Immunohistochemical biomarkers are prognostic relevant in addition to the ESMO-ESGO-ESTRO risk classification in endometrial cancer.

OBJECTIVE: Pre-operative immunohistochemical (IHC) biomarkers are not incorporated in endometrial cancer (EC) risk classification. We aim to investigate the added prognostic relevance of IHC biomarkers to the ESMO-ESGO-ESTRO risk classification and lymph node (LN) status in EC. METHODS: Retrospective multicenter study within the European Network for Individualized Treatment of Endometrial Cancer (ENITEC), analyzing pre-operative IHC expression of p53, L1 cell-adhesion molecule (L1CAM), estrogen receptor (ER) and progesterone receptor (PR), and relate to ESMO-ESGO-ESTRO risk groups, LN status and outcome. RESULTS: A total of 763 EC patients were included with a median follow-up of 5.5-years. Abnormal IHC expression was present for p53 in 112 (14.7%), L1CAM in 79 (10.4%), ER- in 76 (10.0%), and PR- in 138 (18.1%) patients. Abnormal expression of p53/L1CAM/ER/PR was significantly related with higher risk classification groups, and combined associated with the worst outcome within the 'high and advanced/metastatic' risk group. In multivariate analysis p53-abn, ER/PR- and ESMO-ESGO-ESTRO 'high and advanced/metastatic' were independently associated with reduced disease-specific survival (DSS). Patients with abnormal IHC expression and lymph node metastasis (LNM) had the worst outcome. Patients with LNM and normal IHC expression had comparable outcome with patients without LNM and abnormal IHC expression. CONCLUSION: The use of pre-operative IHC biomarkers has important prognostic relevance in addition to the ESMO-ESGO-ESTRO risk classification and in addition to LN status. For daily clinical practice, p53/L1CAM/ER/PR expression could serve as indicator for surgical staging and refine selective adjuvant treatment by incorporation into the ESMO-ESGO-ESTRO risk classification.

Transferrin-functionalized lipid nanoparticles for curcumin brain delivery.

Curcumin is an anti-inflammatory and antioxidant compound with potent neuroprotective activity. Due to its poor water solubility, low bioavailability, rapid elimination and the challenges for crossing and transposing the blood-brain barrier (BBB), solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) loaded with curcumin were successfully produced and functionalized with transferrin, in order to mediate the transport of these particles through the BBB endothelium to the brain. The nanosystems revealed Z-averages under 200 nm, polydispersity index below 0.2 and zeta potential around -30 mV. Curcumin encapsulation around 65 % for SLNs and 80 % for NLCs was accomplished, while the functionalized nanoparticles presented a value around 70-75 %. A stability study revealed these characteristics remained unchanged for at least 3 months. hCMEC/D3 cells viability was firstly analysed by MTT and LDH assays, respectively, and a concentration of 10 µM of curcumin-loaded nanoparticles were then selected for the subsequent permeability assay. The permeability study was conducted using transwell devices with hCMEC/D3 cells monolayers and a 1.5-fold higher permeation of curcumin through the BBB was verified. Both SLNs and NLCs are promising for curcumin brain delivery, protecting the incorporated curcumin and targeting to the brain by the addition of transferrin to the nanoparticles surface.

Neoadjuvant chemotherapy followed by surgery for advanced-stage endometrial cancer.

Background: Data showing the value of neoadjuvant chemotherapy (nact) followed by interval debulking surgery (ids) in the management of advanced-stage serous endometrial carcinoma (eca) are limited; the aim of the present study was to expand the knowledge about that treatment strategy in patients with advanced eca, including endometrioid eca. Methods: Data were collected retrospectively from all patients with advanced-stage eca treated with nact between 2005 and 2014 at 3 oncology referral centres. Primary outcomes were the radiologic response to nact and achievement of optimal or complete ids. Secondary outcomes were recurrence rate and progression-free and overall survival. Results: Of 102 eca cases included, a complete radiologic response was achieved in only 4 cases, with a partial response being achieved in 72% (64% of endometrioid cases, 80% of serous cases). Complete ids was achieved in 62% of the endometrioid cases and in 56% of the serous eca cases, with optimal ids achieved in 31% and 28% of those cases respectively. Survival rates were calculated for all patients with complete and optimal ids; recurrence was observed in 56% and 67% of the cases respectively, and progression-free survival was 18 months and 13 months respectively. Median survival duration was 24 months for endometrioid eca and 28 months for serous eca. Conclusions: For patients with advanced eca who are not suitable for primary debulking, nact followed by ids can be considered regardless of histologic subtype. The treatment options for this group of patients are limited and have to be explored.

3D-printed polymer antiresonant waveguides for short-reach terahertz applications.

In this work, we present a 3D-printed waveguide that provides effective electromagnetic guidance in the THz regime. The waveguide is printed using low-cost polycarbonate and a conventional fused deposition modeling printer. Light guidance in the hollow core is achieved through antiresonance, and it improves the energy effectively transported to the receiver compared to free space propagation. Our demonstration adds to the field of 3D-printed terahertz components, providing a low-cost way of guiding terahertz radiation.

The opinion of gynecologists on the management of early-stage, high-grade endometrioid endometrial cancer.

PURPOSE OF INVESTIGATION: There is no consensus on the management of Stage I endometrioid endometrial cancer (EEC) with grade 3 histology. This study evaluates the opinion of gynecologists in The Netherlands on the management of Stage I, grade 3 EEC. MATERIALS AND METHODS: Members of the Dutch Gynecologic Oncology Working Group were requested to complete a digital questionnaire on the management of Stage I, grade 3 EEC. Actual treatment of patients with Stage I, grade 3 EEC was assessed by analysis of PALGA, the Dutch Pathology Registry. RESULTS: Most gynecologists prefer routine lymphadenectomy or complete staging (62.3%), while these were actually performed in 27.3% of the cases. Gynecologic oncologists are more likely to perform a lymphadenectomy than general gynecologists. There was a wide variation of clinical practice. CONCLUSION: The results of this study underline the need for additional research into management of Stage I, grade 3 EEC as well as the need for conclusive guidelines.

Salvage surgery in post-chemoradiation laryngeal and hypopharyngeal carcinoma: outcome and review.

Our objective was to evaluate recurrence patterns of hypopharyngeal and laryngeal carcinoma after chemoradiation and options for salvage surgery, with special emphasis on elderly patients. In a retrospective study all patients who underwent chemoradiation for hypopharyngeal and laryngeal carcinoma in a tertiary care academic center from 1990 through 2010 were evaluated. Primary outcome measures were the survival and complication rates of patients undergoing salvage surgery, especially in elderly patients. Secondary outcome measures were the predictors for salvage surgery for patients with locoregional recurrence after failed chemoradiotherapy. A review of the literature was performed. Of the 136 included patients, 60 patients had recurrent locoregional disease, of whom 22 underwent salvage surgery. Fifteen patients underwent a total laryngectomy with neck dissection(s) and 7 neck dissection without primary tumour surgery. Independent predictors for salvage surgery within the group of 60 patients with recurrent disease, were age under the median of 59 years (p = 0.036) and larynx vs. hypopharynx (p = 0.002) in multivariate analyses. The complication rate was 68% (14% major and 54% minor), with fistulas in 23% of the patients. Significantly more wound related complications occurred in patients with current excessive alcohol use (p = 0.04). Five-year disease free control rate of 35%, overall survival rate of 27% and disease specific survival rate of 35% were found. For the 38 patients who were not suitable for salvage surgery, median survival was 12 months. Patients in whom the tumour was controlled had a 5-year overall survival of 70%. In patients selected for salvage surgery age was not predictive for complications and survival. In conclusion, at two years follow-up after chemoradiation 40% of the patients were diagnosed with recurrent locoregional disease. One third underwent salvage surgery with 35% 5-year disease specific survival and 14% major complications. Older patients selected for salvage surgery had a similar complication rate and survival as younger patients.

Gluten-dependent antibodies in horses with inflammatory small bowel disease (ISBD).

BACKGROUND: Equine inflammatory small bowel disease (ISBD) is an idiopathic pathologic condition seeming to increase in prevalence. OBJECTIVE: To investigate the potential role of gluten in equine ISBD. ANIMALS & METHODS: Antibodies known to be important in the diagnosis of human coeliac disease (CD): IgA antibodies to human recombinant and guinea pig tissue-transglutaminase (TGA), native gliadin (AGA), deamidated-gliadin-peptides (DGPA), and primate and equine endomysium (EMA) were assessed in blood samples from three different groups of horses: ISBD affected (n = 12) on a gluten-rich diet and controls either on gluten-rich (n = 22) or gluten-poor (n = 25) diets. Significant differences (p < 0.05) between groups were assessed using the Wilcoxon test. RESULTS: Both ISBD-affected horses and gluten-rich controls had significantly (p < 0.0004) higher hrTGA titers than gluten-poor controls. However, ISBD horses did not show significantly increased levels of any of the CD related antibodies when compared to gluten-rich controls. Nevertheless, markedly increased antibody levels (TGA, EMA and DGPA) were found in one of the ISBD horses. The introduction of a gluten-free ration in this 14-year-old warmblood stallion resulted after 6 months in the reduction of antibody levels and clinical recovery associated with improved duodenal histopathology. CONCLUSION: To the best of our knowledge, this is the first study assessing gluten-related antibodies in horses and results suggest a potential pathogenic role of gluten in at least some cases of equine ISBD. Clinical importance and impact for human medicine: Given serology and concurrent clinical findings, this study warrants further investigations into the immunologic basis of possible gluten-sensitive enteropathy in horses and analogy with human disease.

Diffusion-weighted MR imaging in head and neck cancer: comparison between half-fourier acquired single-shot turbo spin-echo and EPI techniques.

BACKGROUND AND PURPOSE: Several studies have reported on the clinical utility of DWI in head and neck cancer, but none of these studies compared HASTE with EPI-DWI in patients with head and neck cancer. The aim of our study was to compare detection and delineation of primary tumors and lymph nodes by using HASTE and EPI-DWI techniques in patients with HNSCC. MATERIALS AND METHODS: Twelve patients with HNSCC and a total of 12 primary tumors and 77 visualized lymph nodes on MR imaging underwent DWI by using both EPI-based and HASTE techniques. Interobserver agreement for detection, delineation, and ADC values of primary tumors and lymph nodes was assessed by 2 radiologists, and artifacts for both DWI techniques were described. RESULTS: The number of lesions (primary tumors and lymph nodes) identified on pretreatment EPI-DWI was higher compared with pretreatment HASTE-DWI, with means of total lesions of 88.5 and 69.0, respectively. Delineation of lesions was also better on pretreatment EPI-DWI compared with pretreatment HASTE-DWI, with means of well-delineated lesions of 80.5 and 27.5, respectively. Both EPI- and HASTE-DWI showed good interobserver agreement between radiologists of ADC values in lesions with ICC values of 0.79 and 0.92, respectively. Intraobserver agreement for ADC values in lesions assessed with EPI- versus HASTE-DWI techniques was low, with ICC values of 0.31 and 0.42, respectively. Significant interobserver disagreement concerning detection was only seen with HASTE-DWI, and none of the DWI techniques showed significant interobserver disagreements regarding delineation. EPI-DWI was more prone to susceptibility artifacts than HASTE-DWI: Ninety-one percent of primary tumors and 16% of lymph nodes were affected by susceptibility artifacts on pretreatment EPI-DWI, whereas these artifacts were not seen on HASTE-DWI. CONCLUSIONS: Primary tumors and lymph nodes are more easily visualized on EPI-DWI compared with HASTE-DWI. EPI-DWI has geometric distortion, however, which has a negative effect on interobserver agreement of ADC values.

Flap reconstruction of the hypopharynx: a defect orientated approach.

The present retrospective analysis evaluated the outcomes of different flap reconstructions for several hypopharyngeal defects in 136 patients who underwent hypopharyngeal reconstruction with a free or pedicled flap after excision of pharyngeal or laryngeal carcinoma.Functional and oncological outcome were the main measures. Nine patients had a type I-a hypopharyngeal defect (partial with larynx preserved), 33 type I-b (partial without larynx preserved), 85 type II (circumferential), 5 type III (extensive superior) and 4 vertical hemipharyngolaryngectomy. The flaps used to reconstruct these defects were pectoralis major (n = 34), free radial forearm (n = 25), jejunum (n = 72), pedicled latissimus dorsi (n = 2), sternocleidomastoid (n = 1), lateral thigh (n = 1) and deltopectoral (n = 1). Twelve defects (9%) needed a secondary flap reconstruction. Surgical and medical complications were seen in 29% and 8% of patients, respectively; 18% of patients developed a fistula. No difference in complication rate or admission days was found for pre-operative versus no previous radiotherapy, type of defect or free versus pedicled flap. After 12 months follow-up, 38% of patients had a tracheo-oesophageal voice prosthesis, in 82% a fully oral diet was obtained and the average body weight gain was 0.9 kg. Five-year overall and disease-specific survival rates were 35% and 49%, respectively, while local and regional control rates were 65% and 91%, respectively. Considering these results, a defect orientated approach may be helpful for deciding which flap should be used for reconstruction of the hypopharynx. An algorithm is proposed with similar functional and oncological outcomes for the different groups. The choice of flap should be based on expected morbidity and functional outcome.

Paratracheal lymph node dissection during laryngectomy after previous (chemo)radiotherapy: a retrospective analysis of complications and histopathological results.

OBJECTIVES: To evaluate complications and histopathological results of paratracheal lymph node dissection (PTLND) at laryngectomy after (chemo)radiotherapy. DESIGN, SETTING AND PARTICIPANTS: In a retrospective analysis, complications and histopathological results of paratracheal lymph node dissections were analysed in 191 patients with a recurrent or second primary laryngeal or hypopharyngeal carcinoma following radiotherapy with or without chemotherapy. MAIN OUTCOME MEASURES: The percentage of complications in patients with bilateral, unilateral or without PTLND. RESULTS: Forty-seven patients underwent laryngectomy with bilateral paratracheal lymph node dissection, 52 with unilateral and 92 without paratracheal lymph node dissection. Although the difference in total complications was not significant, significantly more fistulae developed in patients with bilateral paratracheal lymph node dissection (40%versus 22%; P =0.016). In multivariate analysis, this difference maintained significant (P = 0.038). Pathological examination of the lymph node dissection specimen showed tumour in 3 of the 96 ipsilateral dissections (3%) and in 1 of the 50 contralateral dissections (2%). This suggests that if unilateral instead of a bilateral paratracheal lymph node dissection had been performed, 17% less fistulae would have occurred in this group of patients, while paratracheal lymph node (PTLN) metastases would have been missed in one patient. Three of four patients with paratracheal lymph nodeparatracheal lymph node metastases had glottic carcinoma, all with subglottic extension. CONCLUSION: Because of the low incidence of lymph node metastases and the increased risk of fistulae, there is a need for a strict selection of patients who need a bilateral paratracheal lymph node dissection at laryngectomy after previous (chemo)radiotherapy.

Salvage laryngectomy: oncological and functional outcome.

The purpose of the research was to evaluate postoperative complications, functional outcome and survival after salvage laryngectomy. Second, to evaluate the management of the neck in combination with a laryngectomy in this group of patients. A retrospective analysis of all patients who underwent total laryngectomy for residual or recurrent squamous cell laryngeal carcinoma after (chemo)radiotherapy between November 1990 and June 2007 was performed. Of the 120 patients that were included, the complication rate was 56% (33% major and 23% minor). In univariate analyses, T-stage (p=0.05), bilateral neck dissection (p=0.09) and ASA score (p=0.08) showed a trend for postoperative major complications. Lymph node metastases were found in 26% of the neck dissection specimens, with a trend towards more regional disease at higher initial N-stage (p=0.06) and T-stage (p=0.08). Five-year disease specific survival was 58%. In univariate analyses pre-operative chemoradiation (vs. radiation) (p=0.0001), N3 neck (p=0.001) and positive surgical margins (p=0.02) were significant predictors for a worse disease specific survival, but only positive surgical margins (p<0.001) maintained significance in multivariate analysis. Eighty-seven percent of the patients were able to produce speech using a voice prosthesis, and 84% of the patients were able to have a 'normal' or 'soft' diet. There was an almost significant increase in mean body mass index (BMI) 6-12 months postoperative (p=0.057). Laryngectomy after radiotherapy offers good survival, with a substantial risk of complications and good functional outcome.

2-Deoxy-2[F-18]FDG-PET for detection of recurrent laryngeal carcinoma after radiotherapy: interobserver variability in reporting.

PURPOSE: To evaluate accuracy and interobserver variability in the assessment of 2-deoxy-2[F-18]fluoro-D-glucose-positron emission tomography (FDG-PET) for detection of recurrent laryngeal carcinoma after radiotherapy. PROCEDURES: Eleven experienced nuclear physicians from eight centres assessed 30 FDG-PET scans on the appearance of local recurrence (negative/equivocal/positive). Conservative (equivocal analysed as negative) and sensitive (equivocal analysed as positive) assessment strategies were compared to the reference standard (recurrence within 6months after PET). RESULTS: Seven patients had proven recurrences. For the conservative and sensitive strategy, the mean sensitivity was 87% and 97%, specificity 81% and 63%, positive predictive values 61% and 46% and negative predictive values 96% and 99%, respectively. Interobserver variability showed a reasonable relation in comparison to the reference standard (kappa = 0.55). CONCLUSIONS: FDG-PET has acceptable interobserver agreement and yields good negative predictive value for detection of recurrent laryngeal carcinoma. It could therefore be used as first diagnostic step and may reduce futile invasive diagnostics.

The effect of chronic apomorphine treatment on the ultrastructure of the prolactin cells and on plasma prolactin levels in young and aged male Wistar rats.

Effects of two doses of apomorphine on the plasma prolactin (PRL) levels and on the ultrastructure of PRL cells in young and aged male Wistar rats were investigated. In young and aged control rats no significant differences were found between the plasma PRL levels. Immunocytochemical staining with anti-r-PRL revealed significant differences between young and aged control rats; in young rats the number of PRL cells with polymorphic granules exceeded the number of cells with round granules, whereas in aged rats almost exclusively cells with round granules were found. In young rats, chronic treatment with a low dose (0.01 mg/kg/day) of apomorphine did not result in a significant change in plasma PRL level or cell morphology. However, high dose (0.25 mg/kg/day) of apomorphine resulted in a significant decrease in plasma PRL levels, a decrease of number of cells with polymorphic granules and an increase of cells with round granules. The occurrence of PRL cells with round granules and plasma levels was negatively correlated. In aged rats, apomorphine (0.01 or 0.25 mg/kg/day) treatment did not affect plasma levels nor did it affect the distribution of the cell types. We conclude that in young rats PRL cells are sensitive to apomorphine and that their ultrastructure reflects a phase of the secretory cycle. In aged rats, the cells appear to have lost their sensitivity to apomorphine. The fact, that the distribution over the different cell types in control aged rats is similar to that of the apomorphine-treated young rats, suggests a strong influence of endogenous dopamine on PRL cell physiology in the aged rat.

Prolactin cells and plasma prolactin levels in the aging male Wistar rat: an immunocytochemical and biochemical study.

Non-neoplastic pituitary glands of 12 age-groups of 10 male Wistar rats (subpopulation 1) and of 228 rats with age-related disorders (population 2) were studied. For subpopulation 1 a positive correlation was found between body weight, pars distalis volume and total prolactin (PRL)-cell volume. These values increased during the first half of the life span and decreased to values similar to that found in young rats, after the 50% survival age was reached. Age-related changes were found with respect to the distribution of the PRL cells (from homogeneous into non-homogeneous) and to their ultrastructural features (PRL cells with polymorphic granules were substituted by cells with round granules). Pituitary glands of disordered aged rats (subpopulation 2) showed a similar non-homogeneous distribution of PRL cells. Plasma PRL levels of both subpopulations were similar. No age-related increase of plasma PRL level was found in rats with non-neoplastic pituitary glands.

Immuno-electron-microscopic study of the prolactin cells in the pituitary gland of male Wistar rats during aging.

Prolactin cells were identified by means of immunocytochemistry with protein-A gold as a marker on ultrathin sections of the pituitary gland of young (3-4 months), middle-aged (16-19 months), and aged (26-30 months) male Wistar rats. Point-counting volumetry revealed that the prolactin (PRL) cell-volume density in middle-aged rats was significantly increased in comparison to the volume densities in young and aged rats. Within the PRL-cell population, four types of PRL cells were distinguished on the basis of the shape and size of their secretory granules. During aging, dramatic changes occurred in the relative volumes of the four cell types. The volume percentage of cells with round granules (type I, granule diameter 150-250 nm, and type IIA, granule diameter 250-350 nm) increased from +/- 30% in young rats to +/- 90% in old rats. The volume percentage of cells with round and polymorphic granules (type IIB; granule diameter 350-400 nm and type III; granule diameter 500-600 nm) decreased from +/- 70% in young rats to +/- 7% in old rats. Age-related changes in serum PRL levels were not found. It is concluded that although during the life span of the male Wistar rat considerable changes in PRL-cell volume densities and in the ratios of PRL-cell types occur serum, PRL levels remain more or less constant.

Studies on prolactin-secreting cells in aging rats of different strains. II. Selected morphological and immunocytochemical features of pituitary tumors correlated with serum prolactin levels.

Sixty pituitary tumors from 151 aging rats of the BN/BiRij strain, the WAG/Rij strain and their F1 hybrid were studied light microscopically. The lowest tumor incidence (18%) was found in the BN/BiRij strain, the highest incidence (71%) in the WAG/Rij strain. In the F1 hybrid the incidence (45%) was intermediate between those of the parental strains. With a hematoxylin-phloxin-saffron (HPS) staining two tumor types, i.e. hemorrhagic and solid could be distinguished. Immunocytochemical staining with anti-r-PRL antiserum revealed a positive reaction in the hemorrhagic and a negative reaction in the solid type, whereas staining with anti-sh-GH and anti-ACTH generally were negative. In animals with hemorrhagic as well as with solid tumors elevated serum PRL levels were found, although some differences were noticed. Serum levels in females of the WAG/Rij strain with hemorrhagic adenomas were significantly higher than the levels in females with solid adenomas. In the same strain, age-related differences in PRL levels were found. Significantly higher serum PRL levels were found at the age of 26-32 months than in older animals. The same tendencies were noticed in both other strains.

Studies on prolactin-secreting cells in aging rats of different strains. I. Alterations in pituitary histology and serum prolactin levels as related to aging.

Serum PRL levels and histologically tumor-free pituitary glands of 91 aging rats of the BN/BiRij strain, the WAG/Rij strain and their F1 hybrid were studied. In rats with pituitary glands without signs of hyperplasia, serum PRL levels were, in comparison to rats of 15-24 months, increased 25-29-month-old female BN/BiRij rats and showed a decline with further aging. This rise and decline during aging correlated with changes in the PRL cell volume density and in ultrastructural signs of their synthetic activity. Rats with hyperplastic pituitaries showed similar age-related changes in serum PRL levels, but these levels were higher. Concerning the hyperplasia, some strain differences were found. In BN/BiRij rats anti-r-PRL positive hyperplasia, and in WAG/Rij and F1 rats, anti-r-PRL negative and anti-r-PRL positive hyperplasia were present. All foci of hyperplasia were negative for anti-ACTH and anti-h-GH. In male rats no age-related changes of serum PRL levels could be established, although a decline of PRL cell volume density in the oldest rats is indicated. We conclude that the absence of a continuous age-related rise of serum PRL levels in our animals is caused by exclusion of animals with pituitary tumors.

Characterization of a slow-growing, transplantable rat mammary tumor (MCR-83): a model for endocrine-related cell kinetic studies.

Out of 24 primary mammary tumors, arising in rats of the WAG/Rij Wistar strain after low dose irradiation, with or without prolonged treatment with estrogen, a slow-growing, well differentiated adenocarcinoma (MCR-83) was selected. This tumor, induced by radiation alone, is independent of estrogen pellets for growth after transplantation into adult female rats, but nontransplantable into males or ovariectomized females. Measurements of tumor growth and contents of both estrogen and progesterone receptors on three successive passages are not indicative of a rapid progression in growth rate or to hormone independency. Ovariectomy and treatment with tamoxifen give a pronounced inhibition of tumor growth, whereas neither methotrexate nor cyclophosphamide is effective. Growth rate is significantly increased when rats are given 17 beta-estradiol. Flow cytometric DNA analysis as well as in situ S-phase cell detection with anti-bromodeoxyuridine antibodies show a 3-fold increase in S-phase fraction cells within 4 days after the onset of estrogen treatment. No spontaneous metastases have been found so far, but lung nodules develop after i.v. inoculation of tumor cells. From one of these nodules a fast-growing, hormone independent subline (MCR-86) has been derived, showing both lymphatic and hematogenous dissemination upon s.c. transplantation. By showing several features of hormone responsive human disease in its early stage of progression the MCR-83 tumor system may be a clinically relevant model for studies on endocrine regulation of tumor growth and its therapeutic manipulation.

Ultrastructural localization of exocytotic release sites in immunocytochemically characterized cell types. A combination of two methods.

Preembedding visualization of exocytosis by tannic acid treatment and postembedding immunocytochemical identification of cell types were combined to demonstrate the release of secretory products by exocytosis of characterized cell types. Treatment with tannic acid was carried out by perfusion with Ringer containing tannic acid, followed by fixation, dehydration and embedding. For electron microscopical immunocytochemistry protein A-gold was used as marker. In this study, exocytotic release was demonstrated for prolactin by cells in the pars distalis, and for oxytocin by axon terminals in the pars nervosa of the pituitary gland of the rat.