Polymyxin use as a risk factor for colonization or infection with polymyxin-resistant Acinetobacter baumannii after liver transplantation.

INTRODUCTION: Acinetobacter baumannii is a leading agent of healthcare-associated infection. The objective of this study was to evaluate cases of colonization or infection with polymyxin-resistant A. baumannii (PRAB) in liver transplant recipients and to identify the risk factors for the acquisition of PRAB. METHODS: We evaluated all patients undergoing liver transplantation (LT) between January and November of 2011. The exclusion criterion was death within the first 72 h after transplant. Patients were screened for PRAB through weekly rectal and inguinal swabs during their stay in the intensive care unit (ICU) and at ICU discharge. Patients who came from other hospitals or had been treated in the emergency room for >72 h were screened at ICU admission. The minimum inhibitory concentrations (MICs) for polymyxins were determined by broth microdilution, and clonality was determined by pulsed-field gel electrophoresis. The stepwise logistic regression was used to identify risk factors related to acquisition of PRAB, and Cox forward regression used to identify risk factors for 60-day mortality. RESULTS: We evaluated 65 patients submitted to LT, among whom PRAB was isolated in 7, 4 of whom developed infection. The MICs for polymyxin E ranged from 16 to 128 mg/mL. All patients with PRAB required dialysis. The median time of polymyxin use before PRAB isolation was 21 days. These 4 included 1 case of primary bloodstream infection (BSI), which was treated with the carbapenem-polymyxin combination; 1 case of surgical site infection, which was treated with gentamicin, polymyxin, ampicillin-sulbactam, and tigecycline; and 2 cases of pneumonia, treated with the combination of carbapenem-polymyxin. In the case of BSI and in 1 of the cases of pneumonia, the treatment was considered successful. Mortality was 71% among the cases, compared with 33% among the non-cases. CONCLUSION: In the final model of the survival analysis, PRAB colonization or infection after LT was independently associated with mortality. One predominant clone was identified. The only risk factor identified in the multivariate analysis was polymyxin use. PRAB was an agent with high mortality, and the most important risk factor associated with colonization or infection for such bacterium was polymyxin use.

Impact of the reduction of environmental and equipment contamination on vancomycin-resistant enterococcus rates.

More than 1,500 perirectal swab cultures and 552 environmental and equipment cultures were collected during the study period. Enterococcus faecium was the most frequent species isolated, being responsible for 71% of the positive cultures. Fifty infections were documented, with bloodstream infections (18, 36%) being the most frequent, followed by urinary tract infection (15, 30%). An educational intervention was given to 136 healthcare workers (HCWs), and a questionnaire regarding vancomycin-resistant enterococcus (VRE) transmission was also performed pre- and post-intervention. Overall, 858 opportunities of patient care were evaluated. The compliance with contact precautions did not improve; however, in general, the proportion of correct answers regarding VRE increased significantly when comparing pre- and post-intervention periods (p < 0.05). On the other hand, the proportion of environmental and equipment contaminated by VRE decreased significantly from pre- (23.2%) to post-intervention (8.2%) (p < 0.001) and was associated with a significant decrease in VRE infection from 7.7 to 1.9 when comparing the pre- and post-intervention periods. The use of vancomycin (defined daily dose [DDD]) did not change significantly over the study period (p = 0.970), and the use of teicoplanin increased (p < 0.001). Seventy-six percent of E. faecium belong to type and subtype A by pulsed-field gel electrophoresis (PFGE). This predominant type was found in the environment and caused colonization and infection. In conclusion, the present study showed that reduction of the proportion of environmental and equipment contamination was associated with a decrease of colonization and infection due to VRE, and that the strategy to control VRE dissemination should be based on local problems.

Internal jugular vein thrombosis as paraneoplastic syndrome of primary ovarian non-Hodgkin's lymphoma.

Primary malignant lymphoma involving the ovaries is extremely rare. We present a unique case of a primary Non-Hodgkin's lymphoma (NHL) of both ovaries, preceded by an internal jugular vein trombosis (IJVT) as paraneoplastic syndrome. Currently, 36 months after surgical treatment of this FIGO Stage Ib, Ann Arbor Stage 2E NHL, the patient is clinically free of disease. Based on this case and a review of the literature it is concluded that paraneoplastic syndromes like spontaneous IJVT should prompt the clinician to make a thorough diagnostic work-up in search of an underlying malignancy, including the female genital tract.

Investigation of an outbreak of Enterobacter cloacae in a neonatal unit and review of the literature.

Enterobacter cloacae has emerged as an important pathogen in neonatal units, with several outbreaks of infection being reported. The aim of this study was to investigate an outbreak of sepsis due to E. cloacae in a neonatal unit and to review the literature. A retrospective cohort study was conducted in which cases were compared with all newborns hospitalised for more than 48h in the neonatal intensive care unit (NICU). Cohorting of infected patients and work reorganisation were implemented. Pulsed-field gel electrophoresis was performed. The retrospective cohort included the six cases and 13 control patients that had been in the NICU during April 2006. Univariate analysis showed that the use of dobutamine was significantly associated with infection (P=0.036) and that enteral feeding was a protective factor (P=0.02). Multivariate analysis did not find any independent risk factor. Bed occupancy rate in March 2006 was 109.6%, indicating overcrowding. PFGE identified indistinguishable patterns among isolates from all six newborns. PubMed and OVID was search from 1 January 1983 to 15 January 2008 for papers including the terms 'E. cloacae', 'outbreaks', 'clusters' in combination with 'neonate', 'newborn', and 'infant'. We found 26 reports of outbreaks due to E. cloacae in neonate patients: sixteen (52%) were bloodstream infection outbreaks, of which two (12.5%) were related to multiple-dose medications. The source for our outbreak was not identified. Reinforcement of hygiene practices, restrictions on new admissions and the establishment of single-dose medications helped to control the outbreak.

A decrease in size and number of basal forebrain cholinergic neurons is paralleled by diminished hippocampal cholinergic innervation in mice lacking leukocyte common antigen-related protein tyrosine phosphatase activity.

The leukocyte common antigen-related (LAR) receptor, composed of an extracellular region with three immunoglobulin-like and eight fibronectin type III-like domains, and a cytoplasmic region containing two protein tyrosine phosphatase domains, is thought to play a role in axonal outgrowth and guidance during neural development. LAR mutant mice were generated completely lacking the two cytoplasmic protein tyrosine phosphatase domains, resulting in the loss of ability to bind intracellular associating proteins, but (may be) still containing the ability to perform extracellular functions. A reduction in size of basal forebrain cholinergic neurons and diminished hippocampal innervation reported for knockout mice that contain a leaky gene trap inserted into the 5' part of the LAR gene [Yeo T. T. et al. (1997) J. Neurosci. Res. 47, 348-360] warranted a computer-assisted quantitative image analysis throughout the basal forebrain and hippocampus of our LAR mutant mice. The total number, longest diameter and cell body area were calculated for the choline acetyltransferase-positive neurons in the medial septum and vertical diagonal band, and optical density measurements were performed to determine the extent of acetyl cholinesterase-positive fibre innervation of the different layers in the dentate gyrus. In LAR mutant mice, the number of cholinergic cells was significantly reduced (approximately 25%) in the vertical diagonal band. Also, the cross-sectional area of the cholinergic neurons in the medial septum and vertical diagonal band was reduced (5%). These findings were paralleled by a diminished cholinergic innervation of the supragranular (18%) and molecular (4%) layers of the dentate gyrus. Thus, LAR protein tyrosine phosphatase activity appears crucial for size, number and target projection of basal forebrain cholinergic neurons, further strengthening a role for LAR in CNS development.

A nosocomial outbreak of Salmonella enteritidis associated with lyophilized enteral nutrition.

Outbreaks of Salmonella spp. gastro-enteritis in hospitals are of concern because of the increased susceptibility of patients and associated high morbidity. This study is a report of a nosocomial outbreak of Salmonella enteritidis associated with enteral nutrition. In December 1999, one sample of enteral feed tested positive for S. enteritidis. During the subsequent 6 weeks, eight cases of nosocomial salmonellosis occurred. Patients involved in the outbreak were aged 19-79 years (median = 36.5), and salmonella was isolated from the blood of two patients. All patients were receiving enteral nutrition at the time and all had diarrhoea. Three patients died. All 13 employees of the Nutrition Department were asymptomatic and their stool samples were negative. Environmental and water samples were also negative. The diet, however, contained lyophilized egg albumin. Molecular typing showed that the isolates of seven patients were indistinguishable from the one obtained from the enteral diet. It was thought that the nosocomial salmonellosis probably occurred due to the use of a commercial lyophilized diet. Another method of processing diets may be necessary to ensure patient safety.

Transposon leads to contamination of clinical pDNA vaccine.

We report an unexpected contamination during clinical manufacture of a Human Papilomavirus (HPV) 16 E6 encoding plasmid DNA (pDNA) vaccine, with a transposon originating from the Escherichia coli DH5 host cell genome. During processing, presence of this transposable element, insertion sequence 2 (IS2) in the plasmid vector was not noticed until quality control of the bulk pDNA vaccine when results of restriction digestion, sequencing, and CGE analysis were clearly indicative for the presence of a contaminant. Due to the very low level of contamination, only an insert-specific PCR method was capable of tracing back the presence of the transposon in the source pDNA and master cell bank (MCB). Based on the presence of an uncontrolled contamination with unknown clinical relevance, the product was rejected for clinical use. In order to prevent costly rejection of clinical material, both in-process controls and quality control methods must be sensitive enough to detect such a contamination as early as possible, i.e. preferably during plasmid DNA source generation, MCB production and ultimately during upstream processing. However, as we have shown that contamination early in the process development pipeline (source pDNA, MCB) can be present below limits of detection of generally applied analytical methods, the introduction of "engineered" or transposon-free host cells seems the only 100% effective solution to avoid contamination with movable elements and should be considered when searching for a suitable host cell-vector combination.

Modified core wash cytology (CWC), an asset in the diagnostic work-up of breast lesions.

AIM: A quick and reliable preliminary diagnosis is essential in the management of a same-day breast clinic. In a preclinical study we developed an alternative method of core wash cytology (CWC). This study is an evaluation of this new CWC method introduced into the clinical setting. METHODS: From April 2008 to April 2009, biopsies were taken from lesions in the breast. CWC was obtained from core needle biopsy (CNB) with a modified technique and classified into the categories: malignant, suspicious for malignancy, atypical, benign and inadequate. CWC and CNB diagnoses were correlated with the histopathology of subsequently obtained resection specimens. The sensitivity and specificity were calculated. RESULTS: CWC was obtained from 226 breast lesions. In 167 of these cases subsequent resection of the lesion was performed revealing 149 carcinomas and 18 benign lesions. Of the 149 malignant cases, 136 were considered as either malignant or suspicious for malignancy by CWC, 7 as atypical, 4 as benign and 2 as inadequate. None of the 18 benign lesions were classified as suspicious or malignant on CWC. Eight out of 149 resected carcinomas were not recognized as malignant by histological analysis of the CNB, while 7 of these cases the CWC was considered malignant. The sensitivity and specificity were 97% and 100%, respectively. CONCLUSIONS: In the vast majority of patients the modified CWC technique can provide a quick and reliable diagnosis of malignant breast lesions. Furthermore, combining CWC with CNB histology can improve adequate, preoperative recognition of the malignant character of breast lesions.

Candida colonisation as a source for candidaemia.

Candida spp. are important healthcare-associated pathogens. Identifying the source of infection is important for prevention and control strategies. The objective of this study was to evaluate candida colonisation sites as potential sources for candidaemia. Sixty-three consecutive patients with a positive blood culture for candida were included. Surveillance cultures were collected from urine, rectum, oropharynx, skin, intravascular catheter tip and skin around catheter. Molecular typing was performed when the same species of candida was isolated from blood and surveillance sites of a patient. C. albicans was associated with 42% of candidaemias, C. parapsilosis 33%, C. tropicalis 16% and C. guilliermondii, C. krusei, C. glabrata, C. holmii and C. metapsilosis were all 2% each. Six of 10 C. parapsilosis catheter tip isolates were indistinguishable from corresponding blood isolates (all in neonates). C. albicans isolates from blood were indistinguishable from corresponding gastrointestinal tract isolates in 13 of 26 patients and from catheter tip isolates in two patients. In conclusion, the results suggest that gastrointestinal colonisation is the probable source of C. albicans candidaemia and C. parapsilosis is exogenous.

A spinal intradural enterogenous cyst with well-differentiated muscularis propria.

We report a case of a newborn presenting with severe compression of the spinal cord due to a large, solitary mass extending from C4 to T2. Neurosurgical exploration revealed a large intradural, extramedullary cystic lesion, compressing the spinal cord. Slowly progressive respiratory failure due to severe myelopathy led to the death of the child 19 days postpartum. At autopsy, a well-differentiated enterogenous cyst was found, the cyst wall containing gastric and esophageal type mucosa, and a bona fide muscularis propria. The gastrointestinal tract was completely normal. The possible developmental history of intradural enterogenous cysts is discussed.

Detection of multiple viral DNA species in synovial tissue and fluid of patients with early arthritis.

OBJECTIVE: Viruses have a role in the pathogenesis of various forms of arthritis. This study aimed at determining whether viral DNA can be detected in joint samples in the early stages of idiopathic arthritides. METHODS: Synovial fluid (SF) and synovial tissue (ST) samples were obtained from 73 patients, with undifferentiated arthritis (n=22), rheumatoid arthritis (n=13), spondyloarthropathy (n=17), crystal arthropathy (n=8), osteoarthritis (n=7), septic arthritis (n=5), and trauma (n=1). The presence of viral DNA was investigated by polymerase chain reaction analysis. RESULTS: Cytomegalovirus was present in 25 patients, parvovirus B19 in 15 patients, Epstein-Barr virus in 12 patients, and herpes simplex virus in 16 patients (in ST, SF, or both), respectively. The joint samples were negative for viral DNA from adenovirus and varicella-zoster virus. In ST, eight patients were double positive for parvovirus B19 and another viral DNA, with herpes simplex virus being the most prevalent. Seven patients were double positive for other viruses (cytomegalovirus, herpes simplex virus, Epstein-Barr virus). In SF, four patients were double or triple positive for viral DNA. Paired samples were available in 56 patients. In these, viral DNA was detected in 37 patients in ST, as compared with 19 in SF. CONCLUSION: These data show that one or more viruses can be detected in the synovial specimens of patients with early arthritis, irrespective of the clinical diagnosis. This observation might be explained by migration of inflammatory cells harbouring viral DNA into the inflamed joints.

Presence of bacterial DNA and bacterial peptidoglycans in joints of patients with rheumatoid arthritis and other arthritides.

OBJECTIVE: The continuous presence of bacteria or their degraded antigens in the synovium may be involved in the pathogenesis of rheumatoid arthritis (RA). The aim of this study was to determine the presence of bacterial nucleic acids and bacterial cell wall constituents in the joints of patients with RA and other forms of arthritis. METHODS: Joint samples were obtained from patients with RA (n = 26), septic arthritis (n = 2), inflammatory osteoarthritis (n = 5), and gout (n = 6), and joint trauma (n = 1). Universal 16S-ribosomal RNA primers were used to detect the presence of bacterial DNA in these samples, using stringent regimens for sample collection and molecular microbiologic analysis. Automated sequencing and comparative data analysis were performed to identify the species. The presence of bacterial peptidoglycan-polysaccharide complexes in synovial tissue was detected by immunohistologic analysis with a specific antibody. RESULTS: The bacterial species cultured from the synovium could be identified in both of the patients with septic arthritis. DNA amplicons were also detected in the synovial fluid and/or tissue samples from 5 patients with RA and 2 patients with crystal-induced arthritis; these originated from multiple bacterial species. Staining for peptidoglycan-polysaccharide complexes was positive in the synovial tissue of both patients with septic arthritis, 16 with RA, 4 with inflammatory osteoarthritis, 4 with crystal-induced arthropathy, and 1 with joint trauma. The staining was mainly found in cells in the synovial sublining, including macrophages. CONCLUSION: The results indicate that bacterial DNA and bacterial cell wall constituents are retained in the joints of some patients with arthritis, where they might enhance synovial inflammation.

Detection of mycobacteria in joint samples from patients with arthritis using a genus-specific polymerase chain reaction and sequence analysis.

OBJECTIVE: Mycobacteria have been implicated in the pathogenesis of various forms of arthritis. The aim of this study was to examine the diagnostic potential of molecular biological techniques as well as to investigate the pathogenetic role of mycobacteria in chronic arthritis. PATIENTS AND METHODS: DNA, extracted from synovial fluid and synovial tissue samples from patients with mycobacterial septic arthritis (n = 2), seronegative spondyloarthropathies (SpA) (n = 18), undifferentiated arthritis (UA) (n = 21) and rheumatoid arthritis (RA) (n = 40), was analysed using a mycobacterial genus-specific polymerase chain reaction (PCR) applied to amplify mycobacterial DNA. Subsequently, automated sequencing was performed for speciation. Samples from patients with either non-mycobacterial septic arthritis, osteoarthritis (OA), crystal arthritis or joint trauma served as negative controls (n = 19). RESULTS: Mycobacterium tuberculosis complex and Mycobacterium marinum were detected in the two patients with mycobacterial septic arthritis. The other species identified were Mycobacterium hodleri (in one RA patient), Mycobacterium smegmatis (in one OA patient and two RA patients) and Mycobacterium austroafricanum (in one crystal arthritis patient). All other samples were negative. CONCLUSIONS: The results suggest that the mycobacterial genus-specific PCR applied on DNA extracts isolated directly from joint samples may be employed as an additional diagnostic tool in the case of clinical suspicion of a mycobacterial infection. No evidence was obtained for a pathogenetic role of mycobacteria in SpA, UA or RA.

Yersinia enterocolitica: a cause of chronic polyarthritis.

To investigate the role of Yersinia persistence in chronic undifferentiated arthritis, two patients who had chronic undifferentiated polyarthritis and circulating IgA and IgG antibodies to Yersinia outer proteins were studied. Immunofluorescence using antibodies directed against Yersinia adhesin A was performed on colonic and synovial tissue. Synovial tissue T cells were cloned aspecifically and screened for their proliferative responses to Yersinia enterocolitica. Furthermore, a Yersinia-specific polymerase chain reaction (PCR) was performed on synovial tissue. Both patients were found to have Yersinia antigens in colonic and synovial tissue. Y. enterocolitica-positive T-cell clones were grown from the synovial tissue: 4 CD4+ clones of 37 clones from patient 1 and 6 CD4+ clones of 53 clones from patient 2. Yersinia-specific PCR products were not detected in the synovial tissue specimens. The results support the hypothesis that an immune-mediated response to Yersinia antigens may play an important role in the pathogenesis of chronic undifferentiated arthritis.

Detection of bacterial DNA in joint samples from patients with undifferentiated arthritis and reactive arthritis, using polymerase chain reaction with universal 16S ribosomal RNA primers.

OBJECTIVE: Bacteria are considered to be important in the pathogenesis of several forms of arthritis. The goal of this study was to apply the 16S ribosomal RNA (rRNA)-polymerase chain reaction method for the detection of bacterial DNA in synovial fluid (SF) and synovial tissue (ST) from inflamed joints. METHODS: Samples from 5 patients with septic arthritis and from 7 with osteoarthritis or arthritis secondary to joint trauma were used as controls. Samples from 6 patients with spondylarthropathy (SpA) and from 20 with undifferentiated arthritis (UA) were analyzed for the presence of bacterial DNA using universal 16S rRNA primers. Automated sequencing and comparative data analysis were performed to identify the species. RESULTS: In the positive control group, the bacterial species cultured from the synovium could be identified in all cases. No bacterial DNA was detected in the SF and ST from patients in the negative control group. In 4 of 6 patients with SpA and 7 of 20 with UA, the analysis of joint samples revealed the presence of bacterial DNA. Sequence analysis indicated the presence of multiple species, which was confirmed by sequencing of cloned products. CONCLUSION: When the the above techniques were used with a stringent regimen, we were able to demonstrate that it is possible to collect and analyze joint samples without contaminating bacterial DNA. The accumulation of phagocytic cells that contain bacterial DNA of various species could play a role in the pathogenesis of both SpA and UA.

Detection of bacterial DNA in serial synovial samples obtained during antibiotic treatment from patients with septic arthritis.

OBJECTIVE: The management of septic arthritis could benefit from sensitive tests that detect the persistence of microorganisms in the joint. The aim of this study was to determine the feasibility of monitoring the presence of bacterial DNA in synovial samples from septic arthritis patients during antibiotic treatment. METHODS: Synovial fluid (SF) and synovial tissue (ST) samples were collected serially from 6 patients with septic arthritis before and during antibiotic therapy. In addition, peripheral blood (PB) samples were available for polymerase chain reaction (PCR) analysis from 5 of the 6 patients before treatment. All samples were analyzed for the presence of bacterial DNA with the use of a PCR with universal 16S ribosomal RNA primers. Automated sequencing and comparative data analysis were performed to identify the species. These data were compared with Gram staining and culture results. RESULTS: The bacterial species cultured from the synovium could be identified in all 6 patients using PCR and subsequent sequence analysis of the amplicons. In virtually all cases, positive Gram stain and culture findings in the synovial samples became negative after 2-3 days of antibiotic treatment. Bacterial DNA persisted in the SF and/or ST after culture conversion; in 2 patients, bacterial DNA was still detected at day 10, in 1 patient, at day 20, and in another patient, at day 22 after the initiation of treatment. Synovial samples were available for PCR analysis from 2 patients at day 26. At this time point, bacterial DNA could not be detected anymore. All PB samples were negative by both culture and PCR analysis. CONCLUSION: PCR analysis can be used to monitor the presence of bacterial DNA in synovial samples from patients with septic arthritis during antibiotic treatment. The absence of bacterial DNA could help in the decision to discontinue antibiotic treatment.

Detection of Borrelia burgdorferi sensu stricto by reverse line blot in the joints of Dutch patients with Lyme arthritis.

OBJECTIVE: To analyze the presence of Borrelia burgdorferi sensu lato in synovial samples from the knee joint of patients with Lyme arthritis by polymerase chain reaction, and to differentiate the species by reverse line blot (RLB). METHODS: Synovial fluid (SF) and synovial tissue (ST) samples were obtained from patients with Lyme arthritis (n = 4) and from patients with various other forms of arthritis (n = 9). DNA extracted from synovial samples was amplified by using, as a target, the spacer region between the 5S and 23S ribosomal RNA genes of B. burgdorferi sensu lato. Subsequently, 4 species-specific DNA probes were used in the RLB for specific hybridization. RESULTS: DNA from B. burgdorferi sensu stricto DNA was detected in the SF and ST from 3 patients with Lyme arthritis. B. burgdorferi sensu lato DNA was not detected in the synovial samples from 9 control patients. CONCLUSION: The relationship between different species of B. burgdorferi sensu lato and arthritis can be studied using direct analysis of extracted DNA from joint samples. This method can be used to study the association between particular clinical manifestations of Lyme disease and different species of B. burgdorferi sensu lato.

Increased expression of IL-15 in the synovium of patients with rheumatoid arthritis compared with patients with Yersinia-induced arthritis and osteoarthritis.

Recently, a new player in the cytokine network has been described that is produced by monocytes and can be detected in the rheumatoid synovium: interleukin-15 (IL-15). Since this cytokine may play a role in the accumulation and activation of T-cells, B-cells, and natural killer (NK) cells characteristic of synovial tissue (ST) from patients with rheumatoid arthritis (RA), the expression of IL-15 was studied in ST from RA patients in comparison with ST from patients with reactive arthritis (ReA) and osteoarthritis (OA) and the phenotype of IL-15-positive cells was determined. IL-15 expression was investigated by immunohistochemical analysis of ST from ten patients with RA, ten patients with Yersinia enterocolitica-induced ReA, and nine patients with OA. The immunohistological findings were quantified and the results obtained in the different patient groups were compared. To determine the phenotype of IL-15-expressing cells, double-labelling immunofluorescence was performed. The expression of IL-15 was significantly higher in ST from patients with RA than in ST from patients with ReA or OA. In double-label experiments, co-expression was observed with markers for macrophages, T-cells, and NK cells. The composition of the cellular infiltrate in the synovium of patients with RA might be partly explained by the specific increase in expression of IL-15 in rheumatoid ST. It can be speculated that IL-15 production by inflammatory cells other than macrophages may occur in the rheumatoid synovium.

Cleavage and inactivation of human C1 inhibitor by the human leukocyte proteinase, proteinase 3.

Incubation of highly purified human C1 inhibitor with equally pure human leukocyte proteinase 3, resulted in a dose- and time-dependent inactivation of C1 inhibitor hemolytic activity. Furthermore, this inactivation was accompanied by proteinase 3-dependent cleavage of the C1 inhibitor into an 83,000 molecular weight fragment. The formation of the 83,000 molecular weight fragment followed a time course which was similar to that observed for the inactivation of hemolytic activity. Within 120 minutes more than 90% of the hemolytic activity was lost. This inactivation of C1 inhibitor appeared to be selective as purified human C1q was not degraded in a similar time period. Moreover, when 100 micrograms IgG, isolated from each of 21 Wegener's granulomatosis patients with cytoplasmic anti-nuclear antibodies immunofluorescent titers to proteinase 3 greater then 1:64, was incubated with 3 milliunits of proteinase 3, little to no cleavage of C1 inhibitor was observed. In contrast, 100 micrograms of IgG isolated from 14 normal donors was ineffective in affording protection to C1 inhibitor upon incubation with proteinase 3. Our results suggest that neutrophil infiltration and activation could lead to local complement consumption at the tissue sites.

Delayed peripheral nerve regeneration and central nervous system collateral sprouting in leucocyte common antigen-related protein tyrosine phosphatase-deficient mice.

Cell adhesion molecule-like receptor-type protein tyrosine phosphatases have been shown to be important for neurite outgrowth and neural development in several animal models. We have previously reported that in leucocyte common antigen-related (LAR) phosphatase deficient (LAR-deltaP) mice the number and size of basal forebrain cholinergic neurons, and their innervation of the hippocampal area, is reduced. In this study we compared the sprouting response of LAR-deficient and wildtype neurons in a peripheral and a central nervous system lesion model. Following sciatic nerve crush lesion, LAR-deltaP mice showed a delayed recovery of sensory, but not of motor, nerve function. In line with this, neurofilament-200 immunostaining revealed a significant reduction in the number of newly outgrowing nerve sprouts in LAR-deltaP animals. Morphometric analysis indicated decreased axonal areas in regenerating LAR-deltaP nerves when compared to wildtypes. Nonlesioned nerves in wildtype and LAR-deltaP mice did not differ regarding myelin and axon areas. Entorhinal cortex lesion resulted in collateral sprouting of septohippocampal cholinergic fibres into the dentate gyrus outer molecular layer in both genotype groups. However, LAR-deltaP mice demonstrated less increase in acetylcholinesterase density and fibre number at several time points following the lesion, indicating a delayed collateral sprouting response. Interestingly, a lesion-induced reduction in number of (septo-entorhinal) basal forebrain choline acetyltransferase-positive neurons occurred in both groups, whereas in LAR-deltaP mice the average cell body size was reduced as well. Thus, regenerative and collateral sprouting is significantly delayed in LAR-deficient mice, reflecting an important facilitative role for LAR in peripheral and central nervous system axonal outgrowth.