In vivo and in vitro studies on the roles of neutrophil extracellular traps during secondary pneumococcal pneumonia after primary pulmonary influenza infection

Seasonal influenza virus infections may lead to debilitating disease, and account for significant fatalities annually worldwide. Most of these deaths are attributed to the complications of secondary bacterial pneumonia. Evidence is accumulating to support the notion that neutrophil extracellular traps (NETs) harbor several antibacterial proteins, and trap and kill bacteria. We have previously demonstrated the induction of NETs that contribute to lung tissue injury in severe influenza pneumonia. However, the role of these NETs in secondary bacterial pneumonia is unclear. In this study, we explored whether NETs induced during pulmonary influenza infection have functional significance against infections with Streptococcus pneumoniae and other bacterial and fungal species. Our findings revealed that NETs do not participate in killing of Streptococcus pneumoniae in vivo and in vitro. Dual viral and bacterial infection elevated the bacterial load compared to animals infected with bacteria alone. Concurrently, enhanced lung pathogenesis was observed in dual-infected mice compared to those challenged with influenza virus or bacteria alone. The intensified NETs in dual-infected mice often appeared as clusters that were frequently filled with partially degraded DNA, as evidenced by punctate histone protein staining. The severe pulmonary pathology and excessive NETs generation in dual infection correlated with exaggerated inflammation and damage to the alveolar-capillary barrier. NETs stimulation in vitro did not significantly alter the gene expression of several antimicrobial proteins, and these NETs did not exhibit any bactericidal activity. Fungicidal activity against Candida albicans was observed at similar levels both in presence or absence of NETs. These results substantiate that the NETs released by primary influenza infection do not protect against secondary bacterial infection, but may compromise lung function.

Variation in nephrologist visits to patients on hemodialysis across dialysis facilities and geographic locations

BACKGROUND AND OBJECTIVES

Geographic and other variations in medical practices lead to differences in medical costs, often without a clear link to health outcomes. This work examined variation in the frequency of physician visits to patients receiving hemodialysis to measure the relative importance of provider practice patterns (including those patterns linked to geographic region) and patient health in determining visit frequency.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This work analyzed a nationally representative 2006 database of patients receiving hemodialysis in the United States. A variation decomposition analysis of the relative importance of facility, geographic region, and patient characteristics--including demographics, socioeconomic status, and indicators of health status--in explaining physician visit frequency variation was conducted. Finally, the associations between facility, geographic and patient characteristics, and provider visit frequency were measured using multivariable regression.

RESULTS

Patient characteristics accounted for only 0.9% of the total visit frequency variation. Accounting for case-mix differences, patients' hemodialysis facilities explained about 24.9% of visit frequency variation, of which 9.3% was explained by geographic region. Visit frequency was more closely associated with many facility and geographic characteristics than indicators of health status. More recent dialysis initiation and recent hospitalization were associated with decreased visit frequency.

CONCLUSIONS

In hemodialysis, provider visit frequency depends more on geography and facility location and characteristics than patients' health status or acuity of illness. The magnitude of variation unrelated to patient health suggests that provider visit frequency practices do not reflect optimal management of patients on dialysis.

Proliferating tricholemmal tumour: clinicopathological aspects of a case

We report the case of a 49-year-old man who presented with an enlarging mass over his occipital scalp. The clinical impression was either a squamous cell carcinoma or an unusual adnexal tumour. A wide excision was performed with skin grafting. Gross examination revealed a large exophytic tumour mass measuring 10 cm. Histopathological examination showed a circumscribed, well-differentiated squamoproliferative lesion with a lobulated architecture. Clear cell features, pilar-type keratinisation, microcalcifications and the presence of mucinous degeneration were noted. A diagnosis of proliferating tricholemmal tumour was made. This entity incorporates a spectrum of lesions, ranging from the mostly benign proliferating tricholemmal cyst to tumours having more atypical cellular and invasive features, the latter features correlating with an increased capacity for aggressive behaviour. Management-wise, such tumours require complete excision with follow-up. As the tumours are often large in size at presentation, reconstruction is required.

Multiple idiopathic cervical resorption: case report and discussion of management options

AIM

To present a case of cervical root resorption affecting all teeth and resulting in multiple tooth loss.

SUMMARY

A healthy 33-year-old Chinese male, with no contributory medical or family/social history, presented with generalized cervical root resorption. Lesions varied in severity amongst teeth and even involved an impacted third molar. All cervical root surfaces were affected and lesions often extended coronally, undermining enamel. CBCT demonstrated that the lesions were more extensive and more widely distributed than was seen using conventional radiography. Bone extended into many resorptive defects but without clinical evidence of ankylosis. Periodontal probing, pulp testing, percussion sound and mobility were within normal limits. Key learning points  • Aetiology of the generalized idiopathic cervical root resorption is uncertain. • Management is complex, and options have included surgical exposure and restoration of affected sites, extraction and submergence of affected roots. • A staged approach involving early intervention with restoration of resorptive defects, followed by progressive extraction and replacement with implant-supported prostheses is recommended.

Gastroschisis and omphalocele in Singapore: a ten-year series from 1993 to 2002

INTRODUCTION

Two of the most common malformations of the anterior abdominal wall include gastroschisis and omphalocele, both of which are associated with high morbidity and mortality. Studies have shown an increase in both conditions worldwide. These two conditions are considered separate entities because of their differences in epidemiology, physical characteristics and associations with other structural anomalies and chromosomal aberrations. This is the first local study to examine these two conditions.

METHODS

Data of anterior abdominal wall defect cases of patients born during the period 1993-2002 were retrieved from the National Birth Defects Registry and analysed.

RESULTS

There were a total of 121 cases of anterior abdominal wall defects in the ten-year period from 1993 to 2002, giving an overall incidence of 2.63 per 10,000 livebirths. The individual incidences of gastroschisis (n = 21) and omphalocele (n = 100) were 0.46 and 2.17 per 10,000 livebirths, respectively. 33 percent of women with foetal gastroschisis were younger than 25 years of age, and 31 percent of women with foetal omphalocele were older than 35 years of age. This was statistically significant when compared to the general obstetric population. Incidence of omphalocele was lowest among the Indian population. Total aneuploidy rate was 14.9 percent (18/121 cases), with omphalocele having a higher aneuploidy rate than gastroschisis (17 percent versus 4.8 percent). Omphaloceles are also more likely to be associated with cardiac defects (p-value equals 0.02).

CONCLUSION

Our studies are consistent with the worldwide trend of an increasing prevalence of anterior abdominal wall defects. The race-specific differences suggest genetic and environmental factors that warrant further studies.

Myelolipoma within a non-functional adrenal cortical adenoma

Myelolipoma within an adrenal cortical adenoma is a very rare cause of adrenal incidentaloma, and only nine cases have been reported in the English and Japanese literature. We report a 66-year-old Chinese man, with a history of hypertension and hyperlipidaemia, who presented with lower limb oedema and had a computed tomography (CT ) of the abdomen done to exclude intra-abdominal mass. His lower limb symptoms resolved after switching his antihypertensive medication. CT of the abdomen showed a large heterogeneously-enhancing mass in the left suprarenal region, measuring 72 mm by 55 mm. Clinical history, physical examination and laboratory results did not show any evidence to suggest metabolic disorder such as Cushing's syndrome, hyperaldosteronism or catecholamine hypersecretion. The patient underwent a left adrenalectomy, and a histopathological study confirmed the mass to be a non-functional adrenal cortical adenoma containing myelolipoma. The patient was well postoperatively and was discharged uneventfully. To the best of our knowledge, this is the first non-functional adrenal cortical adenoma reported; in the nine cases of myelolipoma within an adrenal cortical adenoma reported previously, all the patients had Cushing's syndrome. The literature on synchronous myelolipoma with adrenal adenoma, and myelolipoma within functional adrenal adenoma, is reviewed.

Celecoxib reduces microvessel density in patients treated with nasopharyngeal carcinoma and induces changes in gene expression

BACKGROUND

Celecoxib is a selective cyclooxygenase-2 inhibitor with antitumor and antiangiogenic activity. We sought to determine pharmacodynamic change in tumors of patients with nasopharyngeal carcinoma (NPC) treated with celecoxib.

METHODS

Tumor biopsies were obtained before and after treatment with celecoxib 400 mg b.i.d. for 14 days in patients with newly diagnosed, untreated NPC. Tumor angiogenesis and cell proliferation were assessed by immunohistochemistry and gene expression by microarray analysis. Plasma celecoxib concentrations were obtained on days 8 and 14.

RESULTS

Paired samples were analyzed in 15 patients. Microvessel density was reduced in post-treatment samples and mean celecoxib levels reached therapeutic levels. Thirty-five genes (27 down-regulated, eight up-regulated) were differentially expressed on microarray analysis (p < 0.001). Down-regulated genes included cell cycle regulation-related (cyclin-dependent kinase 2, YES1), transcription factor (TRIP-Br2), whereas the antigen processing and presentation-related gene HLA-DM B was up-regulated.

CONCLUSION

Celecoxib reduced angiogenesis and induced tumor transcriptional changes. Further characterization of these transcriptional changes in vivo is needed to provide further insights into the effects of celecoxib in neoplastic tissue. Our findings provide a rationale for clinical studies aimed at assessing the efficacy of celecoxib in the treatment of NPC.

Metastatic testicular carcinoma from the colon with clinical, immunophenotypical, and molecular characterization: report of a case

We report a case of testicular metastasis from a colonic adenocarcinoma. The presentation of testicular metastasis, diagnosis, management, and possible modes of spread are reported. In addition to conventional investigations and histopathologic techniques, a molecular study of the testicular metastasis and colon primary, using microsatellite analysis, was performed to confirm the primary origin. Its potential uses are discussed.

Uncommon benign intrascrotal tumours

INTRODUCTION

Benign intrascrotal tumours are rare.

CLINICAL PICTURE

Three patients with bilateral paratesticular leiomyomas, an adenomatoid tumour of the testis and a left paratesticular dermoid cyst coexisting with a synchronous left paratesticular epidermal cyst are presented. These tumours were discrete, hard and smooth lesions, in which the diagnosis of malignancy could not be safely excluded preoperatively even with ultrasonography.

TREATMENT AND OUTCOME

The first patient had orchiectomy with contralateral testicular preserving surgery, the second patient underwent orchiectomy and the third had conservative testicular surgery.

CONCLUSION

Awareness of these benign tumours may allow for testicular preservation.

Cervical cytology: an audit in a Singapore teaching hospital

OBJECTIVES

To describe the cervical cytology diagnoses and cyto-histological correlation in the Department of Pathology, National University of Singapore in 1997 and to compare the data with international figures.

METHODS

A database search of all cervical cytology cases diagnosed in the department in 1997 as well as follow-up biopsies was carried out. The data was then critically analysed.

RESULTS

10,207 cases were reviewed. 96% of the cases had a diagnosis of "negative". Under 1% of cases were labelled as "inadequate". "Atypia" was diagnosed in 1% and dysplasia and/or malignancy was diagnosed in 1%. These figures correlate well with international data. Of the dysplasia cases, 78% were followed by biopsy. Of the high-grade dysplasia cases that were biopsied, 97% of the biopsy diagnoses were within the acceptable concordance range with the cytology diagnoses and in only 3% was there a significant discrepancy. Of the cases diagnosed as atypia, 39% were subsequently biopsied at the same institution as the next procedure and only one showed high grade dysplasia. A total of six cases showed a significant discrepancy between the cervical cytology result and the subsequent biopsy diagnosis and these were reviewed to elucidate the reasons for the discrepancies.

CONCLUSION

The cervical cytology service is of a high diagnostic standard. A subset of patients is probably being prematurely biopsied and may benefit from having a repeat smear instead. Specific clinical protocols regarding subsequent therapy following cytology results and closer cyto-histological correlation are two main areas where the cytology service can be improved.

Audit of transthoracic fine needle aspiration of the lung: cytological subclassification of bronchogenic carcinomas and diagnosis of tuberculosis

INTRODUCTION

Transthoracic fine-needle aspiration cytology (FNAC) is a useful tool for evaluating neoplastic and inflammatory lung nodules. In view of the relative paucity of published audit studies regionally, such a study was undertaken to assess the use of the technique in our centre.

METHODS

One hundred and fourteen FNACs were performed during 1997-1999. Immediate assessment for specimen adequacy was done. Diagnoses were correlated with clinical-pathological information and selective blind review performed.

RESULTS

Cytologically, 65.8% of cases were malignant, 1.8% were atypical, 25.4% were inflammatory/non-malignant and 7% were inadequate. Cytological-histological tumour diagnostic concordance was 94.4%. Diagnostic sensitivity for malignancy: 93.4%, specificity: 95.8%, accuracy: 94%. Eight inadequate/ benign cases (7%) proved to be malignant with clinical-pathological follow-up. Tuberculosis was confirmed (acid-fast bacilli detected) in six cases (5.3%) and suggested in a further 10 cases (8.8%). The cytological review showed 96% concordance with the original benign/malignant diagnoses. Pneumothorax rate was 18%.

CONCLUSION

FNAC is an accurate and safe method for the evaluation of lung nodules and it enables subclassification of bronchogenic carcinomas in the vast majority of cases. It is also useful for the diagnosis of tuberculous pulmonary nodules. Immediate assessment optimises specimen adequacy; inadequate/non-malignant smears in particular, need clinical correlation, close follow-up and re-biopsy, if necessary.

Expression pattern of human P2Y receptor subtypes: a quantitative reverse transcription-polymerase chain reaction study

The diverse biological actions of extracellular nucleotides in tissues and cells are mediated by two distinct classes of P2 receptor, P2X and P2Y. The G protein-coupled P2Y receptors comprise at least six mammalian subtypes (P2Y(1,2,4,6,11,12)), all of which have been cloned from human tissues, as well as other species. The P2Y receptor subtypes differ in their pharmacological selectivity for various adenosine and uridine nucleotides, which overlap in some cases. Data concerning the mRNA expression patterns of five P2Y receptors (P2Y(1,2,4,6,11)) in different human tissues and cells are currently quite limited, while P2Y mRNA distribution in the human brain has not previously been studied. In this study, we have addressed this deficiency in receptor expression data by using a quantitative reverse transcription-polymerase chain reaction approach to measure the precise mRNA expression pattern of each P2Y receptor subtype in a number of human peripheral tissues and brain regions, from multiple individuals, as well as numerous human cell lines and primary cells. All five P2Y receptors exhibited widespread yet subtype-selective mRNA expression profiles throughout the human tissues, brain regions and cells used. Our extensive expression data indicate the many potentially important roles of P2Y receptors throughout the human body, and will help in elucidating the physiological function of each receptor subtype in a wide variety of human systems.

Application of finite element analysis in implant dentistry: a review of the literature

Finite element analysis (FEA) has been used extensively to predict the biomechanical performance of various dental implant designs as well as the effect of clinical factors on implant success. By understanding the basic theory, method, application, and limitations of FEA in implant dentistry, the clinician will be better equipped to interpret results of FEA studies and extrapolate these results to clinical situations. This article reviews the current status of FEA applications in implant dentistry and discusses findings from FEA studies in relation to the bone-implant interface, the implant-prosthesis connection, and multiple-implant prostheses.

Implant-abutment screw joint preload of 7 hex-top abutment systems

This study measured the screw joint preload of the implant-abutment interface for 7 common hex-top abutment systems. Increasingly, prosthetic designs are utilizing a direct prosthetic connection to the implant, placing the implant-abutment screw joint under direct functional loads and moments. Sufficiently high screw joint preloads are required to maintain screw joint integrity and confer clinical longevity to implant prosthetic components to prevent such complications as abutment screw loosening and screw fracture. Strain-gauged abutment load cells were calibrated to measure screw joint pre-load at the implant-abutment interface. Torque delivery by electronic torque controller was varied at low- and high-speed settings. At manufacturer's recommended torques, the overall mean preload measured was 181.6 +/- 60.0 N for the Nobel Biocare Standard abutment, 291.3 +/- 41.2 N for the Nobel Biocare EsthetiCone abutment, 456.5 +/- 44.0 N for the Nobel Biocare MirusCone abutment, 369.7 +/- 32.9 N for the 3i Titanium Abutment post, 643.4 +/- 143.1 N for the Nobel Biocare CeraOne abutment, 536.3 +/- 68.6 N for the Nobel Biocare "Gold Cylinder to Fixture" abutment, and 556.9 +/- 145.6 N for the Nobel Biocare TiAdapt abutment. Analysis of variance revealed significant differences between abutment systems (P < .001) and between torque driver speed settings (P < .001). Implant-abutment screw joint preload of external-hex implants is dependent on abutment design, screw diameter, material, tightening torque, and torque controller speed.

Pseudo-outer product based fuzzy neural network fingerprint verification system

Fingerprint identification has been used in law enforcement applications over the last century, and has become the de facto international standard for positive identification. With the emergence of automated fingerprint identification technologies, it has assisted in making the once labour-intensive process of classifying, searching and matching a thing of the past. As a biometrics proof of identification, not many have ventured into the world of fingerprint identification using fuzzy neural networks. In this paper, a database of fingerprint images is constructed and a fuzzy neural network called the pseudo outer product fuzzy neural network (POPFNN) [Zhou, R.W. & Quek, C. (1996). A pseudo outer-product based fuzzy neural network. Neural Networks, 9(9), 1569-1581] is trained to detect similarity between two fingerprints and decide whether they belong to the same person. The fundamental idea is that, given a person's fingerprints taken under different conditions, the POPFNN based fingerprint verification system should be sufficiently robust to distinguish the difference. The people providing the fingerprint samples are subjected to different 'adverse' conditions; from wetness to chemical treatments. Fingerprint images are taken after conditions such as: after a shower, holding pineapples (mild acid from fruit), after washing one's hands, etc. The characteristics of POPFNN, such as the learning, generalisation, and high computational abilities, make fingerprint verification particularly powerful when verifying authentic fingerprints subjected to external conditions and recognising spurious ones. In order to demonstrate the efficacy of POPFNN and its application in the fingerprint verification system (FVS), several types of experiments have been designed and implemented in this work. The experimental results and analysis are presented at the end of the paper for discussion.

Cloning, expression, and pharmacological characterization of a novel human histamine receptor

Using a genomics-based reverse pharmacological approach for screening orphan G-protein coupled receptors, we have identified and cloned a novel high-affinity histamine receptor. This receptor, termed AXOR35, is most closely related to the H3 histamine receptor, sharing 37% protein sequence identity. A multiple responsive element/cyclic AMP-responsive element-luciferase reporter assay was used to identify histamine as a ligand for AXOR35. When transfected into human embryonic kidney 293 cells, the AXOR35 receptor showed a strong, dose-dependent calcium mobilization response to histamine and H3 receptor agonists including imetit and immepip. Radioligand binding confirmed that the AXOR35 receptor was a high-affinity histamine receptor. The pharmacology of the AXOR35 receptor was found to closely resemble that of the H3 receptor; the major difference was that (R)-alpha-methylhistamine was a low potency agonist of the AXOR35 receptor. Thioperamide is an antagonist at AXOR 35. Expression of AXOR35 mRNA in human tissues is highest in peripheral blood mononuclear cells and in tissues likely to contain high concentrations of blood cells, such as bone marrow and lung. In situ hybridization analysis of a wide survey of mouse tissues showed that mouse AXOR35 mRNA is selectively expressed in hippocampus. The identification and localization of this new histamine receptor will expand our understanding of the physiological and pathological roles of histamine and may provide additional opportunities for pharmacological modification of these actions.

On-line computerized diagnosis of pain-related disability and psychological status of TMD patients: a pilot study

Temporomandibular disorders (TMD) is a collective term embracing a number of clinical problems, which involve the masticatory musculature, the temporomandibular joint or both. Virtually all theories dealing with the aetiology and treatment of TMD have recognized the importance of psychological factors. This paper reports the development of a computerized on-line program (NUS TMD v1.1) for the diagnosis of pain-related disability and psychological status of TMD patients based on Axis II of the research diagnostic criteria (RDC)/TMD (Dworkin, S.F. & LeResche, L. 1992. Journal of Craniomandibular Disorders: Facial Oral Pain, 6, 301), which was developed to redress the lack of diagnostic criteria in TMD research. Methods adopted by RDC/TMD for use in assessing Axis II status include a seven-item questionnaire for grading chronic pain severity, the Symptom Checklist 90 Revised (SCL-90-R) and a jaw disability checklist. A pilot study, based on 37 new TMD patient records, was conducted to study the pain-related disability and psychological status of TMD patients using this newly developed program. The mean age of the predominantly Chinese population (86.5%) was 32.19 years (range 20-72 years) with a sex distribution of 24 females and 13 males. Most patients (78%) had low disability, with 12 patients having low intensity and 17 patients having high intensity pain. Approximately 73% of the sample population were moderately or severely depressed. Patients that were moderately and severely depressed had significantly higher scores for limitation related to mandibular functioning than normal patients. The three most frequent jaw disabilities were: eating hard foods (84%), yawning (78%) and chewing (65%).

Influence of water exposure on three-body wear of composite restoratives

The objective of this investigation was to study the influence of water exposure on the three-body wear of composite restoratives. A three-body wear instrumentation was used to investigate the wear resistance of five composite restoratives [Silux Plus (SX), Z100 (ZO), Ariston pHc (AR), Surefil (SF) and Tetric Ceram (TC)] with and without exposure to water. An amalgam alloy [Dispersalloy (DA)] was used as control. Ten specimens were made for each material. The specimens were conditioned in artificial saliva at 37 degrees C for 24 h and randomly divided into two groups of 5. The first group was subjected to wear testing immediately after the 24 h conditioning period, while the second group was conditioned in distilled water at 37 degrees C for 7 days prior to wear testing. All materials were wear tested at 15 N contact force against SS304 counter-bodies for 20,000 cycles with millet seed slurry as third-body. Wear depth (microm) was measured using profilometry, and results were analyzed by ANOVA/Scheffe's and independent sample t-tests at significance level 0.05. Ranking of wear resistance was as follows: without water exposure: DA > ZO > SF > AR > SX > TC; with water exposure: DA > ZO > SX > SF > AR > TC. Wear factor ranged from 2.20 for ZO to 7.13 for TC without water exposure and from 46.00 for ZO to 143.00 for TC with exposure to water. Exposure to water significantly increased three-body wear for all composite restoratives, but did not affect wear of the amalgam alloy. The effects of water exposure must be considered for the evaluation of wear in all polymeric composite restoratives.

Receptor for the pain modulatory neuropeptides FF and AF is an orphan G protein-coupled receptor

Opiate tolerance and dependence are major clinical and social problems. The anti-opiate neuropeptides FF and AF (NPFF and NPAF) have been implicated in pain modulation as well as in opioid tolerance and may play a critical role in this process, although their mechanism of action has remained unknown. Here we describe a cDNA encoding a novel neuropeptide Y-like human orphan G protein-coupled receptor (GPCR), referred to as HLWAR77 for which NPAF and NPFF have high affinity. Cells transiently or stably expressing HLWAR77 bind and respond in a concentration-dependent manner to NPAF and NPFF and are also weakly activated by FMRF-amide (Phe-Met-Arg-Phe-amide) and a variety of related peptides. The high affinity and potency of human NPFF and human NPAF for HLWAR77 strongly suggest that these are the cognate ligands for this receptor. Expression of HLWAR77 was demonstrated in brain regions associated with opiate activity, consistent with the pain-modulating activity of these peptides, whereas the expression in adipose tissue suggests other physiological and pathophysiological activities for FMRF-amide neuropeptides. The discovery that the anti-opiate neuropeptides are the endogenous ligands for HLWAR77 will aid in defining the physiological role(s) of these ligands and facilitate the identification of receptor agonists and antagonists.

Identification of an EDG7 variant, HOFNH30, a G-protein-coupled receptor for lysophosphatidic acid

We have identified a cDNA, designated HOFNH30, which encodes a 354 amino acid G-protein-coupled receptor (GPCR). This receptor has 96% amino acid identity to the Jurkat-T cell-derived EDG7 and could be a splice variant. RT-PCR analysis demonstrated that HOFNH30 mRNA is expressed in placenta whereas EDG7 mRNA shows highest expression in prostate. The HOFNH30 gene is localized to human chromosome 1p22. 3-1p31.1. When HOFNH30 was expressed in RBL-2H3 cells, LPA and phosphatidic acid (PA) induced a calcium mobilization response with EC(50) values of 13 nM and 3 microM, respectively. LPA also induced phosphorylation of mitogen-activated protein kinase (p42(MAPK) and p44(MAPK)) in HOFNH30-transfected but not vector-transfected RBL-2H3 cells. In the present study, we have identified a novel variant from the EDG receptor family, a GPCR for which LPA is a high-affinity endogenous ligand.

Identification of SAF-2, a novel siglec expressed on eosinophils, mast cells, and basophils

BACKGROUND

Eosinophils, basophils, and mast cells are believed to be the central tenet cells in allergic conditions including allergic rhinitis, asthma, and eczema. The molecular mechanisms underlying the recruitment of these cells to sites of allergic inflammation are poorly understood.

OBJECTIVES

Our aim was to identify a common adhesion molecule that could potentially be responsible for mediating the recruitment of the allergic cell types to the lungs and other sites of allergy.

METHODS

We have cloned a sialoadhesin molecule from a human eosinophil library with the use of expressed sequence tag technology and characterized its expression on allergic cells by the use of flow cytometry and specific mAbs.

RESULTS

With the use of expressed sequence tag sequencing, we have identified a novel siglec molecule, SAF-2. SAF-2 has homology with other sialoadhesin family members (CD33 and siglec-5) and belongs to a subgroup of the Ig superfamily. SAF-2 is a 431-amino acid protein composed of 3 Ig domains with a 358-amino acid extracellular domain and a 47-amino acid tail. SAF-2 is highly restricted to eosinophils, basophils, and mast cells. Antibodies to SAF-2 do not modulate Ca(++) mobilization or chemotaxis of human eosinophils induced by eotaxin.

CONCLUSION

SAF-2 is a highly restricted sialoadhesin molecule, which may be useful in the detection and/or modulation of allergic cells.

Identification and cloning of a human urea transporter HUT11, which is downregulated during adipogenesis of explant cultures of human bone

Bipotential cells in human trabecular bone explant cultures that express osteoblast characteristics are able to undergo adipogenesis in the presence of 3-isobutyl-1-methylxanthine plus dexamethasone (Nuttall et al. [1998] J Bone Miner Res 13:371-382). The initial studies of these bipotential cells in explant cultures have been extended to examine differential gene expression during osteoblast/adipocyte transdifferentiation. Using differential display, we have identified a gene expressed in trabecular bone explant cultures that is downregulated as these cells differentiate from an osteoblast to an adipocyte phenotype. Homology searching identified this gene as the human urea transporter HUT11. The expression and downregulation of HUT11 have been observed in multiple patient bone explant cultures. The size of the bone explant-derived HUT11 mRNA is approximately 4.4 kb, which is identical to the largest splice variant reported. In this article, we report the cloning and sequencing of this gene from primary human osteoblasts. In addition, we report tissue distribution for the bone explant-derived form of HUT11 mRNA and show a reciprocal relationship between the expression of HUT11 and the nuclear hormone receptor peroxisome proliferator-activated receptor gamma 2, which is a marker of adipocyte differentiation. Because the control of osteoblast/adipocyte transdifferentiation is unknown, selective downregulation of HUT11 during adipogenesis suggests that HUT11 expression may be a marker of the switch from an osteoblast to an adipocyte phenotype. Understanding the role of HUT11 in osteoblasts may provide insights into the mechanism controlling osteoblast and adipocyte differentiation.

Herpesvirus entry mediator ligand (HVEM-L), a novel ligand for HVEM/TR2, stimulates proliferation of T cells and inhibits HT29 cell growth

Herpesvirus entry mediator (HVEM), a member of the tumor necrosis factor (TNF) receptor family, mediates herpesvirus entry into cells during infection. Upon overexpression, HVEM activates NF-kappaB and AP-1 through a TNF receptor-associated factor (TRAF)-mediated mechanism. Using an HVEM-Fc fusion protein, we screened soluble forms of novel TNF-related proteins derived from an expressed sequence tag data base. One of these, which we designated HVEM-L, specifically bound to HVEM-Fc with an affinity of 44 nM. This association was confirmed with soluble and membrane forms of both receptor and ligand. HVEM-L mRNA is expressed in spleen, lymph nodes, macrophages, and T cells and encodes a 240-amino acid protein. A soluble, secreted form of the protein stimulates proliferation of T lymphocytes during allogeneic responses, inhibits HT-29 cell growth, and weakly stimulates NF-kappaB-dependent transcription.