fire beetle Merimna atrata (Buprestidae). In ventral view, each IR organ has a round IR absorbing area under which a sensory complex is attached to the epidermis. The main component of the complex is a single large multipolar neuron and its mass of highly branched dendrites. All parts of this neuron are enveloped in glial cells. The proximal primary dendrites, which arise from the soma, finally branch into several hundred tightly packed terminal dendrites, which contain many mitochondria. We term this unusual morphology of the dendritic region a terminal dendritic mass (TDM). Additionally, two chordotonal organs were found in each sensory complex. Their somata are integrated in the complex and the dendrites extend to the periphery of the absorbing area. The bauplan of the dendritic region is reminiscent of the thermosensitive trigeminal nerve fibers innervating the absorbing structures in the IR receptors in boid and crotalid snakes. Because this multipolar neuron also functions as a thermoreceptor, another example of a functional analogy between insect and vertebrate sensory systems could be demonstrated.

[Sagittal Cobb-angle measurements in scoliosis with MRI whole spine imaging]

AIM

A newly developed MR procedure allows imaging of the whole spine in coronal and sagittal planes. We studied the use of total spine MR imaging in measuring sagittal Cobb angles in scoliosis.

METHOD

64 patents with idiopathic scoliosis (mean age 18.1 years, 35 thoracic, 20 double major, and 9 lumbar curves) and 27 patients without scoliosis were consecutively examined. The MR images were acquired in the supine position. The sagittal Cobb angles were measured between T4-T12 and between T12-L5.

RESULTS

For the group of the thoracic and double major scoliosis the mean sagittal Cobb angle (T4-T12) was 13 degrees and for the group without scoliosis 23 degrees, which was a significant difference (p < 0.01, Mann Whitney-U-test). There was a negative correlation between the sagittal Cobb angles (T4-T12) and the lateral, thoracic curves. The mean sagittal Cobb angle (T12-L5) of the group with lumbar and double major curves was 35 degrees, which was not a significant difference when compared to 37 degrees of the non-scoliotic group.

CONCLUSION

Using total spine MR imaging the lordotic aspect of the thoracic deformation in scoliosis can be reliably measured. Because of the absent radiation exposure the sagittal MR reconstructions could be used as an additional imaging in monitoring scoliosis.

Transfer of primer binding site-mutated simian immunodeficiency virus vectors by genetically engineered artificial and hybrid tRNA-like primers

Simian immunodeficiency viruses (SIV) harbor primer binding sites (PBS) matching tRNA or tRNA. To study determinants of primer usage in SIV, a SIVmac239-based vector was impaired by mutating the PBS to a sequence (PBS-X2) with no match to any tRNA. By cotransfection of a synthetic gene encoding a tRNA(Pro)-like RNA with a match to PBS-X2, the activity of this vector could be restored to a transduction efficiency slightly lower than that of the wild-type vector. A vector with a PBS matching tRNA(Pro) was functional at a level slightly below that of the wild-type vector, but higher transduction efficiency could be obtained by cotransfection of a gene for an engineered tRNA(Pro)-tRNA hybrid with a match to PBS-Pro. The importance of tRNA backbone identity was further analyzed by complementing the PBS-X2 vector with a gene for a matching x2 primer with a tRNA backbone, which led to three- to fourfold-higher titers than those observed for the x2 primer with the tRNA(Pro) backbone. In summary, our results demonstrate flexibility in PBS and primer usage for SIVmac239, with PBS-primer complementarity being the major determinant, in analogy with previous findings for murine leukemia viruses and human immunodeficiency virus type 1.

A new MRI technique for imaging scoliosis in the sagittal plane

The purpose of the present study was to introduce a new magnetic resonance imaging (MRI) procedure showing the whole spine in a coronal and sagittal plane, and to study the assessment of sagittal Cobb angle measurements using this technique. Prospectively we studied 32 patients (average age 14.8 years) with idiopathic scoliosis (mean thoracic Cobb angle 33 degrees on radiograph) and 18 patients (average age 14.5 years) without scoliosis. The MRI investigation was carried out in a standard supine position. The cervical and upper thoracic spine and the lower thoracic and lumbar spine were measured on a 1.5-T Gyroscan ACS-NT Powertrak 6000 system. An algorithm was developed to combine the results of the cranial and caudal scans into a coronal and a sagittal image of the whole spine (MR total spine imaging). Measurement of the sagittal Cobb angle conducted ten times by four independent investigators revealed an intraobserver variance of 1.6 degrees and an interobserver variance of 1.8 degrees. In the group with scoliosis the mean sagittal Cobb angle from T4 to T12 was 12 degrees (range -3 degrees to 24 degrees) and in the group without scoliosis 22 degrees (range 16 degrees to 30 degrees), which was a significant difference. MR total spine imaging makes it possible to image scoliosis in the sagittal plane. On these MR projections, idiopathic thoracic scoliosis was identified by a reduced sagittal Cobb angle. MR total spine imaging would allow monitoring of scoliosis in the sagittal plane, which can reveal relevant clinical data without radiation exposure.

Sensitivity threshold and response characteristics of infrared detection in the beetle Melanophila acuminata (Coleoptera: Buprestidae)

The minimum detection threshold of the infrared sensitive beetle, Melanophila acuminata, was measured with a helium-neon laser that emitted light at a wavelength of 3.39 microm. Extracellular recordings were taken both at the pit organ responsible for detection and at the interganglionic connectives in the thorax of the beetle. At the pit organ, generator and action potentials from single neurons were measured with a sharpened tungsten electrode. At the connectives that linked the fused second meso-/metathoracic and prothoracic ganglia, compound action potentials were measured with a tungsten hook electrode that encircled the connective. The latter recordings confirmed conveyance of infrared information through specific pathways to rostrally-situated sites in the nervous system of the beetle. The 50% probability irradiance threshold at which action potentials were elicited from the receptor and connectives occurred at 17.3 and 14.6 mW/cm(2), respectively. In addition to sensitivity threshold, several other characteristics of the response were quantified including dependence of generator potential latency, generator potential duration, spike frequency, and spike latency on irradiance, dependence of response strength (spike count) on exposure time, and flicker fusion frequency. The ability to detect infrared radiation is rare in nature, and these results provide valuable information necessary to understand this unique sensitivity.

[Incidence of thrombophilic factor V Leiden and prothrombin G20210A mutation in Perthes disease--a pilot study]

AIM

Thrombophilic mutations may play a role in the pathogenesis of the juvenile osteonecrosis of the femoral head, Perthes' disease. We investigated whether children with Perthes' disease have an increased incidence of mutations of factor V (Leiden) and prothrombin (G2O210A), which predispose to thrombosis.

METHODS

For this pilot study, we analysed the data of twenty consecutive children (16 boys, 4 girls, mean age at diagnosis 6.4 years). According to Catterall's classification of severity, 2 children were in group 1, 7 in group 2, 8 in group 3, and 3 were in the most severe group 4. Mutations of factor V and prothrombin were identified in EDTA-blood by PCR amplification, digestion with restriction enzymes, and gel electrophoresis.

RESULTS

Heterozygoty for the factor V mutation was detected in two children, for the prothrombin mutation in one child. Both results did not differ significantly from the incidence in Germany, which is 0.05 for factor V mutations and 0.04 for prothrombin mutations.

CONCLUSIONS

For the presented group of children with Perthes' disease, we did not find an increased rate of factor V or prothrombin mutations compared to the natural incidence. In accordance to other recent studies, our results do not support a link between inherited thrombophilic mutations and Perthes' disease.

Alleviation of murine leukemia virus repression in embryonic carcinoma cells by genetically engineered primer binding sites and artificial tRNA primers

The primer binding site (PBS) plays pivotal roles during reverse transcription of retroviruses and also is the target of a cellular host defense impeding the transcription of murine leukemia virus (MLV) harboring a proline (pro) PBS in embryonic cells. Both the PBS and the tRNA primer are copied during reverse transcription and anneal as complementary DNA sequences creating the PBS of the integrated provirus. The pro PBS of MLV can be exchanged by PBS sequences matching endogenous or engineered tRNAs to allow replication of Akv MLV-derived vectors in fibroblasts. Here we use the PBS escape mutant B2 to demonstrate the capacity of the synthetic tRNA(B2) to function in reverse transcription in competition with endogenous tRNAs in fibroblasts and embryonic carcinoma (EC) cells. We further show symmetry between PBS and the primer by the ability of the synthetic tRNA(B2) to confer escape from EC repression of a PBS-Pro vector. Of a panel of vectors with the repressed pro PBS substituted for other natural or artificial PBS sequences, all except one efficiently expressed the neo marker gene when transferred to NIH/3T3 and EC cells, hence avoiding PBS-mediated silencing in EC cells. A non-natural PBS matching an artificially designed tRNA molecule conferred no further relief from repression than that attained with the B2 escape mutant or the natural alternative PBSs. Interestingly, a vector harboring a PBS matching tRNA(Lys1.2) suffered repression similar to the wild-type PBS-Pro but was partially rescued by a single point mutation of the PBS.

Use of fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography in assessing the process of tuberculous spondylitis

Fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography can be used to quantify the pathologic increase in glucose metabolism of inflammatory processes. Preliminary studies indicate a high level of sensitivity and specificity in detecting and identifying chronic osteomyelitis. This case study shows that positron emission tomography can be used to assess the process of inflammatory activity in tuberculous spondylitis. This technology also has the advantage of higher spatial resolution compared with other nuclear medicine procedures. In addition, it can differentiate between bone and soft tissue infection and allows imaging in the presence of metal implants.

A new type of infrared organ in the Australian "fire-beetle" Merimna atrata (Coleoptera: Buprestidae)

The Australian buprestid beetle Merimna atrata (Coleoptera: Buprestidae) approaches forest fires because its larvae develop in freshly burnt wood. So far nothing is known about possible sensory systems enabling the beetles to detect fires and to cope with the thermal environment close to the flames. We found that M. atrata has two pairs of infrared (IR) organs on the ventrolateral sides of the abdomen. Each IR organ consists of a specialized IR-absorbing area which is innervated by one thermosensitive multipolar neuron. The primary dendritic branches ramify into more than 800 closely packed terminal endings which contain a large number of mitochondria. We called the special morphology of the dendritic region a terminal dendritic mass. The type of IR receptor found in M. atrata is unique in insects and can best be compared with the IR organs of boid snakes.

Lung morphology in rodents (Mammalia, Rodentia) and its implications for systematics

A new nomenclature of the lung lobes and of the bronchial tree is presented, with which the lungs in 40 species of 11 rodent families are described. Whole, fixed lungs and silicone casts of the bronchial tree are tested for 23 characters, based on the distribution of lung lobes, the number and geometry of first order bronchi, the pulmonary blood supply, and lung symmetry. Ten lung morphotypes are recognized, seven of them representing one or more families: Castor type (Castoridae), Cryptomys type (Bathyergidae), Ctenodactylus type (Ctenodactylidae), Eliomys type (Gliridae), Myocastor type (Myocastoridae), Octodon type (Octodontidae and Echimyidae) and Rattus type (Sciuridae, Muridae pt. and Dipodidae). The Hydromys type is found only in Hydromys chrysogaster (Muridae), while Galea type A and B both appear in Galea musteloides (Caviidae). The data are phylogenetically analyzed by the program PAUP 4.0 using as outgroup Lagomorpha or Insectivora. On the species level, there are no well-resolved cladograms. On the family level, the cladograms do not contradict traditional rodent systematics with one exception: the Caviidae do not fall within Caviomorpha or even within the Hystricomorpha, but form a sister group to Dipodidae (Myomorpha). This appears to be a result of convergence. The lungs of Gliridae are more similar to those of Muridae than to those of Sciuridae. Included in the ingroup, Oryctolagus (Lagomorpha) forms a clade with Caviidae + Dipodidae. Thus, the "Glires hypothesis" is neither supported nor refuted.

Morphometric partitioning of respiratory surfaces in amphioxus (Branchiostoma lanceolatum Pallas)

The anatomical diffusing factors (ADFs), defined as the ratio of surface area to the thickness of the diffusion barrier, of possible respiratory surfaces of adult amphioxus (Branchiostoma lanceolatum) were evaluated using stereological methods. The ADF is greatest for the lining of the atrium and for the skin covering the segmental muscles. Calculation of the diffusing capacities for O(2) revealed that the lining of the atrium makes up nearly 83 % of the entire diffusing capacity (8.86 × 10(−3) microl min(−1)mg(−1)kPa(−1) while the skin over the segmental muscles (9%), the skin over the metapleural fold (4%) and the gill bars (4%) are of minor importance. The diffusing capacity of surfaces lying over coelomic cavities makes up 76% of the whole diffusing capacity, which is consistent with the hypothesis that the coelom may function as a circulatory system for respiratory gases. Muscles have approximately 23% of the entire diffusing capacity, indicating that they may be self-sufficient for O(2) uptake. The diffusing capacity of the blood vessels in the gill bars is only 1% of the total. Thus, the ‘gills’ lack significant function as respiratory organs in amphioxus (lancelets).

Measuring statistical dependence and coupling of subsystems

We investigate recently proposed measures for the statistical dependence of systems with complex dynamical behavior. We consider appropriate model systems, to ensure that influences of individual properties of the systems are excluded. We demonstrate that it is indeed possible to obtain nontrivial directional information, but we also argue that the interpretation of this information is difficult.

First data on the molecular phylogeography of scincid lizards of the genus Mabuya

A 487-bp fragment of the mitochondrial 16S rRNA gene was sequenced in 26 species of the circumtropical lizard genus Mabuya and used to analyze phylogenetic relationships within the genus. The species from Africa and Madagascar formed a monophyletic group relative to the included Asian and South American taxa. The Malagasy species included (M. elegans, M. cf. dumasi, and M. comorensis) did not appear as a monophylum. Combined and separate analysis of the 16S data and additional sequences of the mitochondrial 12S rRNA, ND4, and cytochrome b genes (a total of 2255 bp) in one Asian, two Malagasy, and two African species also did not result consistently in a monophyletic grouping of the Malagasy taxa. However, a monophylum containing African and Malagasy taxa was strongly supported by the combined analysis. These preliminary results indicate that Mabuya probably colonized Madagascar from Africa through the Mozambique Channel.

[FDG-PET for diagnosis and follow-up of inflammatory processes: initial results from the orthopedic viewpoint]

AIM

The diagnosis and the assessment of osteomyelitis and spondylodiscitis can be difficult. The aim of this study was to evaluate the usefulness of FGD-PET in the detection of inflammatory processes.

METHOD

23 orthopedic patients suspected of having peripheral osteomyelitis (n = 13) or spondylodiscitis (n = 10) were examined consecutively with FDG-PET. The FDG-PET scans were evaluated by the nuclear physicians in ignorance of the clinical diagnosis by visual interpretation, which was graded on a five-point scale (0 = no infection-4 = definitely infection).

RESULTS

Of 23 patients, 15 had osteomyelitis (n = 8) or spondylodiscitis (n = 7). In these 15 cases, the FDG-PET was true-positive. The sensitivity was 100%. In the 8 cases without infection, the FDG-PET was in 5 cases true-negative and in 3 cases false-positive. Even with inlying metal implants, soft-tissue abscesses could be differentiated from the bony process.

CONCLUSION

The FDG-PET is a very sensitive procedure for the diagnosis of osteomyelitis and spondylodiscitis and for screening of inflammation foci. A further advantage is the high spatial solution. The quantification of the inflammatory activity allowed a monitoring of the therapy.

Chromosomal abnormalities in hypoprolific boars

Four new chromosomal rearrangements are reported in the domestic pig: 3 reciprocal translocations, rcp(4;12)(p13;q13) in a crossbred boar, rcp(1;7)(q17;q26) in a Large White purebred boar, rcp(1;6)(q17;q35) in a purebred synthetic paternal line boar, and a pericentric inversion inv(2)(p13q11) in a crossbred boar. The 1/7 reciprocal translocation and the pericentric inversion were detected in animals that had sired small litters. The effect of the 1/7 translocation was accurately determined: -4.5 piglets born per litter, i.e. -36%. Both the 1/6 and 1/7 reciprocal translocations were of maternal origin. All the chromosomal rearrangements were highlighted using GTG and/or RBG banding techniques. Chromosome painting experiments were also carried out to confirm the proposed hypotheses for the three reciprocal translocations.

The thioredoxin boxes of thyroglobulin: possible implications for intermolecular disulfide bond formation in the follicle lumen

Multimerization of thyroglobulin (TG) takes place extracellularly in the thyroid follicle lumen and is regarded as a mechanism to store TG at high concentrations. Human thyroglobulin (hTG) has been shown to multimerize mainly by intermolecular disulfide cross-links. We recently noted that TG of various mammalian species contains three highly conserved thioredoxin boxes (CXXC). This sequence is known to underlie the enzymatic activity of protein disulfide isomerase (PDI). As hTG formed intermolecular disulfide bonds in the absence of other proteins depending on the redox conditions and hTG concentration, the CXXC-boxes of TG might provide the structural basis for self-assisted intermolecular cross-linking. To test this hypothesis we prepared a recombinant TG fragment containing the three thioredoxin boxes. This fragment exhibited a redox activity amounting to about 10% of the activity of PDI at redox conditions supposed to be present in the extracellular space. This activity might be supplemented by the oxidizing system of the apical cell surfaces of thyrocytes facing the follicle lumen. Indeed, incubation of hTG with peroxidase and H202 resulted in intermolecular disulfide bridge formation. Our results suggest a combined mechanism of self-assisted and peroxidase-mediated disulfide bond formation leading to the intermolecular cross-linking of lumenal hTG.

Identification of a novel human tRNA(Ser(CGA)) functional in murine leukemia virus replication

We have identified a human tRNA(Ser) isoacceptor matching the UCG codon. The tRNA was discovered via its ability to act in reverse transcription of a murine leukemia virus vector containing a complementary tRNA primer binding site (Lund et al., Nucleic Acids Res., 28 (2000) 791-799). The tRNA(Ser(CGA)) was detected in cell lines of human, monkey and mouse origin. The UCG codon is the most rarely used codon in human genes. The cloned human tRNA(Ser(CGA)) gene encodes an 85 nucleotide, intron-less tRNA, contains a consensus split intragenic promoter and is located at region p21.3-22.2 on chromosome 6. The integrity and functionality of the cloned tRNA(Ser(CGA)) gene was verified by in vitro transcription analysis in HeLa nuclear extracts.