Growth, phase transition, and island motion of Au on Ge(111)

Using low energy electron microscopy, Au on Ge(111) is determined to follow a Stranski-Krastanov growth mode consisting of a single layer up to one monolayer (ML), followed by three-dimensional Au-Ge alloy droplets. Near 600 °C, we report the first observation of a reversible first-order phase transition that occurs from the (3 × 3)R30° phase to a (1 × 1) phase, which has a coverage of 0.367 ML. The transition gradually occurs through a coexistence region with a temperature range of about 2 °C and weakly depends on coverage, varying from 640 °C at 1 ML down to 580 °C at 0.8 ML. The phase transition is accompanied by phase fluctuations of small domains or the fluctuations of phase boundaries of large domains. At coverage >1 ML and above 250 °C, the 3D droplets move with stick-slip hopping behavior that has previously been explained by dissolution of Ge at step edges into the alloy droplet, which then comes to concentration and thermal equilibrium via the island motion.

Antioxidant defense mechanisms and its dysfunctional regulation in the mitochondrial disease, Friedreich's ataxia

Redox stress is associated with the pathogenesis of a wide variety of disease states. This can be amplified potentially through redox active iron deposits in oxidatively active organelles such as the mitochondrion. There are a number of disease states, including Friedreich's ataxia (FA) and sideroblastic anemia, where iron metabolism is dysregulated and leads to mitochondrial iron accumulation. Considering FA, which is due to the decreased expression of the mitochondrial protein, frataxin, this iron accumulation does not occur within protective storage proteins such as mitochondrial ferritin. Instead, it forms unbound biomineral aggregates composed of high spin iron(III), phosphorous and sulfur, which probably contributes to the observed redox stress. There is also a dysregulated response to the ensuing redox assault, as the master regulator of oxidative stress, nuclear factor erythroid 2-related factor-2 (Nrf2), demonstrates marked down-regulation. The dysfunctional response of Nrf2 in FA is due to multiple mechanisms including: (1) up-regulation of Keap1 that is involved in Nrf2 degradation; (2) activation of the nuclear Nrf2 export/degradation machinery via glycogen synthase kinase-3β (Gsk3β) signaling; and (3) inhibited nuclear translocation of Nrf2. More recently, increased microRNA (miRNA) 144 expression has been demonstrated to down-regulate Nrf2 in several disease states, including an animal model of FA. Other miRNAs have also demonstrated to be dysregulated upon frataxin depletion in vivo in humans and animal models of FA. Collectively, frataxin depletion results in multiple, complex responses that lead to detrimental redox effects that could contribute to the mechanisms involved in the pathogenesis of FA.

Treatment of dilated cardiomyopathy in a mouse model of Friedreich's ataxia using N-acetylcysteine and identification of alterations in microRNA expression that could be involved in its pathogenesis

Deficient expression of the mitochondrial protein, frataxin, leads to a deadly cardiomyopathy. Our laboratory reported the master regulator of oxidative stress, nuclear factor erythroid 2-related factor-2 (Nrf2), demonstrates marked down-regulation after frataxin deletion in the heart. This was due, in part, to a pronounced increase in Keap1. To assess if this can be therapeutically targeted, cells were incubated with N-acetylcysteine (NAC), or buthionine sulfoximine (BSO), which increases or decreases glutathione (GSH), respectively, or the NRF2-inducer, sulforaphane (SFN). While SFN significantly (p < 0.05) induced NRF2, KEAP1 and BACH1, NAC attenuated SFN-induced NRF2, KEAP1 and BACH1. The down-regulation of KEAP1 by NAC was of interest, as Keap1 is markedly increased in the MCK conditional frataxin knockout (MCK KO) mouse model and this could lead to the decreased Nrf2 levels. Considering this, MCK KO mice were treated with i.p. NAC (500- or 1500-mg/kg, 5 days/week for 5-weeks) and demonstrated slightly less (p > 0.05) body weight loss versus the vehicle-treated KO. However, NAC did not rescue the cardiomyopathy. To additionally examine the dys-regulation of Nrf2 upon frataxin deletion, studies assessed the role of microRNA (miRNA) in this process. In MCK KO mice, miR-144 was up-regulated, which down-regulates Nrf2. Furthermore, miRNA screening in MCK KO mice demonstrated 23 miRNAs from 756 screened were significantly (p < 0.05) altered in KOs versus WT littermates. Of these, miR-21*, miR-34c*, and miR-200c, demonstrated marked alterations, with functional clustering analysis showing they regulate genes linked to cardiac hypertrophy, cardiomyopathy, and oxidative stress, respectively.

Growth kinetics of Kr nano structures encapsulated by graphene

Graphene can acquire salient properties by the intercalated nano structures, and to functionalize the graphene as designed, understanding the growth kinetics of the nano structures is a prerequisite. In that regards, Kr atoms are selectively intercalated just below the surface graphene of C(0001) by the incidence of low energy Kr ions. The growth kinetics of the encapsulated Kr nano structures is investigated by both scanning tunneling microscopy and molecular dynamics simulations. The intercalation proceeds via defect sites, such as surface vacancies. At room temperature, the thermal diffusion of intercalated Kr is almost frustrated by the strain field of the encapsulating graphene layers, and the growth of Kr nano structures proceeds via the transient mobility of both the intercalating Kr atoms and previously intercalated Kr atoms that are mobilized by collision with the incident Kr ions. At the elevated temperatures where thermal diffusion becomes effective, some Kr nano structures disappear, releasing pressurized Kr atoms, while others coalesce to form blisters via the delamination of the adjacent graphene. Some of the larger blisters explode to leave craters of varying depths at the surface. In contrast to growth on the substrate, the growth of each encapsulated nano structure depends significantly on extrinsic variables, such as surface vacancies and local topography around the nano structure, that affect the Kr diffusion and limit the maximal Kr pressure.

Equilibrated Surface Alloys and the Influence of Strain

Structural and thermodynamic properties of equilibrated ultrathin Pd-Au, Cu-Ag, and Co-Ag alloys on Ru(0001) were studied and are comparatively discussed. These studies provide a framework for a detailed understanding of the energetics of surface alloy formation.

Additionally, the differences between the two bulk immiscible systems (Cu-Ag and Co-Ag) and the bulk miscible Pd-Au system are discussed.

First direct observation of a nearly ideal graphene band structure

Angle-resolved photoemission and x-ray diffraction experiments show that multilayer epitaxial graphene grown on the SiC(0001) surface is a new form of carbon that is composed of effectively isolated graphene sheets. The unique rotational stacking of these films causes adjacent graphene layers to electronically decouple leading to a set of nearly independent linearly dispersing bands (Dirac cones) at the graphene K point. Each cone corresponds to an individual macroscale graphene sheet in a multilayer stack where AB-stacked sheets can be considered as low density faults.

Longitudinal profile of retinal ganglion cell damage after optic nerve crush with blue-light confocal scanning laser ophthalmoscopy

PURPOSE

To investigate the long-term longitudinal profile of retinal ganglion cell (RGC) damage after optic nerve crush with a new technique for in vivo imaging of RGCs.

METHODS

A blue-light confocal scanning laser ophthalmoscope (bCSLO; 460 nm excitation, 490 nm detection) was used to image Thy-1 CFP mice aged 6 to 9 months (n = 5) before optic nerve crush, weekly after crush for 3 weeks, and at weeks 10 and 50 after optic nerve crush. A sham procedure was performed in the contralateral eye, and it was imaged as a control. Corresponding retinal areas before and after optic nerve crush were compared, and the fluorescent spots were counted manually. The longitudinal profile of RGC degeneration was modeled and compared with one-phase and two-phase exponential decay equations.

RESULTS

A significant and progressive loss of fluorescent spots was found after optic nerve crush with 18.6% +/- 2.3%, 11.3% +/- 3.4%, 8.8% +/- 5.3%, 4.2% +/- 3.1%, and 3.3% +/- 2.1% of Thy-1-expressing RGCs remaining at weeks 1, 2, 3, 10, and 50, respectively, after optic nerve crush (P < 0.001; n = 5). There was no change in the fluorescence density in the contralateral control (P = 0.893). Two-phase exponential decay (y = 0.03 + 0.83e(-)(2.78t) + 0.14e(-)(0.30t)) was a better fit than one-phase exponential decay (y = 0.94e(-)(1.93t) + 0.06; P = 0.003) equations, with half-lives of fast phase and slow phase of 1.7 days and 16.3 days, respectively.

CONCLUSIONS

The longitudinal profile of RGC degeneration after optic nerve crush is characterized by a two-phase exponential decay model. bCSLO imaging provides an efficient and noninvasive approach to the longitudinal study of progressive RGC damage.

Spontaneous domain switching during phase separation of Pb on Ge(111)

Using low-energy electron microscopy (LEEM), we have discovered a novel phase separation mechanism for Pb on Ge(111). When the low Pb coverage (1 x 1) phase coexists with the high coverage beta phase, the surface consists of approximately 100 nm sized domains that spontaneously switch from one phase to the other. We argue this striking mechanism occurs because nanometer-scale domains can have density fluctuations comparable to the density difference between the two phases.

A phase II trial of RAD001 in patients (Pts) with metastatic renal cell carcinoma (MRCC)

5107

Background: RAD001 is an oral mammalian target of Rapamycin (mTOR) inhibitor. Three mechanisms of anti-tumor activity; shuts down tumor response to nutrients and growth factors; cell cycle arrest at late G1 and anti-angiogenesis via VEGF. Molecular alterations in the mTOR modular pathway increase sensitivity in PTEN deficient tumors such as RCC. Endpoints: time-to-progression (TTP), response rate (RR), overall survival (OS), toxicity, and to assess changes in metabolic imaging utilizing CT-PET. Methods: Eligibility included; predominant clear cell, progressive measurable MRCC, adequate organ/marrow function, zubrod performance status (ZPS) = 2, no more than 1 prior therapy, and no active CNS involvement. RAD001 is given orally at a dose of 10mg daily without an interruption (28-day cycle), with dose modifications for toxicity. Re-evaluation was assessed every 2 cycles (8 weeks). RECIST criteria is utilized. TTP and OS are determined from entry into the study. Results: 41 pts have been enrolled. 37 pts are evaluable for response/toxicity. 2 pts toxicity only. 2 pts screened failures. 31 were male/8 female, median age 60 (38–80) years. 31 pts received prior therapy. 23 pts had a ZPS of 0, 13 /1 and 3/2. Sites of disease included; lung, nodal, liver, bone, adrenal, and kidney. 9 pts had 1 metastatic site, 17 pts/2 and 13 pts/3 or more. 15 pts continue to receive RAD001. 12 pts had partial responses, 19 pts were stable for 3+ months. Median duration of therapy is 8+ (range 01–20+) months. Treatment related adverse events; mucositis, skin rash, pneumonitis, hypophosphatemia, hyperglycemia, hypertriglyceridemia, hypercholesterolemia, thrombocytopenia, anemia and elevated LFTs. PET scans have demonstrated decreased metabolic activity in responding or stable pts. Median overall survival is 11.5+ months (range 01–20+). Conclusion: RAD001 has promising anti-tumor activity in pts with MRCC demonstrated by partial response rate. Anti-tumor activity is further suggested by prolonged TTP =3 months. Anti-tumor activity, toxicity and metabolic imaging correlation will be presented. An additional 40 pts who failed prior sunitinib or sorafenib therapy are being enrolled.

No significant financial relationships to disclose.

The treatment of primary and metastatic renal cell carcinoma (RCC) with image-guided stereotactic body radiation therapy (SBRT)

PURPOSE

Brain metastases from renal cell carcinoma (RCC) have been successfully treated with stereotactic radiosurgery (SRS). Metastases to extra-cranial sites may be treated with similar success using stereotactic body radiation therapy (SBRT), where image-guidance allows for the delivery of precise high-dose radiation in a few fractions. This paper reports the authors' initial experience with image-guided SBRT in treating primary and metastatic RCC.

MATERIALS AND METHODS

The image-guided Brainlab Novalis stereotactic system was used. Fourteen patients with 23 extra-cranial metastatic RCC lesions (orbits, head and neck, lung, mediastinum, sternum, clavicle, scapula, humerus, rib, spine and abdominal wall) and two patients with biopsy-proven primary RCC (not surgical candidates) were treated with SBRT (24-40 Gy in 3-6 fractions over 1-2 weeks). All patients were immobilised in body cast or head and neck mask. Image-guidance was used for all fractions. PET/CT images were fused with simulation CT images to assist in target delineation and dose determination. SMART (simultaneous modulated accelerated radiation therapy) boost approach was adopted. 4D-CT was utilised to assess tumour/organ motion and assist in determining planning target volume margins.

RESULTS

Median follow-up was nine months. Thirteen patients (93%) who received SBRT to extra-cranial metastases achieved symptomatic relief. Two patients had local progression, yielding a local control rate of 87%. In the two patients with primary RCC, tumour size remained unchanged but their pain improved, and their renal function was unchanged post SBRT. There were no significant treatment-related side effects.

CONCLUSION

Image-guided SBRT provides excellent symptom palliation and local control without any significant toxicity. SBRT may represent a novel, non-invasive, nephron-sparing option for the treatment of primary RCC as well as extra-cranial metastatic RCC.

Barriers to repeat mammography: cultural perspectives of African-American, Asian, and Hispanic women

Women of minority races and ethnicities have lower mammography return rates compared to Caucasians. To better understand barriers to mammography, we conducted six focus groups with 49 women of minority races and ethnicities (19 Asian, 16 African-American, and 14 Hispanic) recruited from outpatient medical clinics in Boston. Eligible women had at least one prior mammogram and no personal history of cancer. Discussions were recorded and transcribed, and thematic content analyses were performed. African-Americans and Hispanics felt that lack of insurance was not a barrier to mammography as they were aware of free programs. Some African-Americans avoided mammograms because they were fatalistic and believed that a breast cancer diagnosis would inevitably lead to death. African-Americans agreed that social issues, such as drug and domestic abuse, made obtaining preventive health care less important. Asian participants agreed that mammogram return rates were poor because appointments took time away from work. Asian and Hispanic women identified discourteous behavior by hospital staff as a barrier. Cultural barriers to repeat mammography appear to vary among different racial groups. Interventions to improve screening among minority populations may be more successful if they address group-specific concerns.

Effect of additives on LiMo3Se3 nanowire film chemical sensors

Here we investigate the effect of lithium iodide and cetyltrimethylammonium (CTA) bromide additives on the ability of LiMo(3)Se(3) nanowire film sensors to bind and detect organic solvents electrically. Both additives decrease the electrical conductivity of the films. Lithium iodide increases the response of the films to both polar and nonpolar analytes. CTA increases the response of the films to nonpolar analytes but reduces the response to polar analytes. Quartz crystal microbalance measurements show that the modified electrical sensitivities of the films are due to altered analyte adsorption abilities of the films. These results show that the Li(+) ions are involved in analyte binding in native LiMo(3)Se(3) films and that a programming of LiMo(3)Se(3) nanowire film sensors is possible by replacing lithium cations with other receptors.

The treatment of primary and metastatic renal cell carcinoma (RCC) with stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS)

14572

Background: RCC is often regarded as a radio-resistant tumor. However, brain metastases from RCC have been successful treated with SRS. Therefore, metastases to extra-cranial sites may be treated with similar success using stereotactic body radiation therapy (SBRT), where image-guidance allows for the delivery of precise high dose radiation in a few fractions. We report our experience with SRS/SBRT in the management of primary and metastatic RCC. Methods: The image-guided Novalis radiation therapy system was used. Thirty patients with brain metastases were treated with SRS (16–22 Gy in a single fraction). Five of these patients underwent resection of their metastatic lesions after SRS and their pathology were reviewed. Twenty patients with extra-cranial metastatic lesions (orbits, head and neck, lung, mediatinum, sternum, clavicle, scapula, humerus, rib, spine, abdomen) and 2 patients with biopsy proven primary RCC (not surgical candidates), were treated with SBRT (24–32 Gy in 3–4 fractions over 1–2 weeks). All patients were immobilized in body cast and image-guidance was used for all fractions. 4D-CT was utilized in the treatment planning to assess tumor motion. Results: Of the 30 patients who received SRS to brain metastases, 25 showed decreasing or stable lesion size. Five patients showed an increase in size and underwent resection. Their pathology revealed necrosis in >99% of the specimen, with no viable RCC. Nineteen patients who received SBRT to extra-cranial metastases achieved symptom relief. One patient had local progression, yielding a local control rate of 95%. In the 2 patients with primary RCC, tumor size remained unchanged but their pain improved, and their renal function was unchanged post SBRT. There was no significant treatment related side-effect. Conclusions: Precise high dose radiation can cause significant tumor cell death in “radio-resistant” metastases from RCC. It also offers excellent local control and symptom palliation, without significant toxicity. Therefore, SBRT may represent a novel non-invasive, nephron-sparing option for the treatment of primary RCC as well as extra-cranial metastatic RCC. A prospective clinical trial using SBRT for primary and metastatic RCC is on-going.

No significant financial relationships to disclose.

A phase II trial of RAD001 in patients (Pts) with metastatic renal cell carcinoma (MRCC)

4530

Background: RAD001 an oral serine-threonine kinase inhibitor of mTOR, blocks progression from the GI to the S phase of the cell cycle by a mechanism of action that is unique for an anticancer drug. Mechanistically, it is thought that RAD001 may play a role in VEGF inhibition. Main endpoints were to evaluate: time to progression (TTP), response rate, toxicity and to assess changes in metabolic imaging utilizing CT-PET. Methods: Eligibility included: progressive measurable MRCC, adequate organ/marrow function, zubrod performance status (ZPS) ≤ 2, no more than 1 prior therapy, and no active CNS involvement. RAD001 is given orally at a dose of 10mg daily without an interruption (28-day cycle), with dose modifications for toxicity. Re-evaluation was assessed every 3 cycles (12 weeks). RECIST criteria is utilized to determine response rate. TTP is determined from entry into the study. Results: 25 pts have been enrolled as of this review. 19 male/6 female, range 43–80 (median 60) years. All pts had predominant clear cell elements with progressive MRCC. 17 pts received prior immunotherapy, targeted agents, or chemotherapy. 22 pts had a ZPS of 0, 2/1 and 1/2. Sites of disease included: lung, nodal, bone, adrenal, kidney and liver. 7 pts had 1 metastatic site, 10 pts/2 metastatic sites and 8 pts/3 or more metastatic sites. 22 pts continue to receive RAD001 therapy. 7 pts had partial responses, 11 pts were stable for 3+ months, (5 pts/6+ months). 4 pts too early. Median duration of therapy is 7+ months (range 1+ to 9+). Treatment related adverse events to date include: mucositis, skin rash, pneumonitis, hypophosphatemia, hyperglycemia, thrombocytopenia, anemia and elevated LFTs. Conclusion: RAD001 has promising anti-tumor activity in pts with MRCC as demonstrated by a 33% partial response rate. Anti-tumor activity was further suggested by prolonged TTP ≥ 3 months for 86% of pts. The tumor effect was also demonstrated as a second line therapy. Independent radiology review is planned. Anti-tumor activity, toxicity and metabolic imaging correlation will be presented.

[Table: see text]

Molecular Adsorption to LiMo3Se3 Nanowire Film Chemiresistors

Thin films of metallic nanowire bundles derived from the Chevrel compound LiMo3Se3 undergo reversible increases of their electrical resistance (up to 70%) upon exposure to vapors of organic solvents (Qi, X. B.; Osterloh, F. E. J. Am. Chem. Soc. 2005, 127 (21), 7666-7667). Using quartz crystal microbalance measurements with four analytes, we demonstrate here that the temporal and steady-state resistance changes of the films depend on the time following the adsorption and on the number of molecules that adsorb to the nanowire films at a given pressure. The adsorption ability of the films and the corresponding film resistance increase in the row: hexane < THF < ethanol < DMSO, closely following the polarities of the solvents. On average, approximately 10(5) analyte molecules per LiMo3Se3 unit are required to produce a measurable electrical response. Atomic force microscopy scans on nanowire films reveal that analytes deposit on top of the nanowire bundles and cause the films to swell by approximately 6% in volume. The temporal and steady-state resistance data of the LiMo3Se3 chemiresistors can be explained by assuming that coating of the nanowire bundles with analyte molecules reduces the interwire charge transport in the films.

Linking surface stress to surface structure: measurement of atomic strain in a surface alloy using scanning tunneling microscopy

Annealed submonolayer CoAg/Ru(0001) films form an alloy with a structure that contains droplets of Ag surrounded by Co [G. E. Thayer, V. Ozolins, A. K. Schmid, N. C. Bartelt, M. Asta, J. J. Hoyt, S. Chiang, and R. Q. Hwang, Phys. Rev. Lett. 86, 660 (2001)]. To understand how surface stress contributes to the formation of this structure, we use scanning tunneling microscopy to extract atomic displacements at the boundaries between regions of Co and Ag. Comparing our measurements to Frenkel-Kontorova model calculations, we show how stress due to lattice mismatch contributes to the formation of the alloy droplet structure. In particular, we quantitatively evaluate how competing strain and chemical energy contributions determine surface structure.

T-helper-1 and T-helper-2 responses in psychiatric disorders

The expanding field of psychoneuroimmunology has markedly increased knowledge about the interference of the central nervous system and the immune system. Immunological abnormalities in psychiatric patients have been repeatedly described in the last century. Modern concepts of immunology and the growing knowledge of psychoneuroimmunology may help in understanding the distinct immunological mechanisms in psychiatric disorders. One of these concepts regarding the adaptive immune system is the discrimination between Th1-like cell-mediated and Th2-like antibody-related immune responses. This article systematically describes alterations of Th1- or Th2-specific parameters in the major psychiatric disorders schizophrenia, major depression, and Alzheimer's disease. There are several hints of associations of these two distinct arms of immune response with subgroups of schizophrenia and major depression. The immunological research in Alzheimer's disease has already led to a preclinical model of immunotherapy. Categorization of immune parameters may also help to identify a possible immune-related pathophysiology in psychotic and affective disorders, resulting in specific treatment strategies.

Role of stress in thin film alloy thermodynamics: competition between alloying and dislocation formation

Using scanning tunneling microscopy (STM) and first-principles local-spin-density-approximation calculations to study submonolayer films of Co (1-c)Ag (c)/Ru(0001) alloys, we have discovered a novel phase-separation mechanism. When the Ag concentration c exceeds 0.4, the surface phase separates between a dislocated, pure Ag phase and a pseudomorphically strained Co(0.6)Ag (0.4) surface alloy. We attribute the phase separation to the competition between two stress relief mechanisms: surface alloying and dislocation formation. The agreement between STM measurements and our calculated phase diagram supports this interpretation.

Antitumor efficacy, pharmacokinetics, and biodistribution of NX 211: a low-clearance liposomal formulation of lurtotecan

Lurtotecan is a clinically active water-soluble camptothecin analogue that has been formulated into a low-clearance unilamellar liposome, NX 211. Comparative studies between free drug and NX 211 have been performed assessing pharmacokinetics in nude mice, tissue distribution in tumor-bearing mice, and antitumor efficacy in xenografts. Compared with lurtotecan, NX 211 demonstrated a significant increase in plasma residence time and a subsequent 1500-fold increase in the plasma area under the drug concentration curve. The volume of distribution was also greatly restricted, suggesting altered tissue distribution. Evaluation of tissues 24 h after administration of either [14C]NX 211 or [14C]lurtotecan to ES-2 tumor-bearing mice demonstrated a 40-fold increase in radiolabeled compound in the tumors of NX 211-treated mice compared with mice treated with lurtotecan. In single-dose efficacy studies, NX 211 produced a consistent 3-fold or greater increase in therapeutic index compared with lurtotecan in both the KB and ES-2 xenograft models. When compared at equitoxic levels in repeat-dose efficacy studies, NX 211 generated durable cures lasting >60 days and a 2-8-fold increase in log10 cell kill, compared with lurtotecan and topotecan, respectively. Together, these data demonstrate that NX 211 has significant therapeutic advantage over lurtotecan and that the improved antitumor activity is consistent with increased exposure and enhanced drug delivery to tumor sites.

A modified enzyme-linked immunosorbent assay for the detection of avian pneumovirus antibodies

Avian pneumovirus (APV) infection of turkeys in Minnesota was first confirmed in March 1997. Serum samples (n = 5,194) from 539 submissions to Minnesota Veterinary Diagnostic Laboratory were tested by a modified enzyme-linked immunosorbent assay (ELISA). Of these, 2,528 (48.7%) samples from 269 submissions were positive and 2,666 (51.3%) samples from 270 submissions were negative for APV antibodies. Most positive samples were from Kandiyohi, Stearns, Morrison, and Meeker counties in Minnesota. In addition, 10 samples from South Dakota were positive. The sensitivity and specificity of the ELISA test with anti-chicken and anti-turkey conjugates were compared by testing field and experimental sera. The ELISA test with anti-turkey conjugate was more sensitive than that with anti-chicken conjugate. The ELISA tests with antigens prepared with APV strains isolated from Colorado and Minnesota were also compared. No difference was detectable. Currently, the Minnesota Veterinary Diagnostic Laboratory uses an antigen prepared from the Colorado isolate of APV and a goat anti-turkey conjugate in the ELISA test.

Lower genital tract metastases of placental site trophoblastic tumor: case report and review of the literature

OBJECTIVES

We present a case of metastatic placental site trophoblastic tumor (PSTT) and review the English literature on this entity.

MATERIALS AND METHODS

In addition to the case presentation, literature review describes 23 additional cases with differing treatments and length of survival.

RESULTS

The patient is free of disease more than 5 years after diagnosis. She received multimodality treatment including surgery, chemotherapy, and radiotherapy. Eleven other patients survived the disease from 12 to 36 months after initial diagnosis.

CONCLUSION

Metastatic PSTT has a poor prognosis and requires aggressive treatment. ▪.

Multiple activation steps of the N-formyl peptide receptor

The human N-formyl peptide receptor (FPR) is representative of a growing family of G protein-coupled receptors (GPCR) that respond to chemokines and chemoattractants. Despite the importance of this receptor class to immune function, relatively little is known about the molecular mechanisms involved in their activation. To reveal steps required for the activation of GPCR receptors, we utilized mutants of the FPR which have previously been shown to be incapable of binding and activating G proteins. For this study, the FPR mutants were expressed in human myeloid U937 cells and characterized for functions in addition to G protein coupling, such as receptor phosphorylation and ligand-induced receptor internalization. The results demonstrated that one of the mutants, R123G, though being unable to activate G protein, was capable of undergoing ligand-induced phosphorylation as well as internalization. Receptor internalization was monitored by following the fate of the ligand as well as by directly monitoring the fate of the receptor. The results with the R123G mutant were in contrast to those obtained for mutants D71A and R309G/E310A/R311G which, though being expressed at the cell surface and binding ligand, were incapable of being phosphorylated or internalized upon agonist stimulation. These results suggest that following ligand binding at least two "steps" are required for full activation of the wild-type FPR. That these observations may be of more general importance in GPCR-mediated signaling is suggested by the highly conserved nature of the mutants studied: D71, R123, and the site represented by amino acids 309-311 are very highly conserved throughout the entire superfamily of G protein-coupled receptors. Models of receptor activation based on the observed results are discussed.

Hair cell formation in cultures of dissociated cells from the vestibular sensory epithelium of the bullfrog

HYPOTHESIS

Bullfrog vestibular hair cells are capable of regenerating in vitro.

BACKGROUND

Recent studies have established that sensory organs in the inner ear of vertebrates continue to produce hair cells after birth. However, the mechanisms responsible for the regulation of this process are not well understood. The current study reports the development of a novel method for the culture of dispersed cells from the bullfrog inner ear.

METHODS

New hair cell formation in this in vitro preparation was shown by sequential photomicroscopy. Studies with the selective marker for mitotic activity 5-bromo-2-deoxyuridine (BrdU) were done to estimate the level of cell proliferation and to quantify postmitotic hair cell formation. Finally, confirmation of cell type was obtained by scanning electron microscopy and by the use of specific markers for hair cells.

RESULTS

Once the optimal culture conditions were established in the initial experiments, the formation of new hair cells was directly visualized in all unstained live cultures and fixed preparations without exception. Asymmetric division of progenitor cells, with subsequent differentiation of one of the daughter cells into new hair cells, also was documented by photomicroscopy. Approximately 12% of the cells were labeled with BrdU, of which 6% were hair cells, showing that new hair cell formation was subsequent to mitotic division in vitro. The identity of newly formed hair cells was verified as follows: 1) morphologically by scanning electron microscopy; 2) by positive labeling with phalloidin-rhodamine, a marker for actin; and 3) by positive calmodulin immunocytochemistry.

CONCLUSIONS

This study reports the development of an in vitro culture preparation in which undifferentiated epithelial cells proliferate to become new hair cells. Evidence is provided of division of hair cell progenitors and subsequent differentiation of the daughter cells as one of the mechanisms involved in new hair cell formation in the culture preparation. This newly developed cell culture technique provides a powerful tool for further study of the process of hair cell formation in the vestibular end organ.

Absolute and comparative subcutaneous bioavailability of ardeparin sodium, a low molecular weight heparin

Ardeparin sodium (Normiflo, Wyeth-Ayerst) is a low molecular weight heparin undergoing clinical evaluation as an antithrombotic agent. The objective of this study was to evaluate the absolute and comparative bioavailability of ardeparin following subcutaneous administration of three different formulations [two formulations of ardeparin at 10,000 anti-factor Xa (aXa) U/ml, but with different preservatives, and a 20,000 aXa U/ml formulation]. The study was conducted using a randomized 4-period crossover design (three subcutaneous treatments and one intravenous treatment) in 24 healthy subjects, and the pharmacokinetics of ardeparin were characterized by plasma anti-factor IIa (aIIa) and anti-factor Xa (aXa) activities. The mean absolute bioavailability of ardeparin based on aIIa activity ranged from 62% to 64% and the mean absolute bioavailability based on aXa activity ranged from 88% to 97%. Based on bioequivalence testing criteria, the three ardeparin formulations were bioequivalent.

Cervical cancer in young women in Taiwan: prognosis is independent of papillomavirus or tumor cell type

The objective of this study was to address the hypotheses that younger patients with cervical cancer have a uniquely worse clinical outcome and/or are more likely to have adverse tumor cell types or specific human papillomaviruses (HPV). Cases of stage Ib-IIa cervical cancer among women 35 years of age or younger (82) and over 35 (54) were analyzed and compared with respect to the following: (1) histologic type (squamous vs nonsquamous), (2) human papillomavirus (HPV) type via polymerase chain reaction, and (3) clinical parameters, including tumor size, nodal metastases, and recurrence/persistence. Patients 35 years of age or younger had a survival similar (71.2% vs 72.4%) to that of older women from the same institution. In the younger group, outcome was not correlated with the presence or absence of HPV or HPV type. Nonsquamous carcinomas, including adenocarcinoma and small cell carcinoma, were strongly associated with HPV18, were more prevalent in the younger group, and had a slightly higher risk of recurrence/persistence; however, these differences were not significant and 71% of the recurrences were squamous cell carcinomas. Thus, in young Taiwanese women with stage Ib-IIa cervical cancer, the majority of deaths cannot be attributed to a specific HPV type or unique tumor morphology.

Conformational flexibility and crystallization of tandemly linked type III modules of human fibronectin

Fibronectin is a large cell adhesion molecule that is composed of several functional domains. The cell-binding domain that binds to cell surface integrins consists of repeated homologous type III modules. In this study, recombinant fragments from the cell-binding domain of human fibronectin that participate in a newly characterized fibronectin-fibronectin interaction with FNIII1 were crystallized. In each case, the crystals had more than one fibronectin fragment in the asymmetric unit. Crystals of FNIII10-11 grew in the space group C2 with a = 117.1 A, b = 38.6 A, c = 80.6 A, beta = 97.2 degrees, and two molecules in the asymmetric unit. These crystals diffracted to 2.5 A resolution. Fragment FNIII8-11 and a shorter fragment, FNIII8-10, crystallized in hexagonal space groups with large unit cells and two to four molecules per asymmetric unit. Even very large crystals of these fragments did not diffract beyond 4 A. The crystal packing for this collection of fibronectin fragments suggests conformational flexibility between linked type III modules. The functional relevance of this flexibility for elongated versus compact models of the cell-binding domain of fibronectin is discussed.

Pharmacokinetics of the aldose reductase inhibitor tolrestat: studies in healthy young and elderly male and female subjects and in subjects with diabetes

Tolrestat is an aldose reductase inhibitor undergoing clinical trials in diabetic subjects that may reduce the severity of chronic tissue damage associated with hyperglycemia. These studies were conducted to evaluate the pharmacokinetics of tolrestat in healthy young and elderly male and female subjects and in young and elderly subjects with diabetes. The drug was administered in a multiple-dose regimen, and steady-state parameters were obtained. There were no important gender-related differences, but mean values for apparent oral clearance, renal clearance, and corresponding unbound parameters were significantly lower for the elderly healthy subjects than for the young healthy subjects. The drug is highly bound to plasma proteins, and the unbound fraction (0.75%) did not differ among the subjects. The results from young and elderly diabetic subjects suggest that diabetes per se has no influence on tolrestat disposition but that there is an age-related reduction in apparent oral clearance (30 versus 18 ml/hr/kg) and a corresponding increase in the minimum steady-state plasma concentration (1.2 versus 1.9 micrograms/ml). These data indicate a possible need to reduce the dose of tolrestat in elderly subjects, assuming the same concentration-response relationship.

The dose proportionality of the pharmacokinetics of ardeparin, a low molecular weight heparin, in healthy volunteers

Ardeparin is a low molecular weight heparin currently being evaluated as an antithrombotic agent. The objective of this investigation was to assess the effects of dose on the pharmacokinetics of ardeparin after subcutaneous administration. Eighteen healthy subjects received doses of 30 U/kg, 60 U/kg, and 100 U/kg antifactor Xa (aXa) of ardeparin by subcutaneous injection. Plasma antifactor IIa (aIIa) activity levels after the 30- and 60-U/kg doses of ardeparin were too low to reliably characterize the disposition of the drug. However, the pharmacokinetics of ardeparin could be characterized by using pharmacodynamic measurements of plasma aXa activity. The rate of absorption of ardeparin after subcutaneous administration did not change with increasing dose. The volume of distribution (Vd) of ardeparin was small, reflecting minimal distribution outside the intravascular space, and was independent of dose. The total clearance of ardeparin, however, decreased with increasing dose, and half-life (t1/2) was prolonged at the higher doses. Within the observed dose range, a doubling of the ardeparin dose resulted in an area under the plasma aXa activity-versus-time curve (AUC) that was approximately 25% greater than expected on the basis of linear disposition. The differences in AUC and clearance between the three doses suggest that the mechanism of elimination of ardeparin is saturable.

Prenatal diagnosis of omphalocele associated with umbilical cord cyst

BACKGROUND

To study the cytogenetics, ultrasound findings, biochemical screening, perinatal outcome, and associated abnormalities in cases of omphaloceles associated with umbilical cord cysts.

METHODS

From 1988 to 1994, three cases of omphaloceles with umbilical cord cysts were identified at Mackay Memorial Hospital. We compared the clinical data of our three cases with six other cases in the published literature.

RESULTS

Two cases of omphaloceles with umbilical cord cysts were affected with trisomy 18. One had bilateral choroid plexus cyst, intrauterine growth retardation, low levels of maternal serum alpha-fetoprotein and free beta-human chorionic gonadotropin, and the other had cleft lip and palate, single umbilical artery and intrauterine growth retardation. An elevated level of maternal serum alpha-fetoprotein was found in the case with normal karyotype. Elevated levels of amniotic fluid alpha-fetoprotein were found in two cases. Rupture of the umbilical cord cyst and disruption of the umbilical cord occurred in one case at delivery. Based on the gross and microscopic examinations, the cord cysts we observed are likely to be pseudocysts.

CONCLUSION

The umbilical cord cysts most commonly associated with omphaloceles are pseudocysts and allantoic cysts. Among our three cases and the six other cases published in the literature, four out of these nine cases were trisomy 18. Prenatal diagnosis of omphaloceles or umbilical cord cysts by ultrasound warrants cytogenetic analysis and detailed sonogram to rule out the possible combination of both abnormalities and trisomy 18. If an omphalocele is associated with a large umbilical cord cyst and a normal karyotype, cesarean section is recommended to prevent the dilemma of intrauterine vascular compromise of umbilical blood flow during labor.