Targeted disruption of the mouse Npal3 gene leads to deficits in behavior, increased IgE levels, and impaired lung function.

The non-imprinted in Prader-Willi/Angelman syndrome (NIPA) proteins are highly conserved receptors or transporters. Translocation of NIPA genes were found in patients with Prader-Willi syndrome, and loss-of-function of the NIPA1 gene was identified in hereditary spastic paraplegia. The family of NIPA-like domain containing (NPAL) proteins is closely related to the NIPA proteins, but to date nothing is known about their function. Here, we could demonstrate that both human NPAL3 and mouse NPAL3 are ubiquitously expressed and encode highly conserved proteins. To further elucidate the function of the Npal3 gene, knockout (Npal3(-/-)) mice were generated. Intensive phenotypic analyses revealed that disruption of the Npal3 gene results in a pleiotropic phenotype. The function of the nervous system was impaired in both mutant males and females which could be demonstrated in behavioral tests. In addition, in NPAL3 mutants the number of NK cells was decreased and changes in IgM, IgG(2), and IgA were observed, indicating that the immune system is also affected. Interestingly, increased IgE levels as well as impaired lung functions were observed in mutant males but not in mutant females. It should be noted that the human Npal3 gene is located at 1p36.12-->p35.1, and atopic diseases were previously linked to this genomic region. Thus, the Npal3(-/-) mice could serve as a valuable model system for studying atopic diseases.

Breath-by-breath measurement of particle deposition in the lung of spontaneously breathing rats.

A number of deposition models for humans, as well as experimental animals, have been described. However, no breath-by-breath deposition measurement in rats has been reported to date. The objective of this study is to determine lung deposition of micrometer-sized particles as a function of breathing parameters in the adult rat lung. A new aerosol photometry system was designed to measure deposition of nonhygroscopic, 2-mum sebacate particles in anesthetized, intubated, and spontaneously breathing 90-day-old Wistar-Kyoto rats placed in a size-adjusted body plethysmograph box. Instrumental dead space of the system was minimized down to 310 microl (i.e., approximately 20% of respiratory dead space). The system allows continuous monitoring of particle concentration in the respired volume. Breathing parameters, such as respiratory rate (f), tidal volume (Vt), as well as inspiration/expiration times, were also monitored at different levels of anesthesia. The results showed that Vt typically varied between 1.5 and 4.0 ml for regular breathing and between 4.0 and 10.0 ml for single-sigh breaths; f ranged from 40 to 200 breaths/min. Corresponding deposition values varied between 5 and 50%, depending on breath-by-breath breathing patterns. The best fit of deposition (D) was achieved by a bilinear function of Vt and f and found to be D = 11.0 - 0.09.f + 3.75.Vt. We conclude that our approach provides more realistic conditions for the measurement of deposition than conventional models using ventilated animals and allows us to analyze the correlation between breath-specific deposition and spontaneous breathing patterns.

The German Mouse Clinic: a platform for systemic phenotype analysis of mouse models.

The German Mouse Clinic (GMC) is a large scale phenotyping center where mouse mutant lines are analyzed in a standardized and comprehensive way. The result is an almost complete picture of the phenotype of a mouse mutant line--a systemic view. At the GMC, expert scientists from various fields of mouse research work in close cooperation with clinicians side by side at one location. The phenotype screens comprise the following areas: allergy, behavior, clinical chemistry, cardiovascular analyses, dysmorphology, bone and cartilage, energy metabolism, eye and vision, host-pathogen interactions, immunology, lung function, molecular phenotyping, neurology, nociception, steroid metabolism, and pathology. The German Mouse Clinic is an open access platform that offers a collaboration-based phenotyping to the scientific community (www.mouseclinic.de). More than 80 mutant lines have been analyzed in a primary screen for 320 parameters, and for 95% of the mutant lines we have found new or additional phenotypes that were not associated with the mouse line before. Our data contributed to the association of mutant mouse lines to the corresponding human disease. In addition, the systemic phenotype analysis accounts for pleiotropic gene functions and refines previous phenotypic characterizations. This is an important basis for the analysis of underlying disease mechanisms. We are currently setting up a platform that will include environmental challenge tests to decipher genome-environmental interactions in the areas nutrition, exercise, air, stress and infection with different standardized experiments. This will help us to identify genetic predispositions as susceptibility factors for environmental influences.

[Percutaneous lumbar interbody fusion using autogenous osteoblasts in vivo]. / Perkutane lumbale interkorporelle Spondylodese mit autogenen Osteoblasten in vivo.

AIM: In the present study we have investigated the potential of autogenous osteoblasts for osteoinduction in a spinal arthrodesis model. METHOD: After posterolateral instrumentation of 3 segments of a sheep spine the intervertebral space was filled with cancellous bone, osteoblasts or left empty after nucleotomy and elimination of cartilage. RESULTS: Radiological and histological analyses proved a significant osseous reaction in segments treated with cancellous bone or osteoblasts in contrast to the control segment. This outcome provides evidence of spondylodeses by spinal instrumentation in combination with osteoblasts in a sheep model. CONCLUSION: The results suggest a possible application of autologous osteoblasts as an osteoinductor after percutaneous nucleotomy in spinal fusion. The possible application in a human model should be examined.

Laparoscopic ligation of the infrarenal vena cava in combination with transfemoral thrombin infusion: a new animal model of chronic deep venous thrombosis.

OBJECTIVE: We describe a new technique to create an animal model of chronic venous thrombosis. The morphological and histological properties of the resulting thrombi are described. METHODS: Thirteen pigs underwent laparoscopic ligation of the infrarenal vena cava in combination with transfemoral thrombin infusion. After 1, 3, 6, 9, 12 and 15 days, respectively, two animals were killed and the thrombosed vein segments were explanted. After recording their weight and dimensions, the thrombi underwent histological examination by light microscopy. RESULTS: In all 13 cases, the procedure was completed laparoscopically and all 13 animals survived the procedure. While 12 pigs (92%) had an uneventful postoperative course, one animal died on the first postoperative night of an unknown cause. Autopsy revealed correct placing of the ligature with occlusive thrombosis of the inferior vena cava and the iliac veins in 12 animals, in one animal the ligature had been incorrectly placed around the origin of the right iliac vein with thrombosis limited to that vessel. Histological evaluation demonstrated mixed thrombi that showed increasing signs of organisation with advancing age. CONCLUSIONS: Laparoscopic ligation of the infrarenal vena cava in combination with transfemoral thrombin infusion is a safe and reliable way to produce chronic venous thrombosis in an animal model. The resulting thrombi are comparable to human deep venous thrombosis in terms of extent, size and organisation process.