Modulation of the avian immune system: suppression versus induction of immunity

Knowledge of the potential, but also of the vulnerability of the avian immune system is not only of academic interest. The intact immune system, beginning in the embryo, is of central significance to safeguarding health and productivity in poultry flocks. Interactions between cellular and soluble constituents of the avian immune system on one hand, and the nature of immunosuppressants on the other, determine whether the avian immune system is able to cope with microbial and non-microbial challenges. Modulation of the immune response can be achieved in the classical way by specific vaccinations or possibly in the future by DNA vaccination. Cytokine inducing compounds may provide additional tools to enhance immune reactivity. The future will tell whether these approaches will be applicable in disease preventation or treatment in poultry medicine. In concert with these tools, however, strict hygiene measures from incubation until production, slaughter and processing are equally of vital significance as part of disease prevention strategies, ultimately leading to high quality food products originating from animal production.

Ultrashort-pulse wave-front autocorrelation

Combined spatially resolved collinear autocorrelation and Shack-Hartmann wave-front sensing of femtosecond laser pulses is demonstrated for the first time to our knowledge. The beam is divided into multiple nondiffracting subbeams by thin-film micro-optical arrays. With hybrid refractive-reflective silica/silver microaxicons, wave-front autocorrelation is performed in oblique-angle reflection. Simultaneous two-dimensional detection of local temporal structure and wave-front tilt of propagating few-cycle wave packets is demonstrated.

[Poultry husbandry and animal health]

Close interactions are existing between poultry husbandry and poultry health. The more housing systems and the environment of the animals can be controlled, the less the general risk of disorders in poultry flocks--especially of diseases which are caused by the introduction of microoganisms. Resulting deterimental effects will affect not only the animals themselves, but also pose a risk indirectly for humans via food originating from animals under production. Also, by keeping the risk of infections as low as possible, the use of therapeutics can be avoided. This will reduce the risk of residues in food of animal origin. In summary, with all probability open poultry husbandry systems, especially those including free range systems pose increased risks for poultry health and consequently for the quality of food originating from poultry production. At least, those systems require highest standards of biosecurity, defined as management, location, farm layout, cleaning and desinfection incl. pest control programs, immunization and specific veterinary monitoring concepts to prevent infections.

[Computed tomographic aspects of skull development in a child with cherubism]

The clinical picture of cherubism is similar to that of fibrous dysplasia. The initial clinical appearance involves the deformation of the maxillofacial area with orthodontic disorder. Usually it is found in the mandible giving the child a chubby-faced appearance, and it often occurs together with symmetric submandibular lymph node enlargement. This appearance reminds one of the cherubs seen in art. Only histological evidence for cherubism is inconclusive. The presence of multi-nucleated giant cells resembles fibrous dysplasia. A combination of clinical, radiographical and histological findings eventually leads to the correct diagnosis. An example is given of a patient displaying the typical disease process. Over a period of 12 years, we observed the progression of the disease from its initial appearance in a young child, through the full and characteristic display of a cherubic youth, and finally its regression. In conclusion, we advise restraint in planning surgical intervention. The diseases etiology is not entirely dear. The latest research points to genetic defects that lead to failure in the expression of matrix proteins.

Immunochemical localization of megalin, retinol-binding protein and Tamm-Horsfall glycoprotein in the kidneys of dogs

Megalin, retinol-binding protein (RBP) and Tamm-Horsfall glycoprotein (THP) are involved in the renal metabolism of vitamin A in canine species. The presence of megalin, RBP and THP in the kidneys of dogs was investigated using immunohistochemical methods Megalin was highly expressed in the apical membrane of the proximal convoluted and straight tubule cells. Immunoreactive RBP was detected below the apical plasma membrane, as well as in basolateral granules of the proximal convoluted tubule cells. THP immunoreactivity was seen in the epithelial cells lining the thick ascending limb of the loop of Henle. Furthermore, THP was displayed in a scattered pattern within the distal convoluted tubules. The co-localization of megalin and RBP coincides with biochemical studies that have shown megalin to be responsible for renal RBP absorption in the proximal convoluted tubules after filtration through the renal glomerulus. The presence of THP, the carrier for vitamin A in canine urine, showed that vitamin A excretion in the urine of dogs is not merely a filtration process but also seems to be a pathway located in the distal part of the nephron.

[5-year follow-up study of total knee arthroplasty by means of EMG mapping]

AIM

The objective of the present study was to evaluate the long-term functional results after implantation of a total knee arthroplasty (TKA) objectively and quantitatively.

METHOD

Functional parameters (muscular coordination, strength and range of motion) and the subjective satisfaction of the patients were measured by means of EMG mapping, isokinetics, ultrasound and a questionnaire in 21 patients with TKA 5.1 years after implantation of the TKA.

RESULTS

81 % of the investigated patients were subjectively satisfied. The isokinetic results showed a significant improvement of the extensor strength and of the relation between flexors and extensors. Patients who had been more physically active over these 5 years reached significantly better results. The results of EMG mapping showed good overall retention of the satisfactory coordination levels resulting from the initial in-patient rehabilitation. But the coordination patterns demonstrated clear changes showing highly activated areas in the region of the M. vastus medialis. The range of motion and the contraction capacity showed no further improvement compared with the results 26 weeks after implantation of the TKA.

CONCLUSION

Long-term results after implantation of a TKA showed a good muscular coordination, strength and range of motion. A higher physical activity level led to better functional results and greater overall satisfaction of TKA patients 5 years after implantation.

Neuropathotyping: a new system to classify Marek's disease virus

A statistical approach was used to establish a new classification system of Marek's disease virus (MDV) on the basis of neurologic responses. To develop the system, neurologic response data from 15x7 chickens inoculated with 30 strains of serotype 1 MDV were statistically analyzed by a cluster analysis. The goal was to identify a statistical system that would verify if three neurovirulence groups correlated with the three pathotypes previously described. The system was also validated in two additional strains of specific-pathogen-free (SPF) chickens, SPAFAS and line SC (Hy-Vac). The proposed system is based on analysis of three variables: 1) frequency of birds showing transient paralysis between 9 and 11 days postinoculation (dpi), (2) mortality before 15 dpi, and (3) frequency of birds showing persistent neurologic disease between 21 and 23 dpi. By use of this system, a MDV may be classified in one of three groups, designated neuropathotypes A, B, and C, which roughly correspond to the virulent, very virulent, and very virulent plus pathotypes, respectively. However, correlation between neuropathotype and pathotype was not absolute, and neuropathotyping is more a complement to the current pathotyping system than a replacement for it. Our results showed that neuropathotyping studies can be conducted in two types of commercial SPF chickens by the use of the same variables, although the system would first have to be standardized by the use of prototype viruses. Neuropathotypes can also be estimated with our statistical analysis with reasonable accuracy. By use of this analysis, we established that MDV strains within the very virulent pathotype may be subdivided into neuropathotypes B and C, thus establishing a previously unrecognized pathotypic classification. This finding illustrates how neuropathotyping may extend important information not identified by conventional pathotyping.

Serological status for Chlamydophila psittaci, Newcastle disease virus, avian polyoma virus, and Pacheco disease virus in scarlet macaws (Ara macao) kept in captivity in Costa Rica

From 1998 to 1999, a total of 128 blood samples were collected from scarlet macaws (Ara macao), kept in captivity in 11 different aviaries located in six provinces of Costa Rica. The sera were examined for antibodies directed against Chlamydophila psittaci, Newcastle disease virus (NDV), avian polyoma virus (APV), and Pacheco disease virus (PDV). Testing by enzyme-linked immunosorbent assay (ELISA), showed 16 (12.39%) of the samples (n = 129) exhibited antibodies directed against C. psittaci. Employing haemagglutination inhibition tests for NDV antibodies, all of the samples were found to be negative. The prevalence of antibodies specific for APV was tested with a blocking ELISA and serum neutralization tests (SNT) and 12 of 128 samples (9.37%) were found to be positive with both tests. In SNT, two out of 128 samples (1.56%) were positive for PDV. This is the first description of the serological status in scarlet macaws in captivity in Costa Rica. The study demonstrates the absence of NDV antibodies in the birds investigated on one hand, but also indicates a health hazard for numerous avian species due to the risk of infections with C. psittaci, APV or PDV.

[Combined liver and kidney transplantation: indications and long-term follow-up]

INTRODUCTION

In patients suffering from chronic liver and kidney disease combined liver-kidney transplantation is the only therapeutic option. However, in these patients, it is mandatory to distinguish between chronic and acute renal failure prior to transplantation, because acute renal failure may recover after successful liver transplantation. In this study we investigated the indications and results of this combined procedure.

PATIENTS AND METHODS

We report on 27 patients who underwent liver and kidney transplantation. The underlying diseases were viral hepatitis (n = 12), polycystic liver and kidney disease (n = 9), primary hyperoxaluria (n = 4), and cryptogenic cirrhosis (n = 2) with end-stage renal disease due to glomerulonephritis, diabetic nephropathy or renal failure caused by nephrotoxicity of immunosuppressive therapy after liver transplantation. Nine patients had lymphocytotoxic antibodies and 5/27 patients had a positive crossmatch pretransplant.

RESULTS

One patient died due to bleeding complications, two patients lost the kidney graft due to initial non-function or technical problems. The incidence of acute and steroid-resistant rejections was 60% and 20% in patients with a positive cross-match compared to 32% and 14% in negative cross-match transplants. Only two patients experienced a rejection episode of the kidney (3.7%). No hyperacute rejection of the kidney graft occurred. Long-term patients and graft survival was not impaired in the presence of a positive cross-match. The 1- and 5-year survival rates of patients who underwent combined transplantation was 97% and 93% versus 91% and 83% in patients with liver transplantation alone.

CONCLUSION

Combined liver-kidney transplantation is a safe treatment for endstage liver and kidney disease even in the face of a positive cross-match.

Small dose of exogenous surfactant combined with partial liquid ventilation in experimental acute lung injury: effects on gas exchange, haemodynamics, lung mechanics, and lung pathology

A combination of exogenous surfactant and partial liquid ventilation (PLV) with perfluorocarbons should enhance gas exchange, improve respiratory mechanics and reduce tissue damage of the lung in acute lung injury (ALI). We used a small dose of exogenous surfactant with and without PLV in an experimental model of ALI and studied the effects on gas exchange, haemodynamics, lung mechanics, and lung pathology. ALI was induced by repeated lavages (PaO2/FIO2 less than 13 kPa) in 24 anaesthesized, tracheotomized and mechanically ventilated (FIO2 1.0) juvenile pigs. They were treated randomly with either a single intratracheal dose of surfactant (50 mg kg(-1), Curosurf, Serono AG, München, Germany) (SURF-group, n=8), a single intratracheal dose of surfactant (50 mg kg(-1), Curosurf) followed by PLV with 30 ml kg(-1) of perfluorocarbon (PF 5080, 3M, Germany) (SURF-PLV-group, n=8) or no further intervention (controls, n=8). Pulmonary gas exchange, respiratory mechanics, and haemodynamics were measured hourly for a 6 h period. In the SURF-group, the intrapulmonary right-to-left shunt (QS/QT) decreased significantly from mean 51 (SEM 5)% after lavage to 12 (2)%, and PaO2 increased significantly from 8.1 (0.7) to 61.2 (4.7) kPa compared with controls and compared with the SURF-PLV-group (P<0.05). In the SURF-PLV-group, QS/QT decreased significantly from 54 (3)% after induction of ALI to 26 (3)% and PaO2 increased significantly from 7.2 (0.5) to 30.8 (5.0) kPa compared with controls (P<0.05). Static compliance of the respiratory system (C(RS)), significantly improved in the SURF-PLV-group compared with controls (P<0.05). Upon histological examination, the SURF-group revealed the lowest total injury score compared with controls and the SURF-PLV-group (P<0.05). We conclude that in this experimental model of ALI, treatment with a small dose of exogenous surfactant improves pulmonary gas exchange and reduces the lung injury more effectively than the combined treatment of a small dose of exogenous surfactant and PLV.

Human acid ceramidase: processing, glycosylation, and lysosomal targeting

The biosynthesis of human acid ceramidase (hAC) starts with the expression of a single precursor polypeptide of approximately 53-55 kDa, which is subsequently processed to the mature, heterodimeric enzyme (40 + 13 kDa) in the endosomes/lysosomes. Secretion of hAC by either fibroblasts or acid ceramidase cDNA-transfected COS cells is extraordinarily low. Both lysosomal targeting and endocytosis critically depend on a functional mannose 6-phosphate receptor as judged by the following criteria: (i) hAC-precursor secretion by NH(4)Cl-treated fibroblasts and I-cell disease fibroblasts, (ii) inhibition of the formation of mature heterodimeric hAC in NH(4)Cl-treated fibroblasts or in I-cell disease fibroblasts, and (iii) blocked endocytosis of hAC precursor by mannose 6-phosphate receptor-deficient fibroblasts or the addition of mannose 6-phosphate. The influence of the six individual potential N-glycosylation sites of human acid ceramidase on targeting, processing, and catalytic activity was determined by site-directed mutagenesis. Five glycosylation sites (sites 1-5 from the N terminus) are used. The elimination of sites 2, 4, and 6 has no influence on lysosomal processing or enzymatic activity of recombinant ceramidase. The removal of sites 1, 3, and 5 inhibits the formation of the heterodimeric enzyme form. None of the mutant ceramidases gave rise to an increased rate of secretion, suggesting that lysosomal targeting does not depend on one single carbohydrate chain.

Marek's disease virus infection in the brain: virus replication, cellular infiltration, and major histocompatibility complex antigen expression

Marek's disease virus (MDV) infection in the brain was studied chronologically after inoculating 3-week-old chickens of two genetic lines with two strains of serotype I MDV representing two pathotypes (v and vv+). Viral replication in the brain was strongly associated with the development of lesions. Three viral antigens (pp38, gB, and meq) were detected in the brain of infected chickens. Marked differences between v and vv+ pathotypes of MDV were identified for level of virus replication, time course of brain lesions, and expression of major histocompatibility complex (MHC) antigens. Two pathologic phenomena (inflammatory and proliferative) were detected in the brain of chickens inoculated with vv+MDV, but only inflammatory lesions were observed in those inoculated with vMDV. Inflammatory lesions, mainly composed of macrophages, CD4+ T cells, and CD8+ T cells, started at 6-10 days postinoculation (dpi) and were transient. Proliferative lesions, characterized by severe infiltrates of CD4+CD8- T cells (blasts), started at 19-26 dpi and persisted. Expression of MHC antigens in endothelial cells and infiltrating cells within the brain was influenced by MDV infection. Upregulation of MHC class II antigen occurred in all treatment groups, although it was more severe in those inoculated with vv+MDV. MHC class I antigen was downregulated only in those groups inoculated with vv+MDV. These results enhance our understanding of the nature and pattern of MDV infection in the brain and help to explain the neurovirulence associated with highly virulent MDV.

Performance-driven facial animation: basic research on human judgments of emotional state in facial avatars

Virtual reality is rapidly evolving into a pragmatically usable technology for mental health (MH) applications. As the underlying enabling technologies continue to evolve and allow us to design more useful and usable structural virtual environments (VEs), the next important challenge will involve populating these environments with virtual representations of humans (avatars). This will be vital to create mental health VEs that leverage the use of avatars for applications that require human-human interaction and communication. As Alessi et al.1 pointed out at the 8th Annual Medicine Meets Virtual Reality Conference (MMVR8), virtual humans have mainly appeared in MH applications to "serve the role of props, rather than humans." More believable avatars inhabiting VEs would open up possibilities for MH applications that address social interaction, communication, instruction, assessment, and rehabilitation issues. They could also serve to enhance realism that might in turn promote the experience of presence in VR. Additionally, it will soon be possible to use computer-generated avatars that serve to provide believable dynamic facial and bodily representations of individuals communicating from a distance in real time. This could support the delivery, in shared virtual environments, of more natural human interaction styles, similar to what is used in real life between people. These techniques could enhance communication and interaction by leveraging our natural sensing and perceiving capabilities and offer the potential to model human-computer-human interaction after human-human interaction. To enhance the authenticity of virtual human representations, advances in the rendering of facial and gestural behaviors that support implicit communication will be needed. In this regard, the current paper presents data from a study that compared human raters' judgments of emotional expression between actual video clips of facial expressions and identical expressions rendered on a three-dimensional avatar using a performance-driven facial animation (PDFA) system developed at the University of Southern California Integrated Media Systems Center. PDFA offers a means for creating high-fidelity visual representations of human faces and bodies. This effort explores the feasibility of sensing and reproducing a range of facial expressions with a PDFA system. In order to test concordance of human ratings of emotional expression between video and avatar facial delivery, we first had facial model subjects observe stimuli that were designed to elicit naturalistic facial expressions. The emotional stimulus induction involved presenting text-based, still image, and video clips to subjects that were previously rated to induce facial expressions for the six universals2 of facial expression (happy, sad, fear, anger, disgust, and surprise), in addition to attentiveness, puzzlement and frustration. Videotapes of these induced facial expressions that best represented prototypic examples of the above emotional states and three-dimensional avatar animations of the same facial expressions were randomly presented to 38 human raters. The raters used open-end, forced choice and seven-point Likert-type scales to rate expression in terms of identification. The forced choice and seven-point ratings provided the most usable data to determine video/animation concordance and these data are presented. To support a clear understanding of this data, a website has been set up that will allow readers to view the video and facial animation clips to illustrate the assets and limitations of these types of facial expression-rendering methods (www. USCAvatars.com/MMVR). This methodological first step in our research program has served to provide valuable human user-centered feedback to support the iterative design and development of facial avatar characteristics for expression of emotional communication.

[Objective assessment of results of special hydrotherapy in inpatient rehabilitation following knee prosthesis implantation]

AIM

Based on our own previous surface EMG investigations (EMG mapping), it has been shown that disturbances in coordination, proprioception and strength measured before and after implantation of a total knee arthroplasty (TKA) can be treated successfully with standard physical therapy during in-patient rehabilitation. The objective of the present study was to evaluate the therapeutic effect of a special type of hydrotherapy.

METHOD

25 patients with TKA were treated for 3 weeks with a standardized hydrotherapy training during in-patient rehabilitation. Several diagnostic methods (EMG mapping, Isokinetics, Ultrasound) were applied to objectify and quantify changes in muscular coordination and strength at 4, 7, and 26 weeks postoperative. These results were compared with the results of 38 TKA patients treated with a "standard rehabilitation program" and with the results of 20 healthy persons.

RESULTS

EMG mapping as well as isokinetics and ultrasound permitted an objective characterization of the results. Patients treated with the special hydrotherapy showed greater improvements in the investigated items of coordination and strength than patients treated with the "standard rehabilitation program". For example, in the hydrotherapy group a significantly better contraction capacity of the M. vastus intermedius was measured. The intensive hydrotherapy was tolerated by all patients and reached good acceptance.

CONCLUSION

The investigated hydrotherapy technique leads to better muscular coordination and strength, which can provoke a better stabilization of the knee joint. Therefore, the early and intensive application of hydrotherapy for improving coordination and strength in the rehabilitation of patients with total knee arthroplasty is advisable.

Inhibition of human chymase by 2-amino-3,1-benzoxazin-4-ones

A series of 2-sec.amino-4H-3,1-benzoxazin-4-ones was evaluated as acyl-enzyme inhibitors of human recombinant chymase. The compounds were also assayed for inhibition of human cathepsin G, bovine chymotrypsin, and human leukocyte elastase. Introduction of an aromatic moiety into the 2-substituent resulted in strong inhibition of chymase, cathepsin G, and chymotrypsin. Extension of the N(Me)CH2Ph substituent by one methylene unit was unfavourable to inhibit these proteases. Towards chymase, 2-(N-benzyl-N-methylamino)-4H-3,1-benzoxazin-4-one (32) and 2-(N-benzyl-N-methylamino)-6-methyl-4H-3,1-benzoxazin-4-one (33) were found to exhibit Ki values of 11 and 17 nM, respectively, and form stable acyl-enzymes with half-lives of 53 and 25 min, respectively. Benzoxazinone 33 also inhibited the human chymase-catalyzed formation of angiotensin 11 from angiotensin I.

Molecular analysis of acid ceramidase deficiency in patients with Farber disease

Farber disease is a rare, autosomal recessively inherited sphingolipid storage disorder due to the deficient activity of lysosomal acid ceramidase, leading to the accumulation of ceramide in cells and tissues. Here we report the identification of six novel mutations in the acid ceramidase gene causing Farber disease: three point mutations resulting in single amino acid substitutions, one intronic splice site mutation resulting in exon skipping, and two point mutations also leading to occasional or complete exon skipping. Of interest, these latter two mutations occurred in adjacent nucleotides and led to abnormal splicing of the same exon. Expression of the mutated acid ceramidase cDNAs in COS-1 cells and subsequent determination of acid ceramidase residual enzyme activity demonstrated that each of these mutations was the direct cause of the acid ceramidase deficiency in the respective patients. In contrast, two known polymorphisms had no effect on acid ceramidase activity. Metabolic labeling studies in fibroblasts of four patients showed that even though acid ceramidase precursor protein was synthesized in these individuals, rapid proteolysis of the mutated, mature acid ceramidase occurred within the lysosome.

Postoperative tracheal extubation after orthotopic liver transplantation

BACKGROUND

The duration of postoperative mechanical ventilation and its influence on pulmonary function in liver transplant recipients is still debated controversially.

METHODS

We retrospectively analyzed the incidence of immediate tracheal extubation, prolonged mechanical ventilation (>24 h following surgery), and episodes of reintubation in 546 patients who underwent orthotopic liver transplantation (OLT) at our institution.

RESULTS

Immediate tracheal extubation in the operating theater was achieved in 18.7% of patients, and prolonged mechanical ventilation was required by 11.2% of patients. In these, median time of extubation was 49.5 h, whereas the remaining 70.1% of patients required ventilation support for a median 5 h after OLT. As risk factors for prolonged mechanical ventilation we identified the indications of acute liver failure and retransplantation, as well as factors such as mechanical ventilation prior to OLT, massive intraoperative bleeding, and severe reperfusion injury of the liver graft. The incidence of reintubation was 8.8% in patients who were immediately extubated following surgery, and 13.1% in patients who underwent extubation within 24 h. The incidence was significantly increased in patients requiring prolonged mechanical ventilation (36.1%).

CONCLUSIONS

Immediate tracheal extubation was safe and well tolerated. The incidence of reintubation was not increased when compared to patients in whom extubation succeeded later. However, special attention should be given to transplant recipients presenting in reduced clinical condition at the time of OLT, undergoing complicated surgery, or receiving liver allografts with severe reperfusion injury because of an increased risk for prolonged mechanical ventilation.

[Perforation of the cecum by a toothpick--a rare differential acute appendicitis diagnosis. Case report and review of the literature]

We report the case of a 46-year-old man who was admitted to the medical department of the hospital Reichenbach with a 2-day history of central and upper abdominal pain. The pain was displaced in the right lower abdominal quadrant, which is why the patient was transferred to our department. At laparoscopy a toothpick was found perforating the cecum. Laparoscopic management, therapeutic possibilities and problems of diagnosis are discussed. The patient does not recall having ingested a toothpick. The laparoscopic treatment of perforation of the cecum by a toothpick might be among the rarest operations ever conducted. In the literature no such publication could be found up to now.