An exploratory, open-label, randomized, multicenter study to investigate the pharmacodynamics of a glycoengineered antibody (imgatuzumab) and cetuximab in patients with operable head and neck squamous cell carcinoma

BACKGROUND

In addition to inhibiting epidermal growth factor receptor (EGFR) signaling, anti-EGFR antibodies of the IgG1 'subtype' can induce a complementary therapeutic effect through the induction of antibody-dependent cell-mediated cytotoxicity (ADCC). Glycoengineering of therapeutic antibodies increases the affinity for the Fc-gamma receptor, thereby enhancing ADCC.

PATIENTS AND METHODS

We investigated the changes in immune effector cells and EGFR pathway biomarkers in 44 patients with operable, advanced stage head and neck squamous cell carcinoma treated with two preoperative doses of either glycoengineered imgatuzumab (GA201; 700 or 1400 mg) or cetuximab (standard dosing) in a neoadjuvant setting with paired pre- and post-treatment tumor biopsies.

RESULTS

Significant antitumor activity was observed with both antibodies after just two infusions. Metabolic responses were seen in 23 (59.0%) patients overall. One imgatuzumab-treated patient (700 mg) achieved a 'pathological' complete response. An immediate and sustained decrease in peripheral natural killer cells was consistently observed with the first imgatuzumab infusion but not with cetuximab. The functionality of the remaining peripheral natural killer cells was maintained. Similarly, a pronounced increase in circulating cytokines was seen following the first infusion of imgatuzumab but not cetuximab. Overall, tumor-infiltrating CD3+ cell counts increased following treatment with both antibodies. A significant increase from baseline in CD3+/perforin+ cytotoxic T cells occurred only in the 700-mg imgatuzumab group (median 95% increase, P < 0.05). The most prominent decrease of EGFR-expressing cells was recorded after treatment with imgatuzumab (700 mg, -34.6%; 1400 mg, -41.8%). The post-treatment inflammatory tumor microenvironment was strongly related to baseline tumor-infiltrating immune cell density, and baseline levels of EGFR and pERK in tumor cells most strongly predicted therapeutic response.

CONCLUSIONS

These pharmacodynamic observations and relationship with efficacy are consistent with the proposed mode of action of imgatuzumab combining efficient EGFR pathway inhibition with ADCC-related immune antitumor effects.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01046266 (ClinicalTrials.gov).

Gene Expression Profiling in BRAF-Mutated Melanoma Reveals Patient Subgroups with Poor Outcomes to Vemurafenib That May Be Overcome by Cobimetinib Plus Vemurafenib

Purpose: The association of tumor gene expression profiles with progression-free survival (PFS) outcomes in patients with BRAF^V600-mutated melanoma treated with vemurafenib or cobimetinib combined with vemurafenib was evaluated.Experimental Design: Gene expression of archival tumor samples from patients in four trials (BRIM-2, BRIM-3, BRIM-7, and coBRIM) was evaluated. Genes significantly associated with PFS (P < 0.05) were identified by univariate Cox proportional hazards modeling, then subjected to unsupervised hierarchical clustering, principal component analysis, and recursive partitioning to develop optimized gene signatures.Results: Forty-six genes were identified as significantly associated with PFS in both BRIM-2 (n = 63) and the vemurafenib arm of BRIM-3 (n = 160). Two distinct signatures were identified: cell cycle and immune. Among vemurafenib-treated patients, the cell-cycle signature was associated with shortened PFS compared with the immune signature in the BRIM-2/BRIM-3 training set [hazard ratio (HR) 1.8; 95% confidence interval (CI), 1.3-2.6, P = 0.0001] and in the coBRIM validation set (n = 101; HR, 1.6; 95% CI, 1.0-2.5; P = 0.08). The adverse impact of the cell-cycle signature on PFS was not observed in patients treated with cobimetinib combined with vemurafenib (n = 99; HR, 1.1; 95% CI, 0.7-1.8; P = 0.66).Conclusions: In vemurafenib-treated patients, the cell-cycle gene signature was associated with shorter PFS. However, in cobimetinib combined with vemurafenib-treated patients, both cell cycle and immune signature subgroups had comparable PFS. Cobimetinib combined with vemurafenib may abrogate the adverse impact of the cell-cycle signature. Clin Cancer Res; 23(17); 5238-45. ©2017 AACR.

NRP-1 Receptor Expression Mismatch in Skin of Subjects with Experimental and Diabetic Small Fiber Neuropathy

The in vivo cutaneous nerve regeneration model using capsaicin is applied extensively to study the regenerative mechanisms and therapeutic efficacy of disease modifying molecules for small fiber neuropathy (SFN). Since mismatches between functional and morphological nerve fiber recovery are described for this model, we aimed at determining the capability of the capsaicin model to truly mimic the morphological manifestations of SFN in diabetes. As nerve and blood vessel growth and regenerative capacities are defective in diabetes, we focused on studying the key regulator of these processes, the neuropilin-1 (NRP-1)/semaphorin pathway. This led us to the evaluation of NRP-1 receptor expression in epidermis and dermis of subjects presenting experimentally induced small fiber neuropathy, diabetic polyneuropathy and of diabetic subjects without clinical signs of small fiber neuropathy. The NRP-1 receptor was co-stained with CD31 vessel-marker using immunofluorescence and analyzed with Definiens® technology. This study indicates that capsaicin application results in significant loss of epidermal NRP-1 receptor expression, whereas diabetic subjects presenting small fiber neuropathy show full epidermal NRP-1 expression in contrast to the basal expression pattern seen in healthy controls. Capsaicin induced a decrease in dermal non-vascular NRP-1 receptor expression which did not appear in diabetic polyneuropathy. We can conclude that the capsaicin model does not mimic diabetic neuropathy related changes for cutaneous NRP-1 receptor expression. In addition, our data suggest that NRP-1 might play an important role in epidermal nerve fiber loss and/or defective regeneration and that NRP-1 receptor could change the epidermal environment to a nerve fiber repellant bed possibly through Sem3A in diabetes.

Development and Validation of a Histological Method to Measure Microvessel Density in Whole-Slide Images of Cancer Tissue

Despite all efforts made to develop predictive biomarkers for antiangiogenic therapies, no unambiguous markers have been identified so far. This is due to among others the lack of standardized tests. This study presents an improved microvessel density quantification method in tumor tissue based on stereological principles and using whole-slide images. Vessels in tissue sections of different cancer types were stained for CD31 by an automated and validated immunohistochemical staining method. The stained slides were digitized with a digital slide scanner. Systematic, uniform, random sampling of the regions of interest on the whole-slide images was performed semi-automatically with the previously published applications AutoTag and AutoSnap. Subsequently, an unbiased counting grid was combined with the images generated with these scripts. Up to six independent observers counted microvessels in up to four cancer types: colorectal carcinoma, glioblastoma multiforme, ovarian carcinoma and renal cell carcinoma. At first, inter-observer variability was found to be unacceptable. However, after a series of consensus training sessions and interim statistical analysis, counting rules were modified and inter-observer concordance improved considerably. Every CD31-positive object was counted, with exclusion of suspected CD31-positive monocytes, macrophages and tumor cells. Furthermore, if interconnected, stained objects were considered a single vessel. Ten regions of interest were sufficient for accurate microvessel density measurements. Intra-observer and inter-observer variability were low (intraclass correlation coefficient > 0.7) if the observers were adequately trained.

Abstract PR03: CD8+ T-cell distribution and immunomodulator expression in BRAF-mutant melanoma affect the response to BRAF inhibitor and chemotherapy

Although intense effort has been made in studying immune cell dynamics in tumors after treatment with targeted therapies and to recharacterize tumor stages based on their immune cell components, less is known about how baseline immune cell characteristics in tumors affect response to approved therapies. Here we describe baseline expression of immune regulators and CD8+ T-cell distribution in BRAF-mutated metastatic melanoma and their relationship with progression-free survival (PFS) on vemurafenib and chemotherapy. To our knowledge, we are the first to describe the baseline characteristics of tumor-infiltrating lymphocytes and their impact on outcomes in a large randomized, controlled trial in melanoma.

Archival or baseline samples were collected from patients in 2 clinical trials (BRIM2 and BRIM3) and analyzed. A total of 252 RNA samples were prepared from formalin-fixed, paraffin-embedded (FFPE) tissue samples and profiled for expression using a panel of 96 immune genes on the Fluidigm platform (Fluidigm Corp). Additionally, for 277 patients from the BRIM3 trial, CD8+ T cells were detected by immunohistochemistry (IHC) and quantified using Definiens (Definiens AG). Patients were defined as high or low expressers based on a median cutoff, and hazard ratios (HRs) were determined by cox proportional hazards modeling of PFS. HRs refer to the comparison of high and low expressing groups, where an HR&lt;1 is indicative of a better outcome for the high-expressing group.

A discovery (BRIM2) – validation (BRIM3) scheme was applied to assess the prognostic value of the expression of immune-related genes. Samples from the BRIM3 dacarbazine and vemurafenib arms were compared to assess the predictive value of the markers on the treatment effect of vemurafenib. Of the genes tested, 26 met our discovery criteria in the BRIM2 trial and 2, IL7 and IL12A, were validated in BRIM3. In the vemurafenib arm of BRIM3, patients with high expression of IL7 had improved PFS compared with patients with low IL7, with an HR of 0.63 (95% confidence interval [CI]: 0.41-0.97; P=0.03); high expression of IL12A had an HR of 0.58 (0.38-0.88; P=0.01). Neither gene was associated with PFS in the dacarbazine-treated arm; however, high and low expressers of both genes benefited from vemurafenib treatment.

Because immune contexture is known to be associated with outcomes, slides were stained for CD8+ T-cell content in 3 marker areas: center, peripheral, and invasive margin. In the dacarbazine arm, increased PFS was seen in patients with higher CD8+ T-cell content in the tumor center or periphery, with HRs of 0.58 (0.43-0.94; P=0.02) and 0.39 (0.25-0.59; P&lt;0.01), respectively. CD8+ T-cell content did not show a significant effect in vemurafenib-treated patients, and all groups benefited from vemurafenib treatment.

Based on these characterizations, tumor immune cell components seem to play important but varying roles in response to dacarbazine or vemurafenib treatment in BRAF-mutant melanoma.

This abstract is also being presented as Poster B22.

Citation Format: Matthew Wongchenko, Christina Rabe, Jeffrey Sosman, Grant McArthur, Yuanyuan Xiao, Houston Gilbert, Luc Andries, Mark Kockx, Hartmut Koeppen, Priti Hegde, Lukas Amler, Yibing Yan, Antoni Ribas. CD8+ T-cell distribution and immunomodulator expression in BRAF-mutant melanoma affect the response to BRAF inhibitor and chemotherapy. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Melanoma: From Biology to Therapy; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(14 Suppl):Abstract nr PR03.

AutoTag and AutoSnap: Standardized, semi-automatic capture of regions of interest from whole slide images

Tumor angiogenesis is measured by counting microvessels in tissue sections at high power magnification as a potential prognostic or predictive biomarker. Until now, regions of interest (ROIs) were selected by manual operations within a tumor by using a systematic uniform random sampling (SURS) approach. Although SURS is the most reliable sampling method, it implies a high workload. However, SURS can be semi-automated and in this way contribute to the development of a validated quantification method for microvessel counting in the clinical setting. Here, we report a method to use semi-automated SURS for microvessel counting: •Whole slide imaging with Pannoramic SCAN (3DHISTECH)•Computer-assisted sampling in Pannoramic Viewer (3DHISTECH) extended by two self-written AutoHotkey applications (AutoTag and AutoSnap)•The use of digital grids in Photoshop(®) and Bridge(®) (Adobe Systems) This rapid procedure allows traceability essential for high throughput protein analysis of immunohistochemically stained tissue.

Mapping of carboxypeptidase m in normal human kidney and renal cell carcinoma: expression in tumor-associated neovasculature and macrophages

Although the kidney generally has been regarded as an excellent source of carboxypeptidase M (CPM), little is known about its renal-specific expression level and distribution. This study provides a detailed localization of CPM in healthy and diseased human kidneys. The results indicate a broad distribution of CPM along the renal tubular structures in the healthy kidney. CPM was identified at the parietal epithelium beneath the Bowman's basement membrane and in glomerular mesangial cells. Capillaries, podocytes, and most interstitial cells were CPM negative. Tumor cells of renal cell carcinoma subtypes lose CPM expression upon dedifferentiation. Tissue microarray analysis demonstrated a correlation between low CPM expression and tumor cell type. CPM staining was intense on phagocytotic tumor-associated macrophages. Immunoreactive CPM was also detected in the tumor-associated vasculature. The absence of CPM in normal renal blood vessels points toward a role for CPM in angiogenesis. Coexistence of CPM and the epidermal growth factor receptor (EGFR) was detected in papillary renal cell carcinoma. However, the different subcellular localization of CPM and EGFR argues against an interaction between these h proteins. The description of the distribution of CPM in human kidney forms the foundation for further study of the (patho)physiological activities of CPM in the kidney.

The cholecystokinin CCK2 receptor antagonist, JNJ-26070109, inhibits gastric acid secretion and prevents omeprazole-induced acid rebound in the rat

BACKGROUND AND PURPOSE

JNJ-26070109 [(R)4-bromo-N-[1-(2,4-difluoro-phenyl)-ethyl]-2-(quinoxaline-5-sulfonylamino)-benzamide] is a novel antagonist at cholecystokinin CCK(2) receptors with good pharmacokinetic properties and represents a novel mechanism for the treatment of gastro-oesophageal reflux disease (GORD). The purpose of the present study was to determine whether chronic treatment with JNJ-26070109 could prevent, as well as treat, acid rebound in rats.

EXPERIMENTAL APPROACH

A chronic fistula was surgically inserted into the stomach of rats to enable the measurement of acid secretion under basal, pentagastrin and histamine-stimulated conditions. JNJ-26070109 and omeprazole were administered separately and in combination.

KEY RESULTS

Sustained administration of omeprazole alone and in combination with JNJ-26070109 inhibited gastric acid secretion by >90%. However, 3 days after withdrawing treatment, there was a rebound hypersecretion by ∼1.5-fold in omeprazole-treated animals. No such acid rebound was observed with JNJ-26070109 alone or with co-administration of JNJ-26070109 and omeprazole. The anti-trophic effects of JNJ-26070109 in the gastric mucosal paralleled the effects on acid rebound. Administration of JNJ-26070109 for 3 days after cessation of omeprazole prevented the occurrence of acid rebound. Interestingly, chronic, but not acute, treatment with JNJ-26070109 also inhibited histamine-stimulated acid secretion.

CONCLUSIONS AND IMPLICATIONS

Chronic administration of JNJ-26070109 effectively inhibited gastric acid secretion and suppressed proton pump inhibitor (PPI)-induced acid rebound in the rat. This work advances the field by demonstrating that modest doses of a competitive CCK(2) receptor antagonist have significant and functionally important anti-trophic actions in the gastric mucosa. These properties make JNJ-26070109 a suitable candidate for clinical investigation for the treatment of GORD.

RAS mutations in cutaneous squamous-cell carcinomas in patients treated with BRAF inhibitors

BACKGROUND

Cutaneous squamous-cell carcinomas and keratoacanthomas are common findings in patients treated with BRAF inhibitors.

METHODS

We performed a molecular analysis to identify oncogenic mutations (HRAS, KRAS, NRAS, CDKN2A, and TP53) in the lesions from patients treated with the BRAF inhibitor vemurafenib. An analysis of an independent validation set and functional studies with BRAF inhibitors in the presence of the prevalent RAS mutation was also performed.

RESULTS

Among 21 tumor samples, 13 had RAS mutations (12 in HRAS). In a validation set of 14 samples, 8 had RAS mutations (4 in HRAS). Thus, 60% (21 of 35) of the specimens harbored RAS mutations, the most prevalent being HRAS Q61L. Increased proliferation of HRAS Q61L-mutant cell lines exposed to vemurafenib was associated with mitogen-activated protein kinase (MAPK)-pathway signaling and activation of ERK-mediated transcription. In a mouse model of HRAS Q61L-mediated skin carcinogenesis, the vemurafenib analogue PLX4720 was not an initiator or a promoter of carcinogenesis but accelerated growth of the lesions harboring HRAS mutations, and this growth was blocked by concomitant treatment with a MEK inhibitor.

CONCLUSIONS

Mutations in RAS, particularly HRAS, are frequent in cutaneous squamous-cell carcinomas and keratoacanthomas that develop in patients treated with vemurafenib. The molecular mechanism is consistent with the paradoxical activation of MAPK signaling and leads to accelerated growth of these lesions. (Funded by Hoffmann-La Roche and others; ClinicalTrials.gov numbers, NCT00405587, NCT00949702, NCT01001299, and NCT01006980.).

Vesicular glutamate transporter VGLUT1 has a role in hippocampal long-term potentiation and spatial reversal learning

Vesicular glutamate transporters 1 and 2 (VGLUT1, VGLUT2) show largely complementary distribution in the mature rodent brain and tend to segregate to synapses with different physiological properties. In the hippocampus, VGLUT1 is the dominate subtype in adult animals, whereas VGLUT2 is transiently expressed during early postnatal development. We generated and characterized VGLUT1 knockout mice in order to examine the functional contribution of this transporter to hippocampal synaptic plasticity and hippocampus-dependent spatial learning. Because complete deletion of VGLUT1 resulted in postnatal lethality, we used heterozygous animals for analysis. Here, we report that deletion of VGLUT1 resulted in impaired hippocampal long-term potentiation (LTP) in the CA1 region in vitro. In contrast, heterozygous VGLUT2 mice that were investigated for comparison did not show any changes in LTP. The reduced ability of VGLUT1-deficient mice to express LTP was accompanied by a specific deficit in spatial reversal learning in the water maze. Our data suggest a functional role of VGLUT1 in forms of hippocampal synaptic plasticity that are required to adapt and modify acquired spatial maps to external stimuli and changes.

IMPA1 is essential for embryonic development and lithium-like pilocarpine sensitivity

Lithium has been the standard pharmacological treatment for bipolar disorder over the last 50 years; however, the molecular targets through which lithium exerts its therapeutic effects are still not defined. We characterized the phenotype of mice with a dysfunctional IMPA1 gene (IMPA1-/-) to study the in vivo physiological functions of IMPA1, in general, and more specifically its potential role as a molecular target in mediating lithium-dependent physiological effects. Homozygote IMPA1-/- mice died in utero between days 9.5 and 10.5 post coitum (p.c.) demonstrating the importance of IMPA1 in early embryonic development. Intriguingly, the embryonic lethality could be reversed by myo-inositol supplementation via the pregnant mothers. In brains of adult IMPA1-/- mice, IMPase activity levels were found to be reduced (up to 65% in hippocampus); however, inositol levels were not found to be altered. Behavioral analysis of the IMPA1-/- mice indicated an increased motor activity in both the open-field test and the forced-swim test as well as a strongly increased sensitivity to pilocarpine-induced seizures, the latter supporting the idea that IMPA1 represents a physiologically relevant target for lithium. In conclusion the IMPA1-/- mouse represents a novel model to study inositol homeostasis, and indicates that genetic inactivation of IMPA1 can mimic some actions of lithium.

Real-time gene expression analysis in human xenografts for evaluation of histone deacetylase inhibitors

Real-time analysis of gene expression in experimental tumor models represents a major tool to document disease biology and evaluate disease treatment. However, monitoring gene regulation in vivo still is an emerging field, and thus far it has not been linked to long-term tumor growth and disease outcome. In this report, we describe the development and validation of a fluorescence-based gene expression model driven by the promoter of the cyclin-dependent kinase inhibitor p21waf1,cip1. The latter is a key regulator of tumor cell proliferation and a major determinant in the response to many anticancer agents such as histone deacetylase inhibitors. In response to histone deacetylase inhibitors, induction of fluorescence in A2780 ovarian tumors could be monitored in living mice in a noninvasive real-time manner using whole-body imaging. Single p.o. administration of the histone deacetylase inhibitor MS-275 significantly induces tumor fluorescence in a time- and dose-dependent manner, which accurately predicted long-term antitumoral efficacy in individual mice following extended treatment. These findings illustrate that this technology allows monitoring of the biological response induced by treatment with histone deacetylase inhibitors. In addition to providing experimental pharmacokinetic/pharmacodynamic markers for investigational drugs, this model provides insight into the kinetics of in vivo regulation of transcription, which plays a key role in causing and maintaining the uncontrolled proliferation of tumor tissue.

Detection of autophagy in tissue by standard immunohistochemistry: possibilities and limitations

Transmission electron microscopy (TEM) is currently the standard method to monitor autophagy in tissue. Because TEM is labor intensive, we recently questioned whether marker proteins could be found for unambiguous detection of autophagy in tissue using standard immunohistochemical techniques. Our findings indicated that the identification of autophagy-specific biomarkers for tissue is highly compromised due to lack of differential gene expression. In this respect, TEM remains an indispensable technique for evaluation of autophagy in situ. Nevertheless, immunohistochemical staining of microtubule-associated protein 1 light chain 3 (LC3) appeared to be a valuable technique to detect autophagosome formation in tissue but only when this protein is overexpressed, e.g., in GFP-LC3 transgenic animals. Furthermore, demonstration of granular cytoplasmic ubiquitin inclusions by immunohistochemistry may be an attractive technique to measure autophagic cell degeneration in some human pathologies such as neurodegenerative diseases, heart failure and atherosclerosis.

p53-independent regulation of p21Waf1/Cip1 expression and senescence by Chk2

The Chk2 kinase is a tumor suppressor and key component of the DNA damage checkpoint response that encompasses cell cycle arrest, apoptosis, and DNA repair. It has also been shown to have a role in replicative senescence resulting from dysfunctional telomeres. Some of these functions are at least partially exerted through activation of the p53 transcription factor. High-level expression of virally transduced Chk2 in A549 human lung carcinoma cells led to arrested proliferation, apoptosis, and senescence. These were accompanied by various molecular events, including p21(Waf1/Cip1) (p21) transcriptional induction, consistent with p53 activation. However, Chk2-dependent senescence and p21 transcriptional induction also occurred in p53-defective SK-BR-3 (breast carcinoma) and HaCaT (immortalized keratinocyte) cells. Small interfering RNA-mediated knockdown of p21 in p53-defective cells expressing Chk2 resulted in a decrease in senescent cells. These results revealed a p53-independent role for Chk2 in p21 induction and senescence that may contribute to tumor suppression and genotoxic treatment outcome.

In situ detection of starvation-induced autophagy

Autophagy is a regulated bulk degradation process involved in many different human pathologies. Transmission electron microscopy (TEM) is currently the only reliable method for monitoring autophagy in situ. Because TEM is labor intensive, we questioned whether useful marker proteins can be found for unambiguous detection of autophagy in tissue via routinely used colorimetric, immunohistochemical, or fluorescent techniques. Starved HepG2 hepatocytes and nutrient deprived liver tissue were used as a model for the initiation of autophagy. Our findings indicate that starvation-induced autophagy in HepG2 cells was associated neither with differential mRNA gene expression nor with changes in the expression level of known autophagy-related proteins. On the contrary, both transcription and translation were inhibited, suggesting that the identification of autophagy-specific biomarkers for tissue is highly compromised. Light chain 3 (LC3) protein, which is an attractive marker of autophagosomes, revealed a relatively low expression level in tissue and cultured cells, but could be detected via immunohistochemistry in liver from GFP-LC3 transgenic mice. The number of LC3 immunopositive dot-like structures was significantly upregulated in liver tissue from nutrient-deprived GFP-LC3 mice as compared with nonstarved control tissue. Our results suggest that LC3 immunostaining can be used as an alternative detection method for autophagy in situ, but only when this protein is overexpressed.

In situ detection of starvation-induced autophagy

Autophagy is a regulated bulk degradation process involved in many different human pathologies. Transmission electron microscopy (TEM) is currently the only reliable method for monitoring autophagy in situ. Because TEM is labor intensive, we questioned whether useful marker proteins can be found for unambiguous detection of autophagy in tissue via routinely used colorimetric, immunohistochemical, or fluorescent techniques. Starved HepG2 hepatocytes and nutrient deprived liver tissue were used as a model for the initiation of autophagy. Our findings indicate that starvation-induced autophagy in HepG2 cells was associated neither with differential mRNA gene expression nor with changes in the expression level of known autophagy-related proteins. On the contrary, both transcription and translation were inhibited, suggesting that the identification of autophagy-specific biomarkers for tissue is highly compromised. Light chain 3 (LC3) protein, which is an attractive marker of autophagosomes, revealed a relatively low expression level in tissue and cultured cells, but could be detected via immunohistochemistry in liver from GFP-LC3 transgenic mice. The number of LC3 immunopositive dot-like structures was significantly upregulated in liver tissue from nutrient-deprived GFP-LC3 mice as compared with nonstarved control tissue. Our results suggest that LC3 immunostaining can be used as an alternative detection method for autophagy in situ, but only when this protein is overexpressed.

Alteration of frizzled expression in renal cell carcinoma

To evaluate the involvement of frizzled receptors (Fzds) in oncogenesis, we investigated mRNA expression levels of several human Fzds in more than 30 different human tumor samples and their corresponding (matched) normal tissue samples, using real-time quantitative PCR. We observed that the mRNA level of Fzd5 was markedly increased in 8 of 11 renal carcinoma samples whilst Fzd8 mRNA was increased in 7 of 11 renal carcinoma samples. Western blot analysis of crude membrane fractions revealed that Fzd5 protein expression in the matched tumor/normal kidney samples correlated with the observed mRNA level. Wnt/beta-catenin signaling pathway activation was confirmed by the increased expression of a set of target genes. Using a kidney tumor tissue array, Fzd5 protein expression was investigated in a broader panel of kidney tumor samples. Fzd5 membrane staining was detected in 30% of clear cell carcinomas, and there was a strong correlation with nuclear cyclin D1 staining in the samples. Our data suggested that altered expression of certain members of the Fzd family, and their downstream targets, could provide alternative mechanisms leading to activation of the Wnt signaling pathway in renal carcinogenesis. Fzd family members may have a role as a biomarker.

Flow cytometric evaluation of a model for phagocytosis of cells undergoing apoptosis

Phagocyte recognition of cells undergoing apoptosis is a rapid, efficient way of removing unwanted cells from tissue. The uptake of apoptotic cells prevents the release of potentially toxic cell contents that might otherwise damage neighbouring cells and elicit an inflammatory response. The aim of this work was to evaluate a simple cell culture assay to study phagocytosis of cells undergoing apoptosis. Fluorescent negatively charged beads (1 microm) or fluorescently labelled apoptotic cells, derived from etoposide-treated human monocytes (U937), were co-incubated with J774 cells or human peripheral blood macrophages for 1 h. Flow cytometry (FCM) showed an efficient uptake of both beads and apoptotic bodies. Phagocytosis of apoptotic cells but not of beads was significantly inhibited when macrophages were pre-incubated with cytochalasin D, suggesting that an experimental system based on beads is not an appropriate model of phagocytosis of apoptotic cells.

Inhibition of histone deacetylases by chlamydocin induces apoptosis and proteasome-mediated degradation of survivin

The naturally occurring cyclic tetrapeptide chlamydocin is a very potent inhibitor of cell proliferation. Here we show that chlamydocin is a highly potent histone deacetylase (HDAC) inhibitor, inhibiting HDAC activity in vitro with an IC(50) of 1.3 nM. Like other HDAC inhibitors, chlamydocin induces the accumulation of hyperacetylated histones H3 and H4 in A2780 ovarian cancer cells, increases the expression of p21(cip1/waf1), and causes an accumulation of cells in G(2)/M phase of the cell cycle. In addition, chlamydocin induces apoptosis by activating caspase-3, which in turn leads to the cleavage of p21(cip1/waf1) into a 15-kDa breakdown product and drives cells from growth arrest into apoptosis. Concomitant with the activation of caspase-3 and cleavage of p21(cip1/waf1), chlamydocin decreases the protein level of survivin, a member of the inhibitor of apoptosis protein family that is selectively expressed in tumors. Although our data indicate a potential link between degradation of survivin and activation of the apoptotic pathway induced by HDAC inhibitors, stable overexpression of survivin does not suppress the activation of caspase-3 or cleavage of p21(cip1/waf1) induced by chlamydocin treatment. The decrease of survivin protein level is mediated by degradation via proteasomes since it can be inhibited by specific proteasome inhibitors. Taken together, our results show that induction of apoptosis by chlamydocin involves caspase-dependent cleavage of p21(cip1/waf1), which is strikingly associated with proteasome-mediated degradation of survivin.

Improvement of endocardial and vascular endothelial function on myocardial performance by captopril treatment in postinfarct rat hearts

Background-Endocardial (EE) and myocardial capillary vascular endothelial (myocap VE) cells have been shown to modulate the contractile characteristics of myocardium in a calcium-dependent manner. We evaluated the endothelial-myocardial interaction in the rat postinfarction myocardial infarction (MI) model and the effects of captopril. Methods and Results-Wistar rats were divided into 4 groups treated for 4 weeks: (1) control; (2) infarcted controls (left anterior coronary artery ligation); (3) infarcted+captopril 2 g/L in drinking water; and (4) infarct+captopril+triton intracoronary injection. Coronary VE function was evaluated by infusion of serotonin in Langendorff preparations (n=31), and the myocardial contractile characteristics were investigated by use of isolated papillary muscles (n=44). Cardiac mRNA for endothelial constitutive nitric oxide synthase (ecNOS) was measured, and its cellular location was evaluated by immunohistochemistry. Serotonin-induced increase in coronary flow was decreased in infarct controls compared with controls (4.6% versus 53.4%, P<0.01) but not in the 2 infarct+captopril groups. Intracoronary triton injection decreased serotonin-induced coronary flow in the infarct+captopril+triton group. All MI groups had decreased total tension in isolated papillary muscles. EE removal by triton immersion decreased total tension in all groups except for infarct controls (3.3 versus 3.2 g/mm(2)). Cardiac ecNOS mRNA decreased in the control infarct group but remained normal in the infarct+captopril group. Conclusions-Chronic postinfarction endothelium-induced coronary vasodilatation is impaired, and both EE and myocap VE dysfunction contribute to myocardial depression. Captopril use prevents these abnormalities and the reduction of cardiac ecNOS mRNA.

Vascular endothelial dysfunction contributes to myocardial depression in ischemia-reperfusion in the rat

Endocardial and vascular myocardial capillary endothelium has been shown to modulate the contractile characteristics of myocardium by altering myofibrillar affinity for calcium. Although the release of endothelial-derived substances that modify myocardial contractility has been shown to be altered in certain physiologic and pathologic situations, until now no study has evaluated whether the direct modulatory effects of endothelium on its subjacent myocardium were altered in pathologic situations and contributed to loss of contractile function. This study was designed to evaluate whether the direct contractile modulatory effects of endocardial and (or) vascular endothelium were altered and whether these alterations contributed to contractile dysfunction in a model of ischemia-reperfusion. Sixty-two perfused rat hearts as Langendorff preparations were randomized to no intervention, intracoronary Triton X100 injection (to render vascular endothelium dysfunctional), ischemia (30 min)-reperfusion (20 min), and ischemia-reperfusion followed by intracoronary Triton X100 injection. Coronary endothelial-dependent vascular reactivity and vascular smooth muscle reactivity were assessed by serotonin and sodium nitroprusside, respectively. Myocardial damage was assessed by coronary effluent creatine phosphokinase and by morphologic studies. Papillary muscles were then excised and contractile characteristics evaluated at varying extracellular calcium concentration prior to and after endocardial endothelial removal with Triton X100. All three interventions eliminated all coronary vascular response to serotonin but did not modify response to nitroprusside. Creatine phosphokinase values rose only in hearts with ischemia-reperfusion, and only minor morphologic changes occurred, mostly in hearts with ischemia-reperfusion. Papillary muscles from hearts with intracoronary Triton X100 injection had lower contractile indices compared with normal controls (total tension 4.0 vs. 4.6 g/mm2, p < 0.01) and an abbreviation of contraction duration. Increasing extracellular calcium concentration from to 0.7 to 3.25 mM eliminated these differences. Similar but more marked decreases in contractile indices and twitch duration were noted in the two ischemia-reperfusion groups, but consistent with some myocardial damage being present, increasing extracellular calcium concentration to 3.25 or 7 mM did not fully eliminate these differences. In both ischemia-reperfusion groups and the intracoronary Triton X100 group, the relative increase in total tension with increasing extracellular calcium concentrations was similar (35 to 38%) and greater than that of the control group (25%), consistent with dysfunction of vascular endothelium contributing to myocardial dysfunction in the three intervention groups. Endocardial endothelial removal had a similar effect in all four groups, suggesting that dysfunction of endocardial endothelium does not play a role in this model. We conclude that vascular but not endocardial endothelial dysfunction contributes to the myocardial dysfunction that occurs during ischemia-reperfusion injury.

Vascular endothelial dysfunction contributes to myocardial depression in ischemia-reperfusion in the rat

Endocardial and vascular myocardial capillary endothelium has been shown to modulate the contractile characteristics of myocardium by altering myofibrillar affinity for calcium. Although the release of endothelial-derived substances that modify myocardial contractility has been shown to be altered in certain physiologic and pathologic situations, until now no study has evaluated whether the direct modulatory effects of endothelium on its subjacent myocardium were altered in pathologic situations and contributed to loss of contractile function. This study was designed to evaluate whether the direct contractile modulatory effects of endocardial and (or) vascular endothelium were altered and whether these alterations contributed to contractile dysfunction in a model of ischemia-reperfusion. Sixty-two perfused rat hearts as Langendorff preparations were randomized to no intervention, intracoronary Triton X100 injection (to render vascular endothelium dysfunctional), ischemia (30 min) - reperfusion (20 min), and ischemia-reperfusion followed by intracoronary Triton X100 injection. Coronary endothelial-dependent vascular reactivity and vascular smooth muscle reactivity were assessed by serotonin and sodium nitroprusside, respectively. Myocardial damage was assessed by coronary effluent creatine phosphokinase and by morphologic studies. Papillary muscles were then excised and contractile characteristics evaluated at varying extracellular calcium concentration prior to and after endocardial endothelial removal with Triton X100. All three interventions eliminated all coronary vascular response to serotonin but did not modify response to nitroprusside. Creatine phosphokinase values rose only in hearts with ischemia-reperfusion, and only minor morphologic changes occurred, mostly in hearts with ischemia-reperfusion. Papillary muscles from hearts with intracoronary Triton X100 injection had lower contractile indices compared with normal controls (total tension 4.0 vs. 4.6 g/mm2, p << 0.01) and an abbreviation of contraction duration. Increasing extracellular calcium concentration from 0.7 to 3.25 mM eliminated these differences. Similar but more marked decreases in contractile indices and twitch duration were noted in the two ischemia-reperfusion groups, but consistent with some myocardial damage being present, increasing extracellular calcium concentration to 3.25 or 7 mM did not fully eliminate these differences. In both ischemia-reperfusion groups and the intracoronary Triton X100 group, the relative increase in total tension with increasing extracellular calcium concentrations was similar (35 to 38%) and greater than that of the control group (25%), consistent with dysfunction of vascular endothelium contributing to myocardial dysfunction in the three intervention groups. Endocardial endothelial removal had a similar effect in all four groups, suggesting that dysfunction of endocardial endothelium does not play a role in this model. We conclude that vascular but not endocardial endothelial dysfunction contributes to the myocardial dysfunction that occurs during ischemia-reperfusion injury.Key words: endocardial endothelium, vascular endothelium, ischemia reperfusion, myocardial contractility.

Vascular-derived myocardial contractile factor: positive myocardial inotropic substance released from medial layer of the canine aorta

Interactions between the various cell types that make up the cardiovascular system are known to play an important role in maintaining homeostasis. One area about smooth muscle cells that has received little attention, despite the production of a wide variety of mediators by smooth muscle cells, is their effect on myocardial function. In this study, the myocardial contractile effects of four different types of dog aortic strips on rabbit papillary muscles were evaluated. Of these, medial vascular smooth muscle strips most consistently (65% of the time) produced a "vascular-derived contractile factor" (VDCF), which caused a 15% increase in isometric twitch tension and a 24% increase in isotonic twitch shortening with no change in twitch configuration. Endovascular strips with or without intact endothelium and complete aortic rings had less consistent effects. Vascular-derived contractile factor was stable after freezing at -80 degrees C, its activity was not modified by a broad spectrum peptidase, but it was heat-labile. The angiotensin II blocker, losartan, did not modify its effects. However, incubation with indomethacin did reduce, but did not eliminate, the contractile effects of vascular strips. The addition of alpha 1- and beta-blockers did not further modify the effects of VDCF. Endocardial endothelial removal increased the effects of VDCF. No correlation existed between endothelin levels and the contractile effects of vascular strips. It is concluded that VDCF is produced by the medial layer of large vessels but its exact cellular origin is uncertain. These findings expand the ever-increasing understanding of the inter-relationship between the structures that make up the cardiovascular system, and open the door to new studies evaluating the inter-relationship of vessels and myocardium.

Behaviour of dissociated hypoblast cells on the basal lamina and on extracellular fibrils in the gastrulating chicken embryo

The spreading behaviour of dissociated hypoblast cells on and besides a band of aligned fibrils associated with the basal lamina of the epiblast was investigated by the use of scanning electron microscopy. A horse-shaped band of aligned fibrils, first demonstrated by Wakely and England (1979), is present during the gastrulation stages of chicken embryos on the ventral side of the epiblast at the cranial and lateral borders of the area pellucida. The basal lamina of the area pellucida situated inside the fibrillar band enables the spreading and probably the locomotion of dissociated cells, which appeared as polarized cells. Numerous cells were also found on the fibrillar band, and these cells lacked distinct lamellae and a polarized shape. Extensions of the cells contacted the extracellular fibrils and, at these sites of contact, the pattern of the fibrils was frequently deformed. From these observations and from previous results emerged the concept that spreading and locomotion of dissociated hypoblast cells, as well as single mesoblast cells and healing hypoblast epithelium, are inhibited by the band of extracellular fibrils, which acts as a physical barrier. The cell biological basis of the mechanism by which extracellular fibrils associated with the basal lamina arrest the migration of hypoblast and mesoblast cells, but guide the migration of primordial germ cells, is discussed.

The arrest of cell migration in the chicken blastoderm: experimental evidence for the involvement of a band of extracellular fibrils associated with the basal lamina

This article overviews our current knowledge of the occurrence and distribution of oriented extracellular fibrils associated with the basal lamina, and their presumptive role in contact guidance of cells in early embryos. To investigate the role of the band of extracellular fibrils situated at the basal side of the epiblast at the cranial edge of the area pellucida of the chicken blastoderm, we determined the precise location and morphology of the fibrils using TEM and SEM, described the relationship between migrating mesoblast cells and the fibrillar band, and, finally, tested experimentally the behavior of homologous and heterologous tissues in the vicinity of the fibrillar band. The descriptive analysis demonstrated that a horseshoe-shaped, 170 microns-wide band of fibrils occurs at the cranial and lateral edges of the area pellucida and area opaca, the highest density being found in the area pellucida. Migrating mesoblast cells presented a surface morphology that was different from the morphology of cells reaching the fibrils at the lateral edge of the area pellucida. Mesoblast cells never crossed the fibrils, an observation that may explain why during gastrulation, mesoblast cells invade the area opaca only in the caudal region, where no fibrillar band is present. The experimental analysis, which involved transplantation and healing experiments, demonstrated that the arrest of cell migration, that occurred in all cases in the vicinity of the fibrillar band, was correlated with changes in surface morphology suggesting a decreased cell adhesion to the fibrils. From these observations emerged the view that the horseshoe-shaped fibrillar band functions as a barrier inhibiting migration of individual mesoblast cells and expansion of tissue sheets, rather than as an extracellular substrate mediating the oriented guidance of cells. In addition to its inhibitory role in cell migration, the extracellular band may also be regarded as a factor that stabilizes the polarity of the early embryo by determining the cranial and lateral limits between embryonic and extraembryonic tissues.

Improved endothelial viability of heart valves cryopreserved by a new technique

The aim of this study was to compare different techniques of aortic valve cryopreservation by studying the viability of the endothelial cells. Viability was assessed by measuring their in vitro prostacyclin (PGI2) production under basal and stimulated conditions. Fresh and cryopreserved porcine valves were incubated at 37 degrees C in tissue culture medium and PGI2 content in the medium was measured every 15 min up to 300 min. Cryopreservation by the older procedure A included 5% fetal calf serum (FCS) in the preservation medium, a plastic box inside a freezing plastic bag, a cooling schedule approximating -2 degrees C/min, a long thawing time and few dilution steps of the cryoprotectant dimethylsulphoxide (DMSO). The newer procedure B differed from A in packaging, freezing and thawing rates and DMSO dilution. Procedure C was similar to B with the exception that FCS was omitted. Leaflets preserved by procedure A produced significantly less prostacyclin as compared to those treated according to procedures B or C. We conclude that minor differences in the cryopreservation method can become critical to endothelial functional viability.

A scanning electron-microscopic study of different tympanic grafts

The surface architecture of dried temporalis fascia autografts and preserved tympanic allografts was investigated by scanning electronmicroscopy. During the storage in formaldehyde-cialit solutions the outer epithelial as well as the inner mucosal layer of tympanic allografts are progressively detached, and finally the lamina propria with outer radial and inner circular fiber arrangement remains. Due to dehydration phenomena irregular "crater-like" defects, surrounded by an amorphous structure, appear in dried fascia autografts. While a real lamina propria graft may induce migration and differentiation of the host's canal wall epithelium into a specific tympanic epithelium, one may imagine epithelial spreading toward the middle ear along the observed defects in dried fascia grafts. This latter observation gives new evidence for the immigration cholesteatoma theory.

A scanning electron microscope study of preserved allograft tympanic membranes: a comparison with autogenous grafts, xenografts and the normal eardrum

Scanning electron microscopy was used to investigate the surface architecture of the human tympanic membrane. The morphology of the eardrum was compared with the surface structures of preserved tympanic membranes (allografts), fresh air-dried temporalis fascia and preserved calf jugular veins (xenografts). The role of the physical structure and the composition of the extracellular matrix in the regeneration of a tympanic graft is discussed.

Establishment of a typing system for group D streptococci

Group D streptococci (n = 971, 4037 samples, 139 patients) were isolated from two intensive care units. Differentiation and typing revealed 6 species, 25 phage types, and 85 enterococcinotypes. Distribution of species showed strong differences especially concerning Enterococcus faecium which was rarely isolated from extraintestinal sites (5.9%). Phage typing was species specific and discriminated Enterococcus faecalis (n = 703 typable isolates, 19 phage types) and the other group D streptococci (n = 63 typable isolates, 6 phage types). Based on the production of enterococcines (15 indicator strains used) the isolates could be classified into 6 groups, one of which was further subdivided into 3 subgroups. Enterococcus faecalis ssp. liquefaciens (n = 618), phage type V6b (n = 596), and enterococcine group IVc (n = 568) were most common. The combined use of markers resulted in 187 combinations, which demonstrated the valuable properties of the system.

Combined use of phage typing, enterococcinotyping and species differentiation of group D streptococci as an effective epidemiological tool

Ninety-five group D streptococcal isolates from the feces of 95 healthy persons were compared with 157 group D streptococcal isolates from 38 patients of the surgical intensive care unit (sICU). The typing systems consisted of phage typing, enterococcinotyping and species differentiation. Strains isolated from fecal specimens showed high individuality (66 combination types) whereas strains from the sICU revealed strongly uniform types (32 combination types, three types comprised 83 isolates, i.e. 52.8%). Endogenous colonization was demonstrated by isolation of strains from different locations (throat, trachea, wounds, blood, urine, drains, catheters, and vaginal swabs) from the same patient, and routes of transmission of the same strains to several patients were traced. The combination of three systems revealed a good discrimination between isolates of fecal and extrafecal specimens. The investigation detected highly preferred types in strains of extrafecal origin which were rarely isolated from fecal specimens. This may indicate that only strains with special characters preferably were able to colonize extraintestinal sites.

Differential distribution of cell protrusions on the ventral surface of the deep layer in gastrulating quail and chick embryos

The ventral surface of the deep layer of gastrulating quail and chick embryos was examined using scanning electron microscopy. On the basis of cell protrusions, three or four different cell types were recognized. Cells covered with microplicae were found in the caudal region of the germ and as a narrow band extending along the lateral and anterior borders of the area pellucida. Cells covered with microvilli were found in a horseshoe-shaped zone in the anterior part of the germ. Beneath the rostral end of the primitive streak, the flattened deep-layer cells exhibited intercellular ridges and few microvilli. This area was surrounded by cells that usually had extended microvilli. The pattern of these cell types is discussed in relation to the formation of the different tissues that compose the deep layer in gastrulating embryos.

Microinjection of glycosaminoglycan-degrading enzymes in the chicken blastoderm. An ultrastructural study

The relationship between the presence of glycosaminoglycans (GAGs) and the morphology of the middle layer or mesoblast was examined by performing transmission electron microscopy of chicken blastoderms microinjected with GAG-degrading enzymes. The controls included microinjections with saline or trypsin, as well as solid-phase assays for proteolytic activity in commercially available GAG-degrading preparations. The results indicate that, in normal as well as in saline-injected blastoderms, middle-layer cells are rounded or cuboidal in shape, and are linked to each other by small intercellular junctions in the primitive-streak region. As they migrate laterally along the basal lamina, they appear as typical mesenchymal cells, being separated by large intercellular spaces and covered by cell processes. The removal of hyaluronate (by the microinjection of hyaluronidases) led to compaction of the middle-layer cells in the area lateral to the primitive streak. These cells lost their mesenchymal aspect and retracted their processes, and intercellular junctions were observed. The presence of proteolytic activity in the enzyme preparations did not interfere with the results. On the basis of the results obtained using this microinjection technique, we were able to confirm at the ultrastructural level that hyaluronate, due to its space-creating properties, promotes the detachment of ingressed primitive-streak cells and preserves the mesenchymal aspect of the middle layer during the lateral migration of single cells along the basal lamina. Whether the presence of hyaluronate is necessary to allow positioning of the mesoblast could not be inferred using our experimental procedure. We present evidence that this molecule, as well as having physicochemical properties, is also involved in the modulation of tissue interactions during gastrulation.

[Typing of Streptococcus faecalis and Streptococcus faecium strains with bacteriophages]

With a set of 17 bacteriophages specific for Streptococcus faecalis and a set of 7 bacteriophages specific for Streptococcus faecium 441 strains of S. faecalis and 53 strains of S. faecium were typed. The species identification was done by means of the API 20 STREP system. For S. faecalis 22 and for S. faecium 12 lysotypes were found. Among S. faecalis strains lysotype V6b was most common (27%), followed by the lysotypes XV (9,5%), XIII1 (7%), II1 (5,7%), and I1 (4,3%). These 5 lysotypes comprised 54% of all 441 strains. 21% of the strains of S. faecalis and 6 from 53 strains of S. faecium were untypable. Strains of S. faecium were most frequently isolated from faeces and in rare cases from urine. To the contrary 50% of the S. faecalis strains were isolated from urine. There was no correlation between special lysotypes and age of the patients or the source of specimen. The results of phage typing of several strains from one patient, and especially of strains from mothers and their newborns suggest the usefulness of the typing system to clarify epidemiological questions.

Cell junctions and locomotion of the blastoderm edge in gastrulating chick and quail embryos

The blastoderm edge migrates by the active locomotion of a multilayer of epithelial cells, the so-called margin of overgrowth (MO), that uses the vitelline membrane as its substratum. The structural unity formed by the margin of overgrowth cells and their rapid migration suggest coordination of locomotion between individual cells. Using transmission electron microscopy of thin sections and freeze-fracture, we attempted to determine if the pattern of junctions of the migrating margin of overgrowth is related to the suggested cell—cell cooperation between individual cells in this region. In the leading edge there are large areas of closely apposed cell membranes. Incipient desmosomes and small gap junctions were observed. Tight junctions consisted of isolated strands or isolated networks of tight-junctional strands. In the proximal part of the margin of overgrowth the size of the gap junctions increased and the desmosomes were fully developed. Tight-junctional strands were either isolated or arranged into an isolated network. A broad belt of tight junctions was observed at the transition between margin of overgrowth and non-marginal cells. The distribution of the junctional elements in the MO suggests that junctions contribute to the maintenance of the structural and functional organization of the margin of overgrowth. Furthermore, the spatial distribution of the junctions might give information about the mechanism of locomotion of the margin of overgrowth.

Inhibition of cell spreading on the band of extracellular fibres in early chick and quail embryos

The ventral surface of the upper layer shows a band of extracellular fibrils around the anterior and lateral border of the area pellucida during gastrulation of the chick embryo. Using scanning electron microscopy, we found that this disposition is correlated with the motility of the middle-layer cells of gastrulating chick and quail embryos. Outside the fibrous band, single middle-layer cells and a sheet of mesoblast cells were spread out and possessed lamellae. Single cells on the fibrous band did not form lamellae. The same cell behaviour was obtained with the explants of deep layer on the fibrous band. The fibrous band is assumed to operate as a barrier that inhibits cell motility during gastrulation.

The subgerminal yolk surface and its relationship with the inner germ wall edge of the stages X to XIV chick and quail embryo. A SEM study

SEM reveals that the subgerminal yolk surface of the chick and quail embryo during stages X to XIV possesses microvilli and small pits. Threadlike extensions and globular structures are found on the subgerminal yolk surface mainly in the central area. The cellular nature of the subgerminal yolk was confirmed with TEM that showed the presence of a plasma membrane, mitochondria, micro-invaginations and microfilaments. The ventral cells of the germ wall are yolky and can be attached to the subgerminal yolk surface with filopodial extensions during stages X to XII. From stage XIII, the shape of these cells is usually more flattened and they protrude lamellae and filopodia.

The dorsal surface of the animal pole of the just laid quail egg, studied with SEM

The epiblast and the surface of the perigerminal yolk of the just laid quail blastoderm were examined by scanning electron microscopy (SEM). The dorsal surface structures are microvilli, mainly along the cell borders. The scarcity of the dimples does not support that ingression occurs at this stage. Flat or round cells on the epiblast are possibly deep layer cells that failed to incorporate after passing through the epiblast. The majority of the blastoderms have an irregular margin. The large edge cells possess microvilli at their borders only. A few blastoderms, probably the more developed, have a smooth edge with closely packed cells. The margin of these germs shows round cells and lamellae that could be protruded by deep cells. The process of cell rounding and extension of lamellae may be the onset of the formation of the margin of overgrowth. Concentric zones are present on the surface of the perigerminal yolk, on which microvilli and blebs are found near the germ. The presence of cell projections on the perigerminal surface suggests its living nature.

Resolution in light microscope autoradiography using a carbon-14 labelled line source

Light microscope autoradiographs were prepared from a 14C line source Two factors that affect resolution were studied: emulsion thickness and section thickness. The distribution around the line source was determined using the half-distance (HD) value to quantify the resolution. An increase in HD value was observed with thicker sections or emulsion layers. The shape of the curve reflecting the grain density distributions around these line sources was very similar. After normalization in HD and relative grain density units, an average distribution was calculated and compared with the shape of normalized density distributions obtained from electron microscope autoradiographs. Other than a discrepancy near the source, an acceptable correlation was observed.

Alcian blue staining during the formation of mesoblast in the primitive streak stage chick blastoderm

The distribution of alcian blue (AB) positivity, and its sensitivity to streptococcal and testicular hyaluronidase, were studied in primitive streak stage chick blastoderms. Accumulation of hyaluronate was observed in deep layer (DL) cells and on laterally migrating middle layer (ML) cells. During the formation of the middle layer, a first stage, namely de-epithelialization of the upper layer cells, is recognized and correlated with the absence of hyaluronate. A second stage, namely migration of the de-epithelialized upper layer cells laterally to the edge of the area pellucida, is correlated with the accumulation of AB-positivity. The AB-staining also demonstrated the accumulation of both sulphated and not-sulphated mucopolysaccharides, where a basal lamina is present.

Distribution and turnover of testicular hyaluronidase sensitive macromolecules in the primitive streak stage chick blastoderm as revealed by autoradiography

Primitive streak stage chick blastoderms were cultured for 30 min on a medium containing tritiated glucosamine. Light microscope autoradiography revealed extracellular labeling, and pretreatment of the sections with testicular hyaluronidase suggested the glycosaminoglycan nature of the labeled products. After incorporation of the tritiated precursor, some blastoderms were transferred to a chase medium, and cultured for 30, 90, 210 min. The changes is distribution of the labeled testicular hyaluronidase-sensitive macromolecules during the chase experiment illustrated the ingression of cells in the primitive streak stage chick blastoderm. Grain density differences, resulting from the various chase periods, suggested the renewal of the testicular hyaluronidase-sensitive fraction.

Localisation and characterization of acid mucopolysaccharides in the early chick blastoderm

Acid mucopolysaccharides in the extracellular compartment of early chick blastoderms (16 h of incubation) were labelled with tritiated glucosamine and/or [35S]sulphate. The incorporation pattern was studied autoradiographically. Treatment with testicular hyaluronidase revealed a testicular hyaluronidase-sensitive fraction, mainly at the periphery of Middle Layer and Deep Layer cells, and a testicular hyaluronidase-resistant fraction, mainly at the ventral side of the Upper Layer. A biochemical analysis, utilizing chondroitinase ABC and nitrous acid, followed by cellulose acetate electrophoresis, demonstrated the synthesis of a non-sulphated fraction, i.e. hyaluronic acid and/or chondroitin, and a sulphated fraction, comprising two undersulphated components, i.e. chondroitin sulphate, and heparan sulphate or heparin. The appearance of different AMPS in specific areas of the early chick blastoderm is regarded as an early specialization of the extracellular compartment.

Localisation and characterization of acid mucopolysaccharides in the early chick blastoderm

Acid mucopolysaccharides in the extracellular compartment of early chick blastoderms (16 h of incubation) were labelled with tritiated glucosamine and/or ]35S]sulphate. The incorporation pattern was studied autoradiographically. Treatment with testicular hyaluronidase revealed a testicular hyaluronidase-sensitive fraction, mainly at the periphery of Middle Layer and Deep Layer cells, and a testicular hyaluronidase-resistant fraction, mainly at the ventral side of the Upper Layer.

A biochemical analysis, utilizing chondroitinase ABC and nitrous acid, followed by cellulose acetate electrophoresis, demonstrated the synthesis of a non-sulphated fraction, i.e. hyaluronic acid and/or chondroitin, and a sulphated fraction, comprising two undersulphated components, i.e. chondroitin sulphate, and heparan sulphate or heparin. The appearance of different AMPS in specific areas of the early chick blastoderm is regarded as an early specialization of the extracellular compartment.

[A fi- tetracyclin resistance plasmid with specific restriction of phages on salmonella typhi, S. paratyphi B and S. typhi-murium (author's transl)]

Among 262 strains of Salmonella typhi from an epidemic outbreak of typhoid fever in Baden-Württemberg in 1974 2 strains were isolated which were tetracyclin resistant and showed no reactions with the Vi testphages T, D6 and VII whilst all other strains belonged to lysotype A, subtype Tananarive. It turned out that the Tc resistance in both strains was caused by a fi- R plasmid which could be transfered to other S. typhi strains, to E. coli K12, S. paratyphi B, S. java and S. typhi-murium as well as from Tc resistant E. coli K12 back to S. typhi. The Tc R plasmid introduced in S. typhi, lysotype A, caused specific restrictions of typing phages T, D6 and VII. Also, the transfer of the plasmids to strains of S. paratyphi B and S. typhi-murium resulted in restrictions of a number of typing phages. Both plasmids had identical patterns of restriction. In this pattern the Tc R plasmid differed from those described in the literature.