[Open educational resources for otorhinolaryngology : A pilot study on needs assessment and implementation]

BACKGROUND

Open educational resources (OER) are educational materials licensed openly by authors, permitting usage, redistribution, and in some instances, modification. OER platforms thereby serve as a medium for distributing and advancing teaching materials and innovative educational methodologies.

OBJECTIVE

This study aims to determine the present state of OER in otorhinolaryngology and to examine the prerequisites for seamlessly integrating OER into the curricular teaching of medical schools, specifically through the design of two OER blended learning modules.

METHODS

OER content in the field of otorhinolaryngology was analyzed on OER platforms, ensuring its relevance to the German medical curriculum. Data protection concerns were addressed with legal counsel. The blended learning modules were developed in collaboration with medical students and subsequently published as OER.

RESULTS AND CONCLUSION

This project yielded the first OER from a German ENT department, tailored to the German medical curriculum. One significant barrier to OER use in medicine, more than in other fields, is data protection. This challenge can be navigated by obtaining consent to publish patient data as OER. OER hold the promise to play a pivotal role in fostering cooperation and collaboration among educators, aiding educators in lesson preparation, and simultaneously enhancing didactic quality.

Increasing the COVID-19 immunization rate through allergy testing

BACKGROUND

Vaccination of the population is required to combat the COVID-19 pandemic. Allergy testing could reduce anxiety towards COVID-19 vaccination and thereby may increase vaccination rate, however, its effectiveness remains unclear.

METHODS

One hundred and thirty prospective real-life patients in need of but not daring to get vaccinated asked for allergy workup for COVID-19 vaccine hypersensitivity in 2021/2022. Characterization of patients, identification of anxieties, decrease of patient's anxiety levels, overall vaccination rate and adverse reactions after vaccination were assessed.

RESULTS

Tested patients were characterized by being female (91.5%) and having a high rate of previous allergies (e.g. to food 55.4%, drugs 54.6%, or previous vaccinations 50%) and dermatological disease (29.2%) but not always had medical contraindications for COVID-19 vaccination. Sixty one patients (49.6%) were highly concerned (4-6, Likert scale 0-6) about vaccination and 47 (37.6%) expressed resolving thoughts about vaccinaion anaphylaxis (3-6, Likert scale 0-6). However only 35 patients (28.5%) were scared of getting COVID-19 within 2 months (4-6, Likert scale 0-6) and only 11 (9%) patients had high expectations of getting COVID-19 (4-6, Likert scale 0-6). Allergy testing significantly (p < 0.01 to p < 0.05 respectively) reduced the median anxiety of allergic symptoms following vaccination: dyspnoea (4.2-3.1), to faint (3.7-2.7), long-term consequences (3.6-2.2), pruritus (3.4-2.6), skin rash (3.3-2.6) and death (3.2-2.6). After allergy testing, most patients (108/122, 88.5%) let themselves be vaccinated within 60 days. Revaccinated patients with previous symptoms experienced a reduction of symptoms (p < 0.05) upon revaccination.

CONCLUSIONS

Patients not daring to get vaccinated have more anxiety towards vaccination than to acquire COVID-19. For those, allergy testing excludes vaccine allergy, and is a tool to increase vaccination willingness and thereby helps to combat vaccination hesitancy.

GPR55 deficiency in B-cells promotes atherosclerosis and regulates plasma cell maturation

 

Atherosclerosis is a chronic and multifactorial disease accompanied by an imbalance between resolving and pro-inflammatory lipid mediators. Targeting lipid signaling might offer new therapeutical targets for improving the clinical outcome in cardiovascular disease patients. We considered lysophosphatidylinositol (LPI) and its receptor G protein-coupled receptor (GPR)55 as a potential modulator of atherosclerosis. Its role in regulating atherosclerosis and B cell function is unknown.

We hypothesize that GPR55 signaling affects atherosclerosis by regulating B cell function.

Atherosclerotic plaques were compared between apolipoprotein-E-deficient (ApoE−/−) and ApoE−/−Gpr55−/− mice after 4 to 16 weeks Western Diet (WD; 0.15% cholesterol; n=12–15 per group). To test the role of B cell GPR55, we generated mixed chimeras by irradiating low density lipoprotein receptor deficient (Ldlr−/−) mice and reconstituting with a mixture of μMT and wildtype or μMT and Gpr55−/− bone marrow cells. Circulating B cells were sorted and bulk RNA sequencing analysis was performed. We performed atheroma plaque characterization, qPCR and ELISA of tissue lysates and measure plasma immunoglobulins. Circulating and tissue leukocyte counts were determined.

We confirmed Gpr55 expression on circulating B cells, which was higher compared to T and myeloid cells. ApoE−/−Gpr55−/− mice had significantly larger plaques after 4 & 16 weeks WD compared to ApoE−/−, with increased body weight & cholesterol levels. In addition, global Gpr55 deficiency resulted in enhanced aortic pro-inflammatory cytokine mRNA expression, a massively upregulated IgG levels and increased counts of splenic germinal center and plasma cells. ApoE−/−Gpr55−/− B-cell RNA-seq analysis showed 460 differential expressed genes compared to ApoE−/−. The main pathways affected were calcium ion transport, immunoglobulin production, T & B cell activation, and cellular response to stress. B cell specific Gpr55 deficiency blunted the metabolic effects but still translated in larger atherosclerotic plaques and elevated plasma IgG levels.

Both global and B cell-restricted Gpr55 deficiency promotes atherosclerosis and is associated with a pro-inflammatory phenotype.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The authors received funds from the Deutsche Forschungsgemeinschaft (STE1053/6-1, STE1053/8-1 to S.S. and SFB1123 to S.S., C.W. and L.M.), the German Ministry of Research and Education (DZHK FKZ 81Z0600205 to S.S.) and the LMU Medical Faculty FöFoLe program (1061 to R.G.P.). I.H. is supported by the DFG (HI1573/2 and CRC1425 #422681845).

Audiological profile of adult long COVID patients

Introduction

Hearing loss is one of the self-reported symptoms of Long COVID patients, however data from objective and subjective audiological tests demonstrating diminished hearing in Long COVID patients has not been published.

Materials and methods

Respondents of a large Long COVID online survey were invited to the ENT-department for an otologic exam. The participants were split into three groups based on their history of SARS-CoV-2 infection and persistence of symptoms. Respondents with a history of a SARS-CoV-2 infection were allocated to the Long COVID group, if they reported persistent symptoms and to the Ex COVID group, if they had regained their previous level of health. Participants without a history of SARS-CoV-2 infection made up the No COVID control group. In total, 295 ears were examined with otoscopy, tympanograms, pure tone audiometry and otoacoustic emissions. Ears with known preexisting hearing loss or status post ear surgery, as well as those with abnormal otoscopic findings, non-type A tympanograms or negative Rinne test were excluded.

Results

Compared to the No COVID and Ex COVID groups, we did not find a clinically significant difference in either hearing thresholds or frequency specific TEOAEs. However, at 500 Hz the data from the left ear, but not the right ear showed a significantly better threshold in the Ex COVID group, compared to Long COVID and No COVID groups. Any of the other tested frequencies between 500 Hz and 8 kHz were not significantly different between the different groups. There was a significantly lower frequency-specific signal-to-noise-ratio of the TEOAEs in the Long COVID compared to the No COVID group at 2.8 kHz. At all other frequencies, there were no significant differences between the three groups in the TEOAE signal-to-noise-ratio.

Conclusion

This study detected no evidence of persistent cochlear damage months after SARS-CoV-2 infection in a large cohort of Long COVID patients, as well as those fully recovered.

B cell-specific GPR55 deficiency promotes atherosclerosis

Background

Atherosclerosis is accompanied by an imbalance between resolving and pro-inflammatory lipid mediators. Targeting lipid signaling pathways might offer a new anti-inflammatory therapy for improving the clinical outcome in cardiovascular disease patients. We considered lysophosphatidylinositol (LPI) and its receptor G protein-coupled receptor (GPR)55 as a potential modulator of atherosclerosis. Its role in regulating atherosclerosis and B cell function is unknown.

Hypothesis

We assessed the hypothesis that GPR55 signaling causally affects atherosclerosis and whether it has a specific role in regulating B cell function in this disease.

Methods

Atherosclerotic plaques were compared between apolipoprotein E deficient (ApoE−/−) and ApoE−/−Gpr55−/− mice after 4 to 16 weeks Western Diet (WD; 0.15% cholesterol; n=12–15 per group). To specifically test the role of B cell GPR55 in atherosclerosis, we generated mixed chimeras by lethally irradiating low density lipoprotein receptor deficient (Ldlr−/−) mice and reconstituting with a mixture of μMT and wildtype (control) or μMT and Gpr55−/− bone marrow cells. Circulating B cells were sorted and bulk RNA sequencing analysis was performed. We performed lipid and immunostainings of murine aortic root plaques, qPCR and ELISA of tissue lysates, as well as multiplex analysis of plasma immunoglobulins. Leukocyte plasma and tissue counts were determined by flow cytometry.

Results

GPR55 expression in mouse and human atherosclerotic plaques was detected by immunostaining. Furthermore, we confirmed murine Gpr55 mRNA expression on sorted circulating B220+B cells via qPCR, which was higher compared to CD3+ T cells, while CD11+ myeloid cells as well as NK cells had only low Gpr55 mRNA levels. ApoE−/−Gpr55−/− mice had significantly larger plaques after 4&16 weeks WD compared to ApoE−/− controls, with more pronounced body weight increases and higher cholesterol levels at the 16 weeks WD time point. In addition, global Gpr55 deficiency resulted in enhanced aortic pro-inflammatory cytokine mRNA expression (IL-1β, IL-6, TNFα) and a massively upregulated IgG1 plasma levels and increased percentages of splenic germinal center and plasma cells. B-cell RNA-seq analysis showed 460 differential expressed regulated genes in the ApoE−/−Gpr55−/− compared to ApoE−/−. The main pathways affected were calcium ion transport, immunoglobulin production, negative regulation of phosphorylation, and cellular component morphogenesis, suggesting a dsysregulation of B cell function. B cell specific Gpr55 deficiency blunted the metabolic effects on body weight and cholesterol, but still translated in larger atherosclerotic plaques and elevated plasma IgG levels compared to the respective controls.

Conclusion

Both global and B cell-restricted Gpr55 deficiency promotes atherosclerosis and is associated with a more pro-inflammatory phenotype. Our findings suggest a novel role for GPR55 in regulating B cell development and function.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG)

5224Endothelial autophagy triggers nuclear enrichment of miR-126-5p via a Mex3a-dependent pathway to confers endothelial protection and prevent atherosclerosis

Background

MicroRNAs are versatile regulators of gene expression with profound implications for cardiovascular diseases and atherosclerosis. Among the most expressed in endothelial cells (ECs), the miR-126 duplex is crucial for angiogenesis and vascular protection, featuring different functional roles and homeostasis of the two strands. In line with separate activities, miR-126-3p and -5p undergo differential regulation in response to shear-stress in a KLF2-dependent manner. As both strands derive from a common precursor, the mechanism for strand specificity is unrelated to miRNA transcription and remains largely elusive as well as unknown is its relevance for vascular biology.

Methods and results

In human ECs (HUVECs) overexpression of KLF2 produced an up-regulation of the miR-126 precursor and miR-126-5p, but not miR-126-3p. Analysis of ECs overexpressing KLF2 or exposed to high-shear stress at transcriptional and protein level revealed the activation of the autophagic flux. Moreover, stimulation of autophagy by rapamycin replicated strand-specific regulation of miR-126. In particular, rapamycin promoted miR-126-3p degradation, while miR-126-5p was preserved and translocated to a nuclear reservoir complexed with the protein argonaute-2 (Ago2). Mutational scanning of fluorescently-labelled miR-126-5p revealed that nuclear shuttling required motifs distinct from the seed sequence. Size exclusion chromatography and Ago2-immunoprecipitation in autophagic ECs, as well as surface plasmon resonance (SPR) and electrophoretic mobility shift assays in vitro showed the formation of a ternary complex with the RNA-binding protein Mex3a. Preferential binding of miR-126-5p to Mex3a was confirmed by SPR, isothermal calorimetry, and nuclear magnetic resonance spectroscopy. Super-resolution microscopy by stimulated emission depletion (STED) visualized the Mex3a/Ago2 interaction on autophagosomal surfaces and silencing of Mex3a dampened rapamycin-induced nuclear miR-126-5p enrichment. Gain- and loss-of-function studies for miR-126-5p and Mex3a showed that Mex3a-guided nuclear miR-126-5p affect apoptosis mediators (e.g. caspase-3) at RNA and protein level, thus reducing the apoptotic rate. High-shear flow at non-predilection sites for atherosclerosis induced endothelial autophagy to promote nuclear enrichment of Ago2 and miR-126-5p in vivo in mice. Consistently, fewer nuclear Ago2 and miR-126-5p were observed in the endothelium of atheromatous area at bifurcations of human carotid arteries. These effects were abrogated in vivo by endothelial-specific deficiency in autophagy, thereby exacerbating atherosclerosis, and by Mex3a knock-out favouring apoptosis.

Conclusion

The autophagy-activated Mex3a-driven nuclear translocation represents a non-canonical mechanism by which miR-126-5p confer endothelial protection. Modulation of this pathway may open new opportunities for prevention and treatment of atherosclerosis.

[c-MET Oncogene in Renal Cell Carcinomas]

c-Met plays a significant role in multiple cellular processes. Being encoded by a proto-oncogene, tyrosine kinase supports aggressive tumour behaviour such as tumour invasiveness and formation of metastases. For some subtypes of renal cell carcinoma studies have shown a association between c-Met expression and clinical outcome or prognosis. Therefore, c-Met represents a prognostic marker in renal cell carcinoma.Furthermore, c-MET will play a decisive role as a possible target for targeted therapies in the era of personalised medicine. Especially for RCC, the dual inhibition of VEGF and c-MET tyrosine kinase in cases of metastatic, treatment-resistant tumours is gaining clinical relevance. The role of c-Met has not been fully elucidated for all subtypes of renal cell carcinomas. The relevance of c-Met for the remaining subtypes of renal tumours has yet to be clarified.

Intratumoral expression of programmed death ligand 1 (PD-L1) in patients with clear cell renal cell carcinoma (ccRCC)

The immunological checkpoints of programmed death 1 and its ligand (PD-L1) are currently in focus as novel therapeutic targets in renal cell carcinoma (RCC). The aim of this study was to evaluate the prognostic association of PD-L1 expression in clear cell (cc) RCC with clinical parameters, tumor aggressiveness and overall survival (OS). Patients who underwent renal surgery due to RCC between 1994 and 2003 were retrospectively evaluated. Tumor specimens were analyzed for PD-L1 expression by immunohistochemistry. One hundred and seventy-seven ccRCC patients were eligible for analysis, in which 140 (79.1 %) were negative and 37 (20.9 %) were positive for PD-L1 expression. PD-L1 positivity was associated with female gender (p = 0.001), lymph node metastasis (p = 0.004), distant metastasis (p = 0.002), higher AJCC stage (p = 0.004), as well as advanced disease (pT3/4 and/or N+ and/or M1) (p < 0.001). Kaplan-Meier analysis revealed a significantly diminished 5- and 10-year overall survival of 46.7 and 28.3 % for PD-L1(+) compared to PD-L1(-) tumors with 66 and 53.4 % (p = 0.005), respectively. Univariate analysis showed a significant negative association of OS with PD-L1 positivity [p = 0.005; HR: 2 (95 % CI 1.2-3.3)], even though PD-L1 positivity only tends to predict independently the OS using multivariate analyses [p = 0.066; HR: 1.6 (95 % CI 0.98-2.7)]. PD-L1 expression in ccRCC is associated with parameters of aggressiveness, as well as with poor OS, even though PD-L1 status was not identified as a significant independent prognostic parameter. However, further studies in larger cohorts are warranted.

Tumour shrinkage measured with first treatment evaluation under VEGF-targeted therapy as prognostic marker in metastatic renal cell carcinoma (mRCC)

BACKGROUND

The aim of our analysis is to further characterise the prognostic relevance of early tumour shrinkage (TS) during VEGF-targeted therapy in mRCC, in order to explore whether this could define a group of patients with long-term survivorship.

METHODS

A hundred patients were stratified into five subgroups according to their change of tumour size with first treatment evaluation: -100% to -60%; -59% to -30% and -29% to 0% TS or gain of tumour size from 1% to 19% and ≤20% or occurrence of new lesions (i.e., progressive disease).

RESULTS

The median PFS and OS were 10.4 months and 28.2 months, respectively. The median OS stratified according to the subgroups as described above was 77.4, 33.5, 26.9, 30.0 and 14.3 months, respectively. Multivariate analysis revealed early TS as a prognostic marker (P=0.021; HR 1.624).

CONCLUSION

The extent of TS defines a small proportion of patients with an excellent prognosis. Larger studies are warranted to define the relationship of long-term survivorship and extent of TS with targeted therapies.

[Utility of the serum CRP value for assessing the prognosis and therapeutic response of urological malignancies]

C-reactive protein (CRP) is an unspecific marker of systemic inflammation. It is known to be elevated in autoimmune disease, traumata and malignancies. Increased CRP levels have specifically been shown to be associated with disease progression and prognosis in various studies on renal cell carcinoma and transitional cell carcinoma. Although CRP, unlike PSA, is neither organ-specific nor tumour-specific, studies were able to show that increased CRP values are an independent prognostic marker for tumour-specific survival of patients with prostate cancer. In metastatic and castration-resistant prostate cancer elevated CRP levels have been approved as a useful marker to estimate the extent of disease and mortality. CRP measurements in serum are standardised worldwide and widely used in daily clinical routine. However, until CRP can be firmly established as a prognostic marker in daily routine, we need validation of its prognostic and predictive value with large and preferably prospective multicentre studies.

[Systemic therapy for metastatic renal cell carcinoma]

A better understanding of molecular biological mechanisms involved in the pathogenesis or, respectively, prognosis of renal cell carcinoma has recently led to a fundamental change in those therapeutic options that are especially effective after systemic disemination. In this context, cytokine-based therapeutic concepts have been replaced by the so-called targeted therapeutic agents that include, above all, tyrosine kinase (TK) and mTOR inhibitors. The present contribution is intended to reflect the current state of the art in the systemic therapy for renal cell carcinoma in first- and second-line use. In addition, the increasing relevance of sequential therapy under consideration of possible side effects is discussed.

Prognostic and diagnostic relevance of hypermethylated in cancer 1 (HIC1) CpG island methylation in renal cell carcinoma

The tumour suppressor gene hypermethylated in cancer 1 (HIC1) is a transcriptional repressor, which functionally cooperates with p53. Loss of HIC1 function is associated with the development of various tumor entities. The aim of this study was to elucidate the relevance of CpG island (CGI) methylation of HIC1 in renal cell carcinoma (RCC). DNA methylation of HIC1 was analysed in a total of 98 tumor and 70 tumor adjacent normal specimens. After conducting bisulfite conversion, relative methylation levels were quantitated using pyrosequencing. Relative methylation values were compared for paired tumor and normal specimen and for correlation with clinico-pathologic and follow-up data of patients. Tumor-specific hypermethylation could not be detected for the subregion of the HIC1 - CGI analyzed in this study. Comparing the level of methylation in tumors to clinicopathological data solely, patients without lymph node metastases demonstrated a higher level of methylation compared to patients with lymph node metastases (p=0.030). Patients recurrence-free survival (p=0.0074) both in univariate as well as bivariate cox regression analysis. This study identifies HIC1 hypermethylation in tumors as an independent predictor of reduced recurrence-free survival, which fits into our current understanding of hypermethylated HIC1 being a marker for poor prognosis. Therefore, HIC1 - CGI methylation could be a candidate marker to improve individualized therapy and risk stratification.

Fibronectin 1 protein expression in clear cell renal cell carcinoma

Fibronectin 1 (FN1) is a glycoprotein that is involved in cell adhesion and migration processes including embryogenesis, wound healing, blood coagulation, host defenses and metastasis. The aim of this study was to elucidate the FN1 protein expression in renal cell carcinoma (RCC) and to determine its potential prognostic relevance. A total of 270 clear cell RCC tissue specimens were collected from patients undergoing surgery for renal tumors. Biomarker expression was determined by immunohistochemistry and correlated with clinical variables. Survival analysis was carried out for 153 patients with complete follow-up data and pathologically proven clear cell carcinoma of the kidney. The follow-up group had a mean follow-up period of 83.8 months (IQR 26.2-136.2 months). The calculated median 5-year overall and tumor-specific survival rate of all 153 evaluable patients was 66.6 and 71.0%, respectively. A higher disease-related mortality rate was observed among patients with cytoplasmic FN1 expression (41.3 vs. 24.7%, p=0.039, Fisher's exact test). No significant correlation was found between FN1 staining and patient characteristics such as age, gender, tumor differentiation and visceral metastasis. However, there was a trend for FN1 expression and correlation with tumor stage and lymph node metastasis (p=0.085 and p=0.203; respectively). The Kaplan-Meier analysis revealed significant differences in the 5-year tumor-specific survival for patients with and without cytoplasmic FN1 expression (64.8 vs. 77.7%; p=0.035, log-rank test). However, results of the multivariate Cox regression analysis showed that FN1 expression was not an independent marker of either overall or tumor-specific survival. In conclusion, FN1 protein expression in RCC is associated with a higher disease-related mortality rate, indicating a possible role in RCC progression. Therefore, our data on FN1 encourage further investigations to determine the role of FN1 in RCC.

The role of the endocannabinoid system in atherosclerosis

Our current understanding of the pathophysiology of atherosclerosis suggests a prominent role for immune responses from its initiation through its complications. Given the increasing prevalence of cardiovascular risk factors worldwide, there is an urgent need to better understand the underlying mechanisms to improve current treatment protocols. A growing body of evidence suggests that endocannabinoid signalling plays a critical role in the pathogenesis of atherogenesis and its clinical manifestations. Blocking CB(1) receptors has been shown to mediate not only weight reduction, but also several cardiometabolic effects in rodents and humans, indicating a potential relevance for the process of atherosclerosis. Activation of CB(2) receptors with Delta(9)-tetrahydrocannabinol (THC) has been shown to inhibit atherosclerotic plaque progression in mice, mainly by inhibiting macrophage recruitment. Endocannabinoids released from endothelial cells, macrophages or platelets, reduce hypertension in rodents, a major risk factor for atherosclerosis. In addition, anandamide inhibits inflammatory gene expression in endothelial cells, and consequently monocyte adhesion. Conversely, endocannabinoids might also mediate pro-atherosclerotic effects by inducing platelet activation. In conclusion, the precise role of the endocannabinoid system during atherosclerosis is not yet understood. Whether increased endocannabinoid signalling is associated with disease progression and increased risk of acute thrombotic events remains to be determined.

Sorbicillactone A: a structurally unprecedented bioactive novel-type alkaloid from a sponge-derived fungus

This chapter deals with the discovery of sorbicillactone A, as an illustrative example of the fruitful cooperation within BIOTECmarin--its isolation and chemical characterization, and its biological activities. Sorbicillactone A was isolated from a strain of Penicillium chrysogenum cultured from a sample of the Mediterranean sponge Ircinia fasciculata; it possesses a unique bicyclic lactone structure, seemingly derived from sorbicillin. Among the numerous known sorbicillin-derived structures, it is the first found to contain nitrogen and thus the first representative of a novel type of 'sorbicillin alkaloids', apparently originating from a likewise remarkable biosynthesis. Furthermore, the compound exhibits promising activities in several mammalian and viral test systems, in particular a highly selective cytostatic activity against murine leukemic lymphoblasts (L5178y) and the ability to protect human T cells against the cytopathic effects of HIV-1. These properties qualify sorbicillactone A or one of its derivatives for animal and (hopefully) also future therapeutic human trials.

Systemic activation of the immune system during ganciclovir treatment following intratumoral herpes simplex virus type 1 thymidine kinase gene transfer in an adolescent ependymoma patient

During ganciclovir treatment of an adolescent ependymoma patient two weeks after intracranial implantation of HSVtk retroviral vector producer cells, increasing numbers of peripheral T- and B-cells were found as well as enhanced T-cell activation and elevated serum levels of interleukin 12 and soluble Fas ligand. These findings suggest the systemic activation of the immune system during ganciclovir treatment in our patient. The induction of an immune response by HSVtk/ganciclovir supports the concept of an anti-tumor vaccination effect by prodrug activating gene therapy systems and may open new promising perspectives for enhancing therapeutic efficiency by combined prodrug activating and immunological gene therapy strategies.

Enhanced green fluorescent protein fusion proteins of herpes simplex virus type 1 thymidine kinase and cytochrome P450 4B1: applications for prodrug-activating gene therapy

To monitor therapeutic transgene expression, we developed fusion genes of enhanced green fluorescent protein (EGFP) with two different prodrug-activating enzyme genes: herpes simplex virus type 1 thymidine kinase (HSV-tk) and rabbit cytochrome P450 4B1 (cyp4b1). Expression of the resulting fusion proteins, TK-EGFP and 4B1-EGFP, rendered transduced human and rodent glioma cells sensitive to cytotoxic treatment with the corresponding prodrugs ganciclovir and 4-ipomeanol. Ganciclovir and 4-ipomeanol sensitivity was comparable with that achieved with the native HSV-TK and CYP4B1 proteins. As shown by fluorescence microscopy, TK-EGFP was expressed predominantly intranuclearly, whereas 4B1-EGFP was detectable in the cytoplasm, thereby displaying the orthotopic subcellular distribution of the corresponding native enzymes. The fluorescence intensity correlated well with the corresponding prodrug sensitivity, as shown by fluorescence-activated cell sorter analysis. EGFP expression was also used for the selection of stably HSV-tk-transduced cells by flow cytometric cell sorting. Resulting cell populations showed a homogeneity of fluorescence intensity similar to single-cell clones after antibiotic selection. In conclusion, tk-egfp and 4b1-egfp fusion genes are valuable tools for monitoring prodrug-activating gene therapy in living cells. EGFP fusion genes/proteins provide a simple and reproducible means for the detection, selection, and characterization of cells expressing enzyme genes for prodrug activation.

[Mammary gland hypoplasia and aplasia (inverted nipples) in female and male swine. 1. Clinical-morphological investigations on the occurrence and development of inverted nipples in female and male swine of various age and production groups]

The development of the shape of teats in 30 female piglets, of which at least one of the parents showed inverted teats, was systematically observed during three to four months. Similar investigations could be carried out in sows with inverted teats from day 60 of pregnancy until the end of lactation. There is no evidence that inflammations or traumatas are causes for teat hypoplasias, and there is no correlation between "teat necroses" of piglets and the incomplete teat development. The wide distribution of teat abnormities is shown by investigations of slaughter pigs: 20% of fattening pigs, 17% of boars and 6% of sows were affected by inverted teats. 75% of the inverted teats were seen periumbilical. The morphology of hypo- and aplastic teats in boars is described. With regard to the selection of affected pigs, a first investigation is recommended in the 12th week of life and a second one at the age of five month is recommended. Particular attention has to be paid to boars for mating and artifical insemination in order to exclude affected boars as early as possible from breeding.