Expression of honey bee (Apis mellifera) sterol homeostasis genes in food jelly producing glands of workers

Adult workers of Western honey bees (Apis mellifera L.) acquire sterols from their pollen diet. These food sterols are transported by the hemolymph to peripheral tissues such as the mandibular and the hypopharyngeal glands in the worker bees' heads that secrete food jelly which is fed to developing larvae. As sterols are obligatory components of biological membranes and essential precursors for molting hormone synthesis in insects, they are indispensable to normal larval development. Thus, the study of sterol delivery to larvae is important for a full understanding of honey bee larval nutrition and development. Whereas hypopharyngeal glands only require sterols for their membrane integrity, mandibular glands add sterols, primarily 24-methylenecholesterol, to its secretion. For this, sterols must be transported through the glandular epithelial cells. We have analyzed for the first time in A. mellifera the expression of genes which are involved in intracellular movement of sterols. Mandibular and hypopharyngeal glands were dissected from newly emerged bees, 6-day-old nurse bees that feed larvae and 26-day-old forager bees. The expression of seven genes involved in intracellular sterol metabolism was measured with quantitative real-time PCR. Relative transcript abundance of sterol metabolism genes was significantly influenced by the age of workers and specific genes but not by gland type. Newly emerged bees had significantly more transcripts for six out of seven genes than older bees indicating that the bulk of the proteins needed for sterol metabolism are produced directly after emergence.

Single-cell transcriptomic landscape and the microenvironment of normal adjacent tissues in hypopharyngeal carcinoma

BACKGROUND

The cellular origin of hypopharyngeal diseases is crucial for further diagnosis and treatment, and the microenvironment in tissues may also be associated with specific cell types at the same time. Normal adjacent tissues (NATs) of hypopharyngeal carcinoma differ from non-tumor-bearing tissues, and can influenced by the tumor. However, the heterogeneity in kinds of disease samples remains little known, and the transcriptomic profile about biological information associated with disease occurrence and clinical outcome contained in it has yet to be fully evaluated. For these reasons, we should quickly investigate the taxonomic and transcriptomic information of NATs in human hypopharynx.

RESULTS

Single-cell suspensions of normal adjacent tissues (NATs) of hypopharyngeal carcinoma were obtained and single-cell RNA sequencing (scRNA-seq) was performed. We present scRNA-seq data from 39,315 high-quality cells in the hypopharyngeal from five human donors, nine clusters of normal adjacent human hypopharyngeal cells were presented, including epithelial cells, endothelial cells (ECs), mononuclear phagocyte system cells (MPs), fibroblasts, T cells, plasma cells, B cells, mural cells and mast cells. Nonimmune components in the microenvironment, including epithelial cells, endothelial cells, fibroblasts and the subpopulations of them were performed.

CONCLUSIONS

Our data provide a solid basis for the study of single-cell landscape in human normal adjacent hypopharyngeal tissues biology and related diseases.

Expression and function of the vitellogenin receptor in the hypopharyngeal glands of the honey bee Apis mellifera (Hymenoptera: Apidae) workers

The vitellogenin receptor (VgR) is essential for the uptake and transport of the yolk precursor, vitellogenin (Vg). Vg is synthesized in the fat body, released in the hemolymph, and absorbed in the ovaries, via receptor-mediated endocytosis. Besides its important role in the reproductive pathway, Vg occurs in nonreproductive worker honey bee, suggesting its participation in other pathways. The objective was to verify if the VgR occurs in the hypopharyngeal glands of Apis mellifera workers and how Vg is internalized by these cells. VgR occurrence in the hypopharyngeal glands was evaluated by qPCR analyses of VgR and immunohistochemistry in workers with different tasks. The VgR gene is expressed in the hypopharyngeal glands of workers with higher transcript levels in nurse honey bees. VgR is more expressed in 11-day-old workers from queenright colonies, compared to orphan ones. Nurse workers with developed hypopharyngeal glands present higher VgR transcripts than those with poorly developed glands. The immunohistochemistry results showed the co-localization of Vg, VgR and clathrin (protein that plays a major role in the formation of coated vesicles in endocytosis) in the hypopharyngeal glands, suggesting receptor-mediated endocytosis. The results demonstrate that VgR performs the transport of Vg to the hypopharyngeal glands, supporting the Ovary Ground Plan Hypothesis and contributing to the understanding of the role of this gland in the social context of honey bees.

Hypopharyngeal Diffuse Large B-Cell Lymphoma in a 74-Year-Old Man Presenting with Dysphagia: A Case Report

BACKGROUND Malignant lymphomas can occur at various sites. Hypopharyngeal tumors are at risk for airway obstruction and require rapid diagnosis and treatment. Most hypopharyngeal malignancies are squamous cell carcinomas; other tumors are rare. To date, only a few cases of malignant hypopharyngeal lymphoma have been reported, and its specific characteristics are unknown. Herein, we report a case of right hypopharyngeal diffuse large B-cell lymphoma (DLBCL) in a 74-year-old man with dysphagia. CASE REPORT A 74-year-old man presented to our hospital with dysphagia. He had no relevant medical history. Endoscopic examination revealed a right hypopharyngeal tumor. The surface of the tumor was smooth, with no evidence of hemorrhage. Computed tomography revealed a 40-mm mass located in the hypopharynx. We performed a tracheotomy and biopsy of the tumor. Histopathological examination revealed a diffuse proliferation of large atypical B cells with negative staining for Epstein-Barr virus by in situ hybridization. Immunohistochemical staining was positive for CD20 but negative for CD3 and CD10. The patient was administered chemotherapy. The tumor reduced in size, and the patient recovered completely. During the two-year follow up, no recurrence of cancer was observed. CONCLUSIONS Although most hypopharyngeal tumors are squamous cell carcinomas (SCCs), the possibility of other types of tumors should also be considered. Malignant lymphoma of the hypopharynx is rare, and more cases need to be studied and reported in the future.

Pepsin Promotes Activation of Epidermal Growth Factor Receptor and Downstream Oncogenic Pathways, at Slightly Acidic and Neutral pH, in Exposed Hypopharyngeal Cells

Pepsin refluxate is considered a risk factor for laryngopharyngeal carcinogenesis. Non-acidic pepsin was previously linked to an inflammatory and tumorigenic effect on laryngopharyngeal cells in vitro. Yet there is no clear evidence of the pepsin-effect on a specific oncogenic pathway and the importance of pH in this process. We hypothesized that less acidic pepsin triggers the activation of a specific oncogenic factor and related-signalling pathway. To explore the pepsin-effect in vitro, we performed intermittent exposure of 15 min, once per day, for a 5-day period, of human hypopharyngeal primary cells (HCs) to pepsin (1 mg/mL), at a weakly acidic pH of 5.0, a slightly acidic pH of 6.0, and a neutral pH of 7.0. We have documented that the extracellular environment at pH 6.0, and particularly pH 7.0, vs. pH 5.0, promotes the pepsin-effect on HCs, causing increased internalized pepsin and cell viability, a pronounced activation of EGFR accompanied by NF-κB and STAT3 activation, and a significant upregulation of EGFR, AKT1, mTOR, IL1β, TNF-α, RELA(p65), BCL-2, IL6 and STAT3. We herein provide new evidence of the pepsin-effect on oncogenic EGFR activation and its related-signaling pathway at neutral and slightly acidic pH in HCs, opening a window to further explore the prevention and therapeutic approach of laryngopharyngeal reflux disease.

Fat body lipolysis connects poor nutrition to hypopharyngeal gland degradation in Apis mellifera

The hypopharyngeal glands (HGs) of honey bee nurse workers secrete the major protein fraction of jelly, a protein and lipid rich substance fed to developing larvae, other worker bees, and queens. A hallmark of poorly nourished nurses is their small HGs, which actively degrade due to hormone-induced autophagy. To better connect nutritional stress with HG degradation, we looked to honey bees and other insect systems, where nutrient stress is often accompanied by fat body degradation. The fat body contains stored lipids that are likely a substrate for ecdysteroid synthesis, so we tested whether starvation caused increased fat body lipolysis. Ecdysteroid signaling and response pathways and IIS/TOR are tied to nutrient-dependent autophagy in honey bees and other insects, and so we also tested whether and where genes in these pathways were differentially regulated in the head and fat body. Last, we injected nurse-aged bees with the honey bee ecdysteroid makisterone A to determine whether this hormone influenced HG size and autophagy. We find that starved nurse aged bees exhibited increased fat body lipolysis and increased expression of ecdysteroid production and response genes in the head. Genes in the IIS/TOR pathway were not impacted by starvation in either the head or fat body. Additionally, bees injected with makisterone A had smaller HGs and increased expression of autophagy genes. These data support the hypothesis that nutritional stress induces fat body lipolysis, which may liberate the sterols important for ecdysteroid production, and that increased ecdysteroid levels induce autophagic HG degradation.

In-depth Proteome of the Hypopharyngeal Glands of Honeybee Workers Reveals Highly Activated Protein and Energy Metabolism in Priming the Secretion of Royal Jelly

Royal jelly (RJ) is a secretion of the hypopharyngeal glands (HGs) of honeybee workers. High royal jelly producing bees (RJBs), a stock of honeybees selected from Italian bees (ITBs), have developed a stronger ability to produce RJ than ITBs. However, the mechanism underpinning the high RJ-producing performance in RJBs is still poorly understood. We have comprehensively characterized and compared the proteome across the life span of worker bees between the ITBs and RJBs. Our data uncover distinct molecular landscapes that regulate the gland ontogeny and activity corresponding with age-specific tasks. Nurse bees (NBs) have a well-developed acini morphology and cytoskeleton of secretory cells in HGs to prime the gland activities of RJ secretion. In RJB NBs, pathways involved in protein synthesis and energy metabolism are functionally induced to cement the enhanced RJ secretion compared with ITBs. In behavior-manipulated RJB NBs, the strongly expressed proteins implicated in protein synthesis and energy metabolism further demonstrate their critical roles in the regulation of RJ secretion. Our findings provide a novel understanding of the mechanism consolidating the high RJ-output in RJBs.

The In Vitro Effect of Acidic-Pepsin on Nuclear Factor KappaB Activation and Its Related Oncogenic Effect on Normal Human Hypopharyngeal Cells

Background

Extra-esophageal carcinogenesis has been widely discussed in relation to the chronic effects of laryngopharyngeal reflux and most prominently with pepsin historically central to this discussion. With refluxate known to include gastric (pepsin) and duodenal (bile) fluids, we recently demonstrated the mechanistic role of NF-κB in mediating the preneoplastic effects of acidic-bile. However, the role of pepsin in promoting hypopharyngeal premalignant events remains historically unclear. Here, we investigate the in vitro effect of acidic-pepsin on the NF-κB oncogenic pathway to better define its potential role in hypopharyngeal neoplasia.

Methods

Human hypopharyngeal primary cells (HHPC) and keratinocytes (HHK) were repetitively exposed to physiologic pepsin concentrations (0.1 mg/ml) at pH 4.0, 5.0 and 7.0. Cellular localization of phospho-NF-κB and bcl-2 was determined using immunofluorescence and western blotting. NF-κB transcriptional activity was tested by luc reporter and qPCR. Analysis of DNA content of pepsin treated HHK and HHPC was performed using Fluorescence-activated-cell sorting assay. To explore a possible dose related effect, pepsin concentration was reduced from 0.1 to 0.05 and 0.01 mg/ml.

Results

At physiologic concentration, acidic-pepsin (0.1 mg/ml at pH 4.0) is lethal to most normal hypopharyngeal cells. However, in surviving cells, no NF-κB transcriptional activity is noted. Acidic-pepsin fails to activate the NF-κB or bcl-2, TNF-α, EGFR, STAT3, and wnt5α but increases the Tp53 mRNAs, in both HHPC and HHK. Weakly acidic-pepsin (pH 5.0) and neutral-pepsin (pH 7.0) induce mild activation of NF-κB with increase in TNF-α mRNAs, without oncogenic transcriptional activity. Lower concentrations of pepsin at varying pH do not produce NF-κB activity or transcriptional activation of the analyzed genes.

Conclusion

Our findings in vitro do not support the role of acidic-pepsin in NF-κB related hypopharyngeal carcinogenesis.

Inhibition of CDK9 induces apoptosis and potentiates the effect of cisplatin in hypopharyngeal carcinoma cells

Myeloid cell leukemia-1 (Mcl-1) plays an important role in survival, chemo- and radioresistance of head and neck squamous cell carcinoma (HNSCC). Cyclin-dependent kinase 9/cyclin T (CDK9) promotes excessive production of multiple pro-survival proteins including Mcl-1, leading to impaired apoptosis of cancer cells. As such, CDK9 is an emerging therapeutic target in cancer therapy. We herein report the first study of targeting CDK9 as a treatment strategy for hypopharyngeal squamous cell carcinoma (HSCC), an aggressive malignancy associated with one of the worst prognoses within HNSCC. We showed that mRNA levels of Mcl-1 were significantly higher in HSCC tumor tissues than in the adjacent non-tumor mucosae. In addition, the levels of Mcl-1 mRNA correlated with the tumor size and clinical stage of HSCC patients. CDKI-73, a potent CDK9 inhibitor, was capable of downregulating the expression of Mcl-1 in the HSCC cells by suppression of the CDK9 mediated phosphorylation of RNA polymerase II. CDKI-73 effectively induced apoptosis as a single agent and synergized anti-tumor activity of cisplatin in HSCC cells. Taken together, our study presents compelling evidence for developing CDK9 inhibitors, such as CDKI-73, as new therapeutic strategy for HSCC.

Transcriptional, translational, and physiological signatures of undernourished honey bees (Apis mellifera) suggest a role for hormonal factors in hypopharyngeal gland degradation

Honey bee colonies function as a superorganism, where facultatively sterile female workers perform various tasks that support the hive. Nurse workers undergo numerous anatomical and physiological changes in preparation for brood rearing, including the growth of hypopharyngeal glands (HGs). These glands produce the major protein fraction of a protein- and lipid-rich jelly used to sustain developing larvae. Pollen intake is positively correlated with HG growth, but growth in the first three days is similar regardless of diet, suggesting that initial growth is a pre-determined process while later HG development depends on nutrient availability during a critical window in early adulthood (>3 d). It is unclear whether the resultant size differences in nurse HG are simply due to growth arrest or active degradation of the tissue. To determine what processes cause such differences in HG size, we catalogued the differential expression of both gene transcripts and proteins in the HGs of 8 d old bees that were fed diets containing pollen or no pollen. 3438 genes and 367 proteins were differentially regulated due to nutrition. Of the genes and proteins differentially expressed, undernourished bees exhibited more gene and protein up-regulation compared to well-nourished bees, with the affected processes including salivary gland apoptosis, oogenesis, and hormone signaling. Protein secretion was virtually the only process up-regulated in well-nourished bees. Further assays demonstrated that inhibition of ultraspiracle, one component of the ecdysteroid receptor, in the fat body caused larger HGs. Undernourished bees also had higher acid phosphatase activity, a physiological marker of cell death, compared to well-nourished bees. These results support a connection between poor nutrition, hormonal signaling, and HG degradation.

Changes in the Gene Expression Profiles of the Hypopharyngeal Gland of Worker Honeybees in Association with Worker Behavior and Hormonal Factors

The hypopharyngeal glands (HPGs) of worker honeybees undergo physiological changes along with the age-dependent role change from nursing to foraging: nurse bee HPGs secrete mainly major royal jelly proteins, whereas forager HPGs secrete mainly α-glucosidase III, which converts the sucrose in the nectar into glucose and fructose. We previously identified two other genes, Apis mellifera buffy (Ambuffy) and Apis mellifera matrix metalloproteinase 1 (AmMMP1), with enriched expression in nurse bee and forager HPGs, respectively. In the present study, to clarify the molecular mechanisms that coordinate HPG physiology with worker behavior, we first analyzed whether Ambuffy, AmMMP1, mrjp2 (a gene encoding one of major royal jelly protein isoforms), and Hbg3 (a gene encoding α-glucosidase III) expression, is associated with worker behavior in 'single-cohort colonies' where workers of almost the same age perform different tasks. Expression of these genes correlated with the worker’s role, while controlling for age, indicating their regulation associated with the worker’s behavior. Associated gene expression suggested the possible involvement of some hormonal factors in its regulation. We therefore examined the relationship between ecdysone- and juvenile hormone (JH)-signaling, and the expression profiles of these ‘indicator’ genes (nurse bee HPG-selective genes: mrjp2 and Ambuffy, and forager HPG-selective genes: Hbg3 and AmMMP1). Expression of both ecdysone-regulated genes (ecdysone receptor, mushroom body large type Kenyon cell specific protein-1, and E74) and JH-regulated genes (Methoprene tolerant and Krüppel homolog 1) was higher in the forager HPGs than in the nurse bee HPGs, suggesting the possible roles of ecdysone- and JH-regulated genes in worker HPGs. Furthermore, 20-hydroxyecdysone-treatment repressed both nurse bee- and forager-selective gene expression, whereas methoprene-treatment enhanced the expression of forager-selective genes and repressed nurse bee-selective genes in the HPGs. Our findings suggest that both ecdysone- and JH-signaling cooperatively regulate the physiological state of the HPGs in association with the worker’s behavior.

CD271 defines a stem cell-like population in hypopharyngeal cancer

Cancer stem cells contribute to the malignant phenotypes of a variety of cancers, but markers to identify human hypopharyngeal cancer (HPC) stem cells remain poorly understood. Here, we report that the CD271(+) population sorted from xenotransplanted HPCs possesses an enhanced tumor-initiating capability in immunodeficient mice. Tumors generated from the CD271(+) cells contained both CD271(+) and CD271(-) cells, indicating that the population could undergo differentiation. Immunohistological analyses of the tumors revealed that the CD271(+) cells localized to a perivascular niche near CD34(+) vasculature, to invasive fronts, and to the basal layer. In accordance with these characteristics, a stemness marker, Nanog, and matrix metalloproteinases (MMPs), which are implicated in cancer invasion, were significantly up-regulated in the CD271(+) compared to the CD271 (-) cell population. Furthermore, using primary HPC specimens, we demonstrated that high CD271 expression was correlated with a poor prognosis for patients. Taken together, our findings indicate that CD271 is a novel marker for HPC stem-like cells and for HPC prognosis.

Hypopharyngeal and distal esophageal pH monitoring in children with gastroesophageal reflux and respiratory symptoms

PURPOSE

Fundoplication is frequently required for gastroesophageal reflux (GER)-related respiratory disease. Correlation between esophageal pH data and respiratory symptoms is poor but may be improved by monitoring hypopharyngeal pH. Reflux to the hypopharynx is underestimated by salivary bicarbonate. The aim of this study was to determine if hypopharyngeal pH monitoring using pH 4 and pH 5 as reflux thresholds could predict children with reflux-related respiratory disease.

METHODS

One hundred five children aged 4 months to 12 years underwent esophageal and hypopharyngeal pH monitoring. Hypopharyngeal pH data were analyzed using pH 4 and pH 5 as reflux thresholds. pH data from 4 groups were compared: group A, control group, no GER, no respiratory symptoms (n = 20); group B, respiratory symptoms, no GER (n = 16); group C, GER, no respiratory symptoms (n = 26); and group D, both GER and respiratory symptoms (n = 37).

RESULTS

Comparing groups C and D, there was no significant difference in hypopharyngeal pH data. Using pH 5 as the reflux threshold, children in group B refluxed to the hypopharynx significantly more frequently than controls. This was most evident in children with wheeze.

CONCLUSION

Hypopharyngeal pH monitoring does not differentiate children with GER and respiratory symptoms from those with GER alone and is therefore of doubtful value in diagnosing recurrent aspiration.

Cyclo-oxygenase 2 expression in laryngeal squamous cell carcinoma and its clinical correlates

OBJECTIVE

To assess the significance of cyclo-oxygenase 2 (COX-2) in laryngeal squamous cell carcinoma (LSCC).

STUDY DESIGN

An immunohistochemical study in which 39 patients with LSCC were included.

METHODS

Immunohistochemical staining of the paraffin-embedded tumour tissues was performed using isoform-specific COX-2 polyclonal antisera (Santa Cruz, Calif., USA). COX-2 results were compared with the clinical parameters of the patients.

RESULTS

COX-2 was detected in all tumour tissues. In the normal laryngeal tissue around the tumour area, which served as control, there was no COX-2 staining. There was no relationship between the COX-2 results and the location of the primary tumour, T stage and N stage, survival, recurrence or pulmonary metastases.

CONCLUSION

The absence of a relation between COX-2 positivity and clinical parameters may suggest an involvement of COX-2 in laryngeal carcinogenesis. Since COX-2 positivity could be detected in all LSCC specimens studied, COX-2 could serve as a therapeutic target in LSCC.

Laryngopharyngeal pH measurement

OBJECTIVES

Most emergency department (ED) intubations are to prevent gastric contents aspiration. The incidence of aspiration is unknown and intubation has complications. Balancing these risks requires an idea of the incidence of aspiration. This study assessed one technique for investigating the aspiration risk in ED patients. Cricoid pressure is used to reduce this risk and the technique may also examine this manoeuvre.

METHODS

Cohorts of unconscious adult ED and elective surgical patients were recruited. The posterior pharyngeal wall pH was measured immediately before and after intubation. Pharyngeal pH was used to indicate risk of aspiration, and pH change to assess the efficacy of cricoid pressure.

RESULTS

Eight ED and 48 control patients were recruited. In the ED cohort, pH ranged from 6.0 to 8.0 before intubation and 4.7 to 8.0 after intubation: a mean decrease of 0.3 (95% CI 1.5 decrease to 0.9 increase). In the control cohort pH ranged from 5.8 to 8.0 before intubation and 6.0 to 8.0 after intubation: a mean increase of 0.4 (95% CI 0.1 to 0.6 increase).

CONCLUSIONS

This is a simple, cheap, and repeatable technique for assessing aspiration risk in emergency intubations. A larger study is required to assess the efficacy of cricoid pressure.

Bumble bees alert to food with pheromone from tergal gland

Foragers of Bombus terrestris are able to alert their nestmates to the presence of food sources. It has been supposed that this happens at least partially through the distribution of a pheromone inside the nest. We substantiate this claim using a behavioral test in which an alerting signal is transmitted from one colony to another by long distance air transport, so excluding all other modalities of information exchange. We then investigated the source of the pheromone and were able to show that a hexane extract from tergites V-VII of bumble bee workers elicits higher activity, like a successful forager does. Extracts from other glands, such as the mandibular, labial, hypopharyngeal, and Dufour's gland as well as extracts from other parts of the cuticle had no effect. This suggests that bumble bees possess a pheromone-producing gland, similar to the Nasanov gland in honey bees. Indeed, an extract from the honey bee Nasanov gland also proved to alert bumble bee workers, suggesting a possible homology of the glands.

Distribution of acid phosphatases in the hypopharyngeal glands from workers, queens and males of a Brazilian stingless bee Scaptotrigona postica Latreille: an ultrastructural cytochemical study

The present study reports the localization of acid phosphatase in the hypopharyngeal gland cells from workers (newly-emerged, nurse and forager), queens (newly-emerged and laying) and males (newly-emerged and mature for mating) of the Brazilian stingless bee, Scaptotrigona postica. The phosphatase activity varied in intensity and localization depending on the individual class, physiological age and the substrate used. In newly-emerged workers, the phosphatase-positive sites suggest the involvement of the enzyme with cellular differentiation that occurs in the presecretory phase, in nurse workers with protein synthesis and in forager workers with changes in cellular activity or glandular regression. In males mature for mating and laying queens, the positive sites are related to secretory activity, showing that the gland maintains some activity in spite of the regressive aspect. Of the substrates used, beta-glycerophosphate gave the least specific localization.

Modes of cell death in the hypopharyngeal gland of the honey bee (Apis mellifera l)

Different modes of cell death have been revealed in the regressing hypopharyngeal glands of worker honey bees. The hypopharyngeal gland, which is well developed in young nursing bees to produce protein for larval food, was seen to regress naturally in foraging adult worker bees. A range of techniques including histology, cytochemistry, in situ TUNEL, Annexin V and Comet assays indicated that cells within the gland demonstrate progressive symptoms of apoptosis, necrosis and a vacuolar form of programmed cell death. The latter mode of cell death did not display chromatin margination, but was accompanied by an enhanced level of autophagic and hydrolytic activity in which a cytosolic source of acid phosphatase became manifest in the extra-cisternal spaces. Normal and annexin-positive cells were found to occur in the younger nursing bees, whilst necrosis and an aberrant vacuolar type of apoptosis predominated in the older foraging bees. The relevance of these results to the classification of programmed cell death is discussed.

Comparative study of the ultrastructure and secretory dynamic of hypopharyngeal glands in queens, workers and males of Scaptotrigona postica Latreille (Hymenoptera, Apinae, Meliponini)

The secretory cycle of hypopharyngeal glands (HPGs) in Scaptotrigona postica resembles that of Apis mellifera: in newly emerged workers the HPGs are in prefunctional state, their maximum development happens in the nurse workers and in forager workers they show signs of reabsorption. In S. postica these glands are also present in queens and males where they are more developed in newly emerged individuals. The ultrastructural features of the HPG secretory cycle in workers of S. postica and A. mellifera are alike: granular endoplasmic reticulum well developed, large secretion masses around the intracellular canaliculus in nurse workers and extensive degenerative structures in forager workers. Then it is suggested that the HPG secrete similar substances in both species. A second secretory cycle seems to occur in early foragers, may be with production of enzymes. The role of the HPGs in queens and males remains unknown but one possibility is enzyme production.

[24 hour pH monitoring of the hypopharymx]

Monitoring of pH of the esophagus is a routine diagnostic procedure, whereas until now pH-monitoring of the hypopharynx has been used only for scientific research. In the present study a critical evaluation scale was used to record the results of 112 patients who underwent pH monitoring to determine possible reflux. Since high refluxes often remain unnoticed clinically, further study is required in certain cases. The extent of reflux in the esophagus may not represent pathological changes in the hypopharynx. In such cases 24-h pH monitoring of the hypopharynx can be a useful diagnostic procedure and may also help detect the pathogenesis of "gastric laryngitis".

Change in the mode of gene expression of the hypopharyngeal gland cells with an age-dependent role change of the worker honeybee Apis mellifera L

Major proteins synthesized in the hypopharyngeal gland of the worker honeybee change from bee-milk proteins to alpha-glucosidase in accordance with the age-dependent role change of the worker bee. Previously, we showed that the gene for alpha-glucosidase is expressed specifically in the forager-bee gland [Ohashi, K., Sawata, M., Takeuchi, H., Natori, S. & Kubo, T. (1996) Biochem. Biophys. Res. Commun. 221, 380-385]. Here, we describe the isolation and analysis of cDNAs for two bee-milk 56-kDa and 64-kDa proteins. The 56-kDa protein was a glycoprotein which shared 63.2% and 56.9% amino acid sequence identities with proteins encoded by cDNA for royal-jelly-related protein 57-1 (pRJP57-1) and pRJP57-2. The 64-kDa protein cDNA was identical to pRJP57-1. Thus, these bee-milk proteins seem to form a structurally related protein family. The gene for the 64-kDa protein/RJP57-1 was expressed specifically in the nurse-bee gland, whereas that for the 56-kDa protein was expressed in both the nurse-bee and forager-bee glands. mRNAs for the 56-kDa and 64-kDa proteins were detected by in situ hybridization in a whole acinus of the nurse-bee gland, whereas mRNAs for the 56-kDa protein and alpha-glucosidase were detected in that of the forager-bee gland. Therefore, the individual secretory cells of the acinus of the hypopharyngeal gland were shown to express these genes differently with the age-dependent role change of the worker bee.

Effect of a brood pheromone on honeybee hypopharyngeal glands

In a honeybee colony, brood stimulates development of hypopharyngeal glands of nurse bees. A chemical signal, a blend of 10 fatty acid esters, has been identified on larval cuticle. We demonstrate that the blend of 10 esters, ethyl oleate, and methyl palmitate stimulates the protein synthesis of hypopharyngeal glands of nurses. Thus, in Apis mellifera the chemical signal from the brood acts as a primer pheromone in addition to its previously shown role as a releaser pheromone.

Continuous hypopharyngeal pH measurements in spontaneously breathing anesthetized outpatients: laryngeal mask airway versus tracheal intubation

We measured the hypopharyngeal pH to compare the incidence of regurgitation associated with the laryngeal mask airway (LMA) and the tracheal tube (TT) in spontaneously breathing, anesthetized patients. Sixty outpatients scheduled for elective peripheral surgery with a standardized general anesthetic technique were randomly allocated to receive either a LMA (n = 28) or a TT (n = 32) for airway management. A 4-mm pH electrode was placed in the hypopharynx, and pH values were continuously collected and stored in a portable pH data logger system until the end of the operation. There were no episodes of hypopharyngeal regurgitation (pH < 4) detected during the course of measurement. At no time did the hypopharyngeal pH value decrease below 5.5. The hypopharyngeal pH values in both groups were similar, ranging between 5.5 and 7.5, with median values of 5.7 and 6.2 in the LMA and TT groups, respectively. The pH in any given patient did not vary more than 1.0 unit from the initial value recorded at the start of the operation. We conclude that continuous monitoring of the hypopharyngeal pH in spontaneously breathing, anesthetized outpatients failed to detect evidence of pharyngeal regurgitation.

[Immunohistochemical investigation on expression of cytokeratins in normal epithelium, precancerous lesions and carcinomas of the hypopharynx]

In order to obtain a more objective method to evaluate epithelial disorders and carcinomas of the hypopharynx, the expression pattern of cytokeratins (CKs) was investigated by ABC technique using several kinds of monoclonal antibodies that react monospecifically with each subclass of CKs. In normal epithelia, CK-19 was strongly positive in the basal layer but apparently reduced in suprabasal layers and completely negative in superficial layers, while CK-13 showed a striking contrast to CK-19, being expressed within the whole thickness of epithelia except only in the basal layer. These 2 subclasses were also observed in "abnormal" epithelia, and characteristic changes of their combination were demonstrated in proportion to the histological gradings. In invasive carcinomas, CK-19 was strongly positive in all carcinoma cells of poorly differentiated carcinomas. It was sporadically positive in moderately differentiated carcinomas, the more differentiated the more sporadic. It was completely negative in well differentiated carcinomas. CK-13, on the other hand, was negative in poorly differentiated carcinomas but positive in keratinized cells of moderately or well differentiated carcinomas. Strong expression of CK-1 was observed only in well keratinized cells of hyperkeratotic epithelia and well differentiated carcinomas. These characteristic findings are consistently observed in all samples and, then, may be useful in evaluating epithelial disorders and carcinomas of the hypopharynx, when used in conjunction with standard histological techniques. It seems most likely that these results play a part in investigating normal and abnormal processes of cell differentiation.