Dampening of IFN-gamma-inducible gene expression in human choriocarcinoma cells is due to phosphatase-mediated inhibition of the JAK/STAT-1 pathway

Trophoblast cells (TBCs) form the blastocyst-derived component of the placenta and play essential roles in fetal maintenance. The proinflammatory cytokine IFN-gamma plays a central role in activating cellular immunity, controlling cell proliferation, and inducing apoptosis. IFN-gamma is secreted by uterine NK cells in the placenta during pregnancy and in mice is required for proper formation of the decidual layer and remodeling of the uterine vasculature. Despite the presence of IFN-gamma in the placenta, TBCs do not express either MHC class Ia or class II Ags, and are resistant to IFN-gamma-mediated apoptosis. In this study, we demonstrate that IFN-gamma-induced expression of multiple genes is significantly reduced in human trophoblast-derived choriocarcinoma cells relative to HeLa epithelial or fibroblast cells. These results prompted us to investigate the integrity of the JAK/STAT-1 pathway in these cells. Choriocarcinoma cells and HeLa cells express comparable levels of the IFN-gamma receptor. However, tyrosine phosphorylation of JAK-2 is compromised in IFN-gamma-treated choriocarcinoma cells. Moreover, phosphorylation of STAT-1 at tyrosine 701 is substantially reduced in both IFN-gamma-treated human choriocarcinoma and primary TBCs compared with HeLa cells or primary foreskin fibroblasts. A corresponding reduction of both IFN regulatory factor 1 mRNA and protein expression was observed in IFN-gamma-treated TBCs. Treatment of choriocarcinoma cells with the tyrosine phosphatase inhibitor pervanadate significantly enhanced IFN-gamma-inducible JAK and STAT-1 tyrosine phosphorylation and select IFN-gamma-inducible gene expression. We propose that phosphatase-mediated suppression of IFN-gamma signaling in TBCs contributes to fetal maintenance by inhibiting expression of genes that could be detrimental to successful pregnancy.

Use of silicone stents for the management of post-tuberculosis tracheobronchial stenosis

The role of bronchoscopic management in post-tuberculosis tracheobronchial stenosis is not well defined. To investigate the role of bronchoscopic intervention, including silicone stenting, in the management of post-tuberculosis tracheobronchial stenosis, the current retrospective study was conducted at a tertiary referral hospital. Under rigid bronchoscopy, 80 patients underwent ballooning, neodymium-yttrium aluminium garnet laser resection and/or bougienation as first-line methods of airway dilatation between January 2000 and December 2003 inclusive, and were followed for a median of 41 months. Silicone stents were required in 75 out of 80 (94%) patients to maintain airway patency. Bronchoscopic intervention provided immediate symptomatic relief and improved lung function in 88% of the patients. After airway stabilisation, stents were removed successfully in 49 out of 75 (65%) patients at a median of 14 months post-insertion. Three patients out of 75 (4%) eventually underwent surgical management. Acute complications included: excessive bleeding (n = 1); pneumothorax (n = 5); and pneumomediastinum without mortality (n = 2). Stent-related late complications, such as migration (51%), granuloma formation (49%), mucostasis (19%) and re-stenosis (40%), were controllable during a median follow-up of 41 months. In conclusion, bronchoscopic intervention, including silicone stenting, could be a useful and safe method for treating post-tuberculosis tracheobronchial stenosis.

Onychomycosis in a premature infant caused by Candida tropicalis

We report a case of onychomycosis caused by Candida tropicalis in a 107-day-old infant.

Regulation of major histocompatibility complex class II gene expression in trophoblast cells

Trophoblast cells are unique because they are one of the few mammalian cell types that do not express major histocompatibility complex (MHC) class II antigens, either constitutively or after exposure to IFN-gamma. The absence of MHC class II antigen expression on trophoblast cells has been postulated to be one of the essential mechanisms by which the semi-allogeneic fetus evades immune rejection reactions by the maternal immune system. Consistent with this hypothesis, trophoblast cells from the placentas of women suffering from chronic inflammation of unknown etiology and spontaneous recurrent miscarriages have been reported to aberrantly express MHC class II antigens. The lack of MHC class II antigen expression on trophoblast cells is due to silencing of expression of the class II transactivator (CIITA), a transacting factor that is essential for constitutive and IFN-gamma-inducible MHC class II gene transcription. Transfection of trophoblast cells with CIITA expression vectors activates both MHC class II and class Ia antigen expression, which confers on trophoblast cells both the ability to activate helper T cells, and sensitivity to lysis by cytotoxic T lymphocytes. Collectively, these studies strongly suggest that stringent silencing of CIITA (and therefore MHC class II) gene expression in trophoblast cells is critical for the prevention of immune rejection responses against the fetus by the maternal immune system. The focus of this review is to summarize studies examining the novel mechanisms by which CIITA is silenced in trophoblast cells. The elucidation of the silencing of CIITA in trophoblast cells may shed light on how the semi-allogeneic fetus evades immune rejection by the maternal immune system during pregnancy.

Class II transactivator (CIITA) promoter methylation does not correlate with silencing of CIITA transcription in trophoblasts

Trophoblast cells are unique because they do not express major histocompatibility complex (MHC) class II antigens, either constitutively or after exposure to interferon-gamma (IFN-gamma). The absence of MHC class II antigens on trophoblasts is thought to play a critical role in preventing rejection of the fetus by the maternal immune system. The inability of trophoblasts to express MHC class II genes is primarily due to lack of the class II transactivator (CIITA), a transacting factor that is required for constitutive and IFN-gamma-inducible MHC class II transcription. We, therefore, investigated the silencing of CIITA expression in trophoblasts. In transient transfection assays, transcription from the IFN-gamma-responsive CIITA type IV promoter was upregulated by IFN-gamma in trophoblasts, which suggests that CIITA is silenced by an epigenetic mechanism in these cells. Polymerase chain reaction analysis demonstrated that the CIITA type IV promoter is methylated in both the human choriocarcinoma cell lines JEG-3 and Jar and in 2fTGH fibrosarcoma cells, which are IFN-gamma inducible for CIITA. Conversely, methylation of the CIITA type IV promoter was not observed in human primary cytotrophoblasts isolated from term placentae or in mouse or rat trophoblast cell lines. Simultaneous treatment with IFN-gamma and the histone deacetylase inhibitor trichostatin A weakly activated CIITA transcription in mouse trophoblasts. Stable hybrids between human choriocarcinoma and fibrosarcoma cells and between mouse trophoblasts and fibroblasts expressed CIITA following treatment with IFN-gamma. These results suggest that silencing of CIITA transcription is recessive in trophoblasts and involves an epigenetic mechanism other than promoter methylation. The fact that CIITA is expressed in the stable hybrids implies that trophoblasts may be missing a factor that regulates chromatin structure at the CIITA promoter.

Porous polyethylene implant for orbital wall reconstruction

Short-term and intermediate-term results from clinical use of high-density porous polyethylene implants for reconstructive orbital surgery have been encouraging. This article presents an intermediate-term result from one institution with a comprehensive comparative analysis of other available alloplastic materials. A patient survey of 32 cases of orbital reconstruction using porous polyethylene sheet implants was performed, with a mean follow-up period of 32 months (range 15 to 67). All cases were trauma-related injuries. The result was compared with that of published reports of other alloplastic materials with specific emphasis on complication rates. Complication rate following the use of porous polyethylene sheet implants was 6%. This finding was consistent with those of other reports on porous polyethylene sheet implants. A consistent, satisfactory surgical outcome and low complication rate were observed. In the authors' review, the porous polyethylene implants compared favorably in a comparative analysis of other alloplastic materials.

Effect of ethanol on spontaneous phasic contractions of cat gastric smooth muscle

BACKGROUND

Ethanol is generally believed to inhibit extracellular Ca2+ influx, thereby inhibiting gastric muscle contraction. Recently, we observed that verapamil inhibited only the amplitude of spontaneous phasic contractions, whereas ethanol inhibited both amplitude and frequency. In our objective to investigate the mechanism of ethanol's inhibition of gastric motility, the involvement of various protein kinases in ethanol-inhibited spontaneous phasic contractions of the stomach muscle strips was tested.

METHODS

Circular muscle strips (2.0 x 0.2 cm) were prepared from the corpus of cat stomach in order to measure isometric contraction in a chamber filled with Krebs-Ringer solution (pH 7.4, temperature 36 degrees C) bubbled with 5% CO2 in O2.

RESULTS

Spontaneous phasic contraction was not affected by various receptor antagonists (I microM atropine, 1 microM hexamethonium, 1 microM phentolamine and 1 microM propranolol) or 1 microM tetrodotoxin. EGTA and verapamil dose-dependently inhibited only the amplitude of spontaneous phasic contractions and not the frequency. Ethanol dose-dependently inhibited both the amplitude and frequency of phasic contractions. The amplitude and frequency of spontaneous phasic contractions were significantly inhibited by protein kinase C and tyrosine kinase inhibitors. However, neither protein kinase C activator nor various phosphatase inhibitors blocked the inhibitory effect of ethanol.

CONCLUSIONS

Ethanol appears to inhibit spontaneous phasic contractions by a mechanism other than the inhibition of protein kinase C or tyrosine kinase or the inhibition of extracellular Ca2+ influx.

Expression of cutaneous lymphocyte-associated antigen and TIA-1 by lymphocytes in pityriasis lichenoides et varioliformis acuta and lymphomatoid papulosis: immunohistochemical study

BACKGROUND

Pityriasis lichenoides et varioliformis acuta (PLEVA) and lymphomatoid papulosis (LyP) are benign self-healing cutaneous eruptions that may be clinically and histologically similar. The purposes of this study were to evaluate immunohistological characteristics of PLEVA and LyP and to investigate whether Epstein-Barr virus (EBV) may be present in PLEVA and LyP.

METHODS

We performed an immunohistochemical staining in 12 cases of PLEVA and 8 cases of LyP using nine antibodies for CD3, CD4, CD8, CD30, CD45RO, CD56, CD79, cutaneous lymphocyte-associated antigen (CLA), and TIA-1. In situ hybridization was performed using fluorescein-conjugated oligonucleotide probes for EBV early regions (EBER).

RESULTS

In PLEVA, immunohistochemical studies revealed that infiltrated lymphocytes consisted of mainly CD3-positive (5+), CD8-positive (4+ to 5+), CLA-positive (4+ to 5+) T cells and partly CD79 positive (+ to 2+) B cells. CD4-positive T cells were less than 25%. In LyP, immunohistochemical studies revealed that infiltrated lymphocytes consisted of partly CD3-positive (5+), CD8-positive (2+ to 3+), CLA-positive (3+ to 4+) T cells and partly CD79-positive (2+ to 3+) B cells. CD4-positive T cells were less than 10%. CD8 and CLA were more strongly expressed in PLEVA than in LyP. CD30 was strongly expressed in LyP but not expressed in PLEVA. CD79 was more expressed in LyP than in PLEVA. TIA-1 was not expressed in any cases. In situ hybridization using antisense EBER probe showed negative reaction in all cases.

CONCLUSIONS

Immunohistochemical stains for CD8, CD30, CD79 and CLA may be valuable tools in the differential diagnosis between PLEVA and LyP. TIA-1 was negative in LyP, which means cytotoxic cells may not be implicated in the pathogenesis of LyP. It was a contradictory result to the previous results. The absence of EBV in PLEVA and LyP suggests that this virus may not be operative in the pathogenesis of these diseases. These results suggest that LyP and PLEVA are separate disorders, thus accounting for their variable prognosis.

Clinicohistopathologic comparison of adult type and juvenile type xanthogranulomas in Korea

Xanthogranuloma (XG) is an uncommon benign disorder characterized by solitary or multiple yellow-red papulonodules on the skin, and occasionally, in other organs. It is predominantly a disease of infancy or early childhood, although adults may rarely be affected. To compare the clinicohistopathological featues of juvenile-type xanthogranulomas UXGs) and adult-type xanthogranulomas (AXGs) (>14 years) in Korea, 30 cases of JXGs and 15 cases of AXGs were compared clinically and histopathologically. Except for the fact AXGs were more often solitary and larger and showed neither other associated systemic diseases nor spontaneous regression, the clinical features such as color, mean number, or site of the lesions in AXGs were not statistically different from JXGs. Histologically, AXCs were not significantly different in amounts of foamy cells, giant cells including Touton cells, and inflammatory cells, although subcutaneous involvement was seen only in the two infant cases. In conclusion, in contrast to AXGs, JXGs need special attention to accompanying systemic diseases and do not need excisional procedures, considering their frequent spontaneous regression.

The involvement of phospholipase A(2) in ethanol-induced gastric muscle contraction

To understand the underlying mechanism of ethanol in tonic contraction, the effect of ethanol on phospholipase A(2) and phospholipase C activities and the effects of phospholipase inhibitors on ethanol-induced contraction of cat gastric smooth muscle were tested. Circular muscle strips (2.0 x 0.2 cm) obtained from the fundus of cat stomach were used to measure isometric contraction. Ethanol elicited tonic contraction and activated phospholipase A(2) activity in a dose-dependent manner. Phospholipase A(2) inhibitors, manoalide (0.1--10 microM) and oleyloxyethyl phosphorylcholine (1--10 microM), significantly inhibited ethanol-induced contraction. Furthermore, 342 mM ethanol-induced contraction was significantly inhibited by cyclooxygenase inhibitors, ibuprofen (10--100 microM) and indomethacin (10--100 microM), but not by lipoxygenase inhibitors. On the other hand, phospholipase C inhibitors had no effect on ethanol-induced contraction, indicating that phospholipase C is not involved in ethanol-induced contraction. It is suggested from the above results that ethanol-induced contraction in cat gastric smooth muscle is, in part, mediated by phospholipase A(2) and cyclooxygenase pathways.

Involvement of cyclic GMP in nitric-oxide-induced gastric relaxation Comparison of the actions of cyclic GMP and cyclic AMP

BACKGROUND

Smooth muscle relaxation induced by various agents that increase the cellular levels of cyclic nucleotides (cAMP and cGMP) is accompanied by a decrease in intracellular Ca2+ concentration. However, little is known about the differences between the inhibitory effects of cAMP and cGMP on the contraction of smooth muscle.

OBJECTIVE

To compare the effects and underlying mechanisms of cAMP and cGMP on the inhibition of gastric smooth muscle contraction, cyclic nucleotide promoting agents, as well as cell membrane permeable cyclic nucleotides were used.

METHODS

Isometric contraction was measured from circular muscle strips prepared from the fundus of cat stomach in a cylinder-shaped chamber filled with Krebs-Ringer solution (pH 7.4, temperature 36 degrees C) bubbled with 5% CO2 in O2. The level of inositol phosphates (IPs) was measured.

RESULTS

Forskolin and sodium nitroprusside significantly inhibited acetylcholine (ACh)-induced gastric smooth muscle contraction and increased the cellular levels of cAMP and cGMP, respectively. Direct application of 8-Br-cAMP and 8-Br-cGMP also significantly inhibited ACh-induced contraction. Both verapamil and TMB-8 inhibited ACh-induced contraction. The combined inhibitory effect of verapamil and TMB-8 was significantly greater than the effect of either one, separately. Forskolin or sodium nitroprusside similarly augmented the effect of verapamil. However, the inhibitory effect of TMB-8 was augmented only by 8-Br-cGMP or sodium nitroprusside but not by 8-BrcAMP or forskolin. Forskolin and 8-Br-cAMP significantly inhibited the formation of inositol phosphates stimulated by ACh.

CONCLUSIONS

cAMP inhibits the contraction mechanism associated with intracellular Ca2+ mobilization as well as extracellular Ca2+ influx, while cGMP inhibits contraction by inhibiting the mechanism associated with extracellular Ca2+ influx.

Computed tomographic characteristics of chronic subdural hematomas

Although medical history and physical examination should lead to diagnosis of chronic subdural hematomas, 40% of these patients are likely to be misdiagnosed because many of these symptoms occur in other disease processes, such as transient ischemic attacks, stroke, dementia, and tumors. Computed tomography remains one of the most useful tools in the evaluation of these patients because of its rapidity, cost, availability, and pathologic sensitivity.

Orthopedic problems in Lesch-Nyhan syndrome

Lesch-Nyhan syndrome is an X-linked disorder of purine metabolism. The orthopedic problems and results of treatment of nine Lesch-Nyhan patients are reviewed. Associated orthopedic problems included hip subluxation or dislocation (nine of 18 hips), fractures (three), autoamputation, infections (three), minor scoliosis, and contractures. Lesch-Nyhan patients can safely undergo orthopedic procedures and the results of surgery are satisfactory and similar to those of patients with spastic cerebral palsy. All of the seven operated-on hips maintained good reduction at 6-year mean follow-up. With adequate cast technique, fractures and hip subluxation/dislocation may be treated successfully. The treating orthopedist should be aware of the increased incidence of heterotopic ossification in this population, as well as the potential for serious complications such as hardware failure or femur fracture, if appropriate immobilization is not used.

Hepatic involvement in hypereosinophilia: sonographic findings

Hypereosinophilic syndrome may cause eosinophil-related tissue damage to various organs. The purpose of this paper is to describe sonographic findings in 13 patients with hypereosinophilia in whom the liver was involved. The diagnosis in these 13 patients was based on liver biopsy in seven patients with bone marrow biopsy in six patients. Eight patients had hypereosinophilic syndrome and five patients had clonorchiasis. All 13 patients had mild to marked hepatomegaly. Seven of 13 patients showed multiple round or oval hypoechoic (n = 6) or variably echogenic (n = 1) lesions measuring 1 to 2 cm with poorly defined margins in both lobes of the liver. Four patients had one or two hypoechoic lesions 3 to 4 cm in size, with geographic pattern and poorly defined margins. Two patients showed diffuse hepatomegaly with increased parenchymal echogenicity. The number of lesions and the extent of diffuse lesions seem to be proportional to the degree of eosinophilia. Hypereosinophilia may produce multiple small focal hepatic lesions or diffuse segmental or lobar echogenic lesions simulating primary or metastatic tumor of the liver.

Potential decreased morbidity of interstitial brachytherapy for gynecologic malignancies using laparoscopy: A pilot study

OBJECTIVES

This pilot study was designed to prospectively assess whether the addition of laparoscopy at the time of interstitial brachytherapy is safe, provides verification and/or guidance of needle placement, and results in a reduction of treatment-related morbidity.

METHODS

Between 7/93 and 2/97 15 consecutive eligible patients were entered into this study. All patients received external pelvic radiation to a dose range between 45 and 61.20 Gy using 1.8-Gy fractions. In each patient the minimum prescribed dose for the brachytherapy portion was 20 Gy. Minimum cumulative doses to sites of gross disease ranged from 71.8 to 115.3 Gy. A Syed-Neblett afterloading perineal template was used in all the procedures. Laparoscopy using established guidelines was performed during placement of interstitial needles. During template placement, verification of interstitial needles on laparoscopy and any subsequent changes or needle rearrangement were noted.

RESULTS

No acute radiation toxicity greater than Grade 2 was noted during the external beam portion of treatment, and no perioperative complications were encountered. These needles were withdrawn under laparoscopic guidance to just below the peritoneal reflection, avoiding proximity to the bowel and improving tumor coverage. Median follow-up time was 26 months. No late radiation morbidity greater than Grade 2 nor any laparoscopic-related complications were noted. To date, one patient has died of disease; six are alive with disease; and eight are alive free of disease with a mean disease-free survival of 17.3 months.

CONCLUSION

Laparoscopy at the time of interstitial brachytherapy appears to be safe. No radiation toxicity greater than Grade 2 has developed. No perioperative complications were seen with the addition of laparoscopy. The addition of laparoscopy to the placement of transperineal interstitial implants impacted needle arrangement and/or loading of sources in 50% of patients.

Medpor Motility Coupling Post: a rabbit model

PURPOSE

To verify if a Medpor porous polyethylene orbital implant (PPOI) (Porex Surgical, Atlanta, GA, U.S.A.), once vascularized, will tolerate a partially exposed titanium screw on its anterior surface.

METHODS

Ten New Zealand white rabbits were enucleated and given Medpor PPOIs. Eight weeks postoperatively, Medpor Motility Coupling Posts (MCPs) (Porex Surgical) were placed into the orbital implants. Clinical tissue tolerance and histologic response to the new device were noted.

RESULTS

The titanium screws were well tolerated by the animals. No case of post-operative infection, conjunctival inflammation, conjunctival erosion, MCP dislocation, or PPOI fragmentation was noted. A fibrous tissue growth over the titanium head was noted in all screws with a head height of 2.5 mm. The fibrous tissue overgrowth was not observed in screws with a head height of 4 mm or more.

CONCLUSION

During the 6-month observation period, all implanted Medpor MCPs demonstrated favorable tissue tolerance and stable interfaces between the MCP and the conjunctiva and between the MCP and the PPOI.

Porous polyethylene channel implants: a modified porous polyethylene sheet implant designed for repairs of large and complex orbital wall fractures

PURPOSE

To evaluate the effectiveness of a modified porous polyethylene implant in orbital fracture repair. A porous polyethylene channel implant (PPCI) has internal channels that accept mini- or microplates from conventional plating systems, facilitating fixation to bone in the reconstruction of large, complex orbital fractures.

METHODS

The authors used 29 PPCIs to repair 25 orbits. Seventeen cases involved repair of an acute (less than two weeks after injury) fracture of one or more orbital walls. Eight cases represented delayed reconstruction of orbital walls for late enophthalmos or for residual defects after previous operations.

RESULTS

A PPCI provides a stable platform for orbital soft tissue. Excellent results were obtained in all patients with acute orbital fractures, whereas good or excellent corrections of enophthalmos and hypoglobus were achieved in all patients who underwent late repair. There were no instances of orbital infection, implant exposure or migration, worsening diplopia, visual loss, or loss of structural support during 31 months of follow-up.

CONCLUSIONS

A PPCI allows controlled placement of a porous polyethylene sheet with secure fixation to stable bone. The implant design allows it to be cantilevered from the orbital rim to serve as a stable platform when fractures are too large to support the implant in the posterior orbit. PPCIs are ideally suited for reconstruction of defects resulting from displacement of orbital walls and for repair of posterior floor fractures, medial wall fractures, and combined floor and medial wall defects.