Impact of gender on surgical site infections in abdominal surgery: A multi-center study

Objective

Male sex is controversially discussed as a risk factor for surgical site infections (SSI). The aim of the present study was to evaluate the impact of gender on SSI in abdominal surgery under elimination of relevant confounders.

Methods

Clinicopathological data of 6603 patients undergoing abdominal surgery from a multi-center prospective database of four Swiss hospitals including patients between 2015 and 2018 were assessed. Patients were stratified according to postoperative SSI and risk factors for SSI were assessed using univariate and multivariate analysis.

Results

In 649 of 6603 patients SSI was reported (9.8%). SSI was significantly associated with increased risk of reoperation (22.7% vs. 3.4%, p <0.001), higher mortality rate (4.6% vs. 0.9%, p <0.001) and higher rate of length of hospital stay > 75th percentile (57.0% vs. 17.9%, p <0.001). In univariate analysis male sex was a significant risk factor for SSI (p = 0.01). In multivariate analysis including multiple confounders’ such as comorbidities and perioperative factors there was no association between male sex and risk of SSI (OR 1.1 [CI 0.8–1.4]). BMI >= 30 kg/m2 (OR 1.8 [CI 1.3–2.3]), duration of surgery > 75th percentile (OR 2.3 [1.8–2.9]), high contamination level (OR 1.3 [1.0–1.6]), laparotomy (OR 1.3 [1.0–1.7]), previous laparotomy (OR 1.4 [1.1–1.7]), blood transfusion (OR 1.7 [1.2–2.4]), cancer (OR 1.3 [1.0–1.8]), malnutrition (OR 2.5 [1.8–3.4]) were independent risk factors for SSI in multivariate analysis.

Conclusion

Under elimination of relevant confounders there is no significant correlation between gender and risk of SSI after abdominal surgery. Independent risk factors for SSI as BMI >= 30 kg/m2, duration of surgery > 75th percentile, high contamination level, surgical approach or malnutrition should be considered during treatment.

Comparison of long-term survivals following hepatectomy for hepatocellular carcinoma according to the time-point of recurrence and treatment modalities for recurrent disease

Objective

Disease recurrence following curatively intended hepatectomy for hepatocellular carcinoma (HCC) limits oncologic outcome. Based on the extent, location and time-point of tumor recurrence, different therapeutic modalities are available to treat recurrent HCC. Therefore, our aim was to investigate the role of these treatments and the time-point of recurrence on long-term survival.

Methods

Clinicopathological data of patients, who underwent hepatectomy for HCC at a major hepatobiliary center in Switzerland between 2012 and 2019, were assessed. Patients suffering tumor recurrence were stratified according to the treatment modalities for recurrent HCC including surgical treatment (repeat hepatectomy or liver transplantation), interventional treatment, and conservative treatment (chemotherapy or best supportive care). Groups were compared regarding to overall survival (OS). Additionally, long-term outcomes were compared between patients with early (≤ 12 months) and late (> 12 months) tumor recurrence.

Results

During the study period, 159 patients underwent hepatectomy for HCC. Median follow-up time was 53 months. After a median time of seven (1-64) months, 74 patients were diagnosed with tumor recurrence (47 %). The majority of patients developed early recurrence (n = 49) and 58 patients had intrahepatic recurrence only. Treatment options were re-resection, liver transplantation, interventional methods, and palliative therapy in 5, 15, 23, and 31 patients, respectively. Surgical treatment was significantly associated with improved OS compared to interventional and conservative treatment (5-year OS: 84% vs. 39% vs. 30%, p < 0.0001). OS was significantly better among patients with late recurrence compared to patients with early recurrence, irrespective of the treatment modality used for the recurrent disease (5-year OS: 70% vs. 38%, p = 0.008).

Conclusion

Repeat hepatectomy or liver transplantation for recurrent HCC following hepatectomy is associated with better long-term survival compared to interventional or conservative therapies, especially for patients with late tumor recurrence. Patients with intrahepatic HCC recurrence should be evaluated according to the extent of tumor burden, liver function, and functional status to identify the best candidates for a surgical treatment.

Prehabilitation in patients undergoing colorectal surgery fails to confer reduction in overall morbidity: Results of a single-center, single-blinded, randomized controlled trial

Objective

Patients undergoing major surgery are prone to a functional decline due to the impairment of muscle, cardiorespiratory and neurological function as a response to surgical stress. Currently, there are solely weak recommendations in the ERAS protocol regarding the role of preoperative physical activity and prehabilitation in patients undergoing colorectal surgery. Studies in heterogenous cohorts showed contradictory results regarding the impact of prehabilitation on the reduction of postoperative complications. This randomized controlled trial assesses the impact of prehabilitation on postoperative complications in patients undergoing colorectal surgery within an ERAS protocol.

Methods

Between July 2016 and June 2019, a single-center, single-blinded , randomized controlled trial designed to test whether physiotherapeutic prehabilitation vs. normal physical activities prior to colorectal surgery may decrease morbidity within a stringent ERAS protocol was carried out. The primary endpoint was postoperative complications assessed by Comprehensive Complications Index (CCI®). Primary and secondary endpoints for both groups were analyzed and compared.

Results

A total of 107 patients (54 in the pERACS and 53 in the control cohort) were included in the study and randomized. Dropout rate was 4.5% (n = 5). Mean age (SD) in the control cohort was 65 (29–86) and 66 (24–90) years in pERACS cohort. The pERACS cohort contained more female patients (40% vs. 55%, p = 0.123) and a higher percentage of colorectal adenocarcinoma (32% vs. 23%, p = 0.384) although not significant. Almost all patients underwent minimally invasive surgery in both cohorts (96% vs 98%, p = 1.000). There was no between-cohort difference in the primary outcome measure 30-day Comprehensive Complications Index (15 [0 – 49] vs. 18 [0 – 43], p = 0.059). Secondary outcome as complications assessed according to Clavien-Dindo, length of hospital stay, reoperation rate and mortality showed no difference between both cohorts.

Conclusion

Routine physiotherapeutic prehabilitation cannot be recommended for patients undergoing colorectal surgery within an ERAS protocol (Grade A recommendation). To eliminate other confounders like geographical difference or difference in surgical technique, further multicenter RCTs are needed.

Parenchymal-sparing hepatectomy for colorectal liver metastases reduces postoperative morbidity while maintaining equivalent oncologic outcomes compared to non-parenchymal-sparing resection

Objective

Modern chemotherapy and repeat hepatectomy allow to tailor the surgical strategies for the treatment of colorectal liver metastases (CRLM). This study addresses the hypothesis that parenchymal-sparing hepatectomy reduces postoperative complications while ensuring similar oncologic outcomes compared to the standardized non-parenchymal-sparing procedures.

Methods

Clinicopathological data of patients who underwent liver resection for CRLM between 2012 and 2019 at a major hepatobiliary center in Switzerland were assessed. Patients were stratified according to the tumor burden score [TBS2 = (maximum tumor diameter in cm)2 + (number of lesions)2)] and were dichotomized in a lower and a higher tumor burden cohort according to the median TBS. Postoperative outcomes, overall survival (OS) and disease-free survival (DFS) of patients following parenchymal-sparing resection (PSR) for CRLM were compared with those of patients undergoing non-PSR.

Results

During the study period, 153 patients underwent liver resection for CRLM with curative intent. PSR was performed in 79 patients with TBS < 4.5, and in 42 patients with TBS ≥ 4.5. In patients with lower tumor burden (TBS < 4.5), PSR was associated with lower complication rate (15.2% vs. 46.2%, p = 0.009), and shorter length of hospital stay (5 vs. 9 days, p = 0.006) in comparison to non-PSR. For TBS < 4.5, PSR resulted in equivalent 5-year OS (48% vs. 39%, p = 0.479) and equivalent 5-year DFS rates (DFS, 44% vs. 29%, p = 0.184) compared to non-PSR. For TBS ≥ 4.5, PSR resulted in lower postoperative complication rate (33.3% vs. 63.2%, p = 0.031), lower length of hospital stay (6 vs. 9 days, p = 0.005), equivalent 5-year OS (29% vs. 22%, p = 0.314), and equivalent 5-year DFS rates (29% vs. 22%, p = 0.896) compared to non-PSR. Among all patients treated with PSR, patients undergoing minimal-invasive hepatectomy had equivalent 5-year OS (42% vs. 37%, p = 0.261) and equivalent 5-year DFS (34% vs. 34%, p = 0.613) rates compared to patients undergoing open hepatectomy.

Conclusion

PSR for CRLM is associated with lower postoperative morbidity, shorter length of hospital stay, and equivalent oncologic outcomes compared to non-PSR independently from tumor burden. Our findings suggest that minimal-invasive PSR should be considered as the preferred method for the treatment of curatively resectable CRLM if allowed by tumor size and location.

Rate of local recurrence in a cohort of 125 patients treated by transanal total mesorectal excision due to rectal cancer

Objective

Transanal total mesorectal excision (taTME) is an alternative to conventional TME owing to its reported superior ability to achieve clear resection margins in low rectal cancers. Yet, nationwide Norwegian data claimed a 12-month local recurrence rate of up to 10%, a three-fold increase compared to conventional TME, questioning the oncological safety of taTME.

Methods

Consecutive patients with low rectal cancer treated by taTME were prospectively included. Patients who required a partial mesorectal excision were excluded. Perioperative outcomes were reported as median and interquartile range (IQR). Data were independently audited and certified.

Results

125 patients (88 men : 37 women) with a low rectal cancer (7 cm to anal verge, IQR 5-9) underwent a taTME. Age and body mass index were 65 years (IQR 56-76) and 26 kg/m2 (IQR 23-29). 87 (70%) patients had neoadjuvant radiochemotherapy. Surgery time was 357 minutes (IQR 303-435), including an ileostomy in all patients. 1 patient (0.8%) required a conversion to laparotomy. Performing taTME in a 2-team technique saved 94 minutes or 19% operating time (p < 0.005, t-test one-team (n = 52, 420 minutes, IQR 349-494) vs. 2-team (n = 73, 326 minutes, IQR 285-372). 30-day morbidity amounted to 36% minor complications (Dindo Clavien I-II) and 25% major complications (Dindo Clavien III-V), including 11 anastomotic leaks (9%) and 3 reoperations (3%). Most of the leaks could be managed endoscopically and the ileostomy reversed at last. Median length of hospital stay was 10 days (IQR 8-14).

Median follow-up was 45 months (IQR 25-67; range 13-95). Dissection of the mesorectum was excellent (Quirke 1 incomplete mesorectal excision rate: 1.6%) with 100% clear margins (distal margin 16mm, IQR 10-30; circumferential margin 10mm, IQR 5-15). Median T stage was 3 (IQR 2-3). 24 patients had positive lymphnodes (median 27, IQR 21-38). Local recurrence occurred in 7 (6%) patients and development of metachronous metastasis was present in 36 (29%) patients. This led to a 5-year disease-free survival of 56% and a 5-year overall survival of 86%.

Conclusion

Transanal total mesorectal excision allows good surgical and oncologic quality to the expenses of a reasonable surgery time and morbidity.

Neutering increases the risk of obesity in male dogs but not in bitches - A cross-sectional study of dog- and owner-related risk factors for obesity in Danish companion dogs

Knowledge of risk factors for canine obesity is an important pre-requisite of effective preventative strategies. This study aimed to investigate risk factors for canine obesity in adult companion dogs across Zealand, Denmark. Client-owned dogs (>2 years of age and without chronic illness) were recruited and examined at eight companion animal veterinary practices in areas with varying socio-economic characteristics. The body condition score (BCS) of the dogs was examined by two investigators based on a 9-point scoring scheme. Dog owners answered a questionnaire that had prompts regarding: 1) dog characteristics, including neuter status, 2) owner characteristics, 3) feeding and exercise practices and 4) the owners' attachment to the dog. The effect of these factors on BCS and the risk of being heavy/obese (BCS scores 7-9) were analysed in two separate analyses. A total of 268 dogs were included in the analysis, of which 20.5% were found to be heavy/obese. The average BCS was 5.46. In terms of dog characteristics, neutering dramatically increased both BCS and the risk of being heavy/obese in male dogs but not in bitches. BCS and the risk of being heavy/obese increased in senior bitches and decreased in senior male dogs. The risk of being heavy/obese was higher in dogs with overweight and obese owners. Regarding feeding and exercise practices, providing only one meal per day increased BCS and risk of being heavy/obese. Treats during relaxation increased the risk of dogs being heavy/obese. It also increased the dogs' BCS, but only if the owners were overweight or obese. An increased duration of daily walking increased the risk of the dog being heavy/obese, but only if the owner was overweight or obese. Allowing the dog to run free in the garden/property decreased the risk of the dog being heavy/obese. The owners' attachment to the dog was not associated with the dogs' BCS or dogs' being heavy/obese. An important and novel finding was that neutering increased the risk of being overweight or obese for male dogs while bitches were at risk irrespective of neuter status. Furthermore, a complex interaction between owners' weight status, feeding practices and the risk of dogs being overweight or obese was found, which stresses the need to consider companion animal obesity from a One Health perspective in future prospective studies. Finally, this study was unable to confirm that canine obesity is a product of owners being too attached to their dogs.

Abstract 4484: AR-mTOR-26 - A potent, selective mTORC 1/2 kinase inhibitor for the treatment of malignancy

As a consequence of a variety of genetic lesions, the PI3K/Akt pathway is constitutively activated in a large proportion of human cancers. The mTOR kinase plays an important role in this pathway as the key component of two independent signaling complexes (TORC1 and TORC2) that are involved at two distinct levels in this signaling cascade. Accordingly, inhibition of mTOR kinase will abrogate signaling from both mTOR complexes and serve as an effective means of targeting this pathway. In addition, the activity of the TORC1 complex is often aberrantly activated in a PI3K-independent manner to allow tumor cells to survive and proliferate despite the many negative influences of the tumor microenvironment such as hypoxia and limited nutrient availability. Therefore, an inhibitor of both TORC1 and TORC2 should effectively block signaling from the PI3K pathway as well as abrogate the cancer cells’ ability to survive in the harsh environment of the tumor thereby providing an effective means of treating cancer.

We report here the profile of our small molecule mTOR kinase inhibitor AR-mTOR-26. On enzyme, this compound inhibits mTOR kinase with an IC50 of 1 nM while exhibiting substantial selectivity against PI3Kα as well as a panel of lipid and protein kinases. In cells, AR-mTOR-26 inhibits the TORC1-dependent readouts pS6 (Ser235/6) and p4E-BP1 (Ser37/46) as well as the TORC2 phosphorylation site on Akt, Ser473, with IC50 values of <50 nM. Consistent with its selectivity over PI3Kα, AR-mTOR-26 does not significantly inhibit Thr308 on AKT, a PI3K/PDK1-dependent readout. In addition, we show that AR-mTOR-26 is broadly and potently anti-proliferative across a panel of solid and hematological cancer cell lines, irrespective of their mutational status suggesting the potential for broad therapeutic utility. We then evaluated the in vivo activity of AR-mTOR-26. By oral administration, AR-mTOR-26 exhibits excellent pharmacokinetics in mice with plasma concentrations that are predicted to be efficacious. Doses ranging from 1-10 mg/kg once daily to tumor-bearing mice results in significant anti-tumor activity in several mouse xenograft models, including PC3 prostate [PTEN null] and H460 lung [KRASG12D/PIK3CA]. These effects ranged from tumor growth inhibition to regressions dependent upon the dose and the xenograft model evaluated. In all, these data show that targeting mTOR kinase with AR-mTOR-26 holds promise as a broadly acting therapeutic for oncology.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4484.

Abstract B90: Understanding the effects of RAF inhibitors on RAF signaling in B-RAF V600E mutant versus wild type tumors

Constitutive activation of the Ras, RAF, mitogen-activated protein kinase (MEK), and extracellular signal regulated kinase (ERK) pathway is a common finding in many human cancers. Activating mutations in K-Ras or B-RAF constitute over 30% of all mutations in human tumors. Therefore, identifying therapeutic strategies to downregulate this pathway could have broad therapeutic impact. It has been demonstrated that RAF inhibitors selectively inhibit B-RAFV600E tumors and not Ras mutant tumors, despite functioning as one of the key effector enzymes downstream of Ras and upstream of MEK. In this work we demonstrate that although RAF inhibitors effectively inhibit phospho-MEK and phospho-ERK levels in B-RAFV600E cells, pathway induction is observed for RAF inhibitors in B-RAF WT/K-Ras Mutant or B-RAF WT/K-Ras WT cell lines as evidenced by increases in phospho-MEK, phospho-ERK and phospho-p90RSK levels. We also show that with increasing concentrations of RAF inhibitors, the downstream pathway can be inhibited in WT B-RAF and mutant K-Ras cell lines. Stimulation of the pathway with growth factors or serum can attenuate phospho-MEK and phospho-ERK induction upon treatment with RAF inhibitors. Additionally, mechanistic studies demonstrate that RAF inhibitors can directly activate RAF kinase activity. Taken together, our data suggests that RAF inhibitors may have opposing functions as both activators and inhibitors of the MAPK pathway, depending on cellular context. These results provide new insight into the therapeutic utility of MAPK pathway inhibitors, and emphasize the importance of correlating target occupancy with pharmacodynamic markers of efficacy, and of targeting defined genetic backgrounds in cancer treatment.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B90.

Abstract B267: AR-mTOR-1: A potent, selective mTORC 1/2 kinase inhibitor for the treatment of malignancy

Through alterations in the PTEN and PI3K genes, the PI3K / Akt pathway is constitutively activated in human cancers. mTOR kinase plays an unique role in this pathway as the key component of two independent signaling complexes (mTORC1 (raptor - rapamycin sensitive) and mTORC2 (rictor - rapamycin insensitive)) that are involved at multiple branch points in this signaling cascade. As such, inhibition of mTOR kinase inactivates both mTOR complexes and therefore serves as an attractive means to target this integral pathway for the treatment of human malignancy.

We report the biological and pharmaceutical evaluation of our selective mTOR 1/2 kinase inhibitor AR-mTOR-1. AR-mTOR-1 inhibits mTOR kinase with an IC50 of < 10 nM while maintaining selectivity against PI3K as well as a panel of additional lipid kinases, serine/threonine kinases and cytoplasmic and receptor tyrosine kinases. In mechanistic cellular assays, AR-mTOR-1 inhibits pAkt (Ser473), 4E-BP1 (Thr36/46) and pS6 (Ser235/6) with nanomolar potency, thus demonstrating inhibition of signaling from both mTORC1 and mTORC2 complexes. In line with its enzymatic selectivity over PI3K , AR-mTOR-1 does not significantly inhibit pAkt (Thr308) in cells. AR-mTOR-1 is broadly anti-proliferative in both epithelial and hematologic cancer cell lines, irrespective of mutational status, with IC50's ranging from 30 to 550 nM across 20 cell lines, suggesting the potential for broad clinical activity. Once daily dosing of AR-mTOR-1 in several mouse xenograft models, including PC3 prostate, U87 glioblastma, and H460 lung, results in robust anti-tumor activity. Finally, AR-mTOR-1 possesses desired in vitro and in vivo preclinical ADME properties including low clearance, high permeability and good absorption in three preclinical species. In total these data demonstrate that selectively targeting mTORC1 and mTORC2 with AR-mTOR-1 holds promise for broad spectrum clinical utility as a single agent across a wide array of cancer types.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B267.

Potent and selective pyrazole-based inhibitors of B-Raf kinase

Herein we describe a novel pyrazole-based class of ATP competitive B-Raf inhibitors. These inhibitors exhibit both excellent cellular potency and striking B-Raf selectivity. A subset of these inhibitors has demonstrated the ability to inhibit downstream ERK phosphorylation in LOX tumors from mouse xenograft studies.

The city-fox phenomenon: genetic consequences of a recent colonization of urban habitat

The red fox (Vulpes vulpes) is one of the best-documented examples of a species that has successfully occupied cities and their suburbs during the last century. The city of Zurich (Switzerland) was colonized by red foxes 15 years ago and the number of recorded individuals has increased steadily since then. Here, we assessed the hypothesis that the fox population within the city of Zurich is isolated from adjacent rural fox populations against the alternative hypothesis that urban habitat acts as a constant sink for rural dispersers. We examined 11 microsatellite loci in 128 foxes from two urban areas, separated by the main river crossing the city, and three adjacent rural areas from the region of Zurich. Mean observed heterozygosity across individuals and the number of detected alleles were lower for foxes collected within the city as compared with their rural conspecifics. Genetic differentiation was significantly lower between rural than between rural and urban populations, and highest value of pairwise FST was recorded between the two urban areas. Our results indicate that the two urban areas were independently founded by a small number of individuals from adjacent rural areas resulting in genetic drift and genetic differentiation between rural and urban fox populations. Population admixture and immigration analysis revealed that urban-rural gene flow was higher than expected from FST statistics. In the five to seven generations since colonization, fox density has dramatically increased. Currently observed levels of migration between urban and rural populations will probably erode genetic differentiation over time.

Tenascin-R is expressed by Schwann cells in the peripheral nervous system

The extracellular matrix glycoprotein tenascin-R (TN-R) has been implicated in a variety of cell-matrix interactions involved in the molecular control of axon guidance and neural cell migration during development and regeneration of the central nervous system (CNS). Whereas TN-R is amply expressed in the early postnatal and adult mammalian CNS, the protein has so far not been detected in different compartments of the peripheral nervous system (PNS). Here we provide first evidence that TN-R (predominantly TN-R 160 isoform) is transiently expressed in the sciatic nerve of late embryonic (E14-18) and neonatal mice, while at later developmental stages, both protein and mRNA are downregulated. In vitro, TN-R protein was found to be expressed by both undifferentiated and neuronally differentiated PC12 cells and by L1-positive Schwann cells (SC), but not by other neural and non-neural cell types in cell cultures derived from embryonic (E17/18) hindlimbs and neonatal sciatic nerves. In the developing PNS, TN-R expression correlated with axon growth and SC migration during the period of skeletal muscle innervation. Based on different in vitro approaches, we found that the substrate-bound glycoprotein selectively inhibits the fibronectin-dependent: (1) neurite outgrowth from dorsal root ganglion neurons (strongly expressing alpha5beta1 integrin and the disialoganglioside GD3) by a ganglioside-sensitive signaling mechanism; and (2) migration of primary myoblasts and other non-neuronal cells in a ganglioside-independent manner. Our findings suggest the functional role of TN-R in PNS pattern formation during distinct stages of axon pathfinding and skeletal muscle innervation.

Expression pattern of galectin-3 in neural tumor cell lines

Galectin-3 is a member of the galectin family of beta-galactoside-specific animal lectins. Here we show that galectin-3 is constitutively expressed in 15 out of 16 glioma cell lines tested, but not by normal or reactive astrocytes, oligodendrocytes, glial O-2A progenitor cells and the oligodendrocyte precursor cell line Oli-neu. Galectin-3 is also expressed by one oligodendroglioma cell line, but not by primitive neuroectodermal tumor and 4 neuroblastoma cell lines tested so far. In all galectin-3 expressing cell lines, the lectin is predominantly, if not exclusively, localized intracellularly and carries an active carbohydrate recognition domain (shown for C6 rat glioma cells). Moreover, in contrast to primary astrocytes, glioma cells do not or only weakly adhere to substratum-bound galectin-3, probably reflecting an unusual glycosylation pattern. Our findings indicate that the expression of galectin-3 selectively correlates with glial cell transformation in the central nervous system and could thus serve as a marker for glial tumor cell lines and glial tumors.

High prevalence of Echinococcus multilocularis in urban red foxes (Vulpes vulpes) and voles (Arvicola terrestris) in the city of Zürich, Switzerland

Over a period of 26 months from January 1996 to February 1998, 388 foxes from the city of Zürich, Switzerland, were examined for intestinal infections with Echinococcus multilocularis and other helminths. The prevalence of E. multilocularis in foxes sampled during winter increased significantly from 47% in the urban to 67% in the adjacent recreational area, whereas prevalence rates of other helminths were similar in both areas. Seasonal differences in the prevalence of E. multilocularis were only found in urban subadult male foxes which were significantly less frequently infected in summer than in winter. The distribution of the Echinococcus biomass, as expressed by worm numbers per fox was overdispersed in 133 infected foxes randomly sampled in winter. Ten of these foxes (8%) were infected with more than 10,000 specimens and carried 72% of the total biomass of E. multilocularis (398,653 worms). Prevalences did not differ significantly in these foxes in regard to age and sex but worm burdens were significantly higher in subadult foxes as compared with adult foxes. In voles (Arvicola terrestris) trapped in a city park of Zürich, E. multilocularis metacestodes were identified by morphological examination and by PCR. The prevalence was 20% among 60 rodents in 1997 and 9% among 75 rodents in 1998. Protoscoleces occurred in 2 of the cases from 1997. The possible risk for human infection is discussed with respect to the established urban E. multilocularis cycle.

Tenascin-R is an intrinsic autocrine factor for oligodendrocyte differentiation and promotes cell adhesion by a sulfatide-mediated mechanism

O4(+) oligodendrocyte (OL) progenitors in the mammalian CNS are committed fully to terminal differentiation into myelin-forming cells. In the absence of other cell types in vitro, OL differentiation reproduces the in vivo development with a correct timing, suggesting the existence of an intrinsic regulatory mechanism that presently is unknown. We have examined the effect of two isoforms of the extracellular matrix (ECM) molecule tenascin-R (TN-R), which is expressed by OLs during the process of myelination, on the adhesion and maturation of OLs in vitro. Here we show that the substrate-bound molecules supported the adhesion of O4(+) OLs independently of the CNS region or age from which they were derived. At the molecular level this process was mediated by protein binding to membrane surface sulfatides (Sulf), as indicated by the interference of O4 antibody and Sulf with the attachment of OLs or other Sulf+ cells, erythrocytes, to TN-R substrates and by direct protein-glycolipid binding studies. In the absence of platelet-derived growth factor (PDGF), exogenous TN-R induced myelin gene expression and the upregulation of its own synthesis by cultured cells, resulting in a rapid terminal differentiation of O4(+) progenitors. Our findings strongly suggest that TN-R represents an intrinsic regulatory molecule that controls the timed OL differentiation by an autocrine mechanism and imply the relevance of TN-R for CNS myelination and remyelination.

C-X-C and C-C chemokines are expressed in the cerebrospinal fluid in bacterial meningitis and mediate chemotactic activity on peripheral blood-derived polymorphonuclear and mononuclear cells in vitro

The appearance of polymorphonuclear and mononuclear leukocytes in the cerebrospinal fluid (csf) is an important hallmark of bacterial meningitis. Chemokines are candidate mediators of cell migration from blood into the subarachnoid space. Therefore, concentrations of C-X-C and C-C chemokines in the csf of patients with pyogenic meningitis were measured by ELISA. Highly significant elevations of chemokine levels in comparison with noninflammatory csf controls were found for IL-8 (median, 21.6 ng/ml; range, < 0.1 to 191.3), growth-related gene product alpha (median, 5.6 ng/ml; range, < 0.1 to 48.2), monocyte chemotactic protein-1 (median, 26.4 ng/ml; range, < 0.2 to 193.8), macrophage inflammatory protein-1 alpha (MIP-1 alpha; median, 1.8 ng/ml; range, < 0.5 to 18.0), MIP-1 beta (median, 10.6 ng/ml; range, < 0.3 to 84.4), but not for RANTES (regulated upon activation, normal T cell expressed and secreted). The csf of bacterial meningitis were chemotactic for neutrophils and mononuclear leukocytes. Correlation analysis demonstrated a strong association between individual chemokine levels and chemotactic activity mediated by csf. A significant reduction of neutrophil chemotaxis was obtained by anti-IL-8 and anti-growth-related gene product alpha Abs, and a reduction of mononuclear cell migration was achieved by a combination of anti-monocyte chemotactic protein-1, anti-MIP-1 alpha, and anti-MIP-1 beta Abs. Since no significant correlation was found between csf leukocyte counts and chemokine concentrations or chemotactic activity mediated by csf, additional factors influence the extent of pleocytosis in vivo.

C-X-C and C-C chemokines are expressed in the cerebrospinal fluid in bacterial meningitis and mediate chemotactic activity on peripheral blood-derived polymorphonuclear and mononuclear cells in vitro

The appearance of polymorphonuclear and mononuclear leukocytes in the cerebrospinal fluid (csf) is an important hallmark of bacterial meningitis. Chemokines are candidate mediators of cell migration from blood into the subarachnoid space. Therefore, concentrations of C-X-C and C-C chemokines in the csf of patients with pyogenic meningitis were measured by ELISA. Highly significant elevations of chemokine levels in comparison with noninflammatory csf controls were found for IL-8 (median, 21.6 ng/ml; range, &lt; 0.1 to 191.3), growth-related gene product alpha (median, 5.6 ng/ml; range, &lt; 0.1 to 48.2), monocyte chemotactic protein-1 (median, 26.4 ng/ml; range, &lt; 0.2 to 193.8), macrophage inflammatory protein-1 alpha (MIP-1 alpha; median, 1.8 ng/ml; range, &lt; 0.5 to 18.0), MIP-1 beta (median, 10.6 ng/ml; range, &lt; 0.3 to 84.4), but not for RANTES (regulated upon activation, normal T cell expressed and secreted). The csf of bacterial meningitis were chemotactic for neutrophils and mononuclear leukocytes. Correlation analysis demonstrated a strong association between individual chemokine levels and chemotactic activity mediated by csf. A significant reduction of neutrophil chemotaxis was obtained by anti-IL-8 and anti-growth-related gene product alpha Abs, and a reduction of mononuclear cell migration was achieved by a combination of anti-monocyte chemotactic protein-1, anti-MIP-1 alpha, and anti-MIP-1 beta Abs. Since no significant correlation was found between csf leukocyte counts and chemokine concentrations or chemotactic activity mediated by csf, additional factors influence the extent of pleocytosis in vivo.

Expression of a Na,K-ATPase beta 3 subunit during development of the zebrafish central nervous system

Zebrafish beta 3, a full length cDNA clone encoding a zebrafish Na,K-ATPase beta subunit, was isolated. The protein shares highest homology with the beta 3 subunits of amphibians and mammals, slightly less homology with the beta 2 subunits, and is distinct from the beta 1 subunits. The fish beta subunit co-assembled with alpha subunits to form Na,K-ATPase enzymes when expressed in Xenopus oocytes. Embryonic expression was first detected by whole-mount in situ hybridization between 8-12 hr post-fertilization (hpf) in the head mesoderm. Subsequently, and up to 24 hpf, the mRNA was confined to four dorsal domains in the anterior neural tube. After a transient downregulation during the second day, expression was again conspicuous in the nervous system of 3-day-old larvae. Based on its distribution pattern, the fish beta subunit could be involved in setting up regional identities in the developing fish CNS and in the differentiation of distinct cell types.

Crystallization and preliminary crystallographic analysis of two β-mannanase isoforms from Thermomonospora fusca KW3

Three beta-mannanase isoforms were isolated from the supernatant of a thermophilic actinomycete culture from Thermomonospora fusca KW3. Two of the isoforms (Q1, Q 1.1) were crystallized by the hanging-drop method at room temperature using ammonium sulfate as a precipitant. The isoforms form rod-shaped colorless crystals. Both belong to the orthorhombic space group P2(1)2(1)2(1). The cell dimensions are a = 46.7, b = 61.1, and c = 128.2 A for isoform Q1, and a = 43.8, b = 46.2, and c = 132.8 A for isoform Q1.1. The asymmetric unit of either isoform contains one mannanase molecule. Native data have been collected to 2.2 A resolution for Q1 and to 1.65 A resolution for Q1.1 using synchrotron radiation.

Furin, PC1/3, and/or PC6A process rabbit, but not human, pro-lactase-phlorizin hydrolase to the 180-kDa intermediate

Small intestinal lactase-phlorizin hydrolase (LPH) is synthesized as a large precursor (prepro-LPH) of 1926 amino acids. In the endoplasmic reticulum, prepro-LPH is split by signal protease. The resulting pro-LPH is cut to mature LPH directly (human) or via a 180-kDa intermediate (rabbit), most likely in the trans-Golgi network or in a later compartment. Antibodies directed against different regions of rabbit pro-LPH locate the cleavage site resulting in the 180-kDa intermediate between amino acid residues 79 and 286. This stretch contains the two sequences -Arg-Cys-Tyr-Arg114 approximately -Arg-Ala-Ser-Arg191 approximately, which are potential cleavage sites for subtilisin-like proprotein convertases. These sites are not conserved in human pro-LPH. By coexpression in COS 7 cells of rabbit prepro-LPH and proprotein convertases (PC 1/3, PC2, PC6A, PC6B, furin), we show that furin, PC 1/3, and PC6A generate a processing intermediate that is immunologically indistinguishable from the one observed in vivo. Furin, PC 1/3, and PC6A are all expressed in the small intestine as shown by a polymerase chain reaction-based approach and, more specifically, in enterocytes, as shown by in situ hybridization. These results suggest that furin, PC 1/3, and/or PC6A are responsible for the in vivo processing of rabbit pro-LPH to the 180-kDa intermediate.

A vector for the synthesis of cRNAs encoding Myc epitope-tagged proteins in Xenopus laevis oocytes

We describe a plasmid, pNKS2-myc, designed for convenient in-frame fusion of an antibody-specific epitope sequence to the N terminus of a desired cDNA and subsequent synthesis of transcripts that direct the synthesis of the tagged polypeptide in Xenopus laevis (Xl) oocytes. pNKS2-myc contains an SP6 promoter, followed by the translation initiation sequence of the Na,K-pump beta 3 subunit of Xl and the sequence encoding an epitope derived from the human c-myc proto-oncogene product. Appropriate restriction sites allow one to insert virtually any desired cDNA fragment directly behind the epitope-specific sequence and before a long poly(A) tail. After linearization with EcoRI or NotI, polyadenylated cRNA can be synthesized that is efficiently translated in Xl oocytes. The utility of pNKS2-myc is demonstrated by cloning cDNAs coding for Na,K-pump subunits into this vector and injecting the corresponding cRNAs into oocytes. The tagged mouse beta 1 and beta 2 subunit isoforms could be purified from detergent extracts of these cells by immunoprecipitation with a generally available monoclonal antibody (mAb) to the tag, 9E10, as well as with specific mAb that recognize individual beta subunit isoforms. Under native conditions, endogenous and coexpressed exogenous alpha 1 subunits (the catalytic subunit of the Na,K-pump) were co-precipitated, indicating that the N-terminal addition of the decapeptide epitope has no adverse effect on the folding of beta subunits nor on their assembly with alpha subunits. Furthermore, the Myc-specific mAb likewise precipitated a Myc-tagged Na,K-pump alpha 1 subunit together with any of the co-synthesized beta subunits.

Functional characterization of beta isoforms of murine Na,K-ATPase. The adhesion molecule on glia (AMOG/beta 2), but not beta 1, promotes neurite outgrowth

We have previously provided evidence for a dual function of the adhesion molecule on glia (AMOG/beta 2), the beta 2 subunit of the murine Na,K-ATPase, both as neural recognition molecule mediating neuron-glia interactions and as functional beta subunit of the sodium pump. To analyze the functional role of AMOG/beta 2 in neurite outgrowth, AMOG/beta 2-expressing L-cells were generated by transfection and used as substrates for neurite outgrowth of cerebellar and hippocampal neurons. AMOG/beta 2-transfected L-cells led to an increase in neurite length after 6 h, which was specifically inhibited by antibodies to AMOG/beta 2 and a neuronal membrane fraction. Moreover, the extracellular domain of AMOG/beta 2 generated as a soluble recombinant protein in Chinese hamster ovary cells partially inhibited the increase in neurite outgrowth on AMOG/beta 2-transfected L-cells. L-cells transfected with the mouse beta 1 subunit had no effect on neurite extension. Our observations show for the first time differences in functional properties for different beta isoforms of the Na,K-ATPase and suggest that AMOG/beta 2 but not beta 1 is able to interact with an unknown neuronal receptor leading to increased neurite outgrowth, most likely via signal transduction.

Production and secretion in CHO cells of the extracellular domain of AMOG/beta 2, a type-II membrane protein

A hybrid gene consisting of the sequences coding for the signal peptide and N terminus of a type-I membrane protein, the neural cell adhesion molecule (N-CAM), and the extracellular domain of the adhesion molecule on glia (AMOG/beta 2), a type-II membrane protein, was constructed. The sequence was inserted into a eukaryotic expression vector containing the human cytomegalovirus promoter and the glutamine synthetase selection marker, and used to transfect Chinese hamster ovary cells. The resulting stably transformed cell lines produced large amounts of soluble recombinant AMOG/beta 2 (reAMOG/beta 2), which was secreted into the culture medium as a heavily glycosylated 40-55-kDa protein. N-terminal sequence analysis revealed that the protein is not cleaved at the natural signal peptide cleavage site of N-CAM, but two amino acids (aa) further downstream. Treatment of reAMOG/beta 2 with N-glycosidase F (GlycoF) reduced the molecular mass to 27 kDa, corresponding to the calculated mass of the unglycosylated form. In contrast to AMOG/beta 2 isolated from mouse brain, which is sensitive to endoglycosidase H, the immunoaffinity-purified re-protein is more resistant to this treatment, indicating that the sugars attached to reAMOG/beta 2 are mainly of the complex type. Our results demonstrate the feasibility of secreting the extracellular domain of a type-II membrane protein, which is usually inserted into the membrane with the C terminus facing the extracellular side.

The adhesion molecule on glia (AMOG/beta 2) and alpha 1 subunits assemble to functional sodium pumps in Xenopus oocytes

The adhesion molecule on glia, AMOG, an integral cell surface glycoprotein highly expressed by cerebellar astrocytes and involved in neuron to astrocyte adhesion and granule neuron migration (Antonicek, H., Persohn, E., and Schachner, M. (1987) J. Cell Biol. 104, 1587-1595) has been identified as a beta 2 subunit isoform of the mouse sodium pump (Gloor, S., Antonicek, H., Sweadner, K.J., Pagliusi, S., Frank, R., Moos, M., and Schachner, M. (1990) J. Cell Biol. 110, 165-174). Here we demonstrate that AMOG/beta 2 expressed by cRNA injection in Xenopus oocytes is capable of combining with endogenous Xenopus alpha 1 subunits or coexpressed Torpedo alpha 1 subunits to yield a functional alpha 1/AMOG sodium pump isozyme. Determinations of the number of ouabain binding sites and ouabain-sensitive 86Rb+ uptake suggest that the alpha 1/AMOG isozyme has slightly lower maximum transport rate and apparent affinity for external K+ than the alpha 1/beta 1 isozyme. Immunoprecipitation of alpha 1/AMOG complexes from digitonin extracts of [35S]methionine-labeled oocytes with a monoclonal anti-AMOG antibody provides direct evidence for a stable association between AMOG and the alpha 1 subunits of Xenopus and Torpedo.

Up-regulation of sodium pump activity in Xenopus laevis oocytes by expression of heterologous beta 1 subunits of the sodium pump

Recent evidence suggests that the beta subunit of the Na+ pump is essential for the alpha subunit to express catalytic activity and for assembly of the holoenzyme in the plasma membrane. We report here that injection into Xenopus laevis oocytes of cRNAs specific for beta 1 subunit isoforms of the Na+ pump of four species (Torpedo californica, chicken, mouse and rat) causes a time-dependent increase in the number of ouabain-binding sites, both in the plasma membrane and in internal membranes. Expression of the beta 1 subunit of the Na+ pump of mouse and rat in the oocytes could be substantiated by immunoprecipitation using a polyclonal antiserum against the mouse beta 1 subunit. Scatchard analysis in permeabilized cells disclosed that the affinity for ouabain is unchanged after expression of each of the beta 1 subunits. A proportional increase in ouabain-sensitive 86Rb+ uptake indicates that the additionally expressed ouabain-binding sites on the cell surface represent functional Na+ pumps. The findings support the concept of Geering. Theulaz, Verrey, Häuptle & Rossier [(1989) Am. J. Physiol. 257, C851-C858] that beta 1 subunits expressed in oocytes associate with an excess of endogenous alpha subunits of the Na+ pump to form a hybrid enzyme. In addition, all of the beta 1 isoforms investigated in the present study were also capable of combining with the co-expressed alpha 1 subunit of the Torpedo Na+ pump to produce a functional enzyme. Injection of cRNA encoding for the Torpedo alpha 1 subunit alone had no effect on the ouabain-binding capacity of the surface and intracellular membranes of the oocyte.

Assignment of Amog (adhesion molecule on glia) gene to mouse chromosome 11 near Zfp-3 and Asgr-1,2 and to human chromosome 17

AMOG, identified as an adhesion molecule that mediates neuron-astrocyte interaction, has structural similarity to the beta-subunit of Na,K ATPase. We have mapped the AMOG gene to human chromosome 17 and mouse chromosome 11 by somatic cell hybrid analysis. Recombinant inbred strain mapping has placed the Amog locus close to genes for zinc finger protein-3 and the asialoglycoprotein receptor in a region of mouse chromosome 11 that is homologous to human 17p.

The adhesion molecule on glia (AMOG) is a homologue of the beta subunit of the Na,K-ATPase

AMOG (adhesion molecule on glia) is a Ca2(+)-independent adhesion molecule which mediates selective neuron-astrocyte interaction in vitro (Antonicek, H., E. Persohn, and M. Schachner. 1987. J. Cell Biol. 104:1587-1595). Here we report the structure of AMOG and its association with the Na,K-ATPase. The complete cDNA sequence of mouse AMOG revealed 40% amino acid identity with the previously cloned beta subunit of rat brain Na,K-ATPase. Immunoaffinity-purified AMOG and the beta subunit of detergent-purified brain Na,K-ATPase had identical apparent molecular weights, and were immunologically cross-reactive. Immunoaffinity-purified AMOG was associated with a protein of 100,000 Mr. Monoclonal antibodies revealed that this associated protein comprised the alpha 2 (and possibly alpha 3) isoforms of the Na,K-ATPase catalytic subunit, but not alpha 1. The monoclonal AMOG antibody that blocks adhesion was shown to interact with Na,K-ATPase in intact cultured astrocytes by its ability to increase ouabain-inhibitable 86Rb+ uptake. AMOG-mediated adhesion occurred, however, both at 4 degrees C and in the presence of ouabain, an inhibitor of the Na,K-ATPase. Both AMOG and the beta subunit are predicted to be extracellularly exposed glycoproteins with single transmembrane segments, quite different in structure from the Na,K-ATPase alpha subunit or any other ion pump. We hypothesize that AMOG or variants of the beta subunit of the Na,K-ATPase, tightly associated with an alpha subunit, are recognition elements for adhesion that subsequently link cell adhesion with ion transport.

Identification of a cDNA clone specific for the neural cell adhesion molecule AMOG

A cDNA clone of the neural cell adhesion molecule AMOG was isolated from a lambda gt10 library constructed from 8-day-old mouse brain poly(A) + RNA with a 17mer oligonucleotide probe designed from a nonapeptide sequence obtained from tryptic peptides of AMOG. The cDNA clone expressed as a fusion protein that is recognized by polyclonal AMOG antibodies; conversely, polyclonal antibodies prepared against the fusion protein react with AMOG. The clone contains the full sequence derived from the nonapeptide. Of all tissues tested, only brain expresses detectable levels of AMOG by ELISA and Northern blot analyses, indicating a high correlation in expression at the protein and mRNA levels. Both brain and astrocytes express a 3 kb long mRNA, which appears to be encoded by a single gene.

A glia-derived neurite promoting factor with protease inhibitory activity belongs to the protease nexins

A glia-derived neurite promoting factor (GdNPF) has serine protease inhibitory activity and in addition regulates the migration of neuronal cells. cDNA cloning of GdNPF is necessary for studying the physiological relevance and the mode of action of this protein and similar cell-derived protease inhibitors. Xenopus oocytes injected with rat glioma cells mRNA release this inhibitor. A rat cDNA clone coding for the previously purified glia-derived neurite promoting factor (GdNPF) was isolated upon hybridization-selected translation, followed by immunoprecipitation. The correct identity of this cDNA is proven by the presence of a sequence coding for a tryptic fragment from pure GdNPF. Northern analysis indicates that GdNPF mRNA is found almost exclusively in brain tissue and could be developmentally regulated. The same cDNA clone has been used to isolate full-length rat and human GdNPF cDNA. The deduced human GdNPF amino acid sequence indicates that the protein is a member of a family of cell-derived protease inhibitors named protease nexins.

Quantitative aspects of membrane behavior in rat parathyroid cells after depression or elevation of serum calcium

The behavior of membranes concerned with parathyroid hormone secretion was studied by electron microscopic morphometry in parathyroid cells of rats with temporarily reduced serum calcium concentration resulting from phosphate ion application and in rats with elevated serum calcium concentration following vitamin D3 administration. The phosphate ion application resulted in an increase of the cell surface area and a concomitant decrease of the surface area of the Golgi complex and secretory granules within 3 hours. After 3 hours, the cell surface area decreased, whereas the surface area of the Golgi complex and the secretory granules increased, and after 12 hours, the surface area of the rough endoplasmic reticulum also increased. In the vitamin D3-treated rats the surface area of the secretory granules increased, but the cell surface area had decreased by 24, 48, and 72 hours after application. These data suggest that parathyroid cells respond to a transient depression of the serum calcium concentration by an initial centrifugal membrane shift indicating enhanced exocytosis, followed by a centripedal membrane shift indicating enhanced endocytic retrieval of the plasma membrane. Later, membrane synthesis led to an increase of the membrane compartments concerned with parathyroid hormone secretion. Elevation of the serum calcium concentration following vitamin D3 treatment resulted in reduced release of parathyroid hormone by exocytosis and enhanced retrieval of plasma membranes by endocytosis. The fate of the retrieval plasma membrane remains unclear.