On the consistency of the blocked neural network estimator in time series analysis

We describe a nonlinear regression problem, where the regression functions have an additive structure and the dependent variable is a one-dimensional time series. Multivariate time series with unknown time delay operators are used as independent variables. By fitting a feedforward neural network with block structure to the data, we estimated the additive regression function and, parallel to this, the time lags. We present the consistency proof of neural network weights estimator and the time lag estimator independently from each other. In the practical part of the article, we present the useful feature of blocked neural networks to estimate the relevance measures of each input variable in a simple way. Furthermore, we propose an approach to solve the well-known variable selection problem for the class of nonlinear multivariate beta-mixing time series models considered here. Finally, we apply the methodology to an artificial example.

[End stage renal disease after ingestion of mushrooms]

This case report describes a 56 year old patient with acute renal failure caused by a mushroom poisoning. Unspecific symptoms like a gastroenteritis followed by kidney insuffiency lead to the diagnosis of an orellanus syndrome. The toxin can be proved by thin layer chromatography in renal biopsy. Fast processing of hemoperfusion may avoid lasting kidney damage and dialysis.

Sequence motifs and prokaryotic expression of the reptilian paramyxovirus fusion protein

Fourteen reptilian paramyxovirus isolates were chosen to represent the known extent of genetic diversity among this novel group of viruses. Selected regions of the fusion (F) gene were sequenced, analyzed and compared. The F gene of all isolates contained conserved motifs homologous to those described for other members of the family Paramyxoviridae including: signal peptide, transmembrane domain, furin cleavage site, fusion peptide, N-linked glycosylation sites, and two heptad repeats, the second of which (HRB-LZ) had the characteristics of a leucine zipper. Selected regions of the fusion gene of isolate Gono-GER85 were inserted into a prokaryotic expression system to generate three recombinant protein fragments of various sizes. The longest recombinant protein was cleaved by furin into two fragments of predicted length. Western blot analysis with virus-neutralizing rabbit-antiserum against this isolate demonstrated that only the longest construct reacted with the antiserum. This construct was unique in containing 30 additional C-terminal amino acids that included most of the HRB-LZ. These results indicate that the F genes of reptilian paramyxoviruses contain highly conserved motifs typical of other members of the family and suggest that the HRB-LZ domain of the reptilian paramyxovirus F protein contains a linear antigenic epitope.

[Ultrasonographic visualization of a Baker-cyst as cause of a peroneal nerve palsy in a patient with rheumatoid arthritis]

With this report we present a patient with rheumatoid arthritis in whom a popliteal cyst could be diagnosed quickly and conclusively by ultrasonography as the possible reason for peroneal palsy. The sonographic investigation of the knee joint revealed an effusion. Within the popliteal fossa (dorsal longitudinal and transverse section) a cyst measuring 54 x 21 x 51 mm in a typical dorsomedial position in between the heads of the gastrocnemius muscles was found. Besides extensive synovectomy, we completely removed the cyst. The common peroneal nerve was entrapped by the Baker's cyst. The complete palsy of the nerve improved postoperatively (grade 4 according to Janda). Ultrasonography is an excellent diagnostic procedure for easy, quick, and reliable differential diagnostic evaluation of a swelling within the popliteal fossa region.

[Visualization of a solitary myeloma of the sternum by ultrasonography]

We report on a 32-year-old patient with a 9 month history of pain of the mid-third of his sternum. The laboratory results as well as other diagnostical methods (MRI and bone scintigraphy) were negative. The ultrasound examination revealed an interruption of the corticalis reflex beneath the sternal synchondrosis of a length of 4 cm. Under suspicion of an osteolysis we performed an open biopsy. The histological analysis made the diagnosis of a solitary myeloma. Therefore ultrasonography is able to depict tumerous infiltrations of the sternum if the anterior corticalis is involved and allows therapeutical consequences.

Enzymatic synthesis of N-acetyllactosamine in aqueous-organic reaction media

Beta-galactosidase from Bacillus circulans was used for the biocatalytic transfer of D-galactose (D-Gal) from o-nitrophenyl-beta-D-galactoside (ONPG) to the O-4 position of 2-acetamido-2-deoxy-D-glucopyranose (D-GlcNAc) forming the disaccharide N-acetyllactosamine (LacNAc, beta-D-Gal-(1 --> 4)-D-GlcNAc). In order to investigate the potential of this biocatalytic synthesis, first the optimal reactant ratio in an aqueous buffer system was determined. On the basis of these standard conditions we then performed reactions in aqueous-organic media applying organic cosolvents of different structure and polarity in various amounts. In this way we received in some cases appreciably better results than without organic cosolvent. The highest obtainable disaccharide yield was 50% in a mixture of 20% (v/v) cyclohexane/80% buffer versus 35% in buffer solution alone.

[Value of ultrasound diagnosis in Legg-Calvé-Perthes disease]

Ultrasound examination of the hip joints in cases of the painful hip in childhood is routinely performed according to the advised standard sections of the German Society for Ultrasound in Medicine (DEGUM) at the special surgery of paediatric orthopaedics of the Orthopaedic University Clinic Magdeburg. Between 1993 and 2000 we performed 418 sonographic examinations of painful hip joints in 153 children. We identified 53 children (159 sonograms) with coxitis fugax, 47 children (188 sonograms) with Morbus Perthes, 28 children with epiphysiolysis capitis femoris, and three children with septic arthritis. In 15 cases (30 sonograms) no sonopathologic changes were observed. However, only in seven cases where ultrasound examination failed to reveal pathological changes, the cause of painful hip was identified by means of radiation depending X-ray or MRI. Sonograms of children with Morbus Perthes were further used to evaluate for stage differentiation and potential surgical treatment. Thus, we could show that ultrasound examination is a powerful tool for identifying the variety of underlying causes of painful hip in childhood and should be used as method-of-choice especially in children to avoid unnecessary radiation exposure.

RES function and liver microcirculation in the early stage of acute experimental pancreatitis

BACKGROUND/AIMS

The reticuloendothelial system and in particular the Kupffer cells in the liver are important for eliminating antigens and toxic substances in many diseases including acute pancreatitis. Optimal Kupffer cell function is believed to depend on numerous factors including intact hepatic blood supply and microcirculation. The aim of the study was to evaluate whether hepatic microcirculation and Kupffer cell function are impaired in acute pancreatitis and whether enhancement of hepatic capillary blood flow leads to improved reticuloendothelial system function.

METHODOLOGY

Acute pancreatitis was induced in rats by intraductal infusion of bile salt followed by i.v. cerulein hyperstimulation. Animals were randomized to receive either a selective endothelin-A receptor antagonist (ET-RA; LU-135252; 50 mg/kg) or saline. Sham-operated animals (intraductal and i.v. saline infusion) treated according to the same protocol served as controls. Liver phagocytic function was evaluated in 6 animals per group 6 and 24 hrs after acute pancreatitis induction and treatment using 99mTc-labeled Nanocoll and a scintillation camera technique. Another 6 animals of each group were used for intravital microscopic determination of hepatic capillary blood flow using fluorescein-labeled erythrocytes.

RESULTS

Six hours after acute pancreatitis induction, hepatic capillary blood flow and nanocoll clearance were significantly decreased in saline-treated animals (compared to saline-treated healthy controls). Endothelin-A receptor antagonist significantly improved hepatic capillary blood flow and nanocoll clearance. This beneficial effect was no longer seen after 24 hrs when these parameters had spontaneously returned to values not significantly different from normal.

CONCLUSIONS

Reticuloendothelial system function and hepatic capillary blood flow are impaired (only) in the early stage of this acute pancreatitis model. Endothelin-A receptor antagonist improves hepatic capillary blood flow at this stage. Enhancement of hepatic capillary blood flow is accompanied by normalization of nanocoll clearance, suggesting that hepatic microcirculation influences phagocytic Kupffer cell function early in acute pancreatitis.

[Spondylitis due to Salmonella typhimurium]

Very little is known about Salmonella typhimurium as an agent of spondylitis. Only single cases have been described in the international literature over the last years. We report on three patients suffering from spondylitis with Salmonella typhimurium being isolated as the triggering agent and point out the subtly differentiated diagnostic and therapeutic procedures, especially the possible complications of a Salmonella spondylitis. For one of the patients, we diagnosed a concomitant abdominal aortic aneurysm. Another patient sustained an infection of a known aortic aneurysm, which had been operated on 3 years ago. The source of the infection could be either the aneurysm or the spine, with the other structure being infected subsequently. We also discuss possible pathogenesis.

[Heparin induced thrombocytopenia type II after the use of low-molecular weight heparin. Case report and review of the literature]

INTRODUCTION

It has been suggested, that HIT-type-II can occur both after the use of low-molecular-weight and unfractionated heparin. The present study investigates the incidence of HIT-type-II after the use of low molecular weight heparin by reviewing the literature and describes one own case.

CASE REPORT

We observed in a 72 year old female patient a HIT-type-II, who received low molecular weight heparin (Clexane 40 o.a.d) after the implantation of an endoprothesis as thrombosis prophylaxis. This occurred on the 9th postoperative day. One year later we performed a second endoprosthesis operation of the contralateral site without complications. With the known HIT-type-II, diagnosed the year before,we used hirudin (Refludan) for thrombosis prophylaxis.

RESULT

A critical view on the international literature revealed only a few cases, where a HIT-type-II was caused by the use of low molecular weight heparin. The incidence seems to be much lower than correlated to the use of unfractionated heparin.

CONCLUSION

It is possible to suffer from a HIT-type-II after low molecular weight heparin. This study confirms the suspicion that the incidence of a HIT-type-II after low molecular weight is lower than after unfractionated heparin. Therefore the further use of unfractioned heparin for thrombosis prophylaxis has to be questioned and low molecular-weight heparin should be preferred.

[Results after resection of juxta-facet-cysts - Which role does a segmental instability play?]

This study demonstrates the results after operative treatment of patients suffering from a lumbar Juxta-Facet-Cyst. We point out diagnostical aspects, possible concomitant problems and deriving therapeutical consequences. Between 01. 01. 1998 and 31. 03. 2001 9 patients were operated on a synovial cyst or a ganglion of the facet joint at our department. 5 patients were female, 4 patients male with a mean age of 61 (45-70) years. The average clinical and radiological follow up was 11 (5-18) months postoperatively. The clinical examination revealed in 5 out of 9 patients a sensible deficit, in 3 out of 9 patients motoric disturbances. There was no positive sign of Lasegue. The resection of the cyst or ganglion was performed in all cases via a dorsal approach. 8 patients underwent for a spinal stenosis and/or an existing instability a laminectomy and a spondylodesis with an internal fixateur. The histological findings showed a synovial cyst in 6 cases and a ganglion cyst in 3 cases. At the follow up all preoperative sensible or motorical deficits had resolved. Juxta-Facet-Cysts are discovered in some cases intraoperatively by chance, the radiological methods (CT, MRT) are especially in case of a concomitant spinal stenosis uncertain. During all operations, which are performed for a spinal stenosis, one should look for a cyst. The resection of the cyst leads to good functional results, a possible instability should by addressed by a spondylodesis.

[Heparin-induced thrombocytopenia as a complication of postoperative prevention of thromboembolism with unfractionated heparin/low molecular weight heparin after hip and knee prosthesis implantation]

AIM

With this prospective study we analysed the occurrence of a heparin-induced thrombocytopenia type II (hit type II) using unfractioned heparin (UFH) or low-molecular-weight heparin (LMWH) as postoperative thrombosis prophylaxis after primary total hip or knee replacements. Furthermore the postoperative course of the platelet count with UFH and LMWH was investigated.

MATERIAL AND METHODS

In a prospective study we looked at the platelet count of 504 primary endoprothesis patients until the 9. postoperative day. 252 patients got UFH (3-mal 5000 IE Liquemin), 252 patients got LMWH (Clexane 40 opd) as thrombosis prophylaxis.

RESULTS

5 patients of the UFH-group developed a HIT type II (incidence 2%; 95%-confidence interval 0.7-4.5) after 9.8 (7-16) days. Within the LMWH-group we saw just one case (incidence 0.4%; 95%-confidence interval 0-2.1). The drop of the platelet count was on average 64% (40.9-81.6). Within the 498 patients without a HIT type II just 2 patients had a drop of the platelet count between the 5. and 9. postoperative day of more than 15% referring to the preoperative value (24% and 33%).

CONCLUSION

The incidence of a HIT type II after the use LMWH seems to be lesser than after the use of UFH. The postoperative platelet count shows a typical course after a total joint replacement. With deviations of that a HIT type II must be excluded.

Identification and molecular characterization of 18 paramyxoviruses isolated from snakes

Viral agents from 18 different snake species (families Colubridae, Viperidae, and Crotalidae) showing respiratory symptoms and neuronal disease were identified as paramyxoviruses by typical cytopathogenic effect (CPE), electron microscopy, and hemagglutination inhibition. Detailed molecular characterization of the viruses was performed by partial L- and F-gene-specific reverse transcription polymerase chain reaction (RT-PCR) and sequencing, nucleotide and amino acid sequence alignment, and phylogenetic analysis (PHYLIP). RT-PCR of the partial L-gene (566 nt) was successful for all 18 viruses; amplicons of the partial F-gene (918 nt) could be obtained in 16 cases. F- and L-sequence alignment revealed similarities to Fer de Lance virus (FDLV) ranging from 79 to 88% on a nucleotide basis, and 94 to 99% on an amino acid basis. Phylogenetic analysis of the ophidian paramyxoviruses resulted in three clusters for the L-gene sequence and corresponding clusters for the F-gene sequence, indicating no species specificity. We analyzed the F-protein of the snake paramyxoviruses, which proved to have an identical conserved motif of heptad repeat A and predicted a furin cleavage site. This uniformity distinguishes the snake virus group from the other type species of the subfamily Paramyxovirinae. For further classification, we aligned the sequences of the ophidian paramyxoviruses and members of the Paramyxoviridae, such as Sendai virus (genus Respirovirus), mumps virus (genus Rubulavirus), measles virus (genus Morbillivirus), human respiratory syncytial virus (genus Pneumovirus) (Van Regenmortel and 10 co-authors, 2000) and Hendra virus, which have recently been suggested as type species of the genus Henipavirus (Wang et al., 2000). Maximum sequence similarity was found to the partial L-gene of Sendai virus, with 56% nucleotide and 61% amino acid identity. The FDLV and Sendai virus cluster in the phylogenetic analysis of L- and F-protein regarding the Paramyxovirus type species and Hendra virus and show the closest relationship. Regarding the biological properties, the antigenic distance, and particularly the low homology of available sequences, we propose a new genus for the reptilian paramyxoviruses within the Paramyxoviridae.

Contribution of lymphatic drainage system in corneal allograft rejection in mice

PURPOSE

To modulate aqueous outflow via the uveoscleral pathway and to determine its influence on corneal graft survival in mice.

METHODS

BALB/c mice received corneal transplants from C3H mice and were placed randomly in three treatment groups: saline, pilocarpine or latanoprost. Three further groups received adjuvant systemic and topical corticosteroids. The kinetics of infiltrating lymphocytes, neutrophils and macrophages in the transplants was investigated in an additional 96 animals. Cytokine expression in the submandibular lymph nodes and spleen was investigated using in-situ hybridization and RNAse protection assay. Tracer experiments were conducted using 99mTC colloidal albumin Nanocoll; count rates were determined in the submandibular lymph nodes, spleen and blood following both subconjunctival and intracameral injection.

RESULTS

Neither pilocarpine nor latanoprost had any influence on aqueous outflow or allograft survival in mice. Neutrophils and macrophages dominated the infiltrating cells 11 days postoperative in both treated and untreated grafts. On postoperative day 13, a greater increase in lymphocytes than in other cell groups was observed in allogeneic grafts. Following allogeneic transplantation, 1% of lymphocytes in ipsilateral submandibular lymph nodes were positive for IFN-gamma. Tracer studies revealed a 16% aqueous outflow via the uveoscleral routes following intracameral injection of Nanocoll; this was increased by 97% with subconjunctival injection.

CONCLUSION

Our data confirm the existence of functional lymphatic drainage via the uveoscleral pathway and conjunctiva in the mouse. Cells within the ipsilateral submandibular lymph node respond to stimuli upstream. This reaction could potentially be manipulated to improve graft survival.

Adenoviral E1A protein nuclear import is preferentially mediated by importin alpha3 in vitro

Nuclear import of some viral proteins depends on importin alpha proteins. However, no preferences of distinct alpha-importins for any viral protein import have been demonstrated. We used in vitro import assays and observed that all ubiquitously expressed human importin alpha isoforms mediate nuclear translocation of adenoviral E1A. Competition with nucleoplasmin suggests that importin alpha3 is the most efficient import mediator of E1A.

[Ultrasonography of the Osgood-Schlatter disease]

AIM

The aim of our study was to asses the value of ultrasound in the diagnosis of M. Osgood-Schlatter. The results of the primary ultrasound examination were compared with the use of X-ray.

METHOD

15 patients were included in our study (average age 11 - 17 years, 8 female, 7male). All patients get an X-ray of the knee in two or three images. There was a reference-group of 10 patients with 20 joints (average age 11 - 14 years).

RESULTS

We observed typical sonographic images in different stages of M. Osgood-Schlatter. The changes depended on the duration of the disease. In every case we found a thickness of the patellar tendon of more than 1 mm (stage I and II), a bursitis infrapatellaris (stage II) and a fragmentation of the cortical bone of the apophysis (stage II). In cases of stage III disease a thickness of the patellar tendon of less than 1 mm was to be seen. In healthy people the average thickness of the patella tendon was 4.8 mm (3.5 - 5.7 mm). The maximal difference between the left and the right side was 0.4 mm.

CONCLUSIONS

With the use ultrasound in cases of M. Osgood-Schlatter a reduced exposure of children to X-ray is possible. Ultrasound examination is a clear and easy way to diagnose the disease correctly and evaluate its course and cure.

Evidence for a nuclear passage of nascent polypeptide-associated complex subunits in yeast

The nascent polypeptide-associated complex (NAC) has been found quantitatively associated with ribosomes in the cytosol by means of cell fractionation or fluorescence microscopy. There have been reports, however, that single NAC subunits may be involved in transcriptional regulation. We reasoned that the cytosolic location might only reflect a steady state equilibrium and therefore investigated the yeast NAC proteins for their ability to enter the nucleus. We found that single subunits of yeast NAC can indeed be transported into the nucleus and that this transport is an active process depending on different nuclear import factors. Translocation into the nucleus was only observed when binding to ribosomes was inhibited. We identified a domain of the ribosome-binding NAC subunit essential for nuclear import via the importin Kap123p/Pse1p-dependent import route. We hypothesize that newly translated NAC proteins travel into the nucleus to bind stoichiometrically to ribosomal subunits and then leave the nucleus together with these subunits to concentrate in the cytosol.